Gitiles
Code Review Sign In
gerrit-public.fairphone.software / platform / external / mesa3d / 72483b29aae62fd5201ce555c574a59e4b5e5e6d / . / docs / faq.html
blob: 4e79bb167f6553ae98dbaf1cf9f0230c3176b95b [file] [log] [blame]
Andreas Bollecd5c7c2012-06-12 09:05:03 +0200[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
2<html lang="en">
3<head>
4 <meta http-equiv="content-type" content="text/html; charset=utf-8">
5 <title>Mesa FAQ</title>
6 <link rel="stylesheet" type="text/css" href="mesa.css">
7</head>
8<body>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]9
Andreas Bollb5da52a2012-09-18 18:57:02 +0200[diff] [blame]10<div class="header">
11 <h1>The Mesa 3D Graphics Library</h1>
12</div>
13
14<iframe src="contents.html"></iframe>
15<div class="content">
16
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]17<center>
18<h1>Mesa Frequently Asked Questions</h1>
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]19Last updated: 9 October 2012
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]20</center>
21
22<br>
23<br>
24<h2>Index</h2>
25<a href="#part1">1. High-level Questions and Answers</a>
26<br>
27<a href="#part2">2. Compilation and Installation Problems</a>
28<br>
29<a href="#part3">3. Runtime / Rendering Problems</a>
30<br>
31<a href="#part4">4. Developer Questions</a>
32<br>
33<br>
34<br>
35
36
37
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]38<h1 id="part1">1. High-level Questions and Answers</h1>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]39
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]40<h2>1.1 What is Mesa?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]41<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]42Mesa is an open-source implementation of the OpenGL specification.
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]43OpenGL is a programming library for writing interactive 3D applications.
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]44See the <a href="http://www.opengl.org/">OpenGL website</a> for more
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]45information.
46</p>
47<p>
Andreas Boll5abb1f82012-09-19 18:22:37 +0200[diff] [blame]48Mesa 9.x supports the OpenGL 3.1 specification.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]49</p>
50
51
52<h2>1.2 Does Mesa support/use graphics hardware?</h2>
53<p>
Brian Paul7e4cc1c2005-10-24 23:33:27 +0000[diff] [blame]54Yes. Specifically, Mesa serves as the OpenGL core for the open-source DRI
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]55drivers for X.org.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]56</p>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]57<ul>
58 <li>See the <a href="http://dri.freedesktop.org/">DRI website</a>
59 for more information.</li>
Eric Engestrom771f6db2016-07-06 17:09:15 +0100[diff] [blame]60 <li>See <a href="https://01.org/linuxgraphics">01.org</a>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]61 for more information about Intel drivers.</li>
62 <li>See <a href="http://nouveau.freedesktop.org">nouveau.freedesktop.org</a>
63 for more information about Nouveau drivers.</li>
64 <li>See <a href="http://www.x.org/wiki/RadeonFeature">www.x.org/wiki/RadeonFeature</a>
65 for more information about Radeon drivers.</li>
66</ul>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]67
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]68<h2>1.3 What purpose does Mesa serve today?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]69<p>
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]70Hardware-accelerated OpenGL implementations are available for most popular
71operating systems today.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]72Still, Mesa serves at least these purposes:
73</p>
74<ul>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]75<li>Mesa is used as the core of the open-source X.org DRI
Brian Paul7e4cc1c2005-10-24 23:33:27 +0000[diff] [blame]76 hardware drivers.
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]77</li>
78<li>Mesa is quite portable and allows OpenGL to be used on systems
79 that have no other OpenGL solution.
80</li>
81<li>Software rendering with Mesa serves as a reference for validating the
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]82 hardware drivers.
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]83</li>
84<li>A software implementation of OpenGL is useful for experimentation,
85 such as testing new rendering techniques.
86</li>
87<li>Mesa can render images with deep color channels: 16-bit integer
88 and 32-bit floating point color channels are supported.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]89 This capability is only now appearing in hardware.
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]90</li>
91<li>Mesa's internal limits (max lights, clip planes, texture size, etc) can be
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]92 changed for special needs (hardware limits are hard to overcome).
Brian Paula376e332003-03-30 16:54:36 +0000[diff] [blame]93</li>
94</ul>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]95
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]96
Andreas Boll5abb1f82012-09-19 18:22:37 +0200[diff] [blame]97<h2>1.4 What's the difference between "Stand-Alone" Mesa and the DRI drivers?</h2>
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]98<p>
99<em>Stand-alone Mesa</em> is the original incarnation of Mesa.
Brian Paul7e4cc1c2005-10-24 23:33:27 +0000[diff] [blame]100On systems running the X Window System it does all its rendering through
101the Xlib API:
Andreas Bolldf2be222012-06-12 09:05:22 +0200[diff] [blame]102</p>
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]103<ul>
104<li>The GLX API is supported, but it's really just an emulation of the
105 real thing.
106<li>The GLX wire protocol is not supported and there's no OpenGL extension
107 loaded by the X server.
108<li>There is no hardware acceleration.
109<li>The OpenGL library, libGL.so, contains everything (the programming API,
110 the GLX functions and all the rendering code).
111</ul>
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]112<p>
113Alternately, Mesa acts as the core for a number of OpenGL hardware drivers
114within the DRI (Direct Rendering Infrastructure):
115<ul>
116<li>The libGL.so library provides the GL and GLX API functions, a GLX
117 protocol encoder, and a device driver loader.
118<li>The device driver modules (such as r200_dri.so) contain a built-in
119 copy of the core Mesa code.
120<li>The X server loads the GLX module.
121 The GLX module decodes incoming GLX protocol and dispatches the commands
122 to a rendering module.
123 For the DRI, this module is basically a software Mesa renderer.
124</ul>
125
126
127
128<h2>1.5 How do I upgrade my DRI installation to use a new Mesa release?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]129<p>
Brian Paul7e4cc1c2005-10-24 23:33:27 +0000[diff] [blame]130This wasn't easy in the past.
131Now, the DRI drivers are included in the Mesa tree and can be compiled
132separately from the X server.
133Just follow the Mesa <a href="install.html">compilation instructions</a>.
Brian Paul824a4fc2003-08-06 19:05:26 +0000[diff] [blame]134</p>
135
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]136
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]137<h2>1.6 Are there other open-source implementations of OpenGL?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]138<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]139Yes, SGI's <a href="http://oss.sgi.com/projects/ogl-sample/index.html">
Nathan Kidd0691b372014-01-03 16:44:00 -0700[diff] [blame]140OpenGL Sample Implementation (SI)</a> is available.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]141The SI was written during the time that OpenGL was originally designed.
142Unfortunately, development of the SI has stagnated.
143Mesa is much more up to date with modern features and extensions.
144</p>
Brian Paul186d4d82004-04-27 12:55:08 +0000[diff] [blame]145
146<p>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]147<a href="http://sourceforge.net/projects/ogl-es/">Vincent</a> is
Brian Paul186d4d82004-04-27 12:55:08 +0000[diff] [blame]148an open-source implementation of OpenGL ES for mobile devices.
149
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]150<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]151<a href="http://www.dsbox.com/minigl.html">miniGL</a>
Brian Paul7df4f952003-11-25 21:13:26 +0000[diff] [blame]152is a subset of OpenGL for PalmOS devices.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]153
Brian Paul7df4f952003-11-25 21:13:26 +0000[diff] [blame]154<p>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]155<a href="http://bellard.org/TinyGL/">TinyGL</a>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]156is a subset of OpenGL.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]157</p>
Brian Paul7df4f952003-11-25 21:13:26 +0000[diff] [blame]158
159<p>
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]160<a href="http://sourceforge.net/projects/softgl/">SoftGL</a>
Brian Paul7df4f952003-11-25 21:13:26 +0000[diff] [blame]161is an OpenGL subset for mobile devices.
162</p>
163
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]164<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]165<a href="http://chromium.sourceforge.net/">Chromium</a>
Brian Paulacbc1e02003-11-26 18:10:31 +0000[diff] [blame]166isn't a conventional OpenGL implementation (it's layered upon OpenGL),
167but it does export the OpenGL API. It allows tiled rendering, sort-last
168rendering, etc.
169</p>
170
Brian Paulacbc1e02003-11-26 18:10:31 +0000[diff] [blame]171<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]172<a href="http://www.ticalc.org/archives/files/fileinfo/361/36173.html">ClosedGL</a>
173is an OpenGL subset library for TI graphing calculators.
Brian Paul0c656042006-06-08 19:59:41 +0000[diff] [blame]174</p>
175
176<p>
Brian Paulacbc1e02003-11-26 18:10:31 +0000[diff] [blame]177There may be other open OpenGL implementations, but Mesa is the most
178popular and feature-complete.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]179</p>
180
Brian Paul65b79052004-11-22 17:49:15 +0000[diff] [blame]181
182
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]183<br>
184<br>
185
186
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]187<h1 id="part2">2. Compilation and Installation Problems</h1>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]188
189
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]190<h2>2.1 What's the easiest way to install Mesa?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]191<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]192If you're using a Linux-based system, your distro CD most likely already
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]193has Mesa packages (like RPM or DEB) which you can easily install.
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]194</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]195
196
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]197<h2>2.2 I get undefined symbols such as bgnpolygon, v3f, etc...</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]198<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]199You're application is written in IRIS GL, not OpenGL.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]200IRIS GL was the predecessor to OpenGL and is a different thing (almost)
201entirely.
202Mesa's not the solution.
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]203</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]204
205
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]206<h2>2.3 Where is the GLUT library?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]207<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]208GLUT (OpenGL Utility Toolkit) is no longer in the separate MesaGLUT-x.y.z.tar.gz file.
José Fonseca9a7f84d2011-07-14 17:28:52 +0100[diff] [blame]209If you don't already have GLUT installed, you should grab
210<a href="http://freeglut.sourceforge.net/">freeglut</a>.
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]211</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]212
213
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]214<h2>2.4 Where is the GLw library?</h2>
Kenneth Graunkec5481922011-08-05 16:59:04 -0700[diff] [blame]215<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]216GLw (OpenGL widget library) is now available from a separate <a href="http://cgit.freedesktop.org/mesa/glw/">git repository</a>. Unless you're using very old Xt/Motif applications with OpenGL, you shouldn't need it.
217</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]218
Kenneth Graunkec5481922011-08-05 16:59:04 -0700[diff] [blame]219
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]220<h2>2.5 What's the proper place for the libraries and headers?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]221<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]222On Linux-based systems you'll want to follow the
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]223<a href="http://oss.sgi.com/projects/ogl-sample/ABI/index.html">Linux ABI</a> standard.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]224Basically you'll want the following:
225</p>
226<ul>
227<li>/usr/include/GL/gl.h - the main OpenGL header
228</li><li>/usr/include/GL/glu.h - the OpenGL GLU (utility) header
229</li><li>/usr/include/GL/glx.h - the OpenGL GLX header
230</li><li>/usr/include/GL/glext.h - the OpenGL extensions header
231</li><li>/usr/include/GL/glxext.h - the OpenGL GLX extensions header
232</li><li>/usr/include/GL/osmesa.h - the Mesa off-screen rendering header
233</li><li>/usr/lib/libGL.so - a symlink to libGL.so.1
234</li><li>/usr/lib/libGL.so.1 - a symlink to libGL.so.1.xyz
235</li><li>/usr/lib/libGL.so.xyz - the actual OpenGL/Mesa library. xyz denotes the
236Mesa version number.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]237</li></ul>
238<p>
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]239When configuring Mesa, there are three autoconf options that affect the install
240location that you should take care with: <code>--prefix</code>,
241<code>--libdir</code>, and <code>--with-dri-driverdir</code>. To install Mesa
242into the system location where it will be available for all programs to use, set
243<code>--prefix=/usr</code>. Set <code>--libdir</code> to where your Linux
244distribution installs system libraries, usually either <code>/usr/lib</code> or
245<code>/usr/lib64</code>. Set <code>--with-dri-driverdir</code> to the directory
246where your Linux distribution installs DRI drivers. To find your system's DRI
247driver directory, try executing <code>find /usr -type d -name dri</code>. For
248example, if the <code>find</code> command listed <code>/usr/lib64/dri</code>,
249then set <code>--with-dri-driverdir=/usr/lib64/dri</code>.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]250</p>
251<p>
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]252After determining the correct values for the install location, configure Mesa
253with <code>./configure --prefix=/usr --libdir=xxx --with-dri-driverdir=xxx</code>
254and then install with <code>sudo make install</code>.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]255</p>
256<br>
257<br>
258
259
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]260<h1 id="part3">3. Runtime / Rendering Problems</h1>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]261
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]262<h2>3.1 Rendering is slow / why isn't my graphics hardware being used?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]263<p>
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]264If Mesa can't use its hardware accelerated drivers it falls back on one of its software renderers.
265(eg. classic swrast, softpipe or llvmpipe)
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]266</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]267<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]268You can run the <code>glxinfo</code> program to learn about your OpenGL
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]269library.
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]270Look for the <code>OpenGL vendor</code> and <code>OpenGL renderer</code> values.
271That will identify who's OpenGL library with which driver you're using and what sort of
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]272hardware it has detected.
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]273</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]274<p>
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]275If you're using a hardware accelerated driver you want <code>direct rendering: Yes</code>.
276</p>
277<p>
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]278If your DRI-based driver isn't working, go to the
Andreas Boll8504f182012-09-20 16:23:15 +0200[diff] [blame]279<a href="http://dri.freedesktop.org/">DRI website</a> for trouble-shooting information.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]280</p>
281
282
283<h2>3.2 I'm seeing errors in depth (Z) buffering. Why?</h2>
284<p>
285Make sure the ratio of the far to near clipping planes isn't too great.
286Look
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]287<a href="http://www.opengl.org/resources/faq/technical/depthbuffer.htm#0040">here</a>
288for details.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]289</p>
290<p>
291Mesa uses a 16-bit depth buffer by default which is smaller and faster
292to clear than a 32-bit buffer but not as accurate.
293If you need a deeper you can modify the parameters to
294<code> glXChooseVisual</code> in your code.
295</p>
296
297
298<h2>3.3 Why Isn't depth buffering working at all?</h2>
299<p>
300Be sure you're requesting a depth buffered-visual. If you set the MESA_DEBUG
301environment variable it will warn you about trying to enable depth testing
302when you don't have a depth buffer.
303</p>
304<p>Specifically, make sure <code>glutInitDisplayMode</code> is being called
305with <code>GLUT_DEPTH</code> or <code>glXChooseVisual</code> is being
306called with a non-zero value for GLX_DEPTH_SIZE.
307</p>
308<p>This discussion applies to stencil buffers, accumulation buffers and
309alpha channels too.
310</p>
311
312
313<h2>3.4 Why does glGetString() always return NULL?</h2>
314<p>
315Be sure you have an active/current OpenGL rendering context before
316calling glGetString.
317</p>
318
319
320<h2>3.5 GL_POINTS and GL_LINES don't touch the right pixels</h2>
321<p>
322If you're trying to draw a filled region by using GL_POINTS or GL_LINES
323and seeing holes or gaps it's because of a float-to-int rounding problem.
324But this is not a bug.
325See Appendix H of the OpenGL Programming Guide - "OpenGL Correctness Tips".
326Basically, applying a translation of (0.375, 0.375, 0.0) to your coordinates
327will fix the problem.
328</p>
329
330<br>
331<br>
332
333
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]334<h1 id="part4">4. Developer Questions</h1>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]335
Andreas Bollcc418882012-06-12 09:05:33 +0200[diff] [blame]336<h2>4.1 How can I contribute?</h2>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]337<p>
Andreas Boll5abb1f82012-09-19 18:22:37 +0200[diff] [blame]338First, join the <a href="lists.html">mesa-dev mailing list</a>.
Brian Pauld5299bf2006-08-21 14:26:06 +0000[diff] [blame]339That's where Mesa development is discussed.
Dan Nicholsonf71032b2007-12-14 09:59:16 -0800[diff] [blame]340</p>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]341<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]342The <a href="http://www.opengl.org/documentation">
Nathan Kidd0691b372014-01-03 16:44:00 -0700[diff] [blame]343OpenGL Specification</a> is the bible for OpenGL implementation work.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]344You should read it.
345</p>
346<p>Most of the Mesa development work involves implementing new OpenGL
347extensions, writing hardware drivers (for the DRI), and code optimization.
348</p>
349
350<h2>4.2 How do I write a new device driver?</h2>
351<p>
352Unfortunately, writing a device driver isn't easy.
353It requires detailed understanding of OpenGL, the Mesa code, and your
354target hardware/operating system.
3553D graphics are not simple.
356</p>
357<p>
358The best way to get started is to use an existing driver as your starting
359point.
Andreas Bollb534c392012-10-05 23:14:10 +0200[diff] [blame]360For a classic hardware driver, the i965 driver is a good example.
361For a Gallium3D hardware driver, the r300g, r600g and the i915g are good examples.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]362</p>
363<p>The DRI website has more information about writing hardware drivers.
364The process isn't well document because the Mesa driver interface changes
Nathan Kidd0691b372014-01-03 16:44:00 -0700[diff] [blame]365over time, and we seldom have spare time for writing documentation.
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]366That being said, many people have managed to figure out the process.
367</p>
368<p>
369Joining the appropriate mailing lists and asking questions (and searching
370the archives) is a good way to get information.
371</p>
372
373
Brian Paul0c656042006-06-08 19:59:41 +0000[diff] [blame]374<h2>4.3 Why isn't GL_EXT_texture_compression_s3tc implemented in Mesa?</h2>
Brian Paulfc528e22003-12-31 20:59:51 +0000[diff] [blame]375<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]376The <a href="http://oss.sgi.com/projects/ogl-sample/registry/EXT/texture_compression_s3tc.txt">specification for the extension</a>
Brian Paulfc528e22003-12-31 20:59:51 +0000[diff] [blame]377indicates that there are intellectual property (IP) and/or patent issues
378to be dealt with.
379</p>
Nathan Kidd0691b372014-01-03 16:44:00 -0700[diff] [blame]380<p>We've been unsuccessful in getting a response from S3 (or whoever owns
Brian Paulfc528e22003-12-31 20:59:51 +0000[diff] [blame]381the IP nowadays) to indicate whether or not an open source project can
382implement the extension (specifically the compression/decompression
383algorithms).
384</p>
385<p>
Andreas Bolla73c59b2012-09-18 19:31:28 +0200[diff] [blame]386In the mean time, a 3rd party <a href="http://dri.freedesktop.org/wiki/S3TC">
387plug-in library</a> is available.
Brian Paulfc528e22003-12-31 20:59:51 +0000[diff] [blame]388</p>
389
Andreas Bollb5da52a2012-09-18 18:57:02 +0200[diff] [blame]390</div>
Brian Paul0b27ace2003-03-08 17:38:57 +0000[diff] [blame]391</body>
392</html>