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Andreas Boll	f85d23c	2012-06-12 09:05:30 +0200	[diff] [blame]	10	<h1 style="text-align: center;">Mesa Subset Specification</h1>
				11	<h2 style="text-align: center;">Tungsten Graphics, Inc.</h2>
				12	<h2 style="text-align: center;">February 26, 2003</h2>
Brian Paul	30cd76e	2010-08-26 11:20:31 -0600	[diff] [blame]	13	<p> Copyright © 2002-2003 by Tungsten Graphics, Inc.,
Brian Paul	bb21846	2003-03-22 18:35:53 +0000	[diff] [blame]	14	Cedar Park, Texas. All Rights Reserved. <br>
				15	<br>
				16	Permission is granted to make and distribute verbatim copies of this
				17	document provided the copyright notice and this permission notice are
				18	preserved on all copies.<br>
				19	</p>
				20	<p> OpenGL is a trademark of <a href="http://www.sgi.com">Silicon
				21	Graphics, Inc.</a>.</p>
				22	<h1>1. Introduction</h1>
				23	This document describes a subset of the Mesa implemented by Tungsten
				24	Graphics, Inc. for embedded devices.  Prior to reading this
				25	document the reader should be familiar with the OpenGL 1.2.1
				26	specification dated April 1, 1999 (available from <a
				27	href="http://www.opengl.org/developers/documentation/specs.html">http://www.opengl.org/developers/documentation/specs.html</a>.)
				28	Experience with OpenGL programming is highly advisable.<a
				29	href="http://www.opengl.org/developers/documentation/specs.html"><br>
				30	</a><br>
				31	Tungsten Graphics, Inc. is working with industry standards
				32	organizations +in an attempt to standardize this Mesa subset and any
				33	other possible subsets +as a result of this work. <br>
				34	<br>
				35	Appendix A contains a list of issues of which some may not be resolved.<br>
				36	<br>
				37	To summarize, the following major features of Mesa are omitted from the
				38	subset:<br>
				39	<ul>
				40	<li>Vertex arrays</li>
				41	<li>Texture coordinate generation</li>
				42	<li>Lighting</li>
				43	<li>Point size</li>
				44	<li>Polygon stipple</li>
				45	<li>DrawPixels, CopyPixels, PixelZoom</li>
				46	<li>1-D and 3-D textures</li>
				47	<li>CopyTex[Sub]Image</li>
				48	<li>Fog</li>
				49	<li>Depth test</li>
				50	<li>Color Index mode</li>
				51	<li>Accumulation buffer</li>
				52	<li>Feedback mode</li>
				53	<li>Evaluators</li>
				54	<li>Push/Pop attributes</li>
				55	<li>Display lists<br>
				56	</li>
				57	</ul>
				58	<p>Further reductions are made at a lower level of detail.<br>
				59	</p>
				60	<p>Mesa function names are printed in <span style="font-weight: bold;">bold
				61	face</span>.  Function parameters are printed in <span
				62	style="font-style: italic;">italics</span>.<br>
				63	</p>
				64	<p>The Tungsten Graphics, Inc. Mesa subset library is hereafter
				65	referred to as <span style="font-style: italic;">the subset.</span><br>
				66	<br>
				67	</p>
				68	<h1>2. Primitive Specification</h1>
				69	<h2>2.1 glBegin, glEnd and glVertex Commands</h2>
				70	The basic rendering primitives are points, lines and triangles.
				71	Quadrilaterals and polygons are composed of triangles.
				72	Primitives are drawn with the <span style="font-weight: bold;">glBegin</span>
				73	and <span style="font-weight: bold;">glEnd</span> commands and a subset
				74	of the <span style="font-weight: bold;">glVertex</span> commands:<br>
				75	<br>
				76	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glBegin</span>(GLenum<span
				77	style="font-style: italic;">mode</span>)<br>
				78	void <span style="font-weight: bold;">glEnd</span>(void)<br>
				79	<br>
				80	void <span style="font-weight: bold;">glVertex2f</span>(GLfloat <span
				81	style="font-style: italic;">x</span>, GLfloat <span
				82	style="font-style: italic;">y</span>)<br>
				83	void <span style="font-weight: bold;">glVertex2fv</span>(const GLfloat
				84	*<span style="font-style: italic;">v</span>)<br>
				85	void <span style="font-weight: bold;">glVertex3f</span>(GLfloat <span
				86	style="font-style: italic;">x</span>, GLfloat <span
				87	style="font-style: italic;">y</span>, GLfloat <span
				88	style="font-style: italic;">z</span>)<br>
				89	void <span style="font-weight: bold;">glVertex3fv</span>(const GLfloat
				90	*<span style="font-style: italic;">v</span>)<br>
				91	</div>
				92	<br>
				93	The <span style="font-style: italic;">mode</span> parameter to <span
				94	style="font-weight: bold;">glBegin</span> may be one of the following<br>
				95	<br>
				96	<div style="margin-left: 40px;">GL_POINTS - a series of individual
				97	points<br>
				98	GL_LINES - a series of disjoint line segments<br>
				99	GL_LINE_STRIP - series of connected line segments<br>
				100	GL_LINE_LOOP - a closed loop of line segments<br>
				101	GL_TRIANGLES - a series of individual triangles<br>
				102	GL_TRIANGLE_STRIP - a connected strip of triangles<br>
				103	GL_TRIANGLE_FAN - a sequence of triangles all sharing a common vertex<br>
				104	GL_QUADS - a sequence of individual quadrilaterals<br>
				105	GL_QUAD_STRIP - a connected strip of quadrilaterals<br>
				106	GL_POLYGON - a closed, convex polygon<br>
				107	<br>
				108	</div>
				109	<br>
				110	The <span style="font-weight: bold;">glVertex</span> commands take two
				111	or three floating point coordinates, or a pointer to an array of two or
				112	three floating point coordinates.  Vertices are actually 4-element
				113	homogeneous coordinates.  The fourth component, unspecified by the
				114	subset's <span style="font-weight: bold;">glVertex</span> commands, is
				115	one.<br>
				116	<br>
				117	<span style="font-weight: bold;"></span>
				118	<h2>2.2 Other Per-vertex Commands<br>
				119	</h2>
				120	The <span style="font-weight: bold;">glColor</span> and <span
				121	style="font-weight: bold;">glTexCoord</span> commands may be used to
				122	specify colors and texture coordinates for each vertex:<br>
				123	<br>
				124	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glColor3f</span>(GLfloat<span
				125	style="font-style: italic;">red</span>, GLfloat <span
				126	style="font-style: italic;">green</span>, GLfloat <span
				127	style="font-style: italic;">blue</span>)<br>
				128	void <span style="font-weight: bold;">glColor3fv</span>(const GLfloat *<span
				129	style="font-style: italic;">rgb</span>)<br>
				130	void <span style="font-weight: bold;">glColor4f</span>(GLfloat <span
				131	style="font-style: italic;">red,</span> GLfloat <span
				132	style="font-style: italic;">green,</span> GLfloat <span
				133	style="font-style: italic;">blue,</span> GLfloat <span
				134	style="font-style: italic;">alpha</span>)<br>
				135	void <span style="font-weight: bold;">glColor4fv</span>(const GLfloat *<span
				136	style="font-style: italic;">rgba</span>)<br>
				137	void <span style="font-weight: bold;">glTexCoord2f</span>(GLfloat <span
				138	style="font-style: italic;">s</span>, GLfloat<span
				139	style="font-style: italic;"> t</span>)<br>
				140	void <span style="font-weight: bold;">glTexCoord2fv</span>(const
				141	GLfloat *<span style="font-style: italic;">c</span>)<br>
				142	<br>
				143	</div>
				144	The <span style="font-weight: bold;">glColor</span> commands specify
				145	the color and optionally, the alpha value, for subsequent vertices.
				146	For the <span style="font-weight: bold;">glColor3</span> commands,
				147	alpha is set to one.<br>
				148	<br>
				149	The <span style="font-weight: bold;">glTexCoord2</span> commands
				150	specify the texture coordinate for subsequent vertices.  Texture
				151	coordinates are actually four-component coordinates: (s, t, r, q).
				152	The <span style="font-weight: bold;">glTexCoord2</span> commands
				153	set s and t explicitly.  The r and q components are zero and one,
				154	respectively.<br>
				155	<br>
				156	<span style="font-weight: bold;"></span>Only <span
				157	style="font-weight: bold;">glVertex, glColor</span> and <span
				158	style="font-weight: bold;">glTexCoord</span> commands are allowed
				159	between <span style="font-weight: bold;">glBegin</span> and <span
				160	style="font-weight: bold;">glEnd.</span>  Calling any other
				161	command between <span style="font-weight: bold;">glBegin</span> and <span
				162	style="font-weight: bold;">glEnd</span> will result in the error
				163	GL_INVALID_OPERATION.<br>
				164	<br>
				165	<h2>2.3 Unsupported Commands</h2>
				166	None of the following commands related to primitive specification are
				167	supported by the subset:<br>
				168	<br>
				169	<div style="margin-left: 40px;">Per-Vertex commands:<br>
				170	</div>
				171	<div style="margin-left: 40px;">
				172	<div style="margin-left: 40px;"><span style="font-weight: bold;">glVertex2d,
				173	glVertex2i, glVertex2s, glVertex3d, glVertex3i, glVertex3s, glVertex4d,
				174	glVertex4i, glVertex4s, glVertex2dv, glVertex2iv, glVertex2sv,
				175	glVertex3dv, glVertex3iv, glVertex3sv, glVertex4dv, glVertex4iv,
				176	glVertex4sv,<br>
				177	glNormal3b, glNormal3d, glNormal3f, glNormal3i, glNormal3s, </span><span
				178	style="font-weight: bold;">glNormal3bv, glNormal3dv, glNormal3fv,
				179	glNormal3iv, glNormal3sv,<br>
				180	glIndexd, glIndexf, glIndexi, glIndexs, glIndexub, glIndexdv,
				181	glIndexfv, glIndexiv, glIndexsv, glIndexubv,<br>
				182	glColor3b, glColor3d, glColor3i, glColor3s, glColor3ub, glColor3ui,
				183	glColor3us, </span><span style="font-weight: bold;">glColor3bv,
				184	glColor3dv, glColor3iv, glColor3sv, glColor3ubv, glColor3uiv,
				185	glColor3usv,</span><span style="font-weight: bold;"> lColor4b,
				186	glColor4d, glColor4i, glColor4s, glColor4ub, glColor4ui, glColor4us, </span><span
				187	style="font-weight: bold;">glColor4bv, glColor4dv, glColor4iv,
				188	glColor4sv, glColor4ubv, glColor4uiv, glColor4usv,<br>
				189	</span><span style="font-weight: bold;">glTexCoord1d, glTexCoord1f,
				190	glTexCoord1i, glTexCoord1s, glTexCoord2d, glTexCoord2i, glTexCoord2s,
				191	glTexCoord3d, glTexCoord3f, glTexCoord3i, glTexCoord3s, glTexCoord4d,
				192	glTexCoord4f, glTexCoord4i, glTexCoord4s, glTexCoord1dv, glTexCoord1fv,
				193	glTexCoord1iv, glTexCoord1sv, glTexCoord2dv, glTexCoord2iv,
				194	glTexCoord2sv, glTexCoord3dv, glTexCoord3fv, glTexCoord3iv,
				195	glTexCoord3sv, glTexCoord4dv, glTexCoord4fv, glTexCoord4iv,
				196	glTexCoord4sv,<br>
				197	glEdgeFlag, glEdgeFlagv</span><br style="font-weight: bold;">
				198	<br>
				199	</div>
				200	Vertex array commands:<br>
				201	<div style="margin-left: 40px;"><span style="font-weight: bold;">glVertexPointer,
				202	glColorPointer, glIndexPointer, glTexCoordPointer, glEdgeFlagPointer,
				203	glNormalPointer, glInterleavedArrays, glArrayElement, glDrawArrays,
				204	glDrawElements, glDrawRangeElements, glEnableClientState,
				205	glDisableClientState</span><br>
				206	</div>
				207	</div>
				208	<div style="margin-left: 40px;"><br>
				209	Rectangle commands:<br>
				210	<div style="margin-left: 40px;"><span style="font-weight: bold;">glRects,
				211	glRecti, glRectf, glRectd, glRectsv, glRectiv, glRectfv, glRectdv,<br>
				212	<br>
				213	</span></div>
				214	</div>
				215	<div style="margin-left: 40px;">Lighting commands:<br>
				216	</div>
				217	<div style="margin-left: 80px;"><span style="font-weight: bold;">glMaterialf,
				218	glMateriali, glMaterialfv, glMaterialiv<br>
				219	</span><br>
				220	</div>
				221	<div style="margin-left: 40px;"> Evaluator commands:<br>
				222	<div style="margin-left: 40px;"><span style="font-weight: bold;">glEvalCoord1d,
				223	glEvalCoord1f, glEvalCoord1dv, glEvalCoord1fv, </span><span
				224	style="font-weight: bold;">glEvalCoord2d, glEvalCoord2f,
				225	glEvalCoord2dv, glEvalCoord2fv,<br>
				226	</span><span style="font-weight: bold;">glEvalPoint1, glEvalPoint2</span><br>
				227	<br>
				228	</div>
				229	</div>
				230	<h1>3. Coordinate Transformation</h1>
				231	<h2>3.1 Vertex Transformation</h2>
				232	Vertex coordinates are transformed by the current modelview and
				233	projection matrices then mapped to window coordinates as specified by
				234	the viewport.  The following coordinate transformation commands are
				235	supported by the subset<br>
				236	<br>
				237	<div style="margin-left: 40px; font-weight: bold;">glMatrixMode<span
				238	style="font-weight: normal;">(GLenum <span style="font-style: italic;">mode</span>)</span><br>
				239	glLoadIdentity<span style="font-weight: normal;">(void)</span><br>
				240	glPushMatrix<span style="font-weight: normal;">(void)</span><br>
				241	glPopMatrix<span style="font-weight: normal;">(void)</span><br>
				242	glLoadMatrixf<span style="font-weight: normal;">(const GLfloat *<span
				243	style="font-style: italic;">m</span>)</span><br>
				244	glMultMatrixf<span style="font-weight: normal;">(const GLfloat *<span
				245	style="font-style: italic;">m</span>)</span><br>
				246	glRotatef<span style="font-weight: normal;">(GLfloat <span
				247	style="font-style: italic;">angle</span>, GLfloat <span
				248	style="font-style: italic;">x</span>, GLfloat <span
				249	style="font-style: italic;">y</span>, GLfloat <span
				250	style="font-style: italic;">z</span>)</span><br>
				251	glTranslatef<span style="font-weight: normal;">(GLfloat <span
				252	style="font-style: italic;">x</span>, GLfloat <span
				253	style="font-style: italic;">y</span>, GLfloat <span
				254	style="font-style: italic;">z</span>)</span><br>
				255	glScalef<span style="font-weight: normal;">(GLfloat <span
				256	style="font-style: italic;">x</span>, GLfloat <span
				257	style="font-style: italic;">y</span>, GLfloat <span
				258	style="font-style: italic;">z</span>)<br>
				259	<span style="font-weight: bold;">glFrustum(</span>GLdouble <span
				260	style="font-style: italic;">left,</span> GLdouble <span
				261	style="font-style: italic;">right,</span> GLdouble <span
				262	style="font-style: italic;">bottom,</span> GLdouble <span
				263	style="font-style: italic;">top,</span> GLdouble <span
				264	style="font-style: italic;">near,</span> GLdouble <span
				265	style="font-style: italic;">far</span>)</span><br>
				266	<span style="font-weight: normal;"><span style="font-weight: bold;">glOrtho(</span>GLdouble<span
				267	style="font-style: italic;"> left,</span> GLdouble <span
				268	style="font-style: italic;">right,</span> GLdouble <span
				269	style="font-style: italic;">bottom,</span> GLdouble <span
				270	style="font-style: italic;">top,</span> GLdouble <span
				271	style="font-style: italic;">near,</span> GLdouble <span
				272	style="font-style: italic;">far</span>)</span><br>
				273	glViewport<span style="font-weight: normal;">(GLint <span
				274	style="font-style: italic;">x</span>, GLint <span
				275	style="font-style: italic;">y</span>, GLsize <span
				276	style="font-style: italic;">width,</span> GLsizei <span
				277	style="font-style: italic;">height</span>)</span><br>
				278	</div>
				279	<br>
				280	The <span style="font-weight: bold;">glMatrixMode</span> command
				281	specifies the <span style="font-style: italic;">current matrix.</span>
				282	The mode parameter may be GL_MODELVIEW or GL_PROJECTION to specify
				283	the modelview matrix or projection matrix.  Subsequent matrix
				284	commands will effect the current matrix.  Also associated with the
				285	modelview and projection matrices are a modelview matrix stack and
				286	projection matrix stack.<br>
				287	<br>
				288	The <span style="font-weight: bold;">glLoadIdentity</span> command
				289	replaces the current matrix with the identity matrix.  The matrix
				290	elements are specified in column-major order.<br>
				291	<br>
				292	The <span style="font-weight: bold;">glPushMatrix</span> command pushes
				293	a copy of the current matrix onto either the modelview matrix stack or
				294	the projection matrix stack.  The <span style="font-weight: bold;">glPopMatrix</span>
				295	command replaces the current matrix with a copy of the top matrix off
				296	the modelview matrix stack or projection matrix stack, the pops the
				297	stack.  Matrix stacks are useful for traversing and rendering
				298	hierarchical models.<br>
				299	<br>
				300	The <span style="font-weight: bold;">glMultMatrixf</span> command
				301	post-multiplies the current matrix by the specified matrix.  The
				302	matrix elements are specified in column-major order.<br>
				303	<br>
				304	The <span style="font-weight: bold;">glRotatef</span> command
				305	post-multiplies the current matrix by a rotation matrix defined by the
				306	angle and rotation axis defined by x, y and z.<br>
				307	<br>
				308	The <span style="font-weight: bold;">glTranslatef</span> command
				309	post-multiplies the current matrix by a translation matrix defined by
				310	the <span style="font-style: italic;">x</span>, <span
				311	style="font-style: italic;">y</span> and <span
				312	style="font-style: italic;">z</span> translation parameters.<br>
				313	<span style="font-weight: bold;"></span><br>
				314	The <span style="font-weight: bold;">glScalef</span> command
				315	post-multiplies the current matrix by a scaling matrix defined by the <span
				316	style="font-style: italic;">x</span>, <span
				317	style="font-style: italic;">y</span> and <span
				318	style="font-style: italic;">z</span> scale factors.<br>
				319	<span style="font-weight: bold;"></span><br>
				320	The <span style="font-weight: bold;">glFrustum</span> command
				321	post-multiplies the current matrix by a perspective projection matrix.
				322	The <span style="font-style: italic;">near</span> and <span
				323	style="font-style: italic;">far</span> values specify the position of
				324	the hither and yon Z-axis clipping planes.  The <span
				325	style="font-style: italic;">left, right, bottom</span> and <span
				326	style="font-style: italic;">top</span> parameters are the X and Y
				327	extents at the near clipping plane.  <span
				328	style="font-weight: bold;">glFrustum</span> is normally used to modify
				329	the projection matrix.<br>
				330	<br>
				331	The <span style="font-weight: bold;">glOrtho</span> command
				332	post-multiplies the current matrix by an orthographic projection matrix.
				333	The <span style="font-style: italic;">near</span> and <span
				334	style="font-style: italic;">far</span> values specify the position of
				335	the hither and yon Z-axis clipping planes.  The <span
				336	style="font-style: italic;">left, right, bottom</span> and <span
				337	style="font-style: italic;">top</span> parameters specify the X and
				338	Y-axis clipping planes.  <span style="font-weight: bold;">glOrtho</span>
				339	is normally used to modify the projection matrix.<br>
				340	<br>
				341	The <span style="font-weight: bold;">glViewport</span> command
				342	specifies the mapping of coordinates from normalized device coordinates
				343	to window coordinates.  The <span style="font-style: italic;">x</span>
				344	and <span style="font-style: italic;">y</span> parameters specify the
				345	viewport's lower-left corner in the window and the <span
				346	style="font-style: italic;">width</span> and <span
				347	style="font-style: italic;">height</span> parameters specify the size
				348	of the viewport.  <span style="font-weight: bold;">glViewport</span>
				349	does not effect the current matrix.<br>
				350	<br>
				351	A coordinate transformed to window coordinates is hereafter known as (x<sub>w</sub>,
				352	y<sub>w</sub>, z<sub>w</sub>).<br>
				353	<br>
				354	<h2>3.2 Clipping</h2>
				355	View-volume clipping automatically discards or trims primitives which
				356	lie completely or partially outside of the view volume specified by <span
				357	style="font-weight: bold;">glFrustum</span> and <span
				358	style="font-weight: bold;">glOrtho</span>.  Note that the <span
				359	style="font-weight: bold;">glViewport</span> command does not define a
				360	clipping region.<br>
				361	<br>
				362	Clipping occurs in <span style="font-style: italic;">clip coordinate
				363	space - </span>the coordinates produced after applying the projection
				364	matrix.<br>
				365	<br>
				366	<h2>3.3 Current Raster Position</h2>
				367	The current raster position specifies the location for drawing images
				368	with <span style="font-weight: bold;">glBitmap.</span>  The current
				369	raster position is set with the commands:<br>
				370	<br>
				371	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glRasterPos2f</span>(GLfloat<span
				372	style="font-style: italic;">x</span>, GLfloat <span
				373	style="font-style: italic;">y</span>)<br>
				374	void <span style="font-weight: bold;">glRasterPos2fv</span>(const
				375	GLfloat *<span style="font-style: italic;">v</span>)<br>
				376	void <span style="font-weight: bold;">glRasterPos2i</span>(GLint <span
				377	style="font-style: italic;">x</span>, GLint <span
				378	style="font-style: italic;">y</span>)<br>
				379	void <span style="font-weight: bold;">glRasterPos2iv</span>(const
				380	GLint *<span style="font-style: italic;">v</span>)<br>
				381	</div>
				382	<br>
				383	<span style="font-weight: bold;">glRasterPos</span> specifies a
				384	4-component coordinate (x, y, 0, 1).  The coordinate is processed
				385	like a vertex; it is transformed by the modelview matrix, the projection
				386	matrix and mapped to the viewport.  The resulting window coordinate
				387	is stored as the current raster position.  The coordinate is
				388	clipped-tested against the frustum like a vertex.  If the
				389	coordinate is clipped, then the current raster position becomes invalid
				390	and subsequent <span style="font-weight: bold;">glBitmap</span> commands
				391	have no effect.<br>
				392	<br>
				393	<span style="font-weight: bold;">glRasterPos</span> also updates the
				394	current raster color and current raster texture coordinates.  The
				395	current raster color is updated (copied) from the current color (as
				396	specified by <span style="font-weight: bold;">glColor</span>).
				397	The current raster texture coordinate is updated (copied) from the
				398	current texture coordinate (as specified by <span
				399	style="font-weight: bold;">glTexCoord</span>).<br>
				400	<br>
				401	<h2>3.4 Unsupported Commands</h2>
				402	The following commands related to vertex transformation are not
				403	supported by the subset:<br>
				404	<br>
				405	<div style="margin-left: 40px;">User-defined clip plane commands:<br>
				406	<div style="margin-left: 40px;"><span style="font-weight: bold;">glClipPlane</span><br>
				407	</div>
				408	<span style="font-weight: bold;"></span></div>
				409	<br>
				410	<div style="margin-left: 40px;">Lighting and material commands:</div>
				411	<div style="margin-left: 80px;"><span style="font-weight: bold;">glLightModeli,
				412	glLightModelf, </span><span style="font-weight: bold;">glLightModeliv,
				413	glLightModelfv,</span><span style="font-weight: bold;"> glLightf,
				414	glLighti, glLightfv, glLightiv, glColorMaterial</span><br>
				415	</div>
				416	<br>
				417	<div style="margin-left: 40px;">Automatic texture coordinate generation
				418	commands:<br>
				419	</div>
				420	<div style="margin-left: 40px;">
				421	<div style="margin-left: 40px;"><span style="font-weight: bold;">glTexGend,
				422	glTexGenf, glTexGeni, </span><span style="font-weight: bold;">glTexGendv,
				423	glTexGenfv, glTexGeniv, </span><br>
				424	<br style="font-weight: bold;">
				425	</div>
				426	Double-valued commands:<br>
				427	<div style="margin-left: 40px;"><span style="font-weight: bold;">glLoadMatrixd,
				428	glMultMatrixd, glRotated, glTranslated, glScaled</span><br
				429	style="font-weight: bold;">
				430	</div>
				431	<br>
				432	Depth Range command:<br>
				433	<div style="margin-left: 40px;"><span style="font-weight: bold;">glDepthRange</span>
				434	(the near value is always 0.0 and the far value is always 1.0)<br>
				435	</div>
				436	<br>
				437	Extra RasterPos commands:<br>
				438	<div style="margin-left: 40px;"><span style="font-weight: bold;">glRasterPos2d,
				439	glRasterPos2s, glRasterPos3d, glRasterPos3f, glRasterPos3i,
				440	glRasterPos3s, glRasterPos4d, glRasterPos4f, glRasterPos4i,
				441	glRasterPos4s, glRasterPos2dv, glRasterPos2sv, glRasterPos3dv,
				442	glRasterPos3fv, glRasterPos3iv, glRasterPos3sv, glRasterPos4dv,
				443	glRasterPos4fv, glRasterPos4iv, glRasterPos4sv</span><br>
				444	</div>
				445	<br>
				446	<br>
				447	</div>
				448	<h1>4. Rasterization</h1>
				449	This section describes the commands and options for drawing points,
				450	lines, triangles and bitmaps.  <span style="font-style: italic;">Rasterization</span>
				451	is the term for the process which produces fragments from the geometric
				452	description of a primitive (a point, line, polygon or bitmap).  For
				453	example, given the two coordinates for the end-points of a line segment,
				454	rasterization determines which pixels in the frame buffer are modified
				455	to <span style="font-style: italic;">draw</span> the line.  A
				456	fragment is a tuple which consists of a window coordinate, colors and
				457	texture coordinates.  The fragments produced by rasterization are
				458	subsequently processed by the per-fragment operations described later.<br>
				459	<br>
				460	<h2>4.1 Point Rasterization</h2>
				461	Points are rendered with the command sequence <span
				462	style="font-weight: bold;">glBegin</span>(GL_POINTS), <span
				463	style="font-weight: bold;">glVertex</span>, ... <span
				464	style="font-weight: bold;">glEnd</span>.  The window coordinate (x<sub>w</sub>,
				465	y<sub>w</sub>, z<sub>w</sub>) is truncated to rasterize the point.
				466	The truncated coordinate with its associated color and texture
				467	coordinate is sent as a single fragment to the per-fragment processing
				468	stages.<br>
				469	<br>
				470	The <span style="font-weight: bold;">glPointSize</span> command is not
				471	supported; only 1-pixel points are supported.<br>
				472	<br>
				473	Point smoothing (antialiasing) is also not supported.<br>
				474	<br>
				475	<h2>4.2 Line Rasterization</h2>
				476	Lines are rendered with the command sequence <span
				477	style="font-weight: bold;">glBegin</span>(<span
				478	style="font-style: italic;">mode</span>), <span
				479	style="font-weight: bold;">glVertex</span>, <span
				480	style="font-weight: bold;">glVertex</span>, ... <span
				481	style="font-weight: bold;">glEnd</span> where <span
				482	style="font-style: italic;">mode</span> is one of GL_LINES,
				483	GL_LINE_STRIP or GL_LINE_LOOP.  Lines are rasterized as described
				484	in the OpenGL specification.  Note that OpenGL specifies the <span
				485	style="font-style: italic;">half-open</span> convention for drawing
				486	lines: the last fragment in a line segment is omitted so that endpoint
				487	pixels shared by two line segments will only be drawn once instead of
				488	twice.<br>
				489	<br>
				490	<h3>4.2.1 Line Width</h3>
				491	The width of lines can be controlled by<br>
				492	<br>
				493	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glLineWidth</span>(GLfloat<span
				494	style="font-style: italic;">width</span>)<br>
				495	</div>
				496	<br>
				497	where <span style="font-style: italic;">width</span> is the line width
				498	in pixels.  The width defaults to 1.0.  Attempting to set the
				499	width to a value less than or equal to zero will raise the error
				500	GL_INVALID_VALUE.<br>
				501	<br>
				502	<h3>4.2.2 Line Stipple<br>
				503	</h3>
				504	Lines may be stippled (i.e. dashed) with the command<br>
				505	<br>
				506	<div style="margin-left: 40px;"><span style="font-weight: bold;">glLineStipple</span>(GLint<span
				507	style="font-style: italic;">factor</span>, GLushort <span
				508	style="font-style: italic;">pattern</span>)<br>
				509	</div>
				510	<br>
				511	<span style="font-style: italic;">pattern</span> describes an on/off
				512	pattern for the fragments produced by rasterization and <span
				513	style="font-style: italic;">factor</span> specifies how many subsequent
				514	fragments are kept or culled for each pattern bit.  Line stippling
				515	can be enabled or disabled by the commands <span
				516	style="font-weight: bold;">glEnable</span>(GL_LINE_STIPPLE) and <span
				517	style="font-weight: bold;">glDisable</span>(GL_LINE_STIPPLE).<br>
				518	<br>
				519	<h3>4.2.3 Line Antialiasing</h3>
				520	Lines may be antialiased.  For antialiased lines, each fragment
				521	produced by rasterization is assigned a <span
				522	style="font-style: italic;">coverage value</span> which describes how
				523	much of the fragment's area is considered to be <span
				524	style="font-style: italic;">inside</span> the line.  Later, the
				525	alpha value of each fragment is multiplied by the coverage value.
				526	By blending the fragments into the frame buffer, the edges of
				527	lines appear smoothed.<br>
				528	<br>
				529	Line antialiasing can be enabled or disabled with the commands <span
				530	style="font-weight: bold;">glEnable</span>(GL_LINE_SMOOTH) and <span
				531	style="font-weight: bold;">glDisable</span>(GL_LINE_SMOOTH).<br>
				532	<br>
				533	<h2>4.3 Polygon Rasterization</h2>
				534	Polygons, quadrilaterals and triangles share the same polygon
				535	rasterization options. <br>
				536	<br>
				537	Triangles are rendered by the command sequence <span
				538	style="font-weight: bold;">glBegin</span><span
				539	style="font-style: italic;"><span style="font-style: italic;">(mode</span></span>),<span
				540	style="font-weight: bold;">glVertex</span>, <span
				541	style="font-weight: bold;">glVertex</span>, ... <span
				542	style="font-weight: bold;">glEnd</span> where <span
				543	style="font-style: italic;">mode</span> may be one of GL_TRIANGLES,
				544	GL_TRIANGLE_STRIP or GL_TRIANGLE_FAN.<span style="font-weight: bold;"></span>
				545	For GL_TRIANGLES mode, the number of vertices should be a multiple
				546	of three - extra vertices will be ignored.  For GL_TRIANGLE_STRIP
				547	and GL_TRIANGLE_FAN, at least three vertices should be specified.
				548	If less than three are specified, nothing is drawn.  <br>
				549	<br>
				550	Quadrilaterals are <span style="font-weight: bold;"></span>rendered by
				551	the command sequence <span style="font-weight: bold;">glBegin</span>(<span
				552	style="font-style: italic;"><span style="font-style: italic;">mode</span></span>),<span
				553	style="font-weight: bold;">glVertex</span>, <span
				554	style="font-weight: bold;">glVertex</span>, ... <span
				555	style="font-weight: bold;">glEnd</span> where <span
				556	style="font-style: italic;">mode</span> may be one of GL_QUADS or
				557	GL_QUAD_STRIP.<span style="font-weight: bold;"></span>   For
				558	GL_QUADS, the number of vertices should be a multiple of four - extra
				559	vertices will be ignored.  For GL_QUAD_STRIP, the number of
				560	vertices should be even and at least four.  Extra vertices (one)
				561	will be ignored.<br>
				562	<br>
				563	Convex polygons are <span style="font-weight: bold;"></span>rendered
				564	by the command sequence <span style="font-weight: bold;">glBegin</span><span
				565	style="font-style: italic;"><span style="font-style: italic;"></span></span>(GL_POLYGON),<span
				566	style="font-weight: bold;">glVertex</span>, <span
				567	style="font-weight: bold;">glVertex</span>, ... <span
				568	style="font-weight: bold;">glEnd</span>.<span
				569	style="font-style: italic;"></span><span style="font-weight: bold;"></span>
				570	If less than three vertices are specified, nothing is drawn.<br>
				571	<br>
				572	<h3>4.3.1 Polygon Orientation</h3>
				573	The <span style="font-style: italic;">winding order</span> of vertices
				574	(clockwise or counter-clockwise) is significant.  It is used to
				575	determine the <span style="font-style: italic;">front-facing</span> or <span
				576	style="font-style: italic;">back-facing</span> orientation of polygons.
				577	By default, a front-facing polygon's vertices are in
				578	counter-clockwise order (in window coordinates).  Figures 2.4 and
				579	2.5 of the OpenGL 1.2.1 specification illustrate the winding order for
				580	front-facing triangles and quadrilaterals, respectively.<br>
				581	<br>
				582	The command<br>
				583	<br>
				584	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glFrontFace</span>(GLenum<span
				585	style="font-style: italic;"> mode</span>)<br>
				586	</div>
				587	<br>
				588	specifies whether clockwise or counter-clockwise winding indicates a
				589	front-facing polygon.  If <span style="font-style: italic;">mode</span>
				590	is GL_CW then polygons with clockwise winding are front-facing.  If <span
				591	style="font-style: italic;">mode</span> is GL_CCW then polygons with
				592	counter-clockwise winding are front-facing.  The default value is
				593	GL_CCW.  If <span style="font-style: italic;">mode</span> is not
				594	GL_CCW or GL_CW then the error GL_INVALID_ENUM will be raised.<span
				595	style="font-style: italic;"></span><span style="font-style: italic;"></span><br>
				596	<br>
				597	<h3>4.3.2 Polygon Culling</h3>
				598	Polygons may be culled (discarded) depending on whether they are
				599	front-facing or back-facing.  The command<br>
				600	<br>
				601	<div style="margin-left: 40px;">void<span style="font-weight: bold;">
				602	glCullFace</span>(GLenum <span style="font-style: italic;">mode</span>)<br>
				603	</div>
				604	<br>
				605	specifies whether front-facing, back-facing or all polygons should be
				606	culled.  If <span style="font-style: italic;">mode</span> is
				607	GL_FRONT then front-facing polygons will be culled.  If <span
				608	style="font-style: italic;">mode</span> is GL_BACK then back-facing
				609	polygons will be culled. Otherwise, if <span style="font-style: italic;">mode</span>
				610	is GL_FRONT_AND_BACK then all polygons will be culled.  Any other
				611	value for <span style="font-style: italic;">mode</span> will raise the
				612	error GL_INVALID_ENUM.<br>
				613	<br>
				614	Polygon culling is enabled and disabled with the commands <span
				615	style="font-weight: bold;">glEnable</span>(GL_CULL_FACE) and <span
				616	style="font-weight: bold;">glDisable</span>(GL_CULL_FACE),
				617	respectively.<br>
				618	<br>
				619	<h3>4.3.3 Polygon Antialiasing</h3>
				620	Polygons may be antialiased in order to smooth their edges.
				621	Polygon antialiasing is enabled and disabled with the commands <span
				622	style="font-weight: bold;">glEnable</span>(GL_POLYGON_SMOOTH) and <span
				623	style="font-weight: bold;">glDisable</span>(GL_POLYGON_SMOOTH).<br>
				624	<br>
				625	When polygon antialiasing is enabled each fragment produced by polygon,
				626	triangle and quadrilateral rasterization will be given a <span
				627	style="font-style: italic;">coverage</span> value which indicates how
				628	much of the fragment is covered by the polygon.  Fragments
				629	completely inside the polygon have coverage 1.0.  Fragments
				630	completely outside the polygon have zero coverage (in theory).
				631	Fragments which intersect the polygon's edge have a coverage value
				632	in the range (0, 1).<br>
				633	<br>
				634	The fragment's alpha value is multiplied by the coverage value.
				635	By enabling the appropriate blending mode, polygon edges will
				636	appear smoothed.<br>
				637	<br>
				638	<h2>4.4 Shading</h2>
				639	The command<br>
				640	<br>
				641	<div style="margin-left: 40px;"> void <span style="font-weight: bold;">glShadeModel</span>(GLenum<span
				642	style="font-style: italic;">mode</span>)<br>
				643	</div>
				644	<br>
				645	determines whether colors are interpolated between vertices during
				646	rasterization.  If <span style="font-style: italic;">mode</span> is
				647	GL_FLAT then vertex colors are not interpolated.  The color used
				648	for drawing lines, triangles and quadrilaterals is that of the last
				649	vertex used to specify each primitive.  For polygons, the color of
				650	the first vertex specifies the color for the entire polygon.  If <span
				651	style="font-style: italic;">mode</span> is GL_SMOOTH then vertex colors
				652	are linearly interpolated to produce the fragment colors.<br>
				653	<br>
				654	<h2>4.5 Bitmap Rasterization</h2>
				655	A bitmap is a monochromatic, binary image in which each image element
				656	(or pixel) is represented by one bit.  Fragments are only generated
				657	for the bits (pixels) which are set.  Bitmaps are commonly used to
				658	draw text (glyphs) and markers.<br>
				659	<br>
				660	A bitmap is drawn with the command<br>
				661	<br>
				662	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glBitmap</span>(GLsizei<span
				663	style="font-style: italic;">width</span>, GLsizei <span
				664	style="font-style: italic;">height</span>, GLfloat <span
				665	style="font-style: italic;">xOrig</span>, GLfloat <span
				666	style="font-style: italic;">yOrig</span>, GLfloat <span
				667	style="font-style: italic;">xMove</span>, GLfloat <span
				668	style="font-style: italic;">yMove</span>, const  GLubyte *<span
				669	style="font-style: italic;">image</span>)<br>
				670	</div>
				671	<br>
				672	<span style="font-style: italic;">width </span>and <span
				673	style="font-style: italic;">height</span> specify the image size in
				674	pixels.  <span style="font-style: italic;">xOrig</span> and <span
				675	style="font-style: italic;">yOrig</span> specify the bitmap origin.
				676	<span style="font-style: italic;">xMove</span> and <span
				677	style="font-style: italic;">yMove</span> are added to the current
				678	raster position after the bitmap is rasterized.  <span
				679	style="font-style: italic;">image</span> is a pointer to the bitmap
				680	data.<br>
				681	<br>
				682	If the current raster position is not valid, <span
				683	style="font-weight: bold;">glBitmap</span> has no effect.<br>
				684	<br>
				685	<h3>4.5.1 Bitmap Unpacking</h3>
				686	The first step in bitmap rendering is <span style="font-style: italic;">unpacking.
				687	</span>Unpacking is the process of extracting image data from
				688	client memory subject to byte swapping, non-default row strides, etc.
				689	The unpacking parameters are specified with the command<br>
				690	<br>
				691	<div style="margin-left: 40px;">void<span style="font-weight: bold;">
				692	glPixelStorei</span>(GLenum pname, GLint value)<br>
				693	</div>
				694	<span style="font-style: italic;"></span><br>
				695	The following unpacking parameters may be set:<br>
				696	<br>
				697	<table cellpadding="2" cellspacing="2" border="1"
				698	style="text-align: left; width: 90%; margin-left: auto; margin-right: auto;">
				699	<tbody>
				700	<tr>
				701	<td style="vertical-align: top;">Parameter (<span
				702	style="font-style: italic;">pname</span>)<br>
				703	</td>
				704	<td style="vertical-align: top;">Value (<span
				705	style="font-style: italic;">value</span>)<br>
				706	</td>
				707	<td style="vertical-align: top;">Default<br>
				708	</td>
				709	</tr>
				710	<tr>
				711	<td style="vertical-align: top;">GL_UNPACK_ROW_LENGTH<br>
				712	</td>
				713	<td style="vertical-align: top;">Width of the image in memory, in
				714	pixels.<br>
				715	</td>
				716	<td style="vertical-align: top;">0<br>
				717	</td>
				718	</tr>
				719	<tr>
				720	<td style="vertical-align: top;">GL_UNPACK_LSB_FIRST<br>
				721	</td>
				722	<td style="vertical-align: top;">GL_FALSE indicates that the most
				723	significant bit is unpacked first from each byte.  GL_TRUE
				724	indicates that the least significant bit is unpacked first from each
				725	byte. <br>
				726	</td>
				727	<td style="vertical-align: top;">GL_FALSE<br>
				728	</td>
				729	</tr>
				730	</tbody>
				731	</table>
				732	<br>
				733	<br>
				734	The GL_UNPACK_ROW_LENGTH specifies the stride (in pixels) for advancing
				735	from one row of the image to the next.  If it's zero, the <span
				736	style="font-style: italic;">width</span> parameter to <span
				737	style="font-weight: bold;">glBitmap</span> specifies the width of the
				738	image in memory.<br>
				739	<br>
				740	GL_UNPACK_LSB_FIRST determines whether the least significant or most
				741	significant bit in each byte is unpacked first.  Unpacking occurs
				742	in left to right order (in image space).<br>
				743	<br>
				744	The value of bit (i, j) of the image (where i is the image row and j is
				745	the image column) is found as follows:<br>
				746	<br>
				747	<div style="margin-left: 40px;">rowLength = (GL_UNPACK_ROW_LENGTH != 0)
				748	? GL_UNPACK_ROW_LENGTH : <span style="font-style: italic;">width</span>;<br>
				749	<br>
				750	byte = <span style="font-style: italic;">image</span>[((rowLength + 7)
				751	/ 8) * i + j / 8];<br>
				752	<br>
				753	if (GL_UNPACK_LSB_FIRST != 0)<br>
				754	bitMask = 1 << (j % 8);<br>
				755	else<br>
				756	bitMask = 128 >> (j % 8);<br>
				757	<br>
				758	if (byte & bitMask)<br>
				759	bit = 1;<br>
				760	else<br>
				761	bit = 0;<br>
				762	<br>
				763	</div>
				764	<span style="font-style: italic;"><span style="font-style: italic;"></span></span>
				765	<h3>4.5.2 Rasterization</h3>
				766	If the current raster position is (x<sub>rp</sub>, y<sub>rp</sub>, z<sub>rp</sub>,
				767	w<sub>rp</sub>), then the bitmap is rasterized according to the
				768	following algorithm:<br>
				769	<br>
				770	for (j = 0; j < <span style="font-style: italic;">height</span>;
				771	j++) {<br>
				772	for (i = 0; i < <span style="font-style: italic;">width</span>;
				773	i++) {<br>
				774	if (bit(i,j)) {<br>
				775	fragment.x =
				776	floor(x<sub>rp</sub> - <span style="font-style: italic;">xOrig</span>)
				777	+ i;<br>
				778	fragment.y =
				779	floor(y<sub>rp</sub> - <span style="font-style: italic;">yOrig</span>)
				780	+ j;<br>
				781	fragment.color
				782	= GL_CURRENT_RASTER_COLOR;<br>
				783
				784	fragment.texture = GL_CURRENT_RASTER_TEXTURE_COORDS;<br>
				785
				786	ProcessFragment(fragment)<br>
				787	}<br>
				788	}<br>
				789	}<br>
				790	<br>
				791	After the bitmap has been rendered the current raster position is
				792	updated as follows:<br>
				793	<br>
				794	<div style="margin-left: 40px;">x<sub>rp</sub> = x<sub>rp</sub> + <span
				795	style="font-style: italic;">xMove</span><br>
				796	y<sub>rp</sub> = y<sub>rp</sub> + <span style="font-style: italic;">yMove</span><br>
				797	</div>
				798	<br>
				799	<h3>4.5.3 Per-fragment Operations</h3>
				800	XXX supported?  See issue in appendix A.<br>
				801	<br>
				802	<h2>4.6 Unsupported Commands</h2>
				803	The following commands related to rasterization are not supported by
				804	the subset.<br>
				805	<br>
				806	<div style="margin-left: 40px;">Point commands:<br>
				807	<div style="margin-left: 40px;"><span style="font-weight: bold;">glPointSize</span><br>
				808	</div>
				809	<br>
				810	Polygon commands:<br>
				811	<div style="margin-left: 40px; font-weight: bold;">glPolygonStipple<br>
				812	glPolygonOffset<br>
				813	glPolygonMode<br>
				814	<br>
				815	</div>
				816	</div>
				817	<div style="margin-left: 40px;">Pixel storage commands:<br>
				818	</div>
				819	<div style="font-weight: bold; margin-left: 80px;">glPixelStoref<br>
				820	</div>
				821	<br>
				822	<br>
				823	<h1>5. Texture Mapping<br>
				824	</h1>
				825	There are four elements to texture mapping: texture coordinate
				826	specification, texture image specification, texture sampling and texture
				827	application.<br>
				828	<br>
				829	Texture mapping is enabled and disabled with the commands <span
				830	style="font-weight: bold;">glEnable</span>(GL_TEXTURE_2D) and <span
				831	style="font-weight: bold;">glDisable</span>(GL_TEXTURE_2D).<br>
				832	<br>
				833	<h2>5.1 Texture Image Specification</h2>
				834	A texture image is specified with the command:<br>
				835	<br>
				836	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glTexImage2D</span>(GLenum<span
				837	style="font-style: italic;"> target</span>, GLint <span
				838	style="font-style: italic;">level</span>, GLint <span
				839	style="font-style: italic;">internalFormat,</span> GLsizei <span
				840	style="font-style: italic;">width,</span> GLsizei <span
				841	style="font-style: italic;">height,</span> GLint <span
				842	style="font-style: italic;">border,</span> GLenum <span
				843	style="font-style: italic;">format,</span> GLenum <span
				844	style="font-style: italic;">type,</span> const GLvoid *<span
				845	style="font-style: italic;">pixels</span> )<br>
				846	</div>
				847	<br>
				848	<span style="font-style: italic;">target</span> must be GL_TEXTURE_2D.
				849	<span style="font-style: italic;">level </span>indicates the
				850	mipmap level for mipmap textures.  <span style="font-style: italic;">internalFormat</span>
				851	is a hint to indicate the preferred internal storage format for the
				852	texture.  <span style="font-style: italic;">width</span> and <span
				853	style="font-style: italic;">height </span>indicate the image size in
				854	pixels (or texels).  <span style="font-style: italic;">border </span>must
				855	be zero.  <span style="font-style: italic;">format</span> and <span
				856	style="font-style: italic;">type</span> describe the pixel format and
				857	data type for the incoming image.  <span style="font-style: italic;">pixels</span>
				858	points to the incoming texture image.  These parameters are
				859	described in more detail below.<br>
				860	<br>
				861	<h3>5.1.1 Texture Image Size and Mipmaps</h3>
				862	<h3><span style="font-style: italic;"></span></h3>
				863	Texture images must have dimensions (width and height) that are powers
				864	of two. For example: 256 x 256, 32 x 1024, 1 x 8, etc.  That is, it
				865	must be the case that <span style="font-style: italic;">width </span>=
				866	2<sup>n</sup> and <span style="font-style: italic;">height</span> = 2<sup>m</sup>
				867	for some positive integers n and m.<br>
				868	<br>
				869	Mipmapping is a method of antialiasing or filtering textures to improve
				870	their appearance.  A mipmap is a set of images consisting of a base
				871	image and a set of filtered, reduced-resolution images.  If the
				872	base image (<span style="font-style: italic;">level</span>=0) is of
				873	width 2<sup>n</sup> and height 2<sup>m</sup> then the level 1 image must
				874	be of width 2<sup>n-1</sup> and height 2<sup>m-1</sup>.  Each mipmap
				875	level is half the width and height of the previous level, or at least
				876	one.  The last mipmap level has a width and height of one.<br>
				877	<br>
				878	The following is an example of a mipmap's image levels:<br>
				879	<br>
				880	<table cellpadding="2" cellspacing="2" border="1"
				881	style="text-align: left; width: 50%; margin-left: auto; margin-right: auto;">
				882	<tbody>
				883	<tr>
				884	<td style="vertical-align: top;">mipmap level<br>
				885	</td>
				886	<td style="vertical-align: top;">width<br>
				887	</td>
				888	<td style="vertical-align: top;">height<br>
				889	</td>
				890	</tr>
				891	<tr>
				892	<td style="vertical-align: top;">0<br>
				893	</td>
				894	<td style="vertical-align: top;">256<br>
				895	</td>
				896	<td style="vertical-align: top;">64<br>
				897	</td>
				898	</tr>
				899	<tr>
				900	<td style="vertical-align: top;">1<br>
				901	</td>
				902	<td style="vertical-align: top;">128<br>
				903	</td>
				904	<td style="vertical-align: top;">32<br>
				905	</td>
				906	</tr>
				907	<tr>
				908	<td style="vertical-align: top;">2<br>
				909	</td>
				910	<td style="vertical-align: top;">64<br>
				911	</td>
				912	<td style="vertical-align: top;">16<br>
				913	</td>
				914	</tr>
				915	<tr>
				916	<td style="vertical-align: top;">3<br>
				917	</td>
				918	<td style="vertical-align: top;">32<br>
				919	</td>
				920	<td style="vertical-align: top;">8<br>
				921	</td>
				922	</tr>
				923	<tr>
				924	<td style="vertical-align: top;">4<br>
				925	</td>
				926	<td style="vertical-align: top;">16<br>
				927	</td>
				928	<td style="vertical-align: top;">4<br>
				929	</td>
				930	</tr>
				931	<tr>
				932	<td style="vertical-align: top;">5<br>
				933	</td>
				934	<td style="vertical-align: top;">8<br>
				935	</td>
				936	<td style="vertical-align: top;">2<br>
				937	</td>
				938	</tr>
				939	<tr>
				940	<td style="vertical-align: top;">6<br>
				941	</td>
				942	<td style="vertical-align: top;">4<br>
				943	</td>
				944	<td style="vertical-align: top;">1<br>
				945	</td>
				946	</tr>
				947	<tr>
				948	<td style="vertical-align: top;">7<br>
				949	</td>
				950	<td style="vertical-align: top;">2<br>
				951	</td>
				952	<td style="vertical-align: top;">1<br>
				953	</td>
				954	</tr>
				955	<tr>
				956	<td style="vertical-align: top;">8<br>
				957	</td>
				958	<td style="vertical-align: top;">1<br>
				959	</td>
				960	<td style="vertical-align: top;">1<br>
				961	</td>
				962	</tr>
				963	</tbody>
				964	</table>
				965	<br>
				966	If the <span style="font-style: italic;">width</span> or <span
				967	style="font-style: italic;">height</span> parameters are not powers of
				968	two, the error GL_INVALID_VALUE is raised.  If the image levels in
				969	a mipmap do not satisfy the restrictions listed above the texture is
				970	considered to be <span style="font-style: italic;">inconsistent</span>
				971	and the system will behave as if the texturing is disabled.<br>
				972	<br>
				973	<h3>5.1.2 Texture Image Formats and Unpacking</h3>
				974	The <span style="font-weight: bold;">glTexImage2D</span> command's <span
				975	style="font-style: italic;"><span style="font-weight: bold;"></span></span><span
				976	style="font-style: italic;">format</span> and <span
				977	style="font-style: italic;">type</span> parameters describe the format
				978	of the incoming texture image.  Accepted values for <span
				979	style="font-style: italic;">format</span> are GL_INTENSITY, GL_RGB and
				980	GL_RGBA.  The <span style="font-style: italic;">type</span>
				981	parameter must be GL_UNSIGNED_BYTE.  Pixel component values are
				982	thus in the range 0 through 255.<br>
				983	<br>
				984	If <span style="font-style: italic;">format</span> is GL_INTENSITY then
				985	the image has one byte per pixel which specifies the pixel's red, green,
				986	blue and alpha values.<span style="font-style: italic;"></span><br>
				987	<br>
				988	If <span style="font-style: italic;">format</span> is GL_RGB then the
				989	image has three bytes per pixel which specify the pixel's red, green and
				990	blue values (in that order).  The alpha value defaults to 255.<br>
				991	<br>
				992	If <span style="font-style: italic;">format</span> is GL_RGBA then the
				993	image has four bytes per pixel which specify the pixel's red, green,
				994	blue and alpha values (in that order).<br>
				995	<br>
				996	The command<br>
				997	<br>
				998	<div style="margin-left: 40px;">void<span style="font-weight: bold;">
				999	glPixelStorei</span>(GLenum <span style="font-style: italic;">pname</span>,
				1000	GLint <span style="font-style: italic;">value</span>)<br>
				1001	</div>
				1002	<br>
				1003	controls the unpacking of texture image data from client memory.  <span
				1004	style="font-style: italic;">pname</span> may be GL_UNPACK_ROW_LENGTH to
				1005	indicate the stride, in pixels, between subsequent rows of the image in
				1006	client memory.  If GL_UNPACK_ROW_LENGTH is zero (the default) then
				1007	the <span style="font-style: italic;">width</span> parameter to <span
				1008	style="font-weight: bold;">glTexImage2D </span>determines the stride.<span
				1009	style="font-style: italic;"></span><br>
				1010	<br>
				1011	<h3>5.1.3 Internal Texture Format</h3>
				1012	<span style="font-weight: bold;">glTexImage2D<span
				1013	style="font-style: italic;"> </span></span>converts the incoming
				1014	texture image to one of the supported internal texture formats.<br>
				1015	<br>
				1016	The <span style="font-style: italic;">internalFormat</span> parameter
				1017	indicates the desired internal format for the texture and may be either
				1018	GL_INTENSITY8, GL_RGB5 or GL_RGBA8.<br>
				1019	<br>
				1020	If <span style="font-style: italic;">internalFormat</span> is
				1021	GL_INTENSITY8 then the texture has one byte per texel (texture element)
				1022	which indicates the texel's intensity (or brightness).  The
				1023	intensity is obtained from the incoming image's red channel.<br>
				1024	<br>
				1025	If <span style="font-style: italic;">internalFormat</span> is GL_RGB5
				1026	then the texture is stored with two bytes per texel:  5 bits per
				1027	red value, 5 bits per green value and 5 bits per blue value.<br>
				1028	<br>
				1029	If <span style="font-style: italic;">internalFormat </span>is
				1030	GL_RGBA8 then the texture is stored with four bytes per texel:  8
				1031	bits for each of the red, green,  blue and alpha values.<br>
				1032	<br>
				1033	The internal format is also significant to texture application (see
				1034	section 5.4).<br>
				1035	<br>
				1036	<h2>5.2 Texture Coordinates</h2>
				1037	Texture coordinates control the mapping from local polygon space to
				1038	texture image space.  Texture coordinates are set for each vertex
				1039	with the <span style="font-weight: bold;">glTexCoord</span> commands.
				1040	During line and polygon rasterization the vertex's texture
				1041	coordinates are interpolated across the primitive to produce a texture
				1042	coordinate for each fragment.  The fragment texture coordinates are
				1043	used to sample the current texture image.<br>
				1044	<br>
				1045	Texture coordinates are normally in the range [0, 1].  Values
				1046	outside that range are processed according to the <span
				1047	style="font-style: italic;">texture wrap mode</span>.  The
				1048	texture wrap mode is set with the command<br>
				1049	<br>
				1050	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glTexParameteri</span>(GLenum<span
				1051	style="font-style: italic;"> target</span>, GLenum <span
				1052	style="font-style: italic;">pname</span>, GLint <span
				1053	style="font-style: italic;">value</span>)<br>
				1054	<br>
				1055	</div>
				1056	<span style="font-style: italic;">target</span> must be GL_TEXTURE_2D.
				1057	If <span style="font-style: italic;">pname</span> is
				1058	GL_TEXTURE_WRAP_S or GL_TEXTURE_WRAP_T then <span
				1059	style="font-style: italic;">value</span> must be either
				1060	GL_CLAMP_TO_EDGE or GL_REPEAT.<br>
				1061	<br>
				1062	For GL_CLAMP_TO_EDGE, texture coordinates are effectively clamped to
				1063	the interval [0, 1].<br>
				1064	<br>
				1065	For GL_REPEAT, the integer part of texture coordinates is ignored; only
				1066	the fractional part of the texture coordinates is used.  This
				1067	allows texture images to repeated or tiled across an object.<br>
				1068	<br>
				1069	<h2>5.3 Texture Sampling</h2>
				1070	Texture sampling is the process of using texture coordinates to extract
				1071	a color from the texture image.  Multiple, weighted samples may be
				1072	taken from the texture and combined during the filtering step.<br>
				1073	<br>
				1074	During texture coordinate interpolation a <span
				1075	style="font-style: italic;">level of detail</span> value (lambda) is
				1076	computed for each fragment.  For a mipmapped texture, lambda
				1077	determines which level (or levels) of the mipmap will be sampled to
				1078	obtain the texture color.<br>
				1079	<br>
				1080	If lambda indicates that multiple texels map to a single screen pixel,
				1081	then the texture <span style="font-style: italic;">minification</span>
				1082	filter will be used.  Otherwise, if lambda indicates that a single
				1083	texel maps to multiple screen pixels, then the texture <span
				1084	style="font-style: italic;">magnification</span> filter will be used.<br>
				1085	<span style="font-weight: bold;"></span><span
				1086	style="font-style: italic;"></span><br>
				1087	<h3>5.3.1 Texture Minification</h3>
				1088	The texture minification filter is set with the <span
				1089	style="font-weight: bold;">glTexParameteri </span><span
				1090	style="font-style: italic;"></span><span style="font-weight: bold;"></span><span
				1091	style="font-style: italic;"></span> command by setting <span
				1092	style="font-style: italic;">target</span> to GL_TEXTURE_2D, setting <span
				1093	style="font-style: italic;">pname</span> to GL_TEXTURE_MIN_FILTER and
				1094	setting <span style="font-style: italic;">value</span> to GL_NEAREST,
				1095	GL_LINEAR, GL_NEAREST_MIPMAP_NEAREST,
				1096	GL_NEAREST_MIPMAP_LINEAR,   GL_LINEAR_MIPMAP_NEAREST or
				1097	GL_LINEAR_MIPMAP_LINEAR.<br>
				1098	<br>
				1099	GL_NEAREST samples the texel nearest the texture coordinate in the
				1100	level 0 texture image.<br>
				1101	<br>
				1102	GL_LINEAR samples the four texels around the texture coordinate in the
				1103	level 0 texture image.  The four texels are linearly weighted to
				1104	compute the final texel value.<br>
				1105	<br>
				1106	GL_NEAREST_MIPMAP_NEAREST samples the texel nearest the texture
				1107	coordinate in the level N texture image.  N is the level of detail
				1108	and is computed by the partial derivatives of the texture coordinates
				1109	with respect to the window coordinates.<br>
				1110	<br>
				1111	GL_NEAREST_MIPMAP_LINEAR samples two texels nearest the texture
				1112	coordinates in the level N and N+1 texture images.  The two texels
				1113	are linearly weighted to compute the final texel value.  N is the
				1114	level of detail and is computed by the partial derivatives of the
				1115	texture coordinates with respect to the window coordinates.<br>
				1116	<br>
				1117	GL_LINEAR_MIPMAP_NEAREST samples four texels around the texture
				1118	coordinate in the level N texture image.  The four texels are
				1119	linearly weighted to compute the final texel value.  N is the level
				1120	of detail and is computed by the partial derivatives of the texture
				1121	coordinates with respect to the window coordinates.<br>
				1122	<br>
				1123	GL_LINEAR_MIPMAP_LINEAR samples four texels around the texture
				1124	coordinate in the level N texture image and four texels around the
				1125	texture coordinate in the level N+1 texture image.  The eight
				1126	texels are linearly weighted to compute the final texel value.  N
				1127	is the level of detail and is computed by the partial derivatives of the
				1128	texture coordinates with respect to the window coordinates.<br>
				1129	<br>
				1130	Filter modes other than GL_LINEAR and GL_NEAREST requires that the
				1131	texture have a complete set of mipmaps.  If the mipmap is
				1132	incomplete, it is as if texturing is disabled.<br>
				1133	<br>
				1134	<h3>5.3.2 Texture Magnification</h3>
				1135	The texture magnification filter is set with the <span
				1136	style="font-weight: bold;">glTexParameteri </span><span
				1137	style="font-style: italic;"></span><span style="font-weight: bold;"></span>command
				1138	by setting <span style="font-style: italic;">target</span> to
				1139	GL_TEXTURE_2D, setting <span style="font-style: italic;">pname</span> to
				1140	GL_TEXTURE_MAG_FILTER and setting <span style="font-style: italic;">value</span>
				1141	to GL_NEAREST or GL_LINEAR.<br>
				1142	<br>
				1143	GL_NEAREST samples the texel nearest the texture coordinate in the
				1144	level 0 texture image.<br>
				1145	<br>
				1146	GL_LINEAR samples the four texels around the texture coordinate in the
				1147	level 0 texture image.  The four texels are linearly weighted to
				1148	compute the final texel value.<br>
				1149	<br>
				1150	<h2>5.4 Texture Application</h2>
				1151	The sampled texture value is combined with the incoming fragment color
				1152	to produce a new fragment color.  The fragment and texture colors
				1153	are combined according to the texture environment mode and the current
				1154	texture's base internal format.  The texture environment mode is
				1155	set with the command<br>
				1156	<br>
				1157	<div style="margin-left: 40px;">void<span style="font-weight: bold;">
				1158	glTexEnvi</span>(GLenum <span style="font-style: italic;">target</span>,
				1159	GLenum <span style="font-style: italic;">pname</span>, GLint <span
				1160	style="font-style: italic;">value</span>)<br>
				1161	</div>
				1162	<br>
				1163	<span style="font-style: italic;">target</span> must be GL_TEXTURE_ENV.
				1164	If <span style="font-style: italic;">pname</span> is
				1165	GL_TEXTURE_ENV_MODE then <span style="font-style: italic;">value</span>
				1166	must be one of GL_REPLACE, GL_MODULATE, GL_DECAL, or GL_BLEND.<br>
				1167	<br>
				1168	There is also a <span style="font-style: italic;">texture environment
				1169	color</span> that can factor into texture application.  The texture
				1170	environment color can be set with the command<br>
				1171	<br>
				1172	<div style="margin-left: 40px;">void<span style="font-weight: bold;">
				1173	glTexEnvfv</span>(GLenum <span style="font-style: italic;">target</span>,
				1174	GLenum <span style="font-style: italic;">pname</span>, const GLfloat *<span
				1175	style="font-style: italic;">value</span>)<br>
				1176	</div>
				1177	<span style="font-style: italic;"></span><br>
				1178	<span style="font-style: italic;">target</span> must be GL_TEXTURE_ENV.
				1179	If <span style="font-style: italic;">pname</span> is
				1180	GL_TEXTURE_ENV_COLOR then <span style="font-style: italic;">value </span>must
				1181	point to an array of four values which specify the red, green, blue,
				1182	and alpha values of the texture environment color.  The values are
				1183	clamped to the range [0, 1].  The default color is (0, 0, 0, 0).<br>
				1184	<span style="font-style: italic;"></span><br>
				1185	The following table describes the arithmetic used for each combination
				1186	of environment mode and base internal format.  (Rf, Gf, Bf, Af) is
				1187	the incoming fragment color.  (Rt, Gt, Bt, At) is the sampled
				1188	texture color.  Lt is the sampled texture luminance.  <span
				1189	style="font-style: italic;"></span>'It' is the sampled texture
				1190	intensity.  (Rc, Gc, Bc, Ac) is the texture environment color.
				1191	(Rv, Gv, Bv, Av) is the resulting value.<br>
				1192	<br>
				1193	<br>
				1194	<table cellpadding="2" cellspacing="2" border="1"
				1195	style="text-align: left; width: 90%; margin-left: auto; margin-right: auto;">
				1196	<tbody>
				1197	<tr>
				1198	<td style="vertical-align: top;">Base Internal Format<br>
				1199	</td>
				1200	<td style="vertical-align: top;">GL_REPLACE<br>
				1201	</td>
				1202	<td style="vertical-align: top;">GL_MODULATE<br>
				1203	</td>
				1204	<td style="vertical-align: top;">GL_DECAL<br>
				1205	</td>
				1206	<td style="vertical-align: top;">GL_BLEND<br>
				1207	</td>
				1208	</tr>
				1209	<tr>
				1210	<td style="vertical-align: top;">GL_INTENSITY<br>
				1211	</td>
				1212	<td style="vertical-align: top;">Rv = It<br>
				1213	Gv = It<br>
				1214	Bv = It<br>
				1215	Bf = It<br>
				1216	</td>
				1217	<td style="vertical-align: top;">Rv = Rf * It<br>
				1218	Gv = Gf * It<br>
				1219	Bv = Bf * It<br>
				1220	Av = Af * It</td>
				1221	<td style="vertical-align: top;">undefined<br>
				1222	</td>
				1223	<td style="vertical-align: top;">Rv = Rf(1-It) + RcIt<br>
				1224	Gv = Gf(1-It) + GcIt<br>
				1225	Bv = Bf(1-It) + BcIt<br>
				1226	Av = Af(1-It) + AcIt</td>
				1227	</tr>
				1228	<tr>
				1229	<td style="vertical-align: top;">GL_RGB<br>
				1230	</td>
				1231	<td style="vertical-align: top;">Rv = Rt<br>
				1232	Gv = Gt<br>
				1233	Bv = Bt<br>
				1234	Av = Af<br>
				1235	</td>
				1236	<td style="vertical-align: top;">Rv = Rf * Rt<br>
				1237	Gv = Gf * Gt<br>
				1238	Bv = Bf * Bt<br>
				1239	Av = Af<br>
				1240	</td>
				1241	<td style="vertical-align: top;">Rv = Rt<br>
				1242	Gv = Gt<br>
				1243	Bv = Bt<br>
				1244	Av = Af</td>
				1245	<td style="vertical-align: top;">Rv = Rf(1-Rt) + RcRt<br>
				1246	Gv = Gf(1-Gt) + GcGt<br>
				1247	Bv = Bf(1-Bt) + BcBt<br>
				1248	Av = Af</td>
				1249	</tr>
				1250	<tr>
				1251	<td style="vertical-align: top;">GL_RGBA<br>
				1252	</td>
				1253	<td style="vertical-align: top;">Rv = Rt<br>
				1254	Gv = Gt<br>
				1255	Bv = Bt<br>
				1256	Av = At<br>
				1257	</td>
				1258	<td style="vertical-align: top;">Rv = Rf * Rt<br>
				1259	Gv = Gf * Gt<br>
				1260	Bv = Bf * Bt<br>
				1261	Av = Af * At</td>
				1262	<td style="vertical-align: top;">Rv = Rf(1-At) + RtAt<br>
				1263	Gv = Gf(1-At) + GtAt<br>
				1264	Bv = Bf(1-At) + BtAt<br>
				1265	Av = Af<br>
				1266	</td>
				1267	<td style="vertical-align: top;">Rv = Rf(1-Rt) + RcRt<br>
				1268	Gv = Gf(1-Gt) + GcGt<br>
				1269	Bv = Bf(1-Bt) + BcBt<br>
				1270	Av = Af*At</td>
				1271	</tr>
				1272	</tbody>
				1273	</table>
				1274	<br>
				1275	<br>
				1276	<br>
				1277	<h2>5.5 Texture Objects</h2>
				1278	Texture objects encapsulate a set of texture images (mipmap) and
				1279	related state into a named object.  This facilitates use of
				1280	multiple textures in an application.  Texture objects are named
				1281	with GLuints (unsigned integers).  There is a default texture
				1282	object with the name/identifier zero which can never be deleted.<br>
				1283	<br>
				1284	<h3>5.5.1 Creating Texture Objects</h3>
				1285	A texture object is created by binding a new GLuint identifier to the
				1286	GL_TEXTURE_2D target with the command:<br>
				1287	<br>
				1288	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glBindTexture</span>(GLenum<span
				1289	style="font-style: italic;"> target</span>, GLuint <span
				1290	style="font-style: italic;">textureID</span>)<br>
				1291	</div>
				1292	<br>
				1293	<span style="font-style: italic;">target</span> must be GL_TEXTURE_2D.
				1294	<span style="font-style: italic;">textureID</span> may be any
				1295	unsigned integer.  If <span style="font-style: italic;">textureID</span>
				1296	does not name an existing texture object, a new texture object with that
				1297	ID will be created, initialized to the default state.  Whether the
				1298	ID is new or existed previously, that named texture object is bound as
				1299	the <span style="font-style: italic;">current texture object</span>.
				1300	Subsequent <span style="font-weight: bold;">glTexParameter </span>and<span
				1301	style="font-weight: bold;">glTexImage2D<span
				1302	style="font-style: italic;"> </span></span>calls will effect the
				1303	current texture object.<br>
				1304	<span style="font-style: italic;"></span><span
				1305	style="font-weight: bold;"><span style="font-style: italic;"> </span></span><br>
				1306	<h3>5.5.2 Deleting Texture Objects</h3>
				1307	One or more texture objects may be deleted with the command:<br>
				1308	<br>
				1309	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glDeleteTextures</span>(GLsizei<span
				1310	style="font-style: italic;">n</span>, const GLuint *<span
				1311	style="font-style: italic;">textureIDs</span>)<br>
				1312	</div>
				1313	<br>
				1314	<span style="font-style: italic;">textureIDs</span> is an array of <span
				1315	style="font-style: italic;">n</span> texture IDs.  The named
				1316	texture objects will be deleted.  If the current texture object is
				1317	deleted the default texture object (number 0) will be bound as the
				1318	current texture object.<br>
				1319	<br>
				1320	<h3>5.5.3 Allocating Texture Object Identifiers</h3>
				1321	A list of new, unused texture IDs can be obtained by calling the command<br>
				1322	<br>
				1323	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glGenTextures</span>(GLsizei<span
				1324	style="font-style: italic;"> n</span>, GLuint *<span
				1325	style="font-style: italic;">textureIDs</span>)<br>
				1326	</div>
				1327	<br>
				1328	An array of <span style="font-style: italic;">n</span> unused texture
				1329	IDs will be returned in the <span style="font-style: italic;">textureIDs</span>
				1330	array.<br>
				1331	<br>
				1332	<br>
				1333	<h1>6. Per-fragment Operations</h1>
				1334	The fragments produced by rasterization are subjected to a number of
				1335	operations which either modify the fragment or test the fragment
				1336	(discarding the fragment if the test fails.)  This chapter
				1337	describes the per-fragment operations.  They are presented in the
				1338	order in which they're performed.  If a fragment fails a test it is
				1339	discarded and not subjected to subsequent tests or modifications.<br>
				1340	<br>
				1341	<h2>6.1 Scissor Test</h2>
				1342	The scissor test limits rendering to a 2-D rectangular region of the
				1343	framebuffer.  The command<br>
				1344	<br>
				1345	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glScissor</span>(GLint<span
				1346	style="font-style: italic;">x</span>, GLint <span
				1347	style="font-style: italic;">y</span>, GLsizei <span
				1348	style="font-style: italic;">width</span>, GLsizei<span
				1349	style="font-style: italic;"> height</span>)<br>
				1350	</div>
				1351	<br>
				1352	defines a clipping region with the lower-left corner at (<span
				1353	style="font-style: italic;">x, y</span>) and the given <span
				1354	style="font-style: italic;">width</span> and <span
				1355	style="font-style: italic;">height</span>.  The scissor test is
				1356	enabled and disabled with the command <span style="font-weight: bold;">glEnable</span>(GL_SCISSOR_TEST)
				1357	and <span style="font-weight: bold;">glDisable</span>(GL_SCISSOR_TEST).<br>
				1358	<br>
				1359	If the incoming fragment's position is (x<sub>f</sub>, y<sub>f</sub>)
				1360	then the fragment will pass the test if <span
				1361	style="font-style: italic;">x</span> <= x<sub>f</sub> < <span
				1362	style="font-style: italic;">x</span> + <span
				1363	style="font-style: italic;">width</span> and <span
				1364	style="font-style: italic;">y</span> <= y<sub>f</sub> < <span
				1365	style="font-style: italic;">y</span> + <span
				1366	style="font-style: italic;">height.  </span>Otherwise, the
				1367	fragment is discarded.<br>
				1368	<br>
				1369	If <span style="font-style: italic;">width</span> or <span
				1370	style="font-style: italic;">height</span> is less than zero the error
				1371	GL_INVALID_VALUE is raised.  The default scissor rectangle bounds
				1372	are (0, 0, w, h) where w is the initial window width and h is the
				1373	initial window height.  The scissor test is disabled by default.<br>
				1374	<br>
				1375	<h2>6.2 Alpha Test</h2>
				1376	The alpha test compares the fragment's alpha value against a reference
				1377	value and discards the fragment if the comparison fails.  The test
				1378	is specified by the command<br>
				1379	<br>
				1380	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glAlphaFunc</span>(GLenum<span
				1381	style="font-style: italic;">mode</span>, GLclampf <span
				1382	style="font-style: italic;">reference</span>)<br>
				1383	</div>
				1384	<br>
				1385	<span style="font-style: italic;">mode</span> specifies an inequality
				1386	and <span style="font-style: italic;">reference</span> specifies a value
				1387	to compare against.  The following table lists all possible
				1388	modes <span style="font-style: italic;"></span>and the
				1389	corresponding test:<br>
				1390	<br>
				1391	<table cellpadding="2" cellspacing="2" border="1"
				1392	style="text-align: left; width: 50%; margin-left: auto; margin-right: auto;">
				1393	<tbody>
				1394	<tr>
				1395	<td style="vertical-align: top;">Comparison mode<br>
				1396	</td>
				1397	<td style="vertical-align: top;">The test passes if<br>
				1398	</td>
				1399	</tr>
				1400	<tr>
				1401	<td style="vertical-align: top;">GL_LESS<br>
				1402	</td>
				1403	<td style="vertical-align: top;">alpha < <span
				1404	style="font-style: italic;">reference</span><br>
				1405	</td>
				1406	</tr>
				1407	<tr>
				1408	<td style="vertical-align: top;">GL_LEQUAL<br>
				1409	</td>
				1410	<td style="vertical-align: top;">alpha <= <span
				1411	style="font-style: italic;">reference</span></td>
				1412	</tr>
				1413	<tr>
				1414	<td style="vertical-align: top;">GL_GREATER<br>
				1415	</td>
				1416	<td style="vertical-align: top;">alpha > <span
				1417	style="font-style: italic;">reference</span></td>
				1418	</tr>
				1419	<tr>
				1420	<td style="vertical-align: top;">GL_GEQUAL<br>
				1421	</td>
				1422	<td style="vertical-align: top;">alpha >= <span
				1423	style="font-style: italic;">reference</span></td>
				1424	</tr>
				1425	<tr>
				1426	<td style="vertical-align: top;">GL_EQUAL<br>
				1427	</td>
				1428	<td style="vertical-align: top;">alpha == <span
				1429	style="font-style: italic;">reference</span></td>
				1430	</tr>
				1431	<tr>
				1432	<td style="vertical-align: top;">GL_NOTEQUAL<br>
				1433	</td>
				1434	<td style="vertical-align: top;">alpha != <span
				1435	style="font-style: italic;">reference</span></td>
				1436	</tr>
				1437	<tr>
				1438	<td style="vertical-align: top;">GL_NEVER<br>
				1439	</td>
				1440	<td style="vertical-align: top;">never pass<br>
				1441	</td>
				1442	</tr>
				1443	<tr>
				1444	<td style="vertical-align: top;">GL_ALWAYS<br>
				1445	</td>
				1446	<td style="vertical-align: top;">always passes<br>
				1447	</td>
				1448	</tr>
				1449	</tbody>
				1450	</table>
				1451	<br>
				1452	The <span style="font-style: italic;">reference</span> parameter is
				1453	clamped to the range [0, 1].<br>
				1454	<br>
				1455	The alpha test is enabled and disabled with the commands <span
				1456	style="font-weight: bold;">glEnable</span>(GL_ALPHA_TEST) and <span
				1457	style="font-weight: bold;">glDisable</span>(GL_ALPHA_TEST).<br>
				1458	<br>
				1459	The default mode is GL_ALWAYS and the default reference value is 0.<br>
				1460	<br>
				1461	<h2>6.3 Stencil Test</h2>
				1462	The stencil buffer stores an N-bit integer value for each pixel in the
				1463	frame buffer.  The stencil test compares the stencil buffer value
				1464	at the fragment's position to a reference value and possibly discards
				1465	the fragment based on the outcome.  Furthermore, the stencil buffer
				1466	value may be updated or modified depending on the outcome.  If
				1467	there is no stencil buffer the stencil test is bypassed.<br>
				1468	<br>
				1469	Stenciling is controlled by the commands<br>
				1470	<br>
				1471	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glStencilFunc</span>(GLenum<span
				1472	style="font-style: italic;">func</span>, GLint <span
				1473	style="font-style: italic;">ref</span>, GLuint <span
				1474	style="font-style: italic;">mask</span>)<br>
				1475	void <span style="font-weight: bold;">glStencilOp</span>(GLenum <span
				1476	style="font-style: italic;">stencilFail</span>, GLenum <span
				1477	style="font-style: italic;">depthTestFail</span>, GLenum <span
				1478	style="font-style: italic;">depthTestPass</span>)<br>
				1479	</div>
				1480	<br>
				1481	The <span style="font-weight: bold;">glStencilFunc<span
				1482	style="font-style: italic;"> </span></span>command controls the
				1483	stencil test while <span style="font-weight: bold;">glStencilOp</span>
				1484	command controls the how the stencil buffer is updated/modified after
				1485	the test.<br>
				1486	<br>
				1487	<span style="font-style: italic;">ref</span> is clamped to the range [0,
				1488	2<sup>N</sup>-1] where N is the number of bits per stencil value in the
				1489	stencil buffer.<span style="font-style: italic;"></span><br>
				1490	<br>
				1491	The following table lists all possible values for the <span
				1492	style="font-style: italic;">func</span> parameter and when the stencil
				1493	test will pass.  Both the stencil buffer value and the stencil
				1494	reference value are bit-wise ANDed with the <span
				1495	style="font-style: italic;">mask</span> parameter before the test.<br>
				1496	<br>
				1497	<span style="font-style: italic;"></span><span
				1498	style="font-style: italic;"></span><span style="font-style: italic;"></span>
				1499	<table
				1500	style="text-align: left; margin-left: auto; margin-right: auto; width: 70%;"
				1501	border="1" cellspacing="2" cellpadding="2">
				1502	<tbody>
				1503	<tr>
				1504	<td style="vertical-align: top;">Stencil <span
				1505	style="font-style: italic;">func</span> value<br>
				1506	</td>
				1507	<td style="vertical-align: top;">Stencil test passes if<br>
				1508	</td>
				1509	</tr>
				1510	<tr>
				1511	<td style="vertical-align: top;">GL_LESS<br>
				1512	</td>
				1513	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>&<span
				1514	style="font-style: italic;">mask)</span> < (stencil buffer value
				1515	& <span style="font-style: italic;">mask)</span><br>
				1516	</td>
				1517	</tr>
				1518	<tr>
				1519	<td style="vertical-align: top;">GL_LEQUAL<br>
				1520	</td>
				1521	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>
				1522	& <span style="font-style: italic;">mask) </span><= (stencil
				1523	buffer value & <span style="font-style: italic;">mask)</span></td>
				1524	</tr>
				1525	<tr>
				1526	<td style="vertical-align: top;">GL_GREATER<br>
				1527	</td>
				1528	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>
				1529	& <span style="font-style: italic;">mask) </span>> (stencil
				1530	buffer value & <span style="font-style: italic;">mask)</span></td>
				1531	</tr>
				1532	<tr>
				1533	<td style="vertical-align: top;">GL_GEQUAL<br>
				1534	</td>
				1535	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>
				1536	& <span style="font-style: italic;">mask) </span>>= (stencil
				1537	buffer value & <span style="font-style: italic;">mask)</span></td>
				1538	</tr>
				1539	<tr>
				1540	<td style="vertical-align: top;">GL_EQUAL<br>
				1541	</td>
				1542	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>
				1543	& <span style="font-style: italic;">mask) </span>== (stencil
				1544	buffer value & <span style="font-style: italic;">mask)</span></td>
				1545	</tr>
				1546	<tr>
				1547	<td style="vertical-align: top;">GL_NOTEQUAL<br>
				1548	</td>
				1549	<td style="vertical-align: top;"><span style="font-style: italic;">(ref</span>
				1550	& <span style="font-style: italic;">mask) </span>!= (stencil
				1551	buffer value & <span style="font-style: italic;">mask)</span></td>
				1552	</tr>
				1553	<tr>
				1554	<td style="vertical-align: top;">GL_NEVER<br>
				1555	</td>
				1556	<td style="vertical-align: top;">never passes<br>
				1557	</td>
				1558	</tr>
				1559	<tr>
				1560	<td style="vertical-align: top;">GL_ALWAYS<br>
				1561	</td>
				1562	<td style="vertical-align: top;">always passes<br>
				1563	</td>
				1564	</tr>
				1565	</tbody>
				1566	</table>
				1567	<br>
				1568	<span style="font-style: italic;"></span><br>
				1569	If the stencil test passes, the fragment is passed to the next
				1570	per-fragment operation.  Otherwise, if the stencil test fails, the
				1571	value in the stencil buffer is updated according to the value of the <span
				1572	style="font-style: italic;">stencilFail</span> parameter to <span
				1573	style="font-weight: bold;">glStencilOp</span>.<br>
				1574	<br>
				1575	<table cellpadding="2" cellspacing="2" border="1"
				1576	style="text-align: left; width: 70%; margin-left: auto; margin-right: auto;">
				1577	<tbody>
				1578	<tr>
				1579	<td style="vertical-align: top;"><span style="font-style: italic;">stencilFail</span>
				1580	value<br>
				1581	</td>
				1582	<td style="vertical-align: top;">New stencil buffer value<br>
				1583	</td>
				1584	</tr>
				1585	<tr>
				1586	<td style="vertical-align: top;">GL_KEEP<br>
				1587	</td>
				1588	<td style="vertical-align: top;">originalValue<br>
				1589	</td>
				1590	</tr>
				1591	<tr>
				1592	<td style="vertical-align: top;">GL_ZERO<br>
				1593	</td>
				1594	<td style="vertical-align: top;">0<br>
				1595	</td>
				1596	</tr>
				1597	<tr>
				1598	<td style="vertical-align: top;">GL_INVERT<br>
				1599	</td>
				1600	<td style="vertical-align: top;">BitWiseInvert(originalValue)
				1601	i.e. ~originalValue<br>
				1602	</td>
				1603	</tr>
				1604	<tr>
				1605	<td style="vertical-align: top;">GL_REPLACE<br>
				1606	</td>
				1607	<td style="vertical-align: top;"><span style="font-style: italic;">ref</span><br>
				1608	</td>
				1609	</tr>
				1610	<tr>
				1611	<td style="vertical-align: top;">GL_INCR<br>
				1612	</td>
				1613	<td style="vertical-align: top;">originalValue + 1, clamped to
				1614	[0, 2<sup>N</sup>-1]</td>
				1615	</tr>
				1616	<tr>
				1617	<td style="vertical-align: top;">GL_DECR<br>
				1618	</td>
				1619	<td style="vertical-align: top;">originalValue - 1, clamped to
				1620	[0, 2<sup>N</sup>-1]</td>
				1621	</tr>
				1622	</tbody>
				1623	</table>
				1624	<span style="font-style: italic;"></span><span
				1625	style="font-style: italic;"></span><br>
				1626	<br>
				1627	The <span style="font-style: italic;">depthTestFail</span> and <span
				1628	style="font-style: italic;">depthTestPass</span> parameters to <span
				1629	style="font-weight: bold;">glStencilOp</span> are ignored.  Values
				1630	for <span style="font-style: italic;">func</span> and <span
				1631	style="font-style: italic;">stencilFail</span> other than those listed
				1632	in the table will cause the error GL_INVALID_ENUM to be raised.<br>
				1633	<br>
				1634	The stencil test is enabled and disabled with the commands <span
				1635	style="font-weight: bold;">glEnable</span>(GL_STENCIL_TEST) and <span
				1636	style="font-weight: bold;">glDisable</span>(GL_STENCIL_TEST).<br>
				1637	<br>
				1638	The default stencil function is GL_ALWAYS.  The default stencil
				1639	reference value is 0.  The default stencil mask is ~0.  The
				1640	default stencil fail operation is GL_KEEP.<br>
				1641	<br>
				1642	Values written into the stencil buffer are masked with the command<br>
				1643	<br>
				1644	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glStencilMask</span>(GLuint<span
				1645	style="font-style: italic;">mask</span>)<br>
				1646	</div>
				1647	<br>
				1648	Only the bits which are set in <span style="font-style: italic;">mask</span>
				1649	will be modified in the stencil buffer when written to.  If each
				1650	stencil buffer value has N bits, only the least significant N bits of <span
				1651	style="font-style: italic;">mask</span> are relevant.  The default
				1652	stencil mask is ~0.<br>
				1653	<br>
				1654	<h2>6.4 Blending and Logicop</h2>
				1655	Blending or a logic operation combines the incoming fragment color with
				1656	the destination frame buffer color according to a blending equation or
				1657	bit-wise Boolean logical operation.<br>
				1658	<br>
				1659	Blending is enabled and disabled with the commands <span
				1660	style="font-weight: bold;">glEnable</span>(GL_BLEND) and <span
				1661	style="font-weight: bold;">glDisable</span>(GL_BLEND).<br>
				1662	<br>
				1663	The logic operation is enabled and disabled with the commands <span
				1664	style="font-weight: bold;">glEnable</span>(GL_LOGIC_OP) and <span
				1665	style="font-weight: bold;">glDisable</span>(GL_LOGIC_OP).<br>
				1666	<br>
				1667	If both blending and the logic operation are enabled, the logic
				1668	operation has higher priority; blending is bypassed.<br>
				1669	<br>
				1670	<h3>6.4.1 Logic Op</h3>
				1671	The command<br>
				1672	<br>
				1673	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glLogicop</span>(GLenum<span
				1674	style="font-style: italic;">mode</span>)<br>
				1675	<br>
				1676	</div>
				1677	Specifies the Boolean logic operation for combining the incoming
				1678	fragment color with the destination frame buffer color.  Both the
				1679	incoming fragment color and destination frame buffer colors are
				1680	interpreted as four-tuples of unsigned integer color components in the
				1681	range [0, 2<sup>N</sup>-1] where N is the number of bits per color
				1682	channel.  N may not be the same for all color channels.<br>
				1683	<br>
				1684	The following table lists all values for <span
				1685	style="font-style: italic;">mode</span> and the boolean arithmetic used
				1686	to combine the incoming fragment color value (src)<span
				1687	style="font-style: italic;"></span><span style="font-style: italic;"></span><span
				1688	style="font-style: italic;"></span><span style="font-style: italic;"></span><span
				1689	style="font-style: italic;"></span> with the destination framebuffer
				1690	color value (dst).  Standard ANSI C operators used.<br>
				1691	<br>
				1692	<table cellpadding="2" cellspacing="2" border="1"
				1693	style="text-align: left; width: 50%; margin-left: auto; margin-right: auto;">
				1694	<tbody>
				1695	<tr>
				1696	<td style="vertical-align: top;">LogicOp <span
				1697	style="font-style: italic;">mode</span><br>
				1698	</td>
				1699	<td style="vertical-align: top;">Resulting channel value<br>
				1700	</td>
				1701	</tr>
				1702	<tr>
				1703	<td style="vertical-align: top;">GL_CLEAR<br>
				1704	</td>
				1705	<td style="vertical-align: top;">0<br>
				1706	</td>
				1707	</tr>
				1708	<tr>
				1709	<td style="vertical-align: top;">GL_SET<br>
				1710	</td>
				1711	<td style="vertical-align: top;">~0<br>
				1712	</td>
				1713	</tr>
				1714	<tr>
				1715	<td style="vertical-align: top;">GL_COPY<br>
				1716	</td>
				1717	<td style="vertical-align: top;">src<br>
				1718	</td>
				1719	</tr>
				1720	<tr>
				1721	<td style="vertical-align: top;">GL_COPY_INVERTED<br>
				1722	</td>
				1723	<td style="vertical-align: top;">~s<br>
				1724	</td>
				1725	</tr>
				1726	<tr>
				1727	<td style="vertical-align: top;">GL_NOOP<br>
				1728	</td>
				1729	<td style="vertical-align: top;">dst<br>
				1730	</td>
				1731	</tr>
				1732	<tr>
				1733	<td style="vertical-align: top;">GL_INVERT<br>
				1734	</td>
				1735	<td style="vertical-align: top;">~dst<br>
				1736	</td>
				1737	</tr>
				1738	<tr>
				1739	<td style="vertical-align: top;">GL_AND<br>
				1740	</td>
				1741	<td style="vertical-align: top;">src & dst<br>
				1742	</td>
				1743	</tr>
				1744	<tr>
				1745	<td style="vertical-align: top;">GL_NAND<br>
				1746	</td>
				1747	<td style="vertical-align: top;">~(src & dst)<br>
				1748	</td>
				1749	</tr>
				1750	<tr>
				1751	<td style="vertical-align: top;">GL_AND_REVERSE<br>
				1752	</td>
				1753	<td style="vertical-align: top;">src & ~dst<br>
				1754	</td>
				1755	</tr>
				1756	<tr>
				1757	<td style="vertical-align: top;">GL_AND_INVERTED<br>
				1758	</td>
				1759	<td style="vertical-align: top;">~src & dst<br>
				1760	</td>
				1761	</tr>
				1762	<tr>
				1763	<td style="vertical-align: top;">GL_OR<br>
				1764	</td>
				1765	<td style="vertical-align: top;">src \| dst<br>
				1766	</td>
				1767	</tr>
				1768	<tr>
				1769	<td style="vertical-align: top;">GL_NOR<br>
				1770	</td>
				1771	<td style="vertical-align: top;">~(src \| dst)<br>
				1772	</td>
				1773	</tr>
				1774	<tr>
				1775	<td style="vertical-align: top;">GL_OR_REVERSE<br>
				1776	</td>
				1777	<td style="vertical-align: top;">src \| ~dst<br>
				1778	</td>
				1779	</tr>
				1780	<tr>
				1781	<td style="vertical-align: top;">GL_OR_INVERTED<br>
				1782	</td>
				1783	<td style="vertical-align: top;">~src \| dst<br>
				1784	</td>
				1785	</tr>
				1786	<tr>
				1787	<td style="vertical-align: top;">GL_XOR<br>
				1788	</td>
				1789	<td style="vertical-align: top;">src ^ dst<br>
				1790	</td>
				1791	</tr>
				1792	<tr>
				1793	<td style="vertical-align: top;">GL_EQUIV<br>
				1794	</td>
				1795	<td style="vertical-align: top;">~(src ^ dst)<br>
				1796	</td>
				1797	</tr>
				1798	</tbody>
				1799	</table>
				1800	<br>
				1801	The fragment's color is replaced by the result of the logic operation.<br>
				1802	<br>
				1803	Specifying any value for <span style="font-style: italic;">mode</span>
				1804	other than those listed in the above table will cause the error
				1805	GL_INVALID_ENUM to be raised.<br>
				1806	<br>
				1807	The default value for <span style="font-style: italic;">mode</span> is
				1808	GL_COPY.  The logic operation is disabled by default.<br>
				1809	<br>
				1810	<h3>6.4.2 Blending</h3>
				1811	The command<br>
				1812	<br>
				1813	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glBlendFunc</span>(GLenum<span
				1814	style="font-style: italic;">srcTerm</span>, GLenum <span
				1815	style="font-style: italic;">dstTerm</span>)<br>
				1816	</div>
				1817	<br>
				1818	specifies the terms of the blending equation.  If Cf = (Rf, Gf,
				1819	Bf, Af) is the incoming fragment color and Cb = (Rb, Gb, Bb, Ab) is the
				1820	frame buffer color, then the resulting color Cv = (Rv, Gv, Bv, Av) is
				1821	computed by:<br>
				1822	<br>
				1823	<div style="margin-left: 40px;">Cv = Cf * <span
				1824	style="font-style: italic;">srcTerm</span> + Cb * <span
				1825	style="font-style: italic;">dstTerm</span><br>
				1826	<span style="font-style: italic;"></span></div>
				1827	<span style="font-style: italic;"> </span><br>
				1828	All possible values for <span style="font-style: italic;">srcTerm</span>
				1829	and the corresponding arithmetic term are listed in the following table:<br>
				1830	<br>
				1831	<table cellpadding="2" cellspacing="2" border="1"
				1832	style="text-align: left; width: 70%; margin-left: auto; margin-right: auto;">
				1833	<tbody>
				1834	<tr>
				1835	<td style="vertical-align: top;"><span style="font-style: italic;">srcTerm</span><br>
				1836	</td>
				1837	<td style="vertical-align: top;"><span style="font-style: italic;">srcTerm</span>Arithmetic<br>
				1838	</td>
				1839	</tr>
				1840	<tr>
				1841	<td style="vertical-align: top;">GL_ZERO<br>
				1842	</td>
				1843	<td style="vertical-align: top;">(0, 0, 0, 0)<br>
				1844	</td>
				1845	</tr>
				1846	<tr>
				1847	<td style="vertical-align: top;">GL_ONE<br>
				1848	</td>
				1849	<td style="vertical-align: top;">(1, 1, 1, 1)<br>
				1850	</td>
				1851	</tr>
				1852	<tr>
				1853	<td style="vertical-align: top;">GL_DST_COLOR<br>
				1854	</td>
				1855	<td style="vertical-align: top;">(Rb, Gb, Bb, Ab)<br>
				1856	</td>
				1857	</tr>
				1858	<tr>
				1859	<td style="vertical-align: top;">GL_ONE_MINUS_DST_COLOR<br>
				1860	</td>
				1861	<td style="vertical-align: top;">(1-Rb, 1-Gb, 1-Bb, 1-Ab)<br>
				1862	</td>
				1863	</tr>
				1864	<tr>
				1865	<td style="vertical-align: top;">GL_SRC_ALPHA<br>
				1866	</td>
				1867	<td style="vertical-align: top;">(Af, Af, Af, AF)<br>
				1868	</td>
				1869	</tr>
				1870	<tr>
				1871	<td style="vertical-align: top;">GL_ONE_MINUS_SRC_ALPHA<br>
				1872	</td>
				1873	<td style="vertical-align: top;">(1-Af, 1-Af, 1-Af, 1-Af)<br>
				1874	</td>
				1875	</tr>
				1876	<tr>
				1877	<td style="vertical-align: top;">GL_DST_ALPHA<br>
				1878	</td>
				1879	<td style="vertical-align: top;">(Ab, Ab, Ab, Ab)<br>
				1880	</td>
				1881	</tr>
				1882	<tr>
				1883	<td style="vertical-align: top;">GL_ONE_MINUS_DST_ALPHA<br>
				1884	</td>
				1885	<td style="vertical-align: top;">(1-Ab, 1-Ab, 1-Ab, 1-Ab)<br>
				1886	</td>
				1887	</tr>
				1888	<tr>
				1889	<td style="vertical-align: top;">GL_SRC_ALPHA_SATURATE<br>
				1890	</td>
				1891	<td style="vertical-align: top;">(m, m, m, 1) where m = MIN(Af,
				1892	1-Ab)<br>
				1893	</td>
				1894	</tr>
				1895	</tbody>
				1896	</table>
				1897	<br>
				1898	All possible values for <span style="font-style: italic;">srcTerm</span>
				1899	and the corresponding arithmetic term are listed in the following table:<br>
				1900	<br>
				1901	<table cellpadding="2" cellspacing="2" border="1"
				1902	style="text-align: left; width: 70%; margin-left: auto; margin-right: auto;">
				1903	<tbody>
				1904	<tr>
				1905	<td style="vertical-align: top;"><span style="font-style: italic;">dstTerm</span><br>
				1906	</td>
				1907	<td style="vertical-align: top;"><span style="font-style: italic;">dstTerm</span>Arithmetic<br>
				1908	</td>
				1909	</tr>
				1910	<tr>
				1911	<td style="vertical-align: top;">GL_ZERO<br>
				1912	</td>
				1913	<td style="vertical-align: top;">(0, 0, 0, 0)<br>
				1914	</td>
				1915	</tr>
				1916	<tr>
				1917	<td style="vertical-align: top;">GL_ONE<br>
				1918	</td>
				1919	<td style="vertical-align: top;">(1, 1, 1, 1)<br>
				1920	</td>
				1921	</tr>
				1922	<tr>
				1923	<td style="vertical-align: top;">GL_SRC_COLOR<br>
				1924	</td>
				1925	<td style="vertical-align: top;">(Rf, Gf, Bf, Af)<br>
				1926	</td>
				1927	</tr>
				1928	<tr>
				1929	<td style="vertical-align: top;">GL_ONE_MINUS_SRC_COLOR<br>
				1930	</td>
				1931	<td style="vertical-align: top;">(1-Rf, 1-Gf, 1-Bf, 1-Af)<br>
				1932	</td>
				1933	</tr>
				1934	<tr>
				1935	<td style="vertical-align: top;">GL_SRC_ALPHA<br>
				1936	</td>
				1937	<td style="vertical-align: top;">(Af, Af, Af, AF)<br>
				1938	</td>
				1939	</tr>
				1940	<tr>
				1941	<td style="vertical-align: top;">GL_ONE_MINUS_SRC_ALPHA<br>
				1942	</td>
				1943	<td style="vertical-align: top;">(1-Af, 1-Af, 1-Af, 1-Af)<br>
				1944	</td>
				1945	</tr>
				1946	<tr>
				1947	<td style="vertical-align: top;">GL_DST_ALPHA<br>
				1948	</td>
				1949	<td style="vertical-align: top;">(Ab, Ab, Ab, Ab)<br>
				1950	</td>
				1951	</tr>
				1952	<tr>
				1953	<td style="vertical-align: top;">GL_ONE_MINUS_DST_ALPHA<br>
				1954	</td>
				1955	<td style="vertical-align: top;">(1-Ab, 1-Ab, 1-Ab, 1-Ab)<br>
				1956	</td>
				1957	</tr>
				1958	</tbody>
				1959	</table>
				1960	<br>
				1961	The fragment's color is replaced by the result of the blending equation.<br>
				1962	<br>
				1963	Values for <span style="font-style: italic;">srcTerm</span> and <span
				1964	style="font-style: italic;">dstTerm</span> other than those listed in
				1965	the table will cause the error GL_INVALID_ENUM to be raised.<br>
				1966	<br>
				1967	The default value for <span style="font-style: italic;">srcTerm</span>
				1968	is GL_ONE.  The default value for <span style="font-style: italic;">dstTerm</span>
				1969	is GL_ZERO.  Blending is disabled by default.<br>
				1970	<br>
				1971	<h2>6.5 Color Mask</h2>
				1972	The final fragment color is written into the current color buffer at
				1973	the end of the per-fragment operations.  Normally, all color
				1974	channels in the frame buffer are replaced with the final fragment color.
				1975	However, the command<br>
				1976	<br>
				1977	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glColorMask</span>(GLboolean<span
				1978	style="font-style: italic;">redMask</span>, GLboolean <span
				1979	style="font-style: italic;">greenMask</span>, GLboolean <span
				1980	style="font-style: italic;">blueMask</span>, GLboolean <span
				1981	style="font-style: italic;">alphaMask</span>)<br>
				1982	</div>
				1983	<br>
				1984	allows selective writing to individual color channels.  If <span
				1985	style="font-style: italic;">redMask</span> is GL_TRUE then writing to
				1986	the red color channel is enabled, otherwise it's disabled.
				1987	Similarly, the green, blue and alpha channels can also be masked.<br>
				1988	<br>
				1989	Initially all four mask values are GL_TRUE.<br>
				1990	<br>
				1991	Color masking is not enabled/disabled with the <span
				1992	style="font-weight: bold;">glEnable</span>/<span
				1993	style="font-weight: bold;">glDisable</span> commands.<br>
				1994	<br>
				1995	<h1>7. Frame Buffer Operations</h1>
				1996	The frame buffer is considered to be a two-dimensional array of pixels.
				1997	The frame buffer is also organized into layers or logical buffers.
				1998	There may be a front color buffer, back color buffer and stencil
				1999	buffer.  A double-buffered frame buffer has both a front color
				2000	buffer and back color buffer.  A single-buffered framebuffer only
				2001	has a front color buffer.  Each pixel in a color buffer has a red,
				2002	green and blue value and an optional alpha value.<br>
				2003	<br>
				2004	<h2>7.1 Clearing Buffers</h2>
				2005	Buffers are cleared (set to uniform values) with the command<br>
				2006	<br>
				2007	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glClear</span>(GLbitfield<span
				2008	style="font-style: italic;">buffers</span>)<br>
				2009	</div>
				2010	<br>
				2011	<span style="font-style: italic;">buffers</span> is a bitmask for which
				2012	the value may be the bitwise-OR of the values GL_COLOR_BUFFER_BIT and
				2013	GL_STENCIL_BUFFER_BIT.  If the GL_COLOR_BUFFER_BIT bit is
				2014	specified, the current color buffer will be cleared.  If the
				2015	GL_STENCIL_BUFFER_BIT bit is specified, the stencil buffer will be
				2016	cleared.<br>
				2017	<br>
				2018	The current color buffer is specified with the command<br>
				2019	<br>
				2020	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glDrawBuffer</span>(GLenum<span
				2021	style="font-style: italic;"> buffer</span>)<br>
				2022	</div>
				2023	<br>
				2024	<span style="font-style: italic;">buffer</span> may be either GL_FRONT,
				2025	GL_BACK or GL_NONE.  GL_FRONT indicates that the front color buffer
				2026	will be modified by <span style="font-weight: bold;">glClear</span> and
				2027	any drawing command.  GL_BACK indicates that the back color buffer
				2028	will be modified by <span style="font-weight: bold;">glClear</span> and
				2029	any drawing command.  GL_NONE indicates that neither color buffer
				2030	will be modified by <span style="font-weight: bold;">glClear</span> or
				2031	any drawing command.  GL_BACK is only valid for double-buffered
				2032	frame buffers.<br>
				2033	<br>
				2034	The current scissor rectangle, set by the <span
				2035	style="font-weight: bold;">glScissor</span> command, effects <span
				2036	style="font-weight: bold;">glClear</span><span
				2037	style="font-style: italic;">,</span><span style="font-style: italic;"> </span>limiting
				2038	the clear to the scissor rectangle, if it's enabled.  Furthermore, <span
				2039	style="font-weight: bold;"></span>only the color channels enabled by <span
				2040	style="font-weight: bold;">glColorMask</span> will be effected by <span
				2041	style="font-weight: bold;">glClear</span>(GL_COLOR_BUFFER_BIT).
				2042	Likewise, only the stencil bits enabled by <span
				2043	style="font-weight: bold;">glStencilMask</span> will be effected by <span
				2044	style="font-weight: bold;">glClear</span>(GL_STENCIL_BUFFER_BIT).<br>
				2045	<br>
				2046	The current clear color is set with the command<br>
				2047	<br>
				2048	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glClearColor</span>(GLclampf<span
				2049	style="font-style: italic;">red</span>, GLclampf <span
				2050	style="font-style: italic;">green</span>, GLclampf <span
				2051	style="font-style: italic;">blue</span>, GLclampf <span
				2052	style="font-style: italic;">alpha</span>)<br>
				2053	</div>
				2054	<br>
				2055	Subsequent calls to <span style="font-weight: bold;">glClear</span>
				2056	will use the color (<span style="font-style: italic;">red, green, blue,
				2057	alpha</span>) to clear the front or back color buffers.<br>
				2058	<span style="font-style: italic;"></span><br>
				2059	The current stencil clear value is set with the command<br>
				2060	<br>
				2061	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glClearStencil</span>(GLint<span
				2062	style="font-style: italic;">clearValue</span>)<br>
				2063	</div>
				2064	<br>
				2065	If the stencil buffer is N bits deep, the least significant N bits of <span
				2066	style="font-style: italic;">clearValue</span> will be used to clear the
				2067	stencil buffer.<br>
				2068	<br>
				2069	<br>
				2070	<h1>8. Other Features</h1>
				2071	<h2>8.1 Frame Buffer Readback</h2>
				2072	A rectangular region of pixels can be read from the frame buffer and
				2073	placed in client memory with the command<br>
				2074	<br>
				2075	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glReadPixels</span>(GLint<span
				2076	style="font-style: italic;">x</span>, GLint <span
				2077	style="font-style: italic;">y</span>, GLsizei <span
				2078	style="font-style: italic;">width</span>, GLsizei <span
				2079	style="font-style: italic;">height</span>, GLenum <span
				2080	style="font-style: italic;">format</span>, GLenum <span
				2081	style="font-style: italic;">type</span>, GLvoid *<span
				2082	style="font-style: italic;">data</span>)<br>
				2083	</div>
				2084	<br>
				2085	<span style="font-style: italic;">x</span> and <span
				2086	style="font-style: italic;">y</span> specify the coordinate of the
				2087	lower-left corner of the region to read and <span
				2088	style="font-style: italic;">width</span> and <span
				2089	style="font-style: italic;">height</span> specify the size of the
				2090	rectangular region to read.  <span style="font-style: italic;">format</span>
				2091	specifies the format of image data and must be either GL_RGB or
				2092	GL_RGBA.  <span style="font-style: italic;">type</span> specify the
				2093	data type of the image data and must be either GL_UNSIGNED_BYTE or
				2094	GL_FLOAT.  Other values for <span style="font-style: italic;">format</span>
				2095	or <span style="font-style: italic;">type</span> will cause the error
				2096	GL_INVALID_ENUM to be raised.<br>
				2097	<br>
				2098	The framebuffer may contain 3-component colors (red, green, blue) or
				2099	4-component colors (red, green, blue, alpha).  If an alpha channel
				2100	is not present, alpha values default to 1.0.<br>
				2101	<br>
				2102	The frame buffer color components (red, green, blue, alpha) are either
				2103	converted to 8-bit unsigned integers in the range[0, 255] if <span
				2104	style="font-style: italic;">type </span>is GL_UNSIGNED_BYTE or
				2105	converted to floating point values in the range [0, 1] if <span
				2106	style="font-style: italic;">type</span> is GL_FLOAT.  The (red,
				2107	green, blue, alpha) tuples are then stored as GL_RGB triplets (by
				2108	dropping the alpha component) or GL_RGBA quadruples in client memory.<br>
				2109	<br>
				2110	Image data is <span style="font-style: italic;">packed</span> into
				2111	client memory according to the pixel packing parameters which are set by
				2112	the command<br>
				2113	<br>
				2114	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glPixelStorei</span>(GLenum<span
				2115	style="font-style: italic;"> pname</span>, GLint <span
				2116	style="font-style: italic;">value</span>)<br>
				2117	</div>
				2118	<br>
				2119	<span style="font-style: italic;">pname</span> must be
				2120	GL_PACK_ROW_LENGTH.  <span style="font-style: italic;">value</span>
				2121	indicates the stride (in pixels) between subsequent rows in the
				2122	destination image.  If GL_PACK_ROW_LENGTH is zero (the default)
				2123	then the <span style="font-style: italic;">width</span> parameter to <span
				2124	style="font-weight: bold;">glReadPixels</span> indicates the row stride.<br>
				2125	<br>
				2126	Pixel readback takes place as follows:<br>
				2127	<br>
				2128	<div style="margin-left: 40px;">if (GL_PACK_ROW_LENGTH == 0)<br>
				2129	rowLength = <span style="font-style: italic;">width</span>;<br>
				2130	else<br>
				2131	rowLength = GL_PACK_ROW_LENGTH<br>
				2132	<br>
				2133	if (<span style="font-style: italic;">format</span> == GL_RGB) {<br>
				2134	for (i = 0; i < <span style="font-style: italic;">height</span>;
				2135	i++) {<br>
				2136	for (j = 0; j < <span
				2137	style="font-style: italic;">width</span>; j++) {<br>
				2138	k = (i *
				2139	rowLength + j) * 3;<br>
				2140	<span
				2141	style="font-style: italic;">data</span>[k+0] = FrameBuffer(<span
				2142	style="font-style: italic;">x</span> + j, <span
				2143	style="font-style: italic;">y</span> + i).red;<br>
				2144	<span
				2145	style="font-style: italic;">data</span>[k+1] = FrameBuffer(<span
				2146	style="font-style: italic;">x</span> + j, <span
				2147	style="font-style: italic;">y</span> + i).green;<br>
				2148	<span
				2149	style="font-style: italic;">data</span>[k+2] = FrameBuffer(<span
				2150	style="font-style: italic;">x</span> + j, <span
				2151	style="font-style: italic;">y</span> + i).blue;<span
				2152	style="font-style: italic;"></span><br>
				2153	}<br>
				2154	}<br>
				2155	}<br>
				2156	else {<br>
				2157	for (i = 0; i < <span style="font-style: italic;">height</span>;
				2158	i++) {<br>
				2159	for (j = 0; j < <span
				2160	style="font-style: italic;">width</span>; j++) {<br>
				2161	k = (i *
				2162	rowLength + j) * 4;<br>
				2163	<span
				2164	style="font-style: italic;">data</span>[k+0] = FrameBuffer(<span
				2165	style="font-style: italic;">x</span> + j, <span
				2166	style="font-style: italic;">y</span> + i).red;<br>
				2167	<span
				2168	style="font-style: italic;">data</span>[k+1] = FrameBuffer(<span
				2169	style="font-style: italic;">x</span> + j, <span
				2170	style="font-style: italic;">y</span> + i).green;<br>
				2171	<span
				2172	style="font-style: italic;">data</span>[k+2] = FrameBuffer(<span
				2173	style="font-style: italic;">x</span> + j, <span
				2174	style="font-style: italic;">y</span> + i).blue;<span
				2175	style="font-style: italic;"></span><br>
				2176	<span
				2177	style="font-style: italic;">data</span>[k+3] = FrameBuffer(<span
				2178	style="font-style: italic;">x</span> + j, <span
				2179	style="font-style: italic;">y</span> + i).alpha;<span
				2180	style="font-style: italic;"></span><br>
				2181	}<br>
				2182	}<br>
				2183	}<br>
				2184	</div>
				2185	<br>
				2186	The function FrameBuffer(<span style="font-style: italic;">c, r</span>)
				2187	returns the pixel in the frame buffer at column <span
				2188	style="font-style: italic;">c</span> of row <span
				2189	style="font-style: italic;">r.  </span><span
				2190	style="font-style: italic;">data</span> is considered to be either a
				2191	GLubyte pointer or a GLfloat pointer, depending on the <span
				2192	style="font-style: italic;">type</span> parameter.  Similarly, the
				2193	FrameBuffer function returns either GLubyte values in the range [0, 255]
				2194	or GLfloat values in the range [0,1], depending on the <span
				2195	style="font-style: italic;">type</span> parameter.<br>
				2196	<br>
				2197	Pixels may be read from either the front or back color buffer.
				2198	The command<br>
				2199	<br>
				2200	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glReadBuffer</span>(GLenum<span
				2201	style="font-style: italic;">buffer</span>)<br>
				2202	</div>
				2203	<br>
				2204	specifies the source for reading images with <span
				2205	style="font-weight: bold;">glReadPixels</span>.  If <span
				2206	style="font-style: italic;">buffer</span> is GL_FRONT then front color
				2207	buffer is the source.  If <span style="font-style: italic;">buffer</span>
				2208	is GL_BACK then the back color buffer is the source.  It is illegal
				2209	to specify GL_BACK when the color buffer is not double buffered.
				2210	Any invalid value for <span style="font-style: italic;">buffer</span>
				2211	will raise the error GL_INVALID_ENUM.<br>
				2212	<br>
				2213	The default read source is GL_BACK if the frame buffer is double
				2214	buffered.  Otherwise, the default read source is GL_FRONT.<br>
				2215	<br>
				2216	<h2>8.2 Selection Mode</h2>
				2217	Selection mode is typically used to implement <span
				2218	style="font-style: italic;">picking</span>: determining which
				2219	primitive(s) are present at particular window positions.  The
				2220	command<br>
				2221	<br>
				2222	<div style="margin-left: 40px;">GLint <span style="font-weight: bold;">glRenderMode</span>(GLenum<span
				2223	style="font-style: italic;">mode</span>)<br>
				2224	</div>
				2225	<br>
				2226	is used to enable selection mode.  If <span
				2227	style="font-style: italic;">mode</span> is GL_SELECTION the graphics
				2228	library is put into selection mode.  If <span
				2229	style="font-style: italic;">mode</span> is GL_RENDER the graphic
				2230	library is put into normal rendering mode.  Any other value for <span
				2231	style="font-style: italic;">mode</span> will raise the error
				2232	GL_INVALID_ENUM.<br>
				2233	<br>
				2234	When in selection mode rendering commands will not effect the
				2235	framebuffer.  Instead, a record of the primitives that would have
				2236	been drawn is placed in the <span style="font-style: italic;">selection</span> <span
				2237	style="font-style: italic;">buffer</span>.  The selection buffer
				2238	is specified with the command<br>
				2239	<br>
				2240	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glSelectionBuffer</span>(GLsizei<span
				2241	style="font-style: italic;">n</span>, GLuint *<span
				2242	style="font-style: italic;">buffer</span>)<br>
				2243	</div>
				2244	<span style="font-style: italic;"></span><span
				2245	style="font-style: italic;"><br>
				2246	buffer</span> is an array of <span style="font-style: italic;">n</span>
				2247	unsigned integers.  No more than <span style="font-style: italic;">n</span>
				2248	values will be placed in the buffer.<br>
				2249	<br>
				2250	The <span style="font-style: italic;">name stack</span> is a stack
				2251	(LIFO) of unsigned integer names.  The following commands
				2252	manipulate the name stack:<br>
				2253	<br>
				2254	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glInitNames</span>(void)<br>
				2255	void <span style="font-weight: bold;">glPushName</span>(GLuint <span
				2256	style="font-style: italic;">name</span>)<br>
				2257	void <span style="font-weight: bold;">glPopName</span>(void)<br>
				2258	void <span style="font-weight: bold;">glLoadName</span>(GLuint <span
				2259	style="font-style: italic;">name</span>)<br>
				2260	</div>
				2261	<br>
				2262	<span style="font-weight: bold;">glInitNames</span> resets the name
				2263	stack to an empty state.  <span style="font-weight: bold;">glPushName<span
				2264	style="font-style: italic;"> </span></span>pushes the given <span
				2265	style="font-style: italic;">name</span> value onto the stack.  <span
				2266	style="font-weight: bold;">glPopName</span> pops the top name from the
				2267	stack.  <span style="font-weight: bold;">glLoadName<span
				2268	style="font-style: italic;"> </span></span>replaces the top value on
				2269	the stack with the specified <span style="font-style: italic;">name</span>.
				2270	Stack underflow and overflow conditions cause the errors
				2271	GL_STACK_OVERFLOW and GL_STACK_UNDERFLOW to be raised.<br>
				2272	<br>
				2273	While in selection mode, primitives (points, lines, polygons) are
				2274	transformed and clip-tested normally.  Primitives which aren't
				2275	discarded by clipping cause the <span style="font-style: italic;">hit</span> <span
				2276	style="font-style: italic;">data</span> to be updated.  The hit
				2277	data consists of three pieces of information: a hit flag, a minimum Z
				2278	value and a maximum Z value.  First, the hit flag is set.
				2279	Then, for each of the primitive's vertices, the vertex Z value is
				2280	compared to the minimum and maximum Z values.  The minimum Z value
				2281	is updated if the vertex's Z value is less than the minimum Z value.
				2282	The maximum Z value is updated if the vertex's Z value is greater
				2283	than the maximum Z value.<br>
				2284	<br>
				2285	When any of <span style="font-weight: bold;">glInitNames</span><span
				2286	style="font-style: italic;"><span style="font-style: italic;">, </span></span><span
				2287	style="font-weight: bold;">glPushName</span>, <span
				2288	style="font-weight: bold;">glPopName</span>, <span
				2289	style="font-weight: bold;">glLoadName</span> or <span
				2290	style="font-weight: bold;">glRenderMode</span> are called and the hit
				2291	flag is set, a <span style="font-style: italic;">hit record</span> is
				2292	written to the selection buffer.<br>
				2293	<br>
				2294	A hit record consists of a sequence of unsigned integers.  The
				2295	first value is the size of the name stack.  The second value is the
				2296	minimum Z value multiplied by 2<sup>32</sup>-1.  The third value is
				2297	the maximum Z value multiplied by 2<sup>32</sup>-1.  The remaining
				2298	values are the values in the name stack, in bottom to top order.
				2299	The hit flag is cleared after a hit record is written to the
				2300	selection buffer.  Hit records are places sequentially into the
				2301	selection buffer until it is full or selection mode is terminated.<br>
				2302	<br>
				2303	Selection mode is terminated by calling <span
				2304	style="font-weight: bold;">glRenderMode</span>(GL_RENDER).   The
				2305	return value of <span style="font-weight: bold;">glRenderMode</span>
				2306	will be -1 if the selection buffer overflowed.  Otherwise, the
				2307	return value will indicate the number of values written into the
				2308	selection buffer.<br>
				2309	<br>
				2310	<h2>8.3 Synchronization</h2>
				2311	The command<br>
				2312	<br>
				2313	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glFlush</span>(void)<br>
				2314	</div>
				2315	<br>
				2316	makes the graphics library to flush all pending graphics commands.
				2317	The command<br>
				2318	<div style="margin-left: 40px;"><br>
				2319	void <span style="font-weight: bold;">glFinish</span>(void)<br>
				2320	</div>
				2321	<br>
				2322	makes the graphics library flush the command queue and wait until those
				2323	commands are completed.  <span style="font-weight: bold;">glFlush</span>
				2324	will not return until all previous graphics commands have been fully
				2325	completed.<br>
				2326	<br>
				2327	These commands are typically used to force completion of rendering to
				2328	the front color buffer.  Otherwise, rendering to the front color
				2329	buffer may not appear.  The <span style="font-style: italic;">swapbuffers</span>
				2330	command (part of the window system binding library) does an implicit
				2331	flush before swapping the front and back color buffers.  The <span
				2332	style="font-weight: bold;">glReadPixels</span> command also does an
				2333	implicit flush before reading pixel data from the frame buffer.<br>
				2334	<br>
				2335	<h1>9. State Queries</h1>
				2336	The current value of nearly all library state variables can be queried.
				2337	This chapter describes the commands used for querying the value of
				2338	state variables.<br>
				2339	<br>
				2340	<h2>9.1 General State Queries</h2>
				2341	The command<br>
				2342	<br>
				2343	<div style="margin-left: 40px;">void <span style="font-weight: bold;">glGetFloatv</span>(GLenum<span
				2344	style="font-style: italic;">pname</span>, GLfloat *<span
				2345	style="font-style: italic;">values</span>)<br>
				2346	</div>
				2347	<br>
				2348	returns the value(s) of the state variable specified by <span
				2349	style="font-style: italic;">pname</span>.  The following table
				2350	lists all accepted values for <span style="font-style: italic;">pname</span>
				2351	and a description of the value(s).  Specifying any other value for <span
				2352	style="font-style: italic;">pname</span> causes the error
				2353	GL_INVALID_ENUM to be raised.<br>
				2354	<br>
				2355	<table cellpadding="2" cellspacing="2" border="1"
				2356	style="text-align: left; width: 90%; margin-left: auto; margin-right: auto;">
				2357	<tbody>
				2358	<tr>
				2359	<td style="vertical-align: top;">Variable (<span
				2360	style="font-style: italic;">pname)</span><br>
				2361	</td>
				2362	<td style="vertical-align: top;">Number of values<br>
				2363	</td>
				2364	<td style="vertical-align: top;">Value(s) Description<br>
				2365	</td>
				2366	</tr>
				2367	<tr>
				2368	<td style="vertical-align: top;">GL_ALPHA_BITS<br>
				2369	</td>
				2370	<td style="vertical-align: top;">1<br>
				2371	</td>
				2372	<td style="vertical-align: top;">Number of bits per alpha value
				2373	in the frame buffer.<br>
				2374	</td>
				2375	</tr>
				2376	<tr>
				2377	<td style="vertical-align: top;">GL_ALPHA_TEST<br>
				2378	</td>
				2379	<td style="vertical-align: top;">1<br>
				2380	</td>
				2381	<td style="vertical-align: top;">Zero if the alpha test is
				2382	disabled.<br>
				2383	One if the alpha test is enabled.<br>
				2384	</td>
				2385	</tr>
				2386	<tr>
				2387	<td style="vertical-align: top;">GL_ALPHA_TEST_FUNC<br>
				2388	</td>
				2389	<td style="vertical-align: top;">1<br>
				2390	</td>
				2391	<td style="vertical-align: top;">The alpha test function.<br>
				2392	</td>
				2393	</tr>
				2394	<tr>
				2395	<td style="vertical-align: top;">GL_BLEND<br>
				2396	</td>
				2397	<td style="vertical-align: top;">1<br>
				2398	</td>
				2399	<td style="vertical-align: top;">Zero if blending is disabled.<br>
				2400	One if blending is enabled.<br>
				2401	</td>
				2402	</tr>
				2403	<tr>
				2404	<td style="vertical-align: top;">GL_BLEND_DST<br>
				2405	</td>
				2406	<td style="vertical-align: top;">1<br>
				2407	</td>
				2408	<td style="vertical-align: top;">Blend destination function/term.<br>
				2409	</td>
				2410	</tr>
				2411	<tr>
				2412	<td style="vertical-align: top;">GL_BLEND_SRC<br>
				2413	</td>
				2414	<td style="vertical-align: top;">1<br>
				2415	</td>
				2416	<td style="vertical-align: top;">Blend source function/term.<br>
				2417	</td>
				2418	</tr>
				2419	<tr>
				2420	<td style="vertical-align: top;">GL_BLUE_BITS<br>
				2421	</td>
				2422	<td style="vertical-align: top;">1<br>
				2423	</td>
				2424	<td style="vertical-align: top;">Number of bits per blue value in
				2425	the frame buffer.<br>
				2426	</td>
				2427	</tr>
				2428	<tr>
				2429	<td style="vertical-align: top;">GL_COLOR_CLEAR_VALUE<br>
				2430	</td>
				2431	<td style="vertical-align: top;">4<br>
				2432	</td>
				2433	<td style="vertical-align: top;">Clear color (red, green, blue,
				2434	alpha).<br>
				2435	</td>
				2436	</tr>
				2437	<tr>
				2438	<td style="vertical-align: top;">GL_COLOR_WRITE_MASK<br>
				2439	</td>
				2440	<td style="vertical-align: top;">4<br>
				2441	</td>
				2442	<td style="vertical-align: top;">Color buffer writemask (red,
				2443	green, blue, alpha).<br>
				2444	Zero if writing is disabled.<br>
				2445	One if writing is enabled.<br>
				2446	</td>
				2447	</tr>
				2448	<tr>
				2449	<td style="vertical-align: top;">GL_CULL_FACE<br>
				2450	</td>
				2451	<td style="vertical-align: top;">1<br>
				2452	</td>
				2453	<td style="vertical-align: top;">Zero if polygon culling is
				2454	disabled.<br>
				2455	One if polygon culling is enabled.<br>
				2456	</td>
				2457	</tr>
				2458	<tr>
				2459	<td style="vertical-align: top;">GL_CULL_FACE_MODE<br>
				2460	</td>
				2461	<td style="vertical-align: top;">1<br>
				2462	</td>
				2463	<td style="vertical-align: top;">Polygon cull mode: GL_FRONT,
				2464	GL_BACK or GL_FRONT_AND_BACK.<br>
				2465	</td>
				2466	</tr>
				2467	<tr>
				2468	<td style="vertical-align: top;">GL_CURRENT_COLOR<br>
				2469	</td>
				2470	<td style="vertical-align: top;">4<br>
				2471	</td>
				2472	<td style="vertical-align: top;">Current color (red, green, blue,
				2473	alpha).<br>
				2474	</td>
				2475	</tr>
				2476	<tr>
				2477	<td style="vertical-align: top;">GL_CURRENT_RASTER_COLOR<br>
				2478	</td>
				2479	<td style="vertical-align: top;">4<br>
				2480	</td>
				2481	<td style="vertical-align: top;">Current raster position color
				2482	(red, green, blue, alpha).<br>
				2483	</td>
				2484	</tr>
				2485	<tr>
				2486	<td style="vertical-align: top;">GL_CURRENT_RASTER_TEXTURE_COORDS<br>
				2487	</td>
				2488	<td style="vertical-align: top;">4<br>
				2489	</td>
				2490	<td style="vertical-align: top;">Current raster position texture
				2491	coordinates (s, t, r, q).<br>
				2492	</td>
				2493	</tr>
				2494	<tr>
				2495	<td style="vertical-align: top;">GL_CURRENT_RASTER_POSITION<br>
				2496	</td>
				2497	<td style="vertical-align: top;">4<br>
				2498	</td>
				2499	<td style="vertical-align: top;">Current raster position (x, y,
				2500	z, w).<br>
				2501	</td>
				2502	</tr>
				2503	<tr>
				2504	<td style="vertical-align: top;">GL_CURRENT_POSITION_VALID<br>
				2505	</td>
				2506	<td style="vertical-align: top;">1<br>
				2507	</td>
				2508	<td style="vertical-align: top;">Zero if current raster position
				2509	is invalid.<br>
				2510	One if current raster position is valid.<br>
				2511	</td>
				2512	</tr>
				2513	<tr>
				2514	<td style="vertical-align: top;">GL_CURRENT_TEXTURE_COORDS<br>
				2515	</td>
				2516	<td style="vertical-align: top;">4<br>
				2517	</td>
				2518	<td style="vertical-align: top;">Current texture coordinates (s,
				2519	t, r, q)<br>
				2520	</td>
				2521	</tr>
				2522	<tr>
				2523	<td style="vertical-align: top;">GL_DOUBLEBUFFER<br>
				2524	</td>
				2525	<td style="vertical-align: top;">1<br>
				2526	</td>
				2527	<td style="vertical-align: top;">Zero if color buffer is
				2528	single-buffered.<br>
				2529	One if color buffer is double-buffered.<br>
				2530	</td>
				2531	</tr>
				2532	<tr>
				2533	<td style="vertical-align: top;">GL_DRAW_BUFFER<br>
				2534	</td>
				2535	<td style="vertical-align: top;">1<br>
				2536	</td>
				2537	<td style="vertical-align: top;">Current color draw buffer:
				2538	GL_FRONT or GL_BACK.<br>
				2539	</td>
				2540	</tr>
				2541	<tr>
				2542	<td style="vertical-align: top;">GL_FRONT_FACE</td>
				2543	<td style="vertical-align: top;">1<br>
				2544	</td>
				2545	<td style="vertical-align: top;">Polygon front-face winding:
				2546	GL_CW or GL_CCW.<br>
				2547	</td>
				2548	</tr>
				2549	<tr>
				2550	<td style="vertical-align: top;">GL_GREEN_BITS<br>
				2551	</td>
				2552	<td style="vertical-align: top;">1<br>
				2553	</td>
				2554	<td style="vertical-align: top;">Number of bits per green value
				2555	in the frame buffer.<br>
				2556	</td>
				2557	</tr>
				2558	<tr>
				2559	<td style="vertical-align: top;">GL_LINE_SMOOTH<br>
				2560	</td>
				2561	<td style="vertical-align: top;">1<br>
				2562	</td>
				2563	<td style="vertical-align: top;">Zero if line smoothing is
				2564	disabled.<br>
				2565	One if line smoothing is enabled.<br>
				2566	</td>
				2567	</tr>
				2568	<tr>
				2569	<td style="vertical-align: top;">GL_LINE_STIPPLE<br>
				2570	</td>
				2571	<td style="vertical-align: top;">1<br>
				2572	</td>
				2573	<td style="vertical-align: top;">Zero if line stippling is
				2574	disabled.<br>
				2575	One if line stippling is enabled.<br>
				2576	</td>
				2577	</tr>
				2578	<tr>
				2579	<td style="vertical-align: top;">GL_LINE_STIPPLE_PATTERN<br>
				2580	</td>
				2581	<td style="vertical-align: top;">1<br>
				2582	</td>
				2583	<td style="vertical-align: top;">Line stipple pattern.<br>
				2584	</td>
				2585	</tr>
				2586	<tr>
				2587	<td style="vertical-align: top;">GL_LINE_STIPPLE_REPEAT<br>
				2588	</td>
				2589	<td style="vertical-align: top;">1<br>
				2590	</td>
				2591	<td style="vertical-align: top;">Line stipple repeat factor.<br>
				2592	</td>
				2593	</tr>
				2594	<tr>
				2595	<td style="vertical-align: top;">GL_LINE_WIDTH<br>
				2596	</td>
				2597	<td style="vertical-align: top;">1<br>
				2598	</td>
				2599	<td style="vertical-align: top;">Line width in pixels.<br>
				2600	</td>
				2601	</tr>
				2602	<tr>
				2603	<td style="vertical-align: top;">GL_LINE_WIDTH_GRANULARITY<br>
				2604	</td>
				2605	<td style="vertical-align: top;">1<br>
				2606	</td>
				2607	<td style="vertical-align: top;">Aliased line width granularity.<br>
				2608	</td>
				2609	</tr>
				2610	<tr>
				2611	<td style="vertical-align: top;">GL_LINE_WIDTH_RANGE<br>
				2612	</td>
				2613	<td style="vertical-align: top;">2<br>
				2614	</td>
				2615	<td style="vertical-align: top;">Minimum and maximum aliased line
				2616	widths.<br>
				2617	</td>
				2618	</tr>
				2619	<tr>
				2620	<td style="vertical-align: top;">GL_ALIASED_LINE_WIDTH_RANGE<br>
				2621	</td>
				2622	<td style="vertical-align: top;">2<br>
				2623	</td>
				2624	<td style="vertical-align: top;">Minimum and maximum antialiased
				2625	line widths.</td>
				2626	</tr>
				2627	<tr>
				2628	<td style="vertical-align: top;">GL_COLOR_LOGIC_OP<br>
				2629	</td>
				2630	<td style="vertical-align: top;">1<br>
				2631	</td>
				2632	<td style="vertical-align: top;">Zero if logicop is disabled.<br>
				2633	One if logicop is enabled.<br>
				2634	</td>
				2635	</tr>
				2636	<tr>
				2637	<td style="vertical-align: top;">GL_LOGIC_OP_MODE<br>
				2638	</td>
				2639	<td style="vertical-align: top;">1<br>
				2640	</td>
				2641	<td style="vertical-align: top;">Logicop function.<br>
				2642	</td>
				2643	</tr>
				2644	<tr>
				2645	<td style="vertical-align: top;">GL_MATRIX_MODE<br>
				2646	</td>
				2647	<td style="vertical-align: top;">1<br>
				2648	</td>
				2649	<td style="vertical-align: top;">Matrix mode: GL_MODELVIEW or
				2650	GL_PROJECTION.<br>
				2651	</td>
				2652	</tr>
				2653	<tr>
				2654	<td style="vertical-align: top;">GL_MAX_MODELVIEW_STACK_DEPTH<br>
				2655	</td>
				2656	<td style="vertical-align: top;">1<br>
				2657	</td>
				2658	<td style="vertical-align: top;">Maximum size of the modelview
				2659	matrix stack.<br>
				2660	</td>
				2661	</tr>
				2662	<tr>
				2663	<td style="vertical-align: top;">GL_MAX_NAME_STACK_DEPTH<br>
				2664	</td>
				2665	<td style="vertical-align: top;">1<br>
				2666	</td>
				2667	<td style="vertical-align: top;">Maximum size of the selection
				2668	name stack.<br>
				2669	</td>
				2670	</tr>
				2671	<tr>
				2672	<td style="vertical-align: top;">GL_MAX_PROJECTION_STACK_DEPTH<br>
				2673	</td>
				2674	<td style="vertical-align: top;">1<br>
				2675	</td>
				2676	<td style="vertical-align: top;">Maximum size of the projection
				2677	matrix stack.<br>
				2678	</td>
				2679	</tr>
				2680	<tr>
				2681	<td style="vertical-align: top;">GL_MAX_TEXTURE_SIZE<br>
				2682	</td>
				2683	<td style="vertical-align: top;">1<br>
				2684	</td>
				2685	<td style="vertical-align: top;">Maximum 2D texture image width
				2686	and height.<br>
				2687	</td>
				2688	</tr>
				2689	<tr>
				2690	<td style="vertical-align: top;">GL_MAX_VIEWPORT_DIMS<br>
				2691	</td>
				2692	<td style="vertical-align: top;">2</td>
				2693	<td style="vertical-align: top;">Maximum viewport width and
				2694	height in pixels.<br>
				2695	</td>
				2696	</tr>
				2697	<tr>
				2698	<td style="vertical-align: top;">GL_MODELVIEW_MATRIX<br>
				2699	</td>
				2700	<td style="vertical-align: top;">16<br>
				2701	</td>
				2702	<td style="vertical-align: top;">Current/top modelview matrix
				2703	values.<br>
				2704	</td>
				2705	</tr>
				2706	<tr>
				2707	<td style="vertical-align: top;">GL_MODELVIEW_MATRIX_STACK_DEPTH<br>
				2708	</td>
				2709	<td style="vertical-align: top;">1<br>
				2710	</td>
				2711	<td style="vertical-align: top;">Current size of the modelview
				2712	matrix stack.<br>
				2713	</td>
				2714	</tr>
				2715	<tr>
				2716	<td style="vertical-align: top;">GL_NAME_STACK_DEPTH<br>
				2717	</td>
				2718	<td style="vertical-align: top;">1<br>
				2719	</td>
				2720	<td style="vertical-align: top;">Current size of the selection
				2721	name stack.<br>
				2722	</td>
				2723	</tr>
				2724	<tr>
				2725	<td style="vertical-align: top;">GL_PACK_ROW_LENGTH<br>
				2726	</td>
				2727	<td style="vertical-align: top;">1<br>
				2728	</td>
				2729	<td style="vertical-align: top;">Pixel packing row length.<br>
				2730	</td>
				2731	</tr>
				2732	<tr>
				2733	<td style="vertical-align: top;">GL_POLYGON_SMOOTH<br>
				2734	</td>
				2735	<td style="vertical-align: top;">1<br>
				2736	</td>
				2737	<td style="vertical-align: top;">Zero if polygon smoothing is
				2738	disabled.<br>
				2739	One if polygon smoothing is enabled.<br>
				2740	</td>
				2741	</tr>
				2742	<tr>
				2743	<td style="vertical-align: top;">GL_PROJECTION_MATRIX<br>
				2744	</td>
				2745	<td style="vertical-align: top;">16<br>
				2746	</td>
				2747	<td style="vertical-align: top;">Current/top projection matrix
				2748	values.<br>
				2749	</td>
				2750	</tr>
				2751	<tr>
				2752	<td style="vertical-align: top;">GL_PROJECTION_STACK_DEPTH<br>
				2753	</td>
				2754	<td style="vertical-align: top;">1<br>
				2755	</td>
				2756	<td style="vertical-align: top;">Current size of projection
				2757	matrix stack.<br>
				2758	</td>
				2759	</tr>
				2760	<tr>
				2761	<td style="vertical-align: top;">GL_READ_BUFFER<br>
				2762	</td>
				2763	<td style="vertical-align: top;">1<br>
				2764	</td>
				2765	<td style="vertical-align: top;">Current read buffer: GL_FRONT or
				2766	GL_BACK.<br>
				2767	</td>
				2768	</tr>
				2769	<tr>
				2770	<td style="vertical-align: top;">GL_RED_BITS<br>
				2771	</td>
				2772	<td style="vertical-align: top;">1<br>
				2773	</td>
				2774	<td style="vertical-align: top;">Number of bits per red value in
				2775	the frame buffer.<br>
				2776	</td>
				2777	</tr>
				2778	<tr>
				2779	<td style="vertical-align: top;">GL_RENDER_MODE<br>
				2780	</td>
				2781	<td style="vertical-align: top;">1<br>
				2782	</td>
				2783	<td style="vertical-align: top;">Current rendering mode:
				2784	GL_RENDER or GL_SELECTION.<br>
				2785	</td>
				2786	</tr>
				2787	<tr>
				2788	<td style="vertical-align: top;">GL_RGBA_MODE<br>
				2789	</td>
				2790	<td style="vertical-align: top;">1<br>
				2791	</td>
				2792	<td style="vertical-align: top;">Always one.<br>
				2793	</td>
				2794	</tr>
				2795	<tr>
				2796	<td style="vertical-align: top;">GL_SCISSOR_BOX<br>
				2797	</td>
				2798	<td style="vertical-align: top;">4<br>
				2799	</td>
				2800	<td style="vertical-align: top;">Scissor box (x, y, width,
				2801	height).<br>
				2802	</td>
				2803	</tr>
				2804	<tr>
				2805	<td style="vertical-align: top;">GL_SCISSOR_TEST<br>
				2806	</td>
				2807	<td style="vertical-align: top;">1<br>
				2808	</td>
				2809	<td style="vertical-align: top;">Zero if scissor test is disabled.<br>
				2810	One if scissor test is enabled.<br>
				2811	</td>
				2812	</tr>
				2813	<tr>
				2814	<td style="vertical-align: top;">GL_SELECTION_BUFFER_SIZE<br>
				2815	</td>
				2816	<td style="vertical-align: top;">1<br>
				2817	</td>
				2818	<td style="vertical-align: top;">Size of selection buffer.<br>
				2819	</td>
				2820	</tr>
				2821	<tr>
				2822	<td style="vertical-align: top;">GL_SHADE_MODEL<br>
				2823	</td>
				2824	<td style="vertical-align: top;">1<br>
				2825	</td>
				2826	<td style="vertical-align: top;">Shade model: GL_FLAT or
				2827	GL_SMOOTH.<br>
				2828	</td>
				2829	</tr>
				2830	<tr>
				2831	<td style="vertical-align: top;">GL_STENCIL_BITS<br>
				2832	</td>
				2833	<td style="vertical-align: top;">1<br>
				2834	</td>
				2835	<td style="vertical-align: top;">Number of bits per stencil value
				2836	in the frame buffer.<br>
				2837	</td>
				2838	</tr>
				2839	<tr>
				2840	<td style="vertical-align: top;">GL_STENCIL_CLEAR_VALUE<br>
				2841	</td>
				2842	<td style="vertical-align: top;">1<br>
				2843	</td>
				2844	<td style="vertical-align: top;">Stencil buffer clear value.<br>
				2845	</td>
				2846	</tr>
				2847	<tr>
				2848	<td style="vertical-align: top;">GL_STENCIL_FAIL<br>
				2849	</td>
				2850	<td style="vertical-align: top;">1<br>
				2851	</td>
				2852	<td style="vertical-align: top;">Stencil fail operation.<br>
				2853	</td>
				2854	</tr>
				2855	<tr>
				2856	<td style="vertical-align: top;">GL_STENCIL_FUNC<br>
				2857	</td>
				2858	<td style="vertical-align: top;">1<br>
				2859	</td>
				2860	<td style="vertical-align: top;">Stencil function.<br>
				2861	</td>
				2862	</tr>
				2863	<tr>
				2864	<td style="vertical-align: top;">GL_STENCIL_REF<br>
				2865	</td>
				2866	<td style="vertical-align: top;">1<br>
				2867	</td>
				2868	<td style="vertical-align: top;">Stencil reference value.<br>
				2869	</td>
				2870	</tr>
				2871	<tr>
				2872	<td style="vertical-align: top;">GL_STENCIL_TEST<br>
				2873	</td>
				2874	<td style="vertical-align: top;">1<br>
				2875	</td>
				2876	<td style="vertical-align: top;">Zero if stencil test is disabled.<br>
				2877	One if stencil test is enabled.<br>
				2878	</td>
				2879	</tr>
				2880	<tr>
				2881	<td style="vertical-align: top;">GL_STENCIL_VALUE_MASK<br>
				2882	</td>
				2883	<td style="vertical-align: top;">1<br>
				2884	</td>
				2885	<td style="vertical-align: top;">Stencil mask value.<br>
				2886	</td>
				2887	</tr>
				2888	<tr>
				2889	<td style="vertical-align: top;">GL_STENCIL_WRITE_MASK<br>
				2890	</td>
				2891	<td style="vertical-align: top;">1<br>
				2892	</td>
				2893	<td style="vertical-align: top;">Stencil buffer write mask.<br>
				2894	</td>
				2895	</tr>
				2896	<tr>
				2897	<td style="vertical-align: top;">GL_TEXTURE_2D<br>
				2898	</td>
				2899	<td style="vertical-align: top;">1<br>
				2900	</td>
				2901	<td style="vertical-align: top;">Zero if 2D texture mapping is
				2902	disabled.<br>
				2903	One if 2D texture mapping is enabled.<br>
				2904	</td>
				2905	</tr>
				2906	<tr>
				2907	<td style="vertical-align: top;">GL_TEXTURE_BINDING_2D</td>
				2908	<td style="vertical-align: top;">1<br>
				2909	</td>
				2910	<td style="vertical-align: top;">Name of currently bound 2D
				2911	texture object.<br>
				2912	</td>
				2913	</tr>
				2914	<tr>
				2915	<td style="vertical-align: top;">GL_TEXTURE_ENV_COLOR<br>
				2916	</td>
				2917	<td style="vertical-align: top;">4<br>
				2918	</td>
				2919	<td style="vertical-align: top;">Texture environment color (red,
				2920	green, blue, alpha).<br>
				2921	</td>
				2922	</tr>
				2923	<tr>
				2924	<td style="vertical-align: top;">GL_TEXTURE_ENV_MODE<br>
				2925	</td>
				2926	<td style="vertical-align: top;">1<br>
				2927	</td>
				2928	<td style="vertical-align: top;">Texture environment mode.<br>
				2929	</td>
				2930	</tr>
				2931	<tr>
				2932	<td style="vertical-align: top;">GL_UNPACK_ROW_LENGTH<br>
				2933	</td>
				2934	<td style="vertical-align: top;">1<br>
				2935	</td>
				2936	<td style="vertical-align: top;">Pixel unpacking row length.<br>
				2937	</td>
				2938	</tr>
				2939	<tr>
				2940	<td style="vertical-align: top;">GL_UNPACK_LSB_FIRST<br>
				2941	</td>
				2942	<td style="vertical-align: top;">1<br>
				2943	</td>
				2944	<td style="vertical-align: top;">Zero if most significant bit is
				2945	unpacked first for bitmaps.<br>
				2946	One if least significant bit is unpacked first for bitmaps.<br>
				2947	</td>
				2948	</tr>
				2949	<tr>
				2950	<td style="vertical-align: top;">GL_VIEWPORT<br>
				2951	</td>
				2952	<td style="vertical-align: top;">4<br>
				2953	</td>
				2954	<td style="vertical-align: top;">Current viewport (x, y, width,
				2955	height).<br>
				2956	</td>
				2957	</tr>
				2958	</tbody>
				2959	</table>
				2960	<br>
				2961	<br>
				2962	<h2>9.2 String Queries</h2>
				2963	The command<br>
				2964	<br>
				2965	<div style="margin-left: 40px;">const GLubyte *<span
				2966	style="font-weight: bold;">glGetString</span>(GLenum <span
				2967	style="font-style: italic;">name</span>)<br>
				2968	</div>
				2969	<br>
				2970	is used to query string-valued values.  The legal values for <span
				2971	style="font-style: italic;">name</span> are described in the following
				2972	table:<br>
				2973	<br>
				2974	<table cellpadding="2" cellspacing="2" border="1"
				2975	style="text-align: left; width: 80%; margin-left: auto; margin-right: auto;">
				2976	<tbody>
				2977	<tr>
				2978	<td style="vertical-align: top;"><span style="font-style: italic;">name</span><br>
				2979	</td>
				2980	<td style="vertical-align: top;">Return value<br>
				2981	</td>
				2982	</tr>
				2983	<tr>
				2984	<td style="vertical-align: top;">GL_VERSION<br>
				2985	</td>
				2986	<td style="vertical-align: top;">The library version, such as
				2987	"1.2".<br>
				2988	</td>
				2989	</tr>
				2990	<tr>
				2991	<td style="vertical-align: top;">GL_RENDERER<br>
				2992	</td>
				2993	<td style="vertical-align: top;">The renderer, such as "Mesa DRI
				2994	Radeon".<br>
				2995	</td>
				2996	</tr>
				2997	<tr>
				2998	<td style="vertical-align: top;">GL_VENDOR<br>
				2999	</td>
				3000	<td style="vertical-align: top;">The vendor of this
				3001	implementation, such as "Tungsten Graphics, Inc."<br>
				3002	</td>
				3003	</tr>
				3004	<tr>
				3005	<td style="vertical-align: top;">GL_EXTENSIONS<br>
				3006	</td>
				3007	<td style="vertical-align: top;">A white-space separated list of
				3008	the supported extensions. </td>
				3009	</tr>
				3010	</tbody>
				3011	</table>
				3012	<br>
				3013	<h2>9.3 Error Queries</h2>
				3014	The command<br>
				3015	<br>
				3016	<div style="margin-left: 40px;">GLenum <span style="font-weight: bold;">glGetError</span>(void)<br>
				3017	</div>
				3018	<br>
				3019	returns the current error code.  The current error code will be
				3020	set by a GL command when an error condition has been detected.  If
				3021	the current error code is already set, subsequent errors will not be
				3022	recorded.  The error code is reset/cleared to GL_NO_ERROR when <span
				3023	style="font-weight: bold;">glGetError</span> returns.  The
				3024	following error codes are possible:<br>
				3025	<br>
				3026	<table cellpadding="2" cellspacing="2" border="1"
				3027	style="text-align: left; width: 80%; margin-left: auto; margin-right: auto;">
				3028	<tbody>
				3029	<tr>
				3030	<td style="vertical-align: top;">Error code<br>
				3031	</td>
				3032	<td style="vertical-align: top;">Meaning<br>
				3033	</td>
				3034	</tr>
				3035	<tr>
				3036	<td style="vertical-align: top;">GL_NO_ERROR<br>
				3037	</td>
				3038	<td style="vertical-align: top;">No error has been recorded.<br>
				3039	</td>
				3040	</tr>
				3041	<tr>
				3042	<td style="vertical-align: top;">GL_INVALID_ENUM<br>
				3043	</td>
				3044	<td style="vertical-align: top;">An enum parameter had an invalid
				3045	value.<br>
				3046	</td>
				3047	</tr>
				3048	<tr>
				3049	<td style="vertical-align: top;">GL_INVALID_VALUE<br>
				3050	</td>
				3051	<td style="vertical-align: top;">A numeric parameter had an
				3052	invalid value.<br>
				3053	</td>
				3054	</tr>
				3055	<tr>
				3056	<td style="vertical-align: top;">GL_INVALID_OPERATION<br>
				3057	</td>
				3058	<td style="vertical-align: top;">A function was called when not
				3059	legal to do so.<br>
				3060	</td>
				3061	</tr>
				3062	<tr>
				3063	<td style="vertical-align: top;">GL_STACK_OVERFLOW<br>
				3064	</td>
				3065	<td style="vertical-align: top;">The current transformation
				3066	matrix stack is full.<br>
				3067	</td>
				3068	</tr>
				3069	<tr>
				3070	<td style="vertical-align: top;">GL_STACK_UNDERFLOW<br>
				3071	</td>
				3072	<td style="vertical-align: top;">The current transformation
				3073	matrix stack is empty.<br>
				3074	</td>
				3075	</tr>
				3076	<tr>
				3077	<td style="vertical-align: top;">GL_OUT_OF_MEMORY<br>
				3078	</td>
				3079	<td style="vertical-align: top;">The system ran out of dynamic
				3080	memory.<br>
				3081	</td>
				3082	</tr>
				3083	</tbody>
				3084	</table>
				3085	<br>
				3086	<br>
				3087	<h1>10. Unsupported Features</h1>
				3088	This section lists other features and functions which are not supported
				3089	and not previously discussed.<br>
				3090	<br>
				3091	<h2>10.1 Feedback Mode</h2>
				3092	Feedback mode and the following related functions are not supported.<br>
				3093	<br>
				3094	<div style="margin-left: 40px;"><span style="font-weight: bold;">glFeedbackBuffer</span><br>
				3095	<span style="font-weight: bold;">glPassThrough</span><br>
				3096	</div>
				3097	<br>
				3098	<h2>10.2 1D and 3D Textures<br>
				3099	</h2>
				3100	Only 2D texture images are supported.  The following functions
				3101	used to specify 1D and 3D texture images are not supported:<br>
				3102	<br>
				3103	<div style="margin-left: 40px;"><span style="font-weight: bold;">glTexImage1D</span><br
				3104	style="font-weight: bold;">
				3105	<span style="font-weight: bold;">glTexImage3D</span><br
				3106	style="font-weight: bold;">
				3107	<span style="font-weight: bold;">glTexSubImage1D</span><br
				3108	style="font-weight: bold;">
				3109	<span style="font-weight: bold;"> glTexSubImage3D</span><br
				3110	style="font-weight: bold;">
				3111	<span style="font-weight: bold;">glCopyTexImage1D</span><br
				3112	style="font-weight: bold;">
				3113	<span style="font-weight: bold;"> glCopyTexSubImage1D</span><br
				3114	style="font-weight: bold;">
				3115	<span style="font-weight: bold;"> glCopyTexSubImage3D</span><br>
				3116	</div>
				3117	<br>
				3118	<h2>10.3 Alternate Texture Image Commands<br>
				3119	</h2>
				3120	Texture images may only be specified with <span
				3121	style="font-weight: bold;">glTexImage2D</span>.  The following
				3122	alternate texture image commands are not supported:<br>
				3123	<br>
				3124	<div style="margin-left: 40px; font-weight: bold;">glTexSubImage2D<br>
				3125	glCopyTexImage2D<br>
				3126	glCopyTexSubImage2D<br>
				3127	</div>
				3128	<br>
				3129	<h2>10.4 Proxy Textures</h2>
				3130	Proxy textures are not supported and the GL_PROXY_TEXTURE_2D token is
				3131	not supported by any function.<br>
				3132	<br>
				3133	<br>
				3134	<h2>10.5 Other Texture Commands</h2>
				3135	The following commands related to texture mapping are not supported by
				3136	the subset:<br>
				3137	<br>
				3138	<div style="margin-left: 40px; font-weight: bold;"> glPrioritizeTextures<br>
				3139	glAreTexturesResident<br>
				3140	glIsTexture<br>
				3141	glTexEnviv<br>
				3142	glTexEnvf<br>
				3143	glTexParameterf<br>
				3144	glTexParameteriv<br>
				3145	glTexParameterfv<br>
				3146	</div>
				3147	<br>
				3148	<br>
				3149	<h2>10.6 Copy and Draw Pixels<br>
				3150	</h2>
				3151	The following commands are not supported:<br>
				3152	<br>
				3153	<div style="margin-left: 40px;"><span style="font-weight: bold;">glDrawPixels<br>
				3154	glCopyPixels<br>
				3155	glPixelZoom<br>
				3156	<br>
				3157	</span></div>
				3158	<h2>10.7 Color Index Mode<br>
				3159	</h2>
				3160	Color index mode and the following related commands are not supported:<br>
				3161	<br>
				3162	<span style="font-weight: bold;"></span>
				3163	<div style="margin-left: 40px;"><span style="font-weight: bold;">glIndexub<br>
				3164	</span><span style="font-weight: bold;">glIndexi</span><br>
				3165	<span style="font-weight: bold;">glIndexs<br>
				3166	glIndexf<br>
				3167	glIndexd<br>
				3168	</span><span style="font-weight: bold;">glIndexubv<br>
				3169	</span><span style="font-weight: bold;">glIndexiv</span><br>
				3170	<span style="font-weight: bold;">glIndexsv<br>
				3171	glIndexfv<br>
				3172	glIndexdv</span><span style="font-weight: bold;"><br>
				3173	glIndexMask<br>
				3174	</span><span style="font-weight: bold;">glClearIndex<br>
				3175	glIndexPointer</span><br style="font-weight: bold;">
				3176	<br>
				3177	</div>
				3178	<h2>10.8 Pixel Transfer Operations</h2>
				3179	The pixel transfer operations (scale, bias, look-up table, etc) are not
				3180	supported and the following commands are omitted:<br>
				3181	<br style="font-weight: bold;">
				3182	<div style="margin-left: 40px;"><span style="font-weight: bold;">glPixelTransferf</span><br
				3183	style="font-weight: bold;">
				3184	<span style="font-weight: bold;">glPixelTransferi</span><br
				3185	style="font-weight: bold;">
				3186	<span style="font-weight: bold;">glPixelMapfv</span><br
				3187	style="font-weight: bold;">
				3188	<span style="font-weight: bold;">glPixelMapuiv</span><br
				3189	style="font-weight: bold;">
				3190	<span style="font-weight: bold;">glPixelMapusv</span><br
				3191	style="font-weight: bold;">
				3192	<span style="font-weight: bold;">glGetPixelMapfv</span><br
				3193	style="font-weight: bold;">
				3194	<span style="font-weight: bold;">glGetPixelMapuiv</span><br
				3195	style="font-weight: bold;">
				3196	<span style="font-weight: bold;">glGetPixelMapusv</span><br>
				3197	</div>
				3198	<br>
				3199	<h2>10.9 Hints</h2>
				3200	Hints and the following related command is not supported:<br>
				3201	<br>
				3202	<div style="margin-left: 40px;"><span style="font-weight: bold;">glHint<br>
				3203	</span><br>
				3204	</div>
				3205	<h2>10.10 State Query Commands<br>
				3206	</h2>
				3207	The following state query commands are not supported:<br>
				3208	<br>
				3209	<div style="margin-left: 40px; font-weight: bold;">glGetBooleanv<br>
				3210	glGetIntegerv<br>
				3211	glGetDoublev<br>
				3212	glGetPointerv<br>
				3213	glGetTexEnvi<br>
				3214	glGetTexEnvf<br>
				3215	glGetTexParameteriv<br>
				3216	glGetTexParameterfv<br>
				3217	glGetTexLevelParameteriv<br>
				3218	glGetTexLevelParameterfv<br>
				3219	glGetTexImage<br>
				3220	glGetClipPlane<br>
				3221	</div>
				3222	<br>
				3223	<h2>10.11 Attribute Stacks</h2>
				3224	State attribute stacks and the following related commands are not
				3225	supported:<br>
				3226	<br>
				3227	<div style="margin-left: 40px;"><span style="font-weight: bold;">glPushAttrib</span><br
				3228	style="font-weight: bold;">
				3229	<span style="font-weight: bold;">glPopAtttrib</span><br>
				3230	<br style="font-weight: bold;">
				3231	</div>
				3232	<h2>10.12 Double-Valued Functions</h2>
				3233	All functions which take double-precision floating point values, but
				3234	for which there is an equivalent single-precision valued function, are
				3235	omitted.  This includes, but is not limited to:<br>
				3236	<br>
				3237	<div style="margin-left: 40px;"><span style="font-weight: bold;">glVertex2d</span><br
				3238	style="font-weight: bold;">
				3239	<span style="font-weight: bold;">glVertex2dv</span><br
				3240	style="font-weight: bold;">
				3241	<span style="font-weight: bold;">glVertex3d</span><br
				3242	style="font-weight: bold;">
				3243	<span style="font-weight: bold;"> glVertex3dv</span><br
				3244	style="font-weight: bold;">
				3245	<span style="font-weight: bold;">glVertex4d</span><br
				3246	style="font-weight: bold;">
				3247	<span style="font-weight: bold;"> glVertex4dv</span><br
				3248	style="font-weight: bold;">
				3249	<span style="font-weight: bold;">glColor3d</span><br
				3250	style="font-weight: bold;">
				3251	<span style="font-weight: bold;">glColor3d</span><span
				3252	style="font-weight: bold;">v</span><br style="font-weight: bold;">
				3253	<span style="font-weight: bold;">glColor4d</span><br
				3254	style="font-weight: bold;">
				3255	<span style="font-weight: bold;"> glColor4dv</span><br
				3256	style="font-weight: bold;">
				3257	<span style="font-weight: bold;">glTexCoord1d</span><br
				3258	style="font-weight: bold;">
				3259	<span style="font-weight: bold;">glTexCoord1d</span><span
				3260	style="font-weight: bold;">v</span><br style="font-weight: bold;">
				3261	<span style="font-weight: bold;">glTexCoord2d</span><br
				3262	style="font-weight: bold;">
				3263	<span style="font-weight: bold;"> glTexCoord2dv</span><br
				3264	style="font-weight: bold;">
				3265	<span style="font-weight: bold;">glTexCoord3d</span><br
				3266	style="font-weight: bold;">
				3267	<span style="font-weight: bold;"> glTexCoord3dv</span><br
				3268	style="font-weight: bold;">
				3269	<span style="font-weight: bold;">glTexCoord4d</span><br
				3270	style="font-weight: bold;">
				3271	<span style="font-weight: bold;"> glTexCoord4dv</span><br
				3272	style="font-weight: bold;">
				3273	<span style="font-weight: bold;">glRasterPos2d</span><br
				3274	style="font-weight: bold;">
				3275	<span style="font-weight: bold;"> glRasterPos2dv</span><br
				3276	style="font-weight: bold;">
				3277	<span style="font-weight: bold;">glRasterPos3d</span><br
				3278	style="font-weight: bold;">
				3279	<span style="font-weight: bold;"> glRasterPos3dv</span><br
				3280	style="font-weight: bold;">
				3281	<span style="font-weight: bold;">glRasterPos4d</span><br
				3282	style="font-weight: bold;">
				3283	<span style="font-weight: bold;"> glRasterPos4dv</span><br
				3284	style="font-weight: bold;">
				3285	<span style="font-weight: bold;">glLoadMatrixd</span><br
				3286	style="font-weight: bold;">
				3287	<span style="font-weight: bold;">glMultMatrixd</span><br
				3288	style="font-weight: bold;">
				3289	<span style="font-weight: bold;">glScaled</span><br
				3290	style="font-weight: bold;">
				3291	<span style="font-weight: bold;">glRotated</span><br
				3292	style="font-weight: bold;">
				3293	<span style="font-weight: bold;">glTranslated<br>
				3294	glRectd<br>
				3295	glRectdv<br>
				3296	</span> <span style="font-weight: bold;"><br>
				3297	</span> </div>
				3298	<h2>10.13 Evaluators</h2>
				3299	Evaluators and the following related commands are not supported:<br>
				3300	<br>
				3301	<div style="margin-left: 40px;"><span style="font-weight: bold;">glMap1f</span><br
				3302	style="font-weight: bold;">
				3303	<span style="font-weight: bold;">glMap2d</span><br
				3304	style="font-weight: bold;">
				3305	<span style="font-weight: bold;">glMap2f</span><br
				3306	style="font-weight: bold;">
				3307	<span style="font-weight: bold;">glGetMapdv</span><br
				3308	style="font-weight: bold;">
				3309	<span style="font-weight: bold;">glGetMapfv</span><br
				3310	style="font-weight: bold;">
				3311	<span style="font-weight: bold;">glGetMapiv</span><br
				3312	style="font-weight: bold;">
				3313	<span style="font-weight: bold;">glEvalCoord1d</span><br
				3314	style="font-weight: bold;">
				3315	<span style="font-weight: bold;">glEvalCoord1f</span><br
				3316	style="font-weight: bold;">
				3317	<span style="font-weight: bold;">glEvalCoord1dv</span><br
				3318	style="font-weight: bold;">
				3319	<span style="font-weight: bold;">glEvalCoord1fv</span><br
				3320	style="font-weight: bold;">
				3321	<span style="font-weight: bold;">glEvalCoord2d</span><br
				3322	style="font-weight: bold;">
				3323	<span style="font-weight: bold;">glEvalCoord2f</span><br
				3324	style="font-weight: bold;">
				3325	<span style="font-weight: bold;">glEvalCoord2dv</span><br
				3326	style="font-weight: bold;">
				3327	<span style="font-weight: bold;">glEvalCoord2fv</span><br
				3328	style="font-weight: bold;">
				3329	<span style="font-weight: bold;">glMapGrid1d</span><br
				3330	style="font-weight: bold;">
				3331	<span style="font-weight: bold;">glMapGrid1f</span><br
				3332	style="font-weight: bold;">
				3333	<span style="font-weight: bold;">glMapGrid2d</span><br
				3334	style="font-weight: bold;">
				3335	<span style="font-weight: bold;">glMapGrid2f</span><br
				3336	style="font-weight: bold;">
				3337	<span style="font-weight: bold;">glEvalPoint1</span><br
				3338	style="font-weight: bold;">
				3339	<span style="font-weight: bold;">glEvalPoint2</span><br
				3340	style="font-weight: bold;">
				3341	<span style="font-weight: bold;">glEvalMesh1</span><br
				3342	style="font-weight: bold;">
				3343	<span style="font-weight: bold;">glEvalMesh2</span><br
				3344	style="font-weight: bold;">
				3345	</div>
				3346	<br>
				3347	<h2>10.14 Display Lists</h2>
				3348	Display lists and the following related commands are not supported:<br>
				3349	<br>
				3350	<div style="margin-left: 40px; font-weight: bold;">glIsList<br>
				3351	glDeleteLists<br>
				3352	glGenLists<br>
				3353	glNewList<br>
				3354	glEndList<br>
				3355	glCallList<br>
				3356	glCallLists<br>
				3357	glListBase<br>
				3358	</div>
				3359	<br>
				3360	<h2>10.15 Accumulation Buffer</h2>
				3361	The accumulation buffer and the following related commands are not
				3362	supported:<br>
				3363	<br style="font-weight: bold;">
				3364	<div style="margin-left: 40px;"><span style="font-weight: bold;">glAccum</span><br
				3365	style="font-weight: bold;">
				3366	<span style="font-weight: bold;">glClearAccum</span><br>
				3367	</div>
				3368	<br>
				3369	<h2>10.16 Fog</h2>
				3370	Fog and the following related commands are not supported:<br>
				3371	<br>
				3372	<div style="margin-left: 40px; font-weight: bold;"> glFogi<br>
				3373	glFogf<br>
				3374	glFogiv<br>
				3375	glFogfv<br>
				3376	</div>
				3377	<br>
				3378	<h2>10.17 Depth Test</h2>
				3379	Depth testing and the following related commands are not supported:<br>
				3380	<br>
				3381	<div style="margin-left: 40px;"><span style="font-weight: bold;">glDepthFunc</span><br
				3382	style="font-weight: bold;">
				3383	<span style="font-weight: bold;">glDepthMask</span><br
				3384	style="font-weight: bold;">
				3385	<span style="font-weight: bold;">glDepthRange</span><br
				3386	style="font-weight: bold;">
				3387	<span style="font-weight: bold;">glClearDepth</span><br>
				3388	</div>
				3389	<br>
				3390	<h2>10.18 Imaging Subset</h2>
				3391	The OpenGL imaging subset (which implements features such as
				3392	convolution, histogram, min/max recording, color matrix and color
				3393	tables) is not supported.<br>
				3394	<br>
				3395	<br>
				3396	<h1>Appendix A: Issues</h1>
				3397	This appendix lists documentation and subset issues with their current
				3398	status.  For items which are still open, the documentation (above)
				3399	follows the recommended solution.<br>
				3400	<br>
				3401	<h2>A.1 Vertex Arrays</h2>
				3402	Should vertex arrays be supported?  Is there a performance
				3403	advantage?<br>
				3404	<br>
				3405	RESOLUTION: No, there isn't enough of a performance advantage to
				3406	justify them.<br>
				3407	<br>
				3408	<h2>A.2 Polygon Antialiasing and Edge Flags</h2>
				3409	Should edge flags be supported for antialiasing?<br>
				3410	<br>
				3411	Edge flags don't effect antialiasing, at least not normally.  A
				3412	number of approaches to antialiasing have been summarized in email.<br>
				3413	<br>
				3414	RECOMMENDATION: don't support edge flags.  They don't effect
				3415	polygon antialiasing.<br>
				3416	<br>
				3417	RESOLUTION: closed, as of 26 Feb 2003.<br>
				3418	<br>
				3419	<h2>A.3 glRasterPos vs. glWindowPos</h2>
				3420	Should glRasterPos and/or glWindowPos commands be supported?<br>
				3421	<br>
				3422	RESOLUTION: Closed: implement glRasterPos commands, but not glWindowPos
				3423	commands.<br>
				3424	<br>
				3425	<h2>A.4 GL_IBM_rasterpos_clip extension</h2>
				3426	Should the GL_IBM_rasterpos_clip extension be implemented?<br>
				3427	<br>
				3428	RESOLUTION:  No.  It's not required.<br>
				3429	<br>
				3430	<h2>A.5 Image Formats and Types</h2>
				3431	Which image formats and types should be supported for <span
				3432	style="font-weight: bold;">glTexImage2D</span> and <span
				3433	style="font-weight: bold;">glReadPixels</span>?<br>
				3434	<br>
				3435	OpenGL specifies a <span style="font-weight: bold;">large</span>
				3436	variety of image formats and data types.  Only a few are commonly
				3437	used.<br>
				3438	<br>
				3439	RECOMMENDATION:  we propose a subset:<br>
				3440	<br>
				3441	For <span style="font-weight: bold;">glTexImage2D</span> only allow <span
				3442	style="font-style: italic;">type</span>=GL_UNSIGNED_BYTE and <span
				3443	style="font-style: italic;">format</span>=GL_RGBA, GL_RGB,
				3444	GL_INTENSITY.   Only allow <span style="font-style: italic;">internalFormat</span>
				3445	to be GL_RGBA, GL_RGB or GL_INTENSITY as well.  Basically, only
				3446	support image formats/types that are directly supported by the Radeon
				3447	hardware.  This will allow <span style="font-weight: bold;">glTexImage2D</span>
				3448	to basically just use <span style="font-weight: bold;">memcpy</span> to
				3449	copy texture images.<br>
				3450	<br>
				3451	For <span style="font-weight: bold;">glReadPixels</span>, only allow <span
				3452	style="font-style: italic;">type</span> = GL_UNSIGNED_BYTE or GL_FLOAT.
				3453	Only allow <span style="font-style: italic;">format</span> =
				3454	GL_RGB or GL_RGBA.  This is just enough to support the OpenGL
				3455	conformance tests.<br>
				3456	<br>
				3457	RESOLUTION: open<br>
				3458	<br>
				3459	<h2>A.6 Texture Environment Modes</h2>
				3460	Which texture environment modes should be supported?  OpenGL 1.2
				3461	has GL_REPLACE, GL_MODULATE, GL_DECAL and GL_BLEND.  GL_DECAL isn't
				3462	defined for all base internal texture formats.  GL_ADD is another
				3463	useful mode.  Perhaps drop GL_DECAL mode and add GL_ADD mode.<br>
				3464	<br>
				3465	RECOMMENDATION: implement the standard modes GL_REPLACE, GL_MODULATE,
				3466	GL_DECAL and GL_BLEND.<br>
				3467	<br>
				3468	RESOLUTION: open<br>
				3469	<br>
				3470	<h2>A.7 Truncated Mipmaps and LOD Control</h2>
				3471	Should we support the GL_TEXTURE_BASE_LEVEL, GL_TEXTURE_MAX_LEVEL,
				3472	GL_TEXTURE_MIN_LOD and GL_TEXTURE_MAX_LOD texture parameters?<br>
				3473	<br>
				3474	RECOMMENDATION:  We propose omitting these features at this time,
				3475	in the interest of simplifying the driver.<br>
				3476	<br>
				3477	RESOLUTION: open<br>
				3478	<br>
				3479	<h2>A.8 Texture Priorities and Residency</h2>
				3480	Should the subset support texture priorities via <span
				3481	style="font-weight: bold;">glPrioritizeTextures</span> and the <span
				3482	style="font-weight: bold;">glAreTexturesResident</span> command?<br>
				3483	<br>
				3484	RECOMMENDATION:  Few applications use these features and
				3485	functions.  We propose omitting them to simplify the driver.<br>
				3486	<br>
				3487	RESOLUTION: open<br>
				3488	<br>
				3489	<h2>A.9 Pixel Pack/Unpack Alignment Control</h2>
				3490	Should we support the GL_PACK_ALIGNMENT and GL_UNPACK_ALIGNMENT options?<br>
				3491	<br>
				3492	These are used to align pixel data addresses to 1, 2 and 4-byte
				3493	multiples for <span style="font-weight: bold;">glBitmap, glTexImage2D</span>
				3494	and <span style="font-weight: bold;">glReadPixels</span>.  These
				3495	aren't strictly needed since the user can provide a 1, 2 or 4-byte
				3496	aligned address and appropriate GL_PACK_ROW_LENGTH or
				3497	GL_UNPACK_ROW_LENGTH values instead.<br>
				3498	<br>
				3499	RECOMMENDATION:  We recommend omitting them to simplify the driver.<br>
				3500	<br>
				3501	RESOLUTION: open<br>
				3502	<br>
				3503	<h2>A.10 Pixel Pack/Unpack Skip Rows/Pixels Control</h2>
				3504	Should we support the GL_UNPACK_SKIP_PIXELS, GL_UNPACK_SKIP_ROWS,
				3505	GL_PACK_SKIP_PIXELS and GL_PACK_SKIP_ROWS options for pixel
				3506	unpacking/packing?<br>
				3507	<br>
				3508	These options aren't really needed since the user can adjust the start
				3509	address and GL_PACK/UNPACK_ROW_LENGTH parameters to achieve the same
				3510	effect.<br>
				3511	<br>
				3512	RECOMMENDATION:  omit these parameters.<br>
				3513	<br>
				3514	RESOLUTION: open<br>
				3515	<br>
				3516	<h2>A.11 Texture State Queries</h2>
				3517	Should we support the command <span style="font-weight: bold;">glGetTexEnvi/fv,
				3518	glGetTexParameteri/fv</span> and <span style="font-weight: bold;">glGetTexLevelParameteri/fv</span>?<br>
				3519	<br>
				3520	RECOMMENDATION:  No. They're seldom needed and their
				3521	implementation is several hundred lines of code in length.<br>
				3522	<br>
				3523	RESOLUTION:  open<br>
				3524	<br>
				3525	<h2>A.12 glGetIntegerv, glGetBooleanv and glGetDoublev</h2>
				3526	Should we support the commands <span style="font-weight: bold;">glGetIntegerv,
				3527	glGetBooleanv </span>and <span style="font-weight: bold;">glGetDoublev</span>
				3528	in addition to <span style="font-weight: bold;">glGetFloatv</span>?<br>
				3529	<br>
				3530	RECOMMENDATION:  Omit the boolean, integer and double-valued
				3531	functions. All state values which can be queried by these commands can
				3532	be expressed as floating point values and queried with <span
				3533	style="font-weight: bold;">glGetFloatv</span>.  The
				3534	implementation of the other three commands involves many lines of code.<br>
				3535	<br>
				3536	RESOLUTION:  open<br>
				3537	<br>
				3538	<h2>A.13 glBitmap and Per-Fragment Operations</h2>
				3539	Should bitmaps rendered with <span style="font-weight: bold;">glBitmap</span>
				3540	be subjected to the per-fragment operations?<br>
				3541	<br>
				3542	If bitmaps are implemented with points it will be easy to implement the
				3543	per-fragment operations.  Otherwise, it could be difficult.<br>
				3544	<br>
				3545	RECOMMENDATION:  Implement glBitmap by drawing points/pixels with
				3546	the hardware.  This will make supporting the per-fragments
				3547	trivially easy.  Also, it makes portrait-mode display relatively
				3548	easy.<br>
				3549	<br>
				3550	RESOLUTION:  open<br>
				3551	<br>
				3552	<h2>A.14 Reduced gl.h Header File</h2>
				3553	Should we produce a reduced gl.h header file which only defines the
				3554	tokens and functions which are implemented by the subset?<br>
				3555	<br>
				3556	RECOMMENDATION: yes.  It would be a useful reference to
				3557	programmers to quickly determine which functions and tokens are
				3558	supported.<br>
				3559	<br>
				3560	RESOLUTION: open<br>
				3561	<br>
				3562	<h2>A.15 glPolygonMode</h2>
				3563	Is <span style="font-weight: bold;">glPolygonMode</span> needed?<br>
				3564	<br>
				3565	RECOMMENDATION: No.  Omit it.<br>
				3566	<br>
				3567	RESOLUTION: closed, as of 26 Feb 2003<br>
				3568	<br>
				3569	<br>
				3570	<p> </p>
				3571	</body>
				3572	</html>