src/mesa/main/extensions.c - fp2-dev/platform/external/mesa3d - Gitiles

 /* $Id: extensions.c,v 1.9 1999/10/16 11:30:31 brianp Exp $ */

 /*
  * Mesa 3-D graphics library
  * Version:  3.1
  *
  * Copyright (C) 1999  Brian Paul   All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included
  * in all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  */


 #include <stdlib.h>
 #include "context.h"
 #include "extensions.h"
 #include "simple_list.h"
 #include "types.h"


 #define MAX_EXT_NAMELEN 80

 struct extension {
    struct extension *next, *prev;
    int enabled;
    char name[MAX_EXT_NAMELEN+1];
    void (*notify)( GLcontext *, GLboolean );
 };


 static struct { int enabled; const char *name; } default_extensions[] = {
    { ALWAYS_ENABLED, "GL_EXT_blend_color" },
    { DEFAULT_OFF,    "ARB_imaging" },
    { DEFAULT_ON,     "GL_EXT_blend_minmax" },
    { DEFAULT_ON,     "GL_EXT_blend_logic_op" },
    { DEFAULT_ON,     "GL_EXT_blend_subtract" },
    { DEFAULT_ON,     "GL_EXT_paletted_texture" },
    { DEFAULT_ON,     "GL_EXT_point_parameters" },
    { ALWAYS_ENABLED, "GL_EXT_polygon_offset" },
    { ALWAYS_ENABLED, "GL_EXT_vertex_array" },
    { ALWAYS_ENABLED, "GL_EXT_texture_object" },
    { DEFAULT_ON,     "GL_EXT_texture3D" },
    { ALWAYS_ENABLED, "GL_MESA_window_pos" },
    { ALWAYS_ENABLED, "GL_MESA_resize_buffers" },
    { ALWAYS_ENABLED, "GL_EXT_shared_texture_palette" },
    { ALWAYS_ENABLED, "GL_EXT_rescale_normal" },
    { ALWAYS_ENABLED, "GL_EXT_abgr" },
    { ALWAYS_ENABLED, "GL_SGIS_texture_edge_clamp" },
    { ALWAYS_ENABLED, "GL_EXT_stencil_wrap" },
    { DEFAULT_ON,     "GL_INGR_blend_func_separate" },
    { DEFAULT_ON,     "GL_ARB_multitexture" },
    { ALWAYS_ENABLED, "GL_NV_texgen_reflection" },
    { DEFAULT_ON,     "GL_PGI_misc_hints" },
    { DEFAULT_ON,     "GL_EXT_compiled_vertex_array" },
    { DEFAULT_OFF,    "GL_EXT_vertex_array_set" },
    { DEFAULT_ON,     "GL_EXT_clip_volume_hint" },
 };


 int gl_extensions_add( GLcontext *ctx,
 		       int state,
 		       const char *name,
 		       void (*notify)(void) )
 {
    (void) notify;

    if (ctx->Extensions.ext_string == 0)
    {
       struct extension *t = MALLOC_STRUCT(extension);
       t->enabled = state;
       strncpy(t->name, name, MAX_EXT_NAMELEN);
       t->name[MAX_EXT_NAMELEN] = 0;
       t->notify = (void (*)(GLcontext *, GLboolean)) notify;
       insert_at_tail( ctx->Extensions.ext_list, t );
       return 0;
    }
    return 1;
 }


 static int set_extension( GLcontext *ctx, const char *name, GLuint state )
 {
    struct extension *i;
    foreach( i, ctx->Extensions.ext_list )
       if (strncmp(i->name, name, MAX_EXT_NAMELEN) == 0)
 	 break;

    if (i == ctx->Extensions.ext_list) return 1;

    if (i->enabled && !(i->enabled & ALWAYS_ENABLED))
    {
       if (i->notify) i->notify( ctx, state );
       i->enabled = state;
    }

    return 0;
 }


 int gl_extensions_enable( GLcontext *ctx, const char *name )
 {
    if (ctx->Extensions.ext_string == 0)
       return set_extension( ctx, name, 1 );
    return 1;
 }


 int gl_extensions_disable( GLcontext *ctx, const char *name )
 {
    if (ctx->Extensions.ext_string == 0)
       return set_extension( ctx, name, 0 );
    return 1;
 }


 void gl_extensions_dtr( GLcontext *ctx )
 {
    struct extension *i, *nexti;

    if (ctx->Extensions.ext_string) {
       FREE( ctx->Extensions.ext_string );
       ctx->Extensions.ext_string = 0;
    }

    if (ctx->Extensions.ext_list) {
       foreach_s( i, nexti, ctx->Extensions.ext_list ) {
 	 remove_from_list( i );
 	 FREE( i );
       }

       FREE(ctx->Extensions.ext_list);
       ctx->Extensions.ext_list = 0;
    }
 }


 void gl_extensions_ctr( GLcontext *ctx )
 {
    GLuint i;

    ctx->Extensions.ext_string = 0;
    ctx->Extensions.ext_list = MALLOC_STRUCT(extension);
    make_empty_list( ctx->Extensions.ext_list );

    for (i = 0 ; i < Elements(default_extensions) ; i++) {
       gl_extensions_add( ctx,
 			 default_extensions[i].enabled,
 			 default_extensions[i].name,
 			 0 );
    }
 }


 const char *gl_extensions_get_string( GLcontext *ctx )
 {
    if (ctx->Extensions.ext_string == 0)
    {
       struct extension *i;
       char *str;
       GLuint len = 0;
       foreach (i, ctx->Extensions.ext_list)
 	 if (i->enabled)
 	    len += strlen(i->name) + 1;

       if (len == 0)
 	 return "";

       str = (char *)MALLOC(len * sizeof(char));
       ctx->Extensions.ext_string = str;

       foreach (i, ctx->Extensions.ext_list)
 	 if (i->enabled) {
 	    strcpy(str, i->name);
 	    str += strlen(str);
 	    *str++ = ' ';
 	 }

       *(str-1) = 0;
    }

    return ctx->Extensions.ext_string;
 }


 /*
  * Return the address of an extension function.
  * This is meant to be called by glXGetProcAddress(), wglGetProcAddress(),
  * or similar function.
  * NOTE: this function could be optimized to binary search a sorted
  * list of function names.
  */
 void (*gl_get_proc_address( const GLubyte *procName ))()
 {
    typedef void (*gl_function)();
    struct proc {
       const char *name;
       gl_function address;
    };
    static struct proc procTable[] = {
       /* OpenGL 1.1 functions */
       { "glEnableClientState", (gl_function) glEnableClientState },
       { "glDisableClientState", (gl_function) glDisableClientState },
       { "glPushClientAttrib", (gl_function) glPushClientAttrib },
       { "glPopClientAttrib", (gl_function) glPopClientAttrib },
       { "glIndexub", (gl_function) glIndexub },
       { "glIndexubv", (gl_function) glIndexubv },
       { "glVertexPointer", (gl_function) glVertexPointer },
       { "glNormalPointer", (gl_function) glNormalPointer },
       { "glColorPointer", (gl_function) glColorPointer },
       { "glIndexPointer", (gl_function) glIndexPointer },
       { "glTexCoordPointer", (gl_function) glTexCoordPointer },
       { "glEdgeFlagPointer", (gl_function) glEdgeFlagPointer },
       { "glGetPointerv", (gl_function) glGetPointerv },
       { "glArrayElement", (gl_function) glArrayElement },
       { "glDrawArrays", (gl_function) glDrawArrays },
       { "glDrawElements", (gl_function) glDrawElements },
       { "glInterleavedArrays", (gl_function) glInterleavedArrays },
       { "glGenTextures", (gl_function) glGenTextures },
       { "glDeleteTextures", (gl_function) glDeleteTextures },
       { "glBindTexture", (gl_function) glBindTexture },
       { "glPrioritizeTextures", (gl_function) glPrioritizeTextures },
       { "glAreTexturesResident", (gl_function) glAreTexturesResident },
       { "glIsTexture", (gl_function) glIsTexture },
       { "glTexSubImage1D", (gl_function) glTexSubImage1D },
       { "glTexSubImage2D", (gl_function) glTexSubImage2D },
       { "glCopyTexImage1D", (gl_function) glCopyTexImage1D },
       { "glCopyTexImage2D", (gl_function) glCopyTexImage2D },
       { "glCopyTexSubImage1D", (gl_function) glCopyTexSubImage1D },
       { "glCopyTexSubImage2D", (gl_function) glCopyTexSubImage2D },

       /* OpenGL 1.2 functions */
       { "glDrawRangeElements", (gl_function) glDrawRangeElements },
       { "glTexImage3D", (gl_function) glTexImage3D },
       { "glTexSubImage3D", (gl_function) glTexSubImage3D },
       { "glCopyTexSubImage3D", (gl_function) glCopyTexSubImage3D },
       /* NOTE: 1.2 imaging subset functions not implemented in Mesa */

       /* GL_EXT_blend_minmax */
       { "glBlendEquationEXT", (gl_function) glBlendEquationEXT },

       /* GL_EXT_blend_color */
       { "glBlendColorEXT", (gl_function) glBlendColorEXT },

       /* GL_EXT_polygon_offset */
       { "glPolygonOffsetEXT", (gl_function) glPolygonOffsetEXT },

       /* GL_EXT_vertex_arrays */
       { "glVertexPointerEXT", (gl_function) glVertexPointerEXT },
       { "glNormalPointerEXT", (gl_function) glNormalPointerEXT },
       { "glColorPointerEXT", (gl_function) glColorPointerEXT },
       { "glIndexPointerEXT", (gl_function) glIndexPointerEXT },
       { "glTexCoordPointerEXT", (gl_function) glTexCoordPointerEXT },
       { "glEdgeFlagPointerEXT", (gl_function) glEdgeFlagPointerEXT },
       { "glGetPointervEXT", (gl_function) glGetPointervEXT },
       { "glArrayElementEXT", (gl_function) glArrayElementEXT },
       { "glDrawArraysEXT", (gl_function) glDrawArraysEXT },

       /* GL_EXT_texture_object */
       { "glGenTexturesEXT", (gl_function) glGenTexturesEXT },
       { "glDeleteTexturesEXT", (gl_function) glDeleteTexturesEXT },
       { "glBindTextureEXT", (gl_function) glBindTextureEXT },
       { "glPrioritizeTexturesEXT", (gl_function) glPrioritizeTexturesEXT },
       { "glAreTexturesResidentEXT", (gl_function) glAreTexturesResidentEXT },
       { "glIsTextureEXT", (gl_function) glIsTextureEXT },

       /* GL_EXT_texture3D */
       { "glTexImage3DEXT", (gl_function) glTexImage3DEXT },
       { "glTexSubImage3DEXT", (gl_function) glTexSubImage3DEXT },
       { "glCopyTexSubImage3DEXT", (gl_function) glCopyTexSubImage3DEXT },

       /* GL_EXT_color_table */
       { "glColorTableEXT", (gl_function) glColorTableEXT },
       { "glColorSubTableEXT", (gl_function) glColorSubTableEXT },
       { "glGetColorTableEXT", (gl_function) glGetColorTableEXT },
       { "glGetColorTableParameterfvEXT", (gl_function) glGetColorTableParameterfvEXT },
       { "glGetColorTableParameterivEXT", (gl_function) glGetColorTableParameterivEXT },

       /* GL_ARB_multitexture */
       { "glActiveTextureARB", (gl_function) glActiveTextureARB },
       { "glClientActiveTextureARB", (gl_function) glClientActiveTextureARB },
       { "glMultiTexCoord1dARB", (gl_function) glMultiTexCoord1dARB },
       { "glMultiTexCoord1dvARB", (gl_function) glMultiTexCoord1dvARB },
       { "glMultiTexCoord1fARB", (gl_function) glMultiTexCoord1fARB },
       { "glMultiTexCoord1fvARB", (gl_function) glMultiTexCoord1fvARB },
       { "glMultiTexCoord1iARB", (gl_function) glMultiTexCoord1iARB },
       { "glMultiTexCoord1ivARB", (gl_function) glMultiTexCoord1ivARB },
       { "glMultiTexCoord1sARB", (gl_function) glMultiTexCoord1sARB },
       { "glMultiTexCoord1svARB", (gl_function) glMultiTexCoord1svARB },
       { "glMultiTexCoord2dARB", (gl_function) glMultiTexCoord2dARB },
       { "glMultiTexCoord2dvARB", (gl_function) glMultiTexCoord2dvARB },
       { "glMultiTexCoord2fARB", (gl_function) glMultiTexCoord2fARB },
       { "glMultiTexCoord2fvARB", (gl_function) glMultiTexCoord2fvARB },
       { "glMultiTexCoord2iARB", (gl_function) glMultiTexCoord2iARB },
       { "glMultiTexCoord2ivARB", (gl_function) glMultiTexCoord2ivARB },
       { "glMultiTexCoord2sARB", (gl_function) glMultiTexCoord2sARB },
       { "glMultiTexCoord2svARB", (gl_function) glMultiTexCoord2svARB },
       { "glMultiTexCoord3dARB", (gl_function) glMultiTexCoord3dARB },
       { "glMultiTexCoord3dvARB", (gl_function) glMultiTexCoord3dvARB },
       { "glMultiTexCoord3fARB", (gl_function) glMultiTexCoord3fARB },
       { "glMultiTexCoord3fvARB", (gl_function) glMultiTexCoord3fvARB },
       { "glMultiTexCoord3iARB", (gl_function) glMultiTexCoord3iARB },
       { "glMultiTexCoord3ivARB", (gl_function) glMultiTexCoord3ivARB },
       { "glMultiTexCoord3sARB", (gl_function) glMultiTexCoord3sARB },
       { "glMultiTexCoord3svARB", (gl_function) glMultiTexCoord3svARB },
       { "glMultiTexCoord4dARB", (gl_function) glMultiTexCoord4dARB },
       { "glMultiTexCoord4dvARB", (gl_function) glMultiTexCoord4dvARB },
       { "glMultiTexCoord4fARB", (gl_function) glMultiTexCoord4fARB },
       { "glMultiTexCoord4fvARB", (gl_function) glMultiTexCoord4fvARB },
       { "glMultiTexCoord4iARB", (gl_function) glMultiTexCoord4iARB },
       { "glMultiTexCoord4ivARB", (gl_function) glMultiTexCoord4ivARB },
       { "glMultiTexCoord4sARB", (gl_function) glMultiTexCoord4sARB },
       { "glMultiTexCoord4svARB", (gl_function) glMultiTexCoord4svARB },

       /* GL_EXT_point_parameters */
       { "glPointParameterfEXT", (gl_function) glPointParameterfEXT },
       { "glPointParameterfvEXT", (gl_function) glPointParameterfvEXT },

       /* GL_INGR_blend_func_separate */
       { "glBlendFuncSeparateINGR", (gl_function) glBlendFuncSeparateINGR },

       /* GL_MESA_window_pos */
       { "glWindowPos2iMESA", (gl_function) glWindowPos2iMESA },
       { "glWindowPos2sMESA", (gl_function) glWindowPos2sMESA },
       { "glWindowPos2fMESA", (gl_function) glWindowPos2fMESA },
       { "glWindowPos2dMESA", (gl_function) glWindowPos2dMESA },
       { "glWindowPos2ivMESA", (gl_function) glWindowPos2ivMESA },
       { "glWindowPos2svMESA", (gl_function) glWindowPos2svMESA },
       { "glWindowPos2fvMESA", (gl_function) glWindowPos2fvMESA },
       { "glWindowPos2dvMESA", (gl_function) glWindowPos2dvMESA },
       { "glWindowPos3iMESA", (gl_function) glWindowPos3iMESA },
       { "glWindowPos3sMESA", (gl_function) glWindowPos3sMESA },
       { "glWindowPos3fMESA", (gl_function) glWindowPos3fMESA },
       { "glWindowPos3dMESA", (gl_function) glWindowPos3dMESA },
       { "glWindowPos3ivMESA", (gl_function) glWindowPos3ivMESA },
       { "glWindowPos3svMESA", (gl_function) glWindowPos3svMESA },
       { "glWindowPos3fvMESA", (gl_function) glWindowPos3fvMESA },
       { "glWindowPos3dvMESA", (gl_function) glWindowPos3dvMESA },
       { "glWindowPos4iMESA", (gl_function) glWindowPos4iMESA },
       { "glWindowPos4sMESA", (gl_function) glWindowPos4sMESA },
       { "glWindowPos4fMESA", (gl_function) glWindowPos4fMESA },
       { "glWindowPos4dMESA", (gl_function) glWindowPos4dMESA },
       { "glWindowPos4ivMESA", (gl_function) glWindowPos4ivMESA },
       { "glWindowPos4svMESA", (gl_function) glWindowPos4svMESA },
       { "glWindowPos4fvMESA", (gl_function) glWindowPos4fvMESA },
       { "glWindowPos4dvMESA", (gl_function) glWindowPos4dvMESA },

       /* GL_MESA_resize_buffers */
       { "glResizeBuffersMESA", (gl_function) glResizeBuffersMESA },

       /* GL_EXT_compiled_vertex_array */
       { "glLockArraysEXT", (gl_function) glLockArraysEXT },
       { "glUnlockArraysEXT", (gl_function) glUnlockArraysEXT },

       { NULL, NULL } /* end of list token */
    };
    GLuint i;

    for (i = 0; procTable[i].address; i++) {
       if (strcmp((const char *) procName, procTable[i].name) == 0)
          return procTable[i].address;
    }

    return NULL;
 }
	/* $Id: extensions.c,v 1.9 1999/10/16 11:30:31 brianp Exp $ */

	/*
	* Mesa 3-D graphics library
	* Version: 3.1
	*
	* Copyright (C) 1999 Brian Paul All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included
	* in all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
	* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
	* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
	*/


	#include <stdlib.h>
	#include "context.h"
	#include "extensions.h"
	#include "simple_list.h"
	#include "types.h"


	#define MAX_EXT_NAMELEN 80

	struct extension {
	struct extension next, prev;
	int enabled;
	char name[MAX_EXT_NAMELEN+1];
	void (notify)( GLcontext , GLboolean );
	};



	static struct { int enabled; const char *name; } default_extensions[] = {
	{ ALWAYS_ENABLED, "GL_EXT_blend_color" },
	{ DEFAULT_OFF, "ARB_imaging" },
	{ DEFAULT_ON, "GL_EXT_blend_minmax" },
	{ DEFAULT_ON, "GL_EXT_blend_logic_op" },
	{ DEFAULT_ON, "GL_EXT_blend_subtract" },
	{ DEFAULT_ON, "GL_EXT_paletted_texture" },
	{ DEFAULT_ON, "GL_EXT_point_parameters" },
	{ ALWAYS_ENABLED, "GL_EXT_polygon_offset" },
	{ ALWAYS_ENABLED, "GL_EXT_vertex_array" },
	{ ALWAYS_ENABLED, "GL_EXT_texture_object" },
	{ DEFAULT_ON, "GL_EXT_texture3D" },
	{ ALWAYS_ENABLED, "GL_MESA_window_pos" },
	{ ALWAYS_ENABLED, "GL_MESA_resize_buffers" },
	{ ALWAYS_ENABLED, "GL_EXT_shared_texture_palette" },
	{ ALWAYS_ENABLED, "GL_EXT_rescale_normal" },
	{ ALWAYS_ENABLED, "GL_EXT_abgr" },
	{ ALWAYS_ENABLED, "GL_SGIS_texture_edge_clamp" },
	{ ALWAYS_ENABLED, "GL_EXT_stencil_wrap" },
	{ DEFAULT_ON, "GL_INGR_blend_func_separate" },
	{ DEFAULT_ON, "GL_ARB_multitexture" },
	{ ALWAYS_ENABLED, "GL_NV_texgen_reflection" },
	{ DEFAULT_ON, "GL_PGI_misc_hints" },
	{ DEFAULT_ON, "GL_EXT_compiled_vertex_array" },
	{ DEFAULT_OFF, "GL_EXT_vertex_array_set" },
	{ DEFAULT_ON, "GL_EXT_clip_volume_hint" },
	};


	int gl_extensions_add( GLcontext *ctx,
	int state,
	const char *name,
	void (*notify)(void) )
	{
	(void) notify;

	if (ctx->Extensions.ext_string == 0)
	{
	struct extension *t = MALLOC_STRUCT(extension);
	t->enabled = state;
	strncpy(t->name, name, MAX_EXT_NAMELEN);
	t->name[MAX_EXT_NAMELEN] = 0;
	t->notify = (void ()(GLcontext , GLboolean)) notify;
	insert_at_tail( ctx->Extensions.ext_list, t );
	return 0;
	}
	return 1;
	}


	static int set_extension( GLcontext ctx, const char name, GLuint state )
	{
	struct extension *i;
	foreach( i, ctx->Extensions.ext_list )
	if (strncmp(i->name, name, MAX_EXT_NAMELEN) == 0)
	break;

	if (i == ctx->Extensions.ext_list) return 1;

	if (i->enabled && !(i->enabled & ALWAYS_ENABLED))
	{
	if (i->notify) i->notify( ctx, state );
	i->enabled = state;
	}

	return 0;
	}


	int gl_extensions_enable( GLcontext ctx, const char name )
	{
	if (ctx->Extensions.ext_string == 0)
	return set_extension( ctx, name, 1 );
	return 1;
	}


	int gl_extensions_disable( GLcontext ctx, const char name )
	{
	if (ctx->Extensions.ext_string == 0)
	return set_extension( ctx, name, 0 );
	return 1;
	}


	void gl_extensions_dtr( GLcontext *ctx )
	{
	struct extension i, nexti;

	if (ctx->Extensions.ext_string) {
	FREE( ctx->Extensions.ext_string );
	ctx->Extensions.ext_string = 0;
	}

	if (ctx->Extensions.ext_list) {
	foreach_s( i, nexti, ctx->Extensions.ext_list ) {
	remove_from_list( i );
	FREE( i );
	}

	FREE(ctx->Extensions.ext_list);
	ctx->Extensions.ext_list = 0;
	}
	}


	void gl_extensions_ctr( GLcontext *ctx )
	{
	GLuint i;

	ctx->Extensions.ext_string = 0;
	ctx->Extensions.ext_list = MALLOC_STRUCT(extension);
	make_empty_list( ctx->Extensions.ext_list );

	for (i = 0 ; i < Elements(default_extensions) ; i++) {
	gl_extensions_add( ctx,
	default_extensions[i].enabled,
	default_extensions[i].name,
	0 );
	}
	}


	const char gl_extensions_get_string( GLcontext ctx )
	{
	if (ctx->Extensions.ext_string == 0)
	{
	struct extension *i;
	char *str;
	GLuint len = 0;
	foreach (i, ctx->Extensions.ext_list)
	if (i->enabled)
	len += strlen(i->name) + 1;

	if (len == 0)
	return "";

	str = (char )MALLOC(len sizeof(char));
	ctx->Extensions.ext_string = str;

	foreach (i, ctx->Extensions.ext_list)
	if (i->enabled) {
	strcpy(str, i->name);
	str += strlen(str);
	*str++ = ' ';
	}

	*(str-1) = 0;
	}

	return ctx->Extensions.ext_string;
	}



	/*
	* Return the address of an extension function.
	* This is meant to be called by glXGetProcAddress(), wglGetProcAddress(),
	* or similar function.
	* NOTE: this function could be optimized to binary search a sorted
	* list of function names.
	*/
	void (gl_get_proc_address( const GLubyte procName ))()
	{
	typedef void (*gl_function)();
	struct proc {
	const char *name;
	gl_function address;
	};
	static struct proc procTable[] = {
	/* OpenGL 1.1 functions */
	{ "glEnableClientState", (gl_function) glEnableClientState },
	{ "glDisableClientState", (gl_function) glDisableClientState },
	{ "glPushClientAttrib", (gl_function) glPushClientAttrib },
	{ "glPopClientAttrib", (gl_function) glPopClientAttrib },
	{ "glIndexub", (gl_function) glIndexub },
	{ "glIndexubv", (gl_function) glIndexubv },
	{ "glVertexPointer", (gl_function) glVertexPointer },
	{ "glNormalPointer", (gl_function) glNormalPointer },
	{ "glColorPointer", (gl_function) glColorPointer },
	{ "glIndexPointer", (gl_function) glIndexPointer },
	{ "glTexCoordPointer", (gl_function) glTexCoordPointer },
	{ "glEdgeFlagPointer", (gl_function) glEdgeFlagPointer },
	{ "glGetPointerv", (gl_function) glGetPointerv },
	{ "glArrayElement", (gl_function) glArrayElement },
	{ "glDrawArrays", (gl_function) glDrawArrays },
	{ "glDrawElements", (gl_function) glDrawElements },
	{ "glInterleavedArrays", (gl_function) glInterleavedArrays },
	{ "glGenTextures", (gl_function) glGenTextures },
	{ "glDeleteTextures", (gl_function) glDeleteTextures },
	{ "glBindTexture", (gl_function) glBindTexture },
	{ "glPrioritizeTextures", (gl_function) glPrioritizeTextures },
	{ "glAreTexturesResident", (gl_function) glAreTexturesResident },
	{ "glIsTexture", (gl_function) glIsTexture },
	{ "glTexSubImage1D", (gl_function) glTexSubImage1D },
	{ "glTexSubImage2D", (gl_function) glTexSubImage2D },
	{ "glCopyTexImage1D", (gl_function) glCopyTexImage1D },
	{ "glCopyTexImage2D", (gl_function) glCopyTexImage2D },
	{ "glCopyTexSubImage1D", (gl_function) glCopyTexSubImage1D },
	{ "glCopyTexSubImage2D", (gl_function) glCopyTexSubImage2D },

	/* OpenGL 1.2 functions */
	{ "glDrawRangeElements", (gl_function) glDrawRangeElements },
	{ "glTexImage3D", (gl_function) glTexImage3D },
	{ "glTexSubImage3D", (gl_function) glTexSubImage3D },
	{ "glCopyTexSubImage3D", (gl_function) glCopyTexSubImage3D },
	/* NOTE: 1.2 imaging subset functions not implemented in Mesa */

	/* GL_EXT_blend_minmax */
	{ "glBlendEquationEXT", (gl_function) glBlendEquationEXT },

	/* GL_EXT_blend_color */
	{ "glBlendColorEXT", (gl_function) glBlendColorEXT },

	/* GL_EXT_polygon_offset */
	{ "glPolygonOffsetEXT", (gl_function) glPolygonOffsetEXT },

	/* GL_EXT_vertex_arrays */
	{ "glVertexPointerEXT", (gl_function) glVertexPointerEXT },
	{ "glNormalPointerEXT", (gl_function) glNormalPointerEXT },
	{ "glColorPointerEXT", (gl_function) glColorPointerEXT },
	{ "glIndexPointerEXT", (gl_function) glIndexPointerEXT },
	{ "glTexCoordPointerEXT", (gl_function) glTexCoordPointerEXT },
	{ "glEdgeFlagPointerEXT", (gl_function) glEdgeFlagPointerEXT },
	{ "glGetPointervEXT", (gl_function) glGetPointervEXT },
	{ "glArrayElementEXT", (gl_function) glArrayElementEXT },
	{ "glDrawArraysEXT", (gl_function) glDrawArraysEXT },

	/* GL_EXT_texture_object */
	{ "glGenTexturesEXT", (gl_function) glGenTexturesEXT },
	{ "glDeleteTexturesEXT", (gl_function) glDeleteTexturesEXT },
	{ "glBindTextureEXT", (gl_function) glBindTextureEXT },
	{ "glPrioritizeTexturesEXT", (gl_function) glPrioritizeTexturesEXT },
	{ "glAreTexturesResidentEXT", (gl_function) glAreTexturesResidentEXT },
	{ "glIsTextureEXT", (gl_function) glIsTextureEXT },

	/* GL_EXT_texture3D */
	{ "glTexImage3DEXT", (gl_function) glTexImage3DEXT },
	{ "glTexSubImage3DEXT", (gl_function) glTexSubImage3DEXT },
	{ "glCopyTexSubImage3DEXT", (gl_function) glCopyTexSubImage3DEXT },

	/* GL_EXT_color_table */
	{ "glColorTableEXT", (gl_function) glColorTableEXT },
	{ "glColorSubTableEXT", (gl_function) glColorSubTableEXT },
	{ "glGetColorTableEXT", (gl_function) glGetColorTableEXT },
	{ "glGetColorTableParameterfvEXT", (gl_function) glGetColorTableParameterfvEXT },
	{ "glGetColorTableParameterivEXT", (gl_function) glGetColorTableParameterivEXT },

	/* GL_ARB_multitexture */
	{ "glActiveTextureARB", (gl_function) glActiveTextureARB },
	{ "glClientActiveTextureARB", (gl_function) glClientActiveTextureARB },
	{ "glMultiTexCoord1dARB", (gl_function) glMultiTexCoord1dARB },
	{ "glMultiTexCoord1dvARB", (gl_function) glMultiTexCoord1dvARB },
	{ "glMultiTexCoord1fARB", (gl_function) glMultiTexCoord1fARB },
	{ "glMultiTexCoord1fvARB", (gl_function) glMultiTexCoord1fvARB },
	{ "glMultiTexCoord1iARB", (gl_function) glMultiTexCoord1iARB },
	{ "glMultiTexCoord1ivARB", (gl_function) glMultiTexCoord1ivARB },
	{ "glMultiTexCoord1sARB", (gl_function) glMultiTexCoord1sARB },
	{ "glMultiTexCoord1svARB", (gl_function) glMultiTexCoord1svARB },
	{ "glMultiTexCoord2dARB", (gl_function) glMultiTexCoord2dARB },
	{ "glMultiTexCoord2dvARB", (gl_function) glMultiTexCoord2dvARB },
	{ "glMultiTexCoord2fARB", (gl_function) glMultiTexCoord2fARB },
	{ "glMultiTexCoord2fvARB", (gl_function) glMultiTexCoord2fvARB },
	{ "glMultiTexCoord2iARB", (gl_function) glMultiTexCoord2iARB },
	{ "glMultiTexCoord2ivARB", (gl_function) glMultiTexCoord2ivARB },
	{ "glMultiTexCoord2sARB", (gl_function) glMultiTexCoord2sARB },
	{ "glMultiTexCoord2svARB", (gl_function) glMultiTexCoord2svARB },
	{ "glMultiTexCoord3dARB", (gl_function) glMultiTexCoord3dARB },
	{ "glMultiTexCoord3dvARB", (gl_function) glMultiTexCoord3dvARB },
	{ "glMultiTexCoord3fARB", (gl_function) glMultiTexCoord3fARB },
	{ "glMultiTexCoord3fvARB", (gl_function) glMultiTexCoord3fvARB },
	{ "glMultiTexCoord3iARB", (gl_function) glMultiTexCoord3iARB },
	{ "glMultiTexCoord3ivARB", (gl_function) glMultiTexCoord3ivARB },
	{ "glMultiTexCoord3sARB", (gl_function) glMultiTexCoord3sARB },
	{ "glMultiTexCoord3svARB", (gl_function) glMultiTexCoord3svARB },
	{ "glMultiTexCoord4dARB", (gl_function) glMultiTexCoord4dARB },
	{ "glMultiTexCoord4dvARB", (gl_function) glMultiTexCoord4dvARB },
	{ "glMultiTexCoord4fARB", (gl_function) glMultiTexCoord4fARB },
	{ "glMultiTexCoord4fvARB", (gl_function) glMultiTexCoord4fvARB },
	{ "glMultiTexCoord4iARB", (gl_function) glMultiTexCoord4iARB },
	{ "glMultiTexCoord4ivARB", (gl_function) glMultiTexCoord4ivARB },
	{ "glMultiTexCoord4sARB", (gl_function) glMultiTexCoord4sARB },
	{ "glMultiTexCoord4svARB", (gl_function) glMultiTexCoord4svARB },

	/* GL_EXT_point_parameters */
	{ "glPointParameterfEXT", (gl_function) glPointParameterfEXT },
	{ "glPointParameterfvEXT", (gl_function) glPointParameterfvEXT },

	/* GL_INGR_blend_func_separate */
	{ "glBlendFuncSeparateINGR", (gl_function) glBlendFuncSeparateINGR },

	/* GL_MESA_window_pos */
	{ "glWindowPos2iMESA", (gl_function) glWindowPos2iMESA },
	{ "glWindowPos2sMESA", (gl_function) glWindowPos2sMESA },
	{ "glWindowPos2fMESA", (gl_function) glWindowPos2fMESA },
	{ "glWindowPos2dMESA", (gl_function) glWindowPos2dMESA },
	{ "glWindowPos2ivMESA", (gl_function) glWindowPos2ivMESA },
	{ "glWindowPos2svMESA", (gl_function) glWindowPos2svMESA },
	{ "glWindowPos2fvMESA", (gl_function) glWindowPos2fvMESA },
	{ "glWindowPos2dvMESA", (gl_function) glWindowPos2dvMESA },
	{ "glWindowPos3iMESA", (gl_function) glWindowPos3iMESA },
	{ "glWindowPos3sMESA", (gl_function) glWindowPos3sMESA },
	{ "glWindowPos3fMESA", (gl_function) glWindowPos3fMESA },
	{ "glWindowPos3dMESA", (gl_function) glWindowPos3dMESA },
	{ "glWindowPos3ivMESA", (gl_function) glWindowPos3ivMESA },
	{ "glWindowPos3svMESA", (gl_function) glWindowPos3svMESA },
	{ "glWindowPos3fvMESA", (gl_function) glWindowPos3fvMESA },
	{ "glWindowPos3dvMESA", (gl_function) glWindowPos3dvMESA },
	{ "glWindowPos4iMESA", (gl_function) glWindowPos4iMESA },
	{ "glWindowPos4sMESA", (gl_function) glWindowPos4sMESA },
	{ "glWindowPos4fMESA", (gl_function) glWindowPos4fMESA },
	{ "glWindowPos4dMESA", (gl_function) glWindowPos4dMESA },
	{ "glWindowPos4ivMESA", (gl_function) glWindowPos4ivMESA },
	{ "glWindowPos4svMESA", (gl_function) glWindowPos4svMESA },
	{ "glWindowPos4fvMESA", (gl_function) glWindowPos4fvMESA },
	{ "glWindowPos4dvMESA", (gl_function) glWindowPos4dvMESA },

	/* GL_MESA_resize_buffers */
	{ "glResizeBuffersMESA", (gl_function) glResizeBuffersMESA },

	/* GL_EXT_compiled_vertex_array */
	{ "glLockArraysEXT", (gl_function) glLockArraysEXT },
	{ "glUnlockArraysEXT", (gl_function) glUnlockArraysEXT },

	{ NULL, NULL } /* end of list token */
	};
	GLuint i;

	for (i = 0; procTable[i].address; i++) {
	if (strcmp((const char *) procName, procTable[i].name) == 0)
	return procTable[i].address;
	}

	return NULL;
	}