extensions.c revision 3464ebd5
1/*
2 * Mesa 3-D graphics library
3 * Version:  7.6
4 *
5 * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
6 * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
7 *
8 * Permission is hereby granted, free of charge, to any person obtaining a
9 * copy of this software and associated documentation files (the "Software"),
10 * to deal in the Software without restriction, including without limitation
11 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
12 * and/or sell copies of the Software, and to permit persons to whom the
13 * Software is furnished to do so, subject to the following conditions:
14 *
15 * The above copyright notice and this permission notice shall be included
16 * in all copies or substantial portions of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
21 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
22 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
24 */
25
26
27/**
28 * \file
29 * \brief Extension handling
30 */
31
32
33#include "glheader.h"
34#include "imports.h"
35#include "context.h"
36#include "extensions.h"
37#include "mfeatures.h"
38#include "mtypes.h"
39
40enum {
41   DISABLE = 0,
42   GL  = 1 << API_OPENGL,
43   ES1 = 1 << API_OPENGLES,
44   ES2 = 1 << API_OPENGLES2,
45};
46
47/**
48 * \brief An element of the \c extension_table.
49 */
50struct extension {
51   /** Name of extension, such as "GL_ARB_depth_clamp". */
52   const char *name;
53
54   /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
55   size_t offset;
56
57   /** Set of API's in which the extension exists, as a bitset. */
58   uint8_t api_set;
59
60   /** Year the extension was proposed or approved.  Used to sort the
61    * extension string chronologically. */
62   uint16_t year;
63};
64
65
66/**
67 * Given a member \c x of struct gl_extensions, return offset of
68 * \c x in bytes.
69 */
70#define o(x) offsetof(struct gl_extensions, x)
71
72
73/**
74 * \brief Table of supported OpenGL extensions for all API's.
75 *
76 * Note: The GL_MESAX_* extensions are placeholders for future ARB extensions.
77 */
78static const struct extension extension_table[] = {
79   /* ARB Extensions */
80   { "GL_ARB_ES2_compatibility",                   o(ARB_ES2_compatibility),                   GL,             2009 },
81   { "GL_ARB_blend_func_extended",                 o(ARB_blend_func_extended),                 GL,             2009 },
82   { "GL_ARB_color_buffer_float",                  o(ARB_color_buffer_float),                  GL,             2004 },
83   { "GL_ARB_copy_buffer",                         o(ARB_copy_buffer),                         GL,             2008 },
84   { "GL_ARB_depth_buffer_float",                  o(ARB_depth_buffer_float),                  GL,             2008 },
85   { "GL_ARB_depth_clamp",                         o(ARB_depth_clamp),                         GL,             2003 },
86   { "GL_ARB_depth_texture",                       o(ARB_depth_texture),                       GL,             2001 },
87   { "GL_ARB_draw_buffers",                        o(ARB_draw_buffers),                        GL,             2002 },
88   { "GL_ARB_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
89   { "GL_ARB_draw_elements_base_vertex",           o(ARB_draw_elements_base_vertex),           GL,             2009 },
90   { "GL_ARB_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2008 },
91   { "GL_ARB_explicit_attrib_location",            o(ARB_explicit_attrib_location),            GL,             2009 },
92   { "GL_ARB_fragment_coord_conventions",          o(ARB_fragment_coord_conventions),          GL,             2009 },
93   { "GL_ARB_fragment_program",                    o(ARB_fragment_program),                    GL,             2002 },
94   { "GL_ARB_fragment_program_shadow",             o(ARB_fragment_program_shadow),             GL,             2003 },
95   { "GL_ARB_fragment_shader",                     o(ARB_fragment_shader),                     GL,             2002 },
96   { "GL_ARB_framebuffer_object",                  o(ARB_framebuffer_object),                  GL,             2005 },
97   { "GL_ARB_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
98   { "GL_ARB_half_float_pixel",                    o(ARB_half_float_pixel),                    GL,             2003 },
99   { "GL_ARB_half_float_vertex",                   o(ARB_half_float_vertex),                   GL,             2008 },
100   { "GL_ARB_instanced_arrays",                    o(ARB_instanced_arrays),                    GL,             2008 },
101   { "GL_ARB_map_buffer_range",                    o(ARB_map_buffer_range),                    GL,             2008 },
102   { "GL_ARB_multisample",                         o(ARB_multisample),                         GL,             1994 },
103   { "GL_ARB_multitexture",                        o(ARB_multitexture),                        GL,             1998 },
104   { "GL_ARB_occlusion_query2",                    o(ARB_occlusion_query2),                    GL,             2003 },
105   { "GL_ARB_occlusion_query",                     o(ARB_occlusion_query),                     GL,             2001 },
106   { "GL_ARB_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
107   { "GL_ARB_point_parameters",                    o(EXT_point_parameters),                    GL,             1997 },
108   { "GL_ARB_point_sprite",                        o(ARB_point_sprite),                        GL,             2003 },
109   { "GL_ARB_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
110   { "GL_ARB_robustness",                          o(dummy_true),                              GL,             2010 },
111   { "GL_ARB_sampler_objects",                     o(ARB_sampler_objects),                     GL,             2009 },
112   { "GL_ARB_seamless_cube_map",                   o(ARB_seamless_cube_map),                   GL,             2009 },
113   { "GL_ARB_shader_objects",                      o(ARB_shader_objects),                      GL,             2002 },
114   { "GL_ARB_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
115   { "GL_ARB_shader_texture_lod",                  o(ARB_shader_texture_lod),                  GL,             2009 },
116   { "GL_ARB_shading_language_100",                o(ARB_shading_language_100),                GL,             2003 },
117   { "GL_ARB_shadow_ambient",                      o(ARB_shadow_ambient),                      GL,             2001 },
118   { "GL_ARB_shadow",                              o(ARB_shadow),                              GL,             2001 },
119   { "GL_ARB_sync",                                o(ARB_sync),                                GL,             2003 },
120   { "GL_ARB_texture_border_clamp",                o(ARB_texture_border_clamp),                GL,             2000 },
121   { "GL_ARB_texture_buffer_object",               o(ARB_texture_buffer_object),               GL,             2008 },
122   { "GL_ARB_texture_compression",                 o(ARB_texture_compression),                 GL,             2000 },
123   { "GL_ARB_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
124   { "GL_ARB_texture_cube_map",                    o(ARB_texture_cube_map),                    GL,             1999 },
125   { "GL_ARB_texture_env_add",                     o(EXT_texture_env_add),                     GL,             1999 },
126   { "GL_ARB_texture_env_combine",                 o(ARB_texture_env_combine),                 GL,             2001 },
127   { "GL_ARB_texture_env_crossbar",                o(ARB_texture_env_crossbar),                GL,             2001 },
128   { "GL_ARB_texture_env_dot3",                    o(ARB_texture_env_dot3),                    GL,             2001 },
129   { "GL_ARB_texture_float",                       o(ARB_texture_float),                       GL,             2004 },
130   { "GL_ARB_texture_mirrored_repeat",             o(ARB_texture_mirrored_repeat),             GL,             2001 },
131   { "GL_ARB_texture_multisample",                 o(ARB_texture_multisample),                 GL,             2009 },
132   { "GL_ARB_texture_non_power_of_two",            o(ARB_texture_non_power_of_two),            GL,             2003 },
133   { "GL_ARB_texture_rectangle",                   o(NV_texture_rectangle),                    GL,             2004 },
134   { "GL_ARB_texture_rgb10_a2ui",                  o(ARB_texture_rgb10_a2ui),                  GL,             2009 },
135   { "GL_ARB_texture_rg",                          o(ARB_texture_rg),                          GL,             2008 },
136   { "GL_ARB_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
137   { "GL_ARB_transform_feedback2",                 o(ARB_transform_feedback2),                 GL,             2010 },
138   { "GL_ARB_transpose_matrix",                    o(ARB_transpose_matrix),                    GL,             1999 },
139   { "GL_ARB_uniform_buffer_object",               o(ARB_uniform_buffer_object),               GL,             2002 },
140   { "GL_ARB_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
141   { "GL_ARB_vertex_array_object",                 o(ARB_vertex_array_object),                 GL,             2006 },
142   { "GL_ARB_vertex_buffer_object",                o(ARB_vertex_buffer_object),                GL,             2003 },
143   { "GL_ARB_vertex_program",                      o(ARB_vertex_program),                      GL,             2002 },
144   { "GL_ARB_vertex_shader",                       o(ARB_vertex_shader),                       GL,             2002 },
145   { "GL_ARB_vertex_type_2_10_10_10_rev",          o(ARB_vertex_type_2_10_10_10_rev),          GL,             2009 },
146   { "GL_ARB_window_pos",                          o(ARB_window_pos),                          GL,             2001 },
147   /* EXT extensions */
148   { "GL_EXT_abgr",                                o(EXT_abgr),                                GL,             1995 },
149   { "GL_EXT_bgra",                                o(EXT_bgra),                                GL,             1995 },
150   { "GL_EXT_blend_color",                         o(EXT_blend_color),                         GL,             1995 },
151   { "GL_EXT_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
152   { "GL_EXT_blend_func_separate",                 o(EXT_blend_func_separate),                 GL,             1999 },
153   { "GL_EXT_blend_logic_op",                      o(EXT_blend_logic_op),                      GL,             1995 },
154   { "GL_EXT_blend_minmax",                        o(EXT_blend_minmax),                        GL | ES1 | ES2, 1995 },
155   { "GL_EXT_blend_subtract",                      o(EXT_blend_subtract),                      GL,             1995 },
156   { "GL_EXT_clip_volume_hint",                    o(EXT_clip_volume_hint),                    GL,             1996 },
157   { "GL_EXT_compiled_vertex_array",               o(EXT_compiled_vertex_array),               GL,             1996 },
158   { "GL_EXT_copy_texture",                        o(EXT_copy_texture),                        GL,             1995 },
159   { "GL_EXT_depth_bounds_test",                   o(EXT_depth_bounds_test),                   GL,             2002 },
160   { "GL_EXT_draw_buffers2",                       o(EXT_draw_buffers2),                       GL,             2006 },
161   { "GL_EXT_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2006 },
162   { "GL_EXT_draw_range_elements",                 o(EXT_draw_range_elements),                 GL,             1997 },
163   { "GL_EXT_fog_coord",                           o(EXT_fog_coord),                           GL,             1999 },
164   { "GL_EXT_framebuffer_blit",                    o(EXT_framebuffer_blit),                    GL,             2005 },
165   { "GL_EXT_framebuffer_multisample",             o(EXT_framebuffer_multisample),             GL,             2005 },
166   { "GL_EXT_framebuffer_object",                  o(EXT_framebuffer_object),                  GL,             2000 },
167   { "GL_EXT_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
168   { "GL_EXT_gpu_program_parameters",              o(EXT_gpu_program_parameters),              GL,             2006 },
169   { "GL_EXT_gpu_shader4",                         o(EXT_gpu_shader4),                         GL,             2006 },
170   { "GL_EXT_multi_draw_arrays",                   o(EXT_multi_draw_arrays),                   GL | ES1 | ES2, 1999 },
171   { "GL_EXT_packed_depth_stencil",                o(EXT_packed_depth_stencil),                GL,             2005 },
172   { "GL_EXT_packed_float",                        o(EXT_packed_float),                        GL,             2004 },
173   { "GL_EXT_packed_pixels",                       o(EXT_packed_pixels),                       GL,             1997 },
174   { "GL_EXT_paletted_texture",                    o(EXT_paletted_texture),                    GL,             1995 },
175   { "GL_EXT_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
176   { "GL_EXT_point_parameters",                    o(EXT_point_parameters),                    GL,             1997 },
177   { "GL_EXT_polygon_offset",                      o(EXT_polygon_offset),                      GL,             1995 },
178   { "GL_EXT_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
179   { "GL_EXT_rescale_normal",                      o(EXT_rescale_normal),                      GL,             1997 },
180   { "GL_EXT_secondary_color",                     o(EXT_secondary_color),                     GL,             1999 },
181   { "GL_EXT_separate_shader_objects",             o(EXT_separate_shader_objects),             GL,             2008 },
182   { "GL_EXT_separate_specular_color",             o(EXT_separate_specular_color),             GL,             1997 },
183   { "GL_EXT_shadow_funcs",                        o(EXT_shadow_funcs),                        GL,             2002 },
184   { "GL_EXT_shared_texture_palette",              o(EXT_shared_texture_palette),              GL,             2000 },
185   { "GL_EXT_stencil_two_side",                    o(EXT_stencil_two_side),                    GL,             2001 },
186   { "GL_EXT_stencil_wrap",                        o(EXT_stencil_wrap),                        GL,             2002 },
187   { "GL_EXT_subtexture",                          o(EXT_subtexture),                          GL,             1995 },
188   { "GL_EXT_texture3D",                           o(EXT_texture3D),                           GL,             1996 },
189   { "GL_EXT_texture_array",                       o(EXT_texture_array),                       GL,             2006 },
190   { "GL_EXT_texture_compression_dxt1",            o(EXT_texture_compression_s3tc),            GL | ES1 | ES2, 2004 },
191   { "GL_EXT_texture_compression_latc",            o(EXT_texture_compression_latc),            GL,             2006 },
192   { "GL_EXT_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
193   { "GL_EXT_texture_compression_s3tc",            o(EXT_texture_compression_s3tc),            GL,             2000 },
194   { "GL_EXT_texture_cube_map",                    o(ARB_texture_cube_map),                    GL,             2001 },
195   { "GL_EXT_texture_edge_clamp",                  o(SGIS_texture_edge_clamp),                 GL,             1997 },
196   { "GL_EXT_texture_env_add",                     o(EXT_texture_env_add),                     GL,             1999 },
197   { "GL_EXT_texture_env_combine",                 o(EXT_texture_env_combine),                 GL,             2006 },
198   { "GL_EXT_texture_env_dot3",                    o(EXT_texture_env_dot3),                    GL,             2000 },
199   { "GL_EXT_texture_filter_anisotropic",          o(EXT_texture_filter_anisotropic),          GL | ES1 | ES2, 1999 },
200   { "GL_EXT_texture_format_BGRA8888",             o(EXT_texture_format_BGRA8888),                  ES1 | ES2, 2009 },
201   { "GL_EXT_texture_integer",                     o(EXT_texture_integer),                     GL,             2006 },
202   { "GL_EXT_texture_lod_bias",                    o(EXT_texture_lod_bias),                    GL | ES1,       1999 },
203   { "GL_EXT_texture_mirror_clamp",                o(EXT_texture_mirror_clamp),                GL,             2004 },
204   { "GL_EXT_texture_object",                      o(EXT_texture_object),                      GL,             1995 },
205   { "GL_EXT_texture",                             o(EXT_texture),                             GL,             1996 },
206   { "GL_EXT_texture_rectangle",                   o(NV_texture_rectangle),                    GL,             2004 },
207   { "GL_EXT_texture_shared_exponent",             o(EXT_texture_shared_exponent),             GL,             2004 },
208   { "GL_EXT_texture_snorm",                       o(EXT_texture_snorm),                       GL,             2009 },
209   { "GL_EXT_texture_sRGB",                        o(EXT_texture_sRGB),                        GL,             2004 },
210   { "GL_EXT_texture_sRGB_decode",                 o(EXT_texture_sRGB_decode),                        GL,      2006 },
211   { "GL_EXT_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
212   { "GL_EXT_texture_type_2_10_10_10_REV",         o(dummy_true),                                         ES2, 2008 },
213   { "GL_EXT_timer_query",                         o(EXT_timer_query),                         GL,             2006 },
214   { "GL_EXT_transform_feedback",                  o(EXT_transform_feedback),                  GL,             2011 },
215   { "GL_EXT_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
216   { "GL_EXT_vertex_array",                        o(EXT_vertex_array),                        GL,             1995 },
217   { "GL_EXT_vertex_array_set",                    o(EXT_vertex_array_set),                    GL,             1997 },
218
219   /* OES extensions */
220   { "GL_OES_blend_equation_separate",             o(EXT_blend_equation_separate),                  ES1,       2009 },
221   { "GL_OES_blend_func_separate",                 o(EXT_blend_func_separate),                      ES1,       2009 },
222   { "GL_OES_blend_subtract",                      o(EXT_blend_subtract),                           ES1,       2009 },
223   { "GL_OES_byte_coordinates",                    o(dummy_true),                                   ES1,       2002 },
224   { "GL_OES_compressed_paletted_texture",         o(dummy_true),                                   ES1,       2003 },
225   { "GL_OES_depth24",                             o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
226   { "GL_OES_depth32",                             o(dummy_false),                     DISABLE,                2005 },
227   { "GL_OES_depth_texture",                       o(ARB_depth_texture),                                  ES2, 2006 },
228#if FEATURE_OES_draw_texture
229   { "GL_OES_draw_texture",                        o(OES_draw_texture),                             ES1 | ES2, 2004 },
230#endif
231#if FEATURE_OES_EGL_image
232   /*  FIXME: Mesa expects GL_OES_EGL_image to be available in OpenGL contexts. */
233   { "GL_OES_EGL_image",                           o(OES_EGL_image),                           GL | ES1 | ES2, 2006 },
234#endif
235   { "GL_OES_element_index_uint",                  o(EXT_vertex_array),                             ES1 | ES2, 2005 },
236   { "GL_OES_fbo_render_mipmap",                   o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
237   { "GL_OES_fixed_point",                         o(dummy_true),                                   ES1,       2002 },
238   { "GL_OES_framebuffer_object",                  o(EXT_framebuffer_object),                       ES1,       2005 },
239   { "GL_OES_mapbuffer",                           o(ARB_vertex_buffer_object),                     ES1 | ES2, 2005 },
240   { "GL_OES_matrix_get",                          o(dummy_true),                                   ES1,       2004 },
241   { "GL_OES_packed_depth_stencil",                o(EXT_packed_depth_stencil),                     ES1 | ES2, 2007 },
242   { "GL_OES_point_size_array",                    o(dummy_true),                                   ES1,       2004 },
243   { "GL_OES_point_sprite",                        o(ARB_point_sprite),                             ES1,       2004 },
244   { "GL_OES_query_matrix",                        o(dummy_true),                                   ES1,       2003 },
245   { "GL_OES_read_format",                         o(OES_read_format),                         GL | ES1,       2003 },
246   { "GL_OES_rgb8_rgba8",                          o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
247   { "GL_OES_single_precision",                    o(dummy_true),                                   ES1,       2003 },
248   { "GL_OES_standard_derivatives",                o(OES_standard_derivatives),                           ES2, 2005 },
249   { "GL_OES_stencil1",                            o(dummy_false),                     DISABLE,                2005 },
250   { "GL_OES_stencil4",                            o(dummy_false),                     DISABLE,                2005 },
251   { "GL_OES_stencil8",                            o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
252   { "GL_OES_stencil_wrap",                        o(EXT_stencil_wrap),                             ES1,       2002 },
253   { "GL_OES_texture_3D",                          o(EXT_texture3D),                                      ES2, 2005 },
254   { "GL_OES_texture_cube_map",                    o(ARB_texture_cube_map),                         ES1,       2007 },
255   { "GL_OES_texture_env_crossbar",                o(ARB_texture_env_crossbar),                     ES1,       2005 },
256   { "GL_OES_texture_mirrored_repeat",             o(ARB_texture_mirrored_repeat),                  ES1,       2005 },
257   { "GL_OES_texture_npot",                        o(ARB_texture_non_power_of_two),                       ES2, 2005 },
258
259   /* Vendor extensions */
260   { "GL_3DFX_texture_compression_FXT1",           o(TDFX_texture_compression_FXT1),           GL,             1999 },
261   { "GL_AMD_conservative_depth",                  o(AMD_conservative_depth),                  GL,             2009 },
262   { "GL_AMD_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
263   { "GL_AMD_seamless_cubemap_per_texture",        o(AMD_seamless_cubemap_per_texture),        GL,             2009 },
264   { "GL_AMD_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
265   { "GL_APPLE_client_storage",                    o(APPLE_client_storage),                    GL,             2002 },
266   { "GL_APPLE_object_purgeable",                  o(APPLE_object_purgeable),                  GL,             2006 },
267   { "GL_APPLE_packed_pixels",                     o(APPLE_packed_pixels),                     GL,             2002 },
268   { "GL_APPLE_vertex_array_object",               o(APPLE_vertex_array_object),               GL,             2002 },
269   { "GL_ATI_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
270   { "GL_ATI_draw_buffers",                        o(ARB_draw_buffers),                        GL,             2002 },
271   { "GL_ATI_envmap_bumpmap",                      o(ATI_envmap_bumpmap),                      GL,             2001 },
272   { "GL_ATI_fragment_shader",                     o(ATI_fragment_shader),                     GL,             2001 },
273   { "GL_ATI_separate_stencil",                    o(ATI_separate_stencil),                    GL,             2006 },
274   { "GL_ATI_texture_compression_3dc",             o(ATI_texture_compression_3dc),             GL,             2004 },
275   { "GL_ATI_texture_env_combine3",                o(ATI_texture_env_combine3),                GL,             2002 },
276   { "GL_ATI_texture_float",                       o(ARB_texture_float),                       GL,             2002 },
277   { "GL_ATI_texture_mirror_once",                 o(ATI_texture_mirror_once),                 GL,             2006 },
278   { "GL_IBM_multimode_draw_arrays",               o(IBM_multimode_draw_arrays),               GL,             1998 },
279   { "GL_IBM_rasterpos_clip",                      o(IBM_rasterpos_clip),                      GL,             1996 },
280   { "GL_IBM_texture_mirrored_repeat",             o(ARB_texture_mirrored_repeat),             GL,             1998 },
281   { "GL_INGR_blend_func_separate",                o(EXT_blend_func_separate),                 GL,             1999 },
282   { "GL_MESA_pack_invert",                        o(MESA_pack_invert),                        GL,             2002 },
283   { "GL_MESA_resize_buffers",                     o(MESA_resize_buffers),                     GL,             1999 },
284   { "GL_MESA_texture_array",                      o(MESA_texture_array),                      GL,             2007 },
285   { "GL_MESA_texture_signed_rgba",                o(EXT_texture_snorm),                       GL,             2009 },
286   { "GL_MESA_window_pos",                         o(ARB_window_pos),                          GL,             2000 },
287   { "GL_MESA_ycbcr_texture",                      o(MESA_ycbcr_texture),                      GL,             2002 },
288   { "GL_NV_blend_square",                         o(NV_blend_square),                         GL,             1999 },
289   { "GL_NV_conditional_render",                   o(NV_conditional_render),                   GL,             2008 },
290   { "GL_NV_depth_clamp",                          o(ARB_depth_clamp),                         GL,             2001 },
291   { "GL_NV_fragment_program",                     o(NV_fragment_program),                     GL,             2001 },
292   { "GL_NV_fragment_program_option",              o(NV_fragment_program_option),              GL,             2005 },
293   { "GL_NV_light_max_exponent",                   o(NV_light_max_exponent),                   GL,             1999 },
294   { "GL_NV_packed_depth_stencil",                 o(EXT_packed_depth_stencil),                GL,             2000 },
295   { "GL_NV_point_sprite",                         o(NV_point_sprite),                         GL,             2001 },
296   { "GL_NV_primitive_restart",                    o(NV_primitive_restart),                    GL,             2002 },
297   { "GL_NV_texgen_reflection",                    o(NV_texgen_reflection),                    GL,             1999 },
298   { "GL_NV_texture_barrier",                      o(NV_texture_barrier),                      GL,             2009 },
299   { "GL_NV_texture_env_combine4",                 o(NV_texture_env_combine4),                 GL,             1999 },
300   { "GL_NV_texture_rectangle",                    o(NV_texture_rectangle),                    GL,             2000 },
301   { "GL_NV_vertex_program1_1",                    o(NV_vertex_program1_1),                    GL,             2001 },
302   { "GL_NV_vertex_program",                       o(NV_vertex_program),                       GL,             2000 },
303   { "GL_S3_s3tc",                                 o(S3_s3tc),                                 GL,             1999 },
304   { "GL_SGIS_generate_mipmap",                    o(SGIS_generate_mipmap),                    GL,             1997 },
305   { "GL_SGIS_texture_border_clamp",               o(ARB_texture_border_clamp),                GL,             1997 },
306   { "GL_SGIS_texture_edge_clamp",                 o(SGIS_texture_edge_clamp),                 GL,             1997 },
307   { "GL_SGIS_texture_lod",                        o(SGIS_texture_lod),                        GL,             1997 },
308   { "GL_SUN_multi_draw_arrays",                   o(EXT_multi_draw_arrays),                   GL,             1999 },
309
310   { 0, 0, 0, 0 },
311};
312
313
314/**
315 * Given an extension name, lookup up the corresponding member of struct
316 * gl_extensions and return that member's offset (in bytes).  If the name is
317 * not found in the \c extension_table, return 0.
318 *
319 * \param name Name of extension.
320 * \return Offset of member in struct gl_extensions.
321 */
322static size_t
323name_to_offset(const char* name)
324{
325   const struct extension *i;
326
327   if (name == 0)
328      return 0;
329
330   for (i = extension_table; i->name != 0; ++i) {
331      if (strcmp(name, i->name) == 0)
332	 return i->offset;
333   }
334
335   return 0;
336}
337
338
339/**
340 * \brief Extensions enabled by default.
341 *
342 * These extensions are enabled by _mesa_init_extensions().
343 *
344 * XXX: Should these defaults also apply to GLES?
345 */
346static const size_t default_extensions[] = {
347   o(ARB_copy_buffer),
348   o(ARB_draw_buffers),
349   o(ARB_multisample),
350   o(ARB_texture_compression),
351   o(ARB_transpose_matrix),
352   o(ARB_vertex_buffer_object),
353   o(ARB_window_pos),
354
355   o(EXT_abgr),
356   o(EXT_bgra),
357   o(EXT_compiled_vertex_array),
358   o(EXT_copy_texture),
359   o(EXT_draw_range_elements),
360   o(EXT_multi_draw_arrays),
361   o(EXT_packed_pixels),
362   o(EXT_polygon_offset),
363   o(EXT_rescale_normal),
364   o(EXT_separate_specular_color),
365   o(EXT_subtexture),
366   o(EXT_texture),
367   o(EXT_texture3D),
368   o(EXT_texture_object),
369   o(EXT_vertex_array),
370
371   o(OES_read_format),
372   o(OES_standard_derivatives),
373
374   /* Vendor Extensions */
375   o(APPLE_packed_pixels),
376   o(IBM_multimode_draw_arrays),
377   o(IBM_rasterpos_clip),
378   o(NV_light_max_exponent),
379   o(NV_texgen_reflection),
380   o(SGIS_generate_mipmap),
381   o(SGIS_texture_edge_clamp),
382   o(SGIS_texture_lod),
383
384   0,
385};
386
387
388/**
389 * Enable all extensions suitable for a software-only renderer.
390 * This is a convenience function used by the XMesa, OSMesa, GGI drivers, etc.
391 */
392void
393_mesa_enable_sw_extensions(struct gl_context *ctx)
394{
395   /*ctx->Extensions.ARB_copy_buffer = GL_TRUE;*/
396   ctx->Extensions.ARB_depth_clamp = GL_TRUE;
397   ctx->Extensions.ARB_depth_texture = GL_TRUE;
398   /*ctx->Extensions.ARB_draw_buffers = GL_TRUE;*/
399   ctx->Extensions.ARB_draw_elements_base_vertex = GL_TRUE;
400   ctx->Extensions.ARB_draw_instanced = GL_TRUE;
401   ctx->Extensions.ARB_explicit_attrib_location = GL_TRUE;
402   ctx->Extensions.ARB_fragment_coord_conventions = GL_TRUE;
403#if FEATURE_ARB_fragment_program
404   ctx->Extensions.ARB_fragment_program = GL_TRUE;
405   ctx->Extensions.ARB_fragment_program_shadow = GL_TRUE;
406#endif
407#if FEATURE_ARB_fragment_shader
408   ctx->Extensions.ARB_fragment_shader = GL_TRUE;
409#endif
410#if FEATURE_ARB_framebuffer_object
411   ctx->Extensions.ARB_framebuffer_object = GL_TRUE;
412#endif
413#if FEATURE_ARB_geometry_shader4 && 0
414   /* XXX re-enable when GLSL compiler again supports geometry shaders */
415   ctx->Extensions.ARB_geometry_shader4 = GL_TRUE;
416#endif
417   ctx->Extensions.ARB_half_float_pixel = GL_TRUE;
418   ctx->Extensions.ARB_half_float_vertex = GL_TRUE;
419   ctx->Extensions.ARB_map_buffer_range = GL_TRUE;
420   ctx->Extensions.ARB_multitexture = GL_TRUE;
421#if FEATURE_queryobj
422   ctx->Extensions.ARB_occlusion_query = GL_TRUE;
423   ctx->Extensions.ARB_occlusion_query2 = GL_TRUE;
424#endif
425   ctx->Extensions.ARB_point_sprite = GL_TRUE;
426#if FEATURE_ARB_shader_objects
427   ctx->Extensions.ARB_shader_objects = GL_TRUE;
428   ctx->Extensions.EXT_separate_shader_objects = GL_TRUE;
429#endif
430#if FEATURE_ARB_shading_language_100
431   ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
432#endif
433   ctx->Extensions.ARB_shadow = GL_TRUE;
434   ctx->Extensions.ARB_shadow_ambient = GL_TRUE;
435   ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
436   ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
437   ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
438   ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
439   ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
440   /*ctx->Extensions.ARB_texture_float = GL_TRUE;*/
441   ctx->Extensions.ARB_texture_mirrored_repeat = GL_TRUE;
442   ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
443   ctx->Extensions.ARB_texture_rg = GL_TRUE;
444   ctx->Extensions.ARB_texture_compression_rgtc = GL_TRUE;
445   ctx->Extensions.ARB_vertex_array_object = GL_TRUE;
446#if FEATURE_ARB_vertex_program
447   ctx->Extensions.ARB_vertex_program = GL_TRUE;
448#endif
449#if FEATURE_ARB_vertex_shader
450   ctx->Extensions.ARB_vertex_shader = GL_TRUE;
451#endif
452#if FEATURE_ARB_vertex_buffer_object
453   /*ctx->Extensions.ARB_vertex_buffer_object = GL_TRUE;*/
454#endif
455#if FEATURE_ARB_sync
456   ctx->Extensions.ARB_sync = GL_TRUE;
457#endif
458   ctx->Extensions.APPLE_vertex_array_object = GL_TRUE;
459#if FEATURE_APPLE_object_purgeable
460   ctx->Extensions.APPLE_object_purgeable = GL_TRUE;
461#endif
462   ctx->Extensions.ATI_envmap_bumpmap = GL_TRUE;
463#if FEATURE_ATI_fragment_shader
464   ctx->Extensions.ATI_fragment_shader = GL_TRUE;
465#endif
466   ctx->Extensions.ATI_texture_compression_3dc = GL_TRUE;
467   ctx->Extensions.ATI_texture_env_combine3 = GL_TRUE;
468   ctx->Extensions.ATI_texture_mirror_once = GL_TRUE;
469   ctx->Extensions.ATI_separate_stencil = GL_TRUE;
470   ctx->Extensions.EXT_blend_color = GL_TRUE;
471   ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
472   ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
473   ctx->Extensions.EXT_blend_logic_op = GL_TRUE;
474   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
475   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
476   ctx->Extensions.EXT_depth_bounds_test = GL_TRUE;
477   ctx->Extensions.EXT_draw_buffers2 = GL_TRUE;
478   ctx->Extensions.EXT_fog_coord = GL_TRUE;
479#if FEATURE_EXT_framebuffer_object
480   ctx->Extensions.EXT_framebuffer_object = GL_TRUE;
481#endif
482#if FEATURE_EXT_framebuffer_blit
483   ctx->Extensions.EXT_framebuffer_blit = GL_TRUE;
484#endif
485#if FEATURE_ARB_framebuffer_object
486   ctx->Extensions.EXT_framebuffer_multisample = GL_TRUE;
487#endif
488   /*ctx->Extensions.EXT_multi_draw_arrays = GL_TRUE;*/
489   ctx->Extensions.EXT_packed_depth_stencil = GL_TRUE;
490   ctx->Extensions.EXT_paletted_texture = GL_TRUE;
491#if FEATURE_EXT_pixel_buffer_object
492   ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
493#endif
494   ctx->Extensions.EXT_point_parameters = GL_TRUE;
495   ctx->Extensions.EXT_provoking_vertex = GL_TRUE;
496   ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
497   ctx->Extensions.EXT_secondary_color = GL_TRUE;
498   ctx->Extensions.EXT_shared_texture_palette = GL_TRUE;
499   ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
500   ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
501   ctx->Extensions.EXT_texture_array = GL_TRUE;
502   ctx->Extensions.EXT_texture_compression_latc = GL_TRUE;
503   ctx->Extensions.EXT_texture_env_add = GL_TRUE;
504   ctx->Extensions.EXT_texture_env_combine = GL_TRUE;
505   ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
506   ctx->Extensions.EXT_texture_filter_anisotropic = GL_TRUE;
507   ctx->Extensions.EXT_texture_mirror_clamp = GL_TRUE;
508   ctx->Extensions.EXT_texture_lod_bias = GL_TRUE;
509   ctx->Extensions.EXT_texture_shared_exponent = GL_TRUE;
510#if FEATURE_EXT_texture_sRGB
511   ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
512   ctx->Extensions.EXT_texture_sRGB_decode = GL_TRUE;
513#endif
514   ctx->Extensions.EXT_texture_swizzle = GL_TRUE;
515#if FEATURE_EXT_transform_feedback
516   /*ctx->Extensions.EXT_transform_feedback = GL_TRUE;*/
517#endif
518   ctx->Extensions.EXT_vertex_array_bgra = GL_TRUE;
519   /*ctx->Extensions.IBM_multimode_draw_arrays = GL_TRUE;*/
520   ctx->Extensions.MESA_pack_invert = GL_TRUE;
521   ctx->Extensions.MESA_resize_buffers = GL_TRUE;
522   ctx->Extensions.MESA_texture_array = GL_TRUE;
523   ctx->Extensions.MESA_ycbcr_texture = GL_TRUE;
524   ctx->Extensions.NV_blend_square = GL_TRUE;
525   ctx->Extensions.NV_conditional_render = GL_TRUE;
526   /*ctx->Extensions.NV_light_max_exponent = GL_TRUE;*/
527   ctx->Extensions.NV_point_sprite = GL_TRUE;
528   ctx->Extensions.NV_texture_env_combine4 = GL_TRUE;
529   ctx->Extensions.NV_texture_rectangle = GL_TRUE;
530   /*ctx->Extensions.NV_texgen_reflection = GL_TRUE;*/
531#if FEATURE_NV_vertex_program
532   ctx->Extensions.NV_vertex_program = GL_TRUE;
533   ctx->Extensions.NV_vertex_program1_1 = GL_TRUE;
534#endif
535#if FEATURE_NV_fragment_program
536   ctx->Extensions.NV_fragment_program = GL_TRUE;
537#endif
538#if FEATURE_NV_fragment_program && FEATURE_ARB_fragment_program
539   ctx->Extensions.NV_fragment_program_option = GL_TRUE;
540#endif
541   /*ctx->Extensions.SGIS_generate_mipmap = GL_TRUE;*/
542   ctx->Extensions.SGIS_texture_edge_clamp = GL_TRUE;
543#if FEATURE_ARB_vertex_program || FEATURE_ARB_fragment_program
544   ctx->Extensions.EXT_gpu_program_parameters = GL_TRUE;
545#endif
546#if FEATURE_texture_fxt1
547   _mesa_enable_extension(ctx, "GL_3DFX_texture_compression_FXT1");
548#endif
549#if FEATURE_texture_s3tc
550   if (ctx->Mesa_DXTn) {
551      _mesa_enable_extension(ctx, "GL_EXT_texture_compression_s3tc");
552      _mesa_enable_extension(ctx, "GL_S3_s3tc");
553   }
554#endif
555}
556
557
558/**
559 * Enable common EXT extensions in the ARB_imaging subset.
560 */
561void
562_mesa_enable_imaging_extensions(struct gl_context *ctx)
563{
564   ctx->Extensions.EXT_blend_color = GL_TRUE;
565   ctx->Extensions.EXT_blend_logic_op = GL_TRUE;
566   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
567   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
568}
569
570
571
572/**
573 * Enable all OpenGL 1.3 features and extensions.
574 * A convenience function to be called by drivers.
575 */
576void
577_mesa_enable_1_3_extensions(struct gl_context *ctx)
578{
579   /*ctx->Extensions.ARB_multisample = GL_TRUE;*/
580   ctx->Extensions.ARB_multitexture = GL_TRUE;
581   ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
582   /*ctx->Extensions.ARB_texture_compression = GL_TRUE;*/
583   ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
584   ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
585   ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
586   ctx->Extensions.EXT_texture_env_add = GL_TRUE;
587   /*ctx->Extensions.ARB_transpose_matrix = GL_TRUE;*/
588}
589
590
591
592/**
593 * Enable all OpenGL 1.4 features and extensions.
594 * A convenience function to be called by drivers.
595 */
596void
597_mesa_enable_1_4_extensions(struct gl_context *ctx)
598{
599   ctx->Extensions.ARB_depth_texture = GL_TRUE;
600   ctx->Extensions.ARB_shadow = GL_TRUE;
601   ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
602   ctx->Extensions.ARB_texture_mirrored_repeat = GL_TRUE;
603   ctx->Extensions.ARB_window_pos = GL_TRUE;
604   ctx->Extensions.EXT_blend_color = GL_TRUE;
605   ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
606   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
607   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
608   ctx->Extensions.EXT_fog_coord = GL_TRUE;
609   /*ctx->Extensions.EXT_multi_draw_arrays = GL_TRUE;*/
610   ctx->Extensions.EXT_point_parameters = GL_TRUE;
611   ctx->Extensions.EXT_secondary_color = GL_TRUE;
612   ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
613   ctx->Extensions.EXT_texture_lod_bias = GL_TRUE;
614   /*ctx->Extensions.SGIS_generate_mipmap = GL_TRUE;*/
615}
616
617
618/**
619 * Enable all OpenGL 1.5 features and extensions.
620 * A convenience function to be called by drivers.
621 */
622void
623_mesa_enable_1_5_extensions(struct gl_context *ctx)
624{
625   ctx->Extensions.ARB_occlusion_query = GL_TRUE;
626   /*ctx->Extensions.ARB_vertex_buffer_object = GL_TRUE;*/
627   ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
628}
629
630
631/**
632 * Enable all OpenGL 2.0 features and extensions.
633 * A convenience function to be called by drivers.
634 */
635void
636_mesa_enable_2_0_extensions(struct gl_context *ctx)
637{
638   /*ctx->Extensions.ARB_draw_buffers = GL_TRUE;*/
639#if FEATURE_ARB_fragment_shader
640   ctx->Extensions.ARB_fragment_shader = GL_TRUE;
641#endif
642   ctx->Extensions.ARB_point_sprite = GL_TRUE;
643   ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
644   ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
645#if FEATURE_ARB_shader_objects
646   ctx->Extensions.ARB_shader_objects = GL_TRUE;
647#endif
648#if FEATURE_ARB_shading_language_100
649   ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
650#endif
651   ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
652#if FEATURE_ARB_vertex_shader
653   ctx->Extensions.ARB_vertex_shader = GL_TRUE;
654#endif
655}
656
657
658/**
659 * Enable all OpenGL 2.1 features and extensions.
660 * A convenience function to be called by drivers.
661 */
662void
663_mesa_enable_2_1_extensions(struct gl_context *ctx)
664{
665#if FEATURE_EXT_pixel_buffer_object
666   ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
667#endif
668#if FEATURE_EXT_texture_sRGB
669   ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
670#endif
671}
672
673
674/**
675 * Either enable or disable the named extension.
676 * \return GL_TRUE for success, GL_FALSE if invalid extension name
677 */
678static GLboolean
679set_extension( struct gl_context *ctx, const char *name, GLboolean state )
680{
681   size_t offset;
682
683   if (ctx->Extensions.String) {
684      /* The string was already queried - can't change it now! */
685      _mesa_problem(ctx, "Trying to enable/disable extension after glGetString(GL_EXTENSIONS): %s", name);
686      return GL_FALSE;
687   }
688
689   offset = name_to_offset(name);
690   if (offset == 0) {
691      _mesa_problem(ctx, "Trying to enable/disable unknown extension %s",
692	            name);
693      return GL_FALSE;
694   } else if (offset == o(dummy_true) && state == GL_FALSE) {
695      _mesa_problem(ctx, "Trying to disable a permanently enabled extension: "
696	                  "%s", name);
697      return GL_FALSE;
698   } else {
699      GLboolean *base = (GLboolean *) &ctx->Extensions;
700      base[offset] = state;
701      return GL_TRUE;
702   }
703}
704
705
706/**
707 * Enable the named extension.
708 * Typically called by drivers.
709 */
710void
711_mesa_enable_extension( struct gl_context *ctx, const char *name )
712{
713   if (!set_extension(ctx, name, GL_TRUE))
714      _mesa_problem(ctx, "Trying to enable unknown extension: %s", name);
715}
716
717
718/**
719 * Disable the named extension.
720 * XXX is this really needed???
721 */
722void
723_mesa_disable_extension( struct gl_context *ctx, const char *name )
724{
725   if (!set_extension(ctx, name, GL_FALSE))
726      _mesa_problem(ctx, "Trying to disable unknown extension: %s", name);
727}
728
729
730/**
731 * Test if the named extension is enabled in this context.
732 */
733GLboolean
734_mesa_extension_is_enabled( struct gl_context *ctx, const char *name )
735{
736   size_t offset;
737   GLboolean *base;
738
739   if (name == 0)
740      return GL_FALSE;
741
742   offset = name_to_offset(name);
743   if (offset == 0)
744      return GL_FALSE;
745   base = (GLboolean *) &ctx->Extensions;
746   return base[offset];
747}
748
749
750/**
751 * \brief Apply the \c MESA_EXTENSION_OVERRIDE environment variable.
752 *
753 * \c MESA_EXTENSION_OVERRIDE is a space-separated list of extensions to
754 * enable or disable. The list is processed thus:
755 *    - Enable recognized extension names that are prefixed with '+'.
756 *    - Disable recognized extension names that are prefixed with '-'.
757 *    - Enable recognized extension names that are not prefixed.
758 *    - Collect unrecognized extension names in a new string.
759 *
760 * \return Space-separated list of unrecognized extension names (which must
761 *    be freed). Does not return \c NULL.
762 */
763static char *
764get_extension_override( struct gl_context *ctx )
765{
766   const char *env_const = _mesa_getenv("MESA_EXTENSION_OVERRIDE");
767   char *env;
768   char *ext;
769   char *extra_exts;
770   int len;
771
772   if (env_const == NULL) {
773      /* Return the empty string rather than NULL. This simplifies the logic
774       * of client functions. */
775      return calloc(1, sizeof(char));
776   }
777
778   /* extra_exts: List of unrecognized extensions. */
779   extra_exts = calloc(strlen(env_const), sizeof(char));
780
781   /* Copy env_const because strtok() is destructive. */
782   env = strdup(env_const);
783   for (ext = strtok(env, " "); ext != NULL; ext = strtok(NULL, " ")) {
784      int enable;
785      int recognized;
786      switch (ext[0]) {
787      case '+':
788         enable = 1;
789         ++ext;
790         break;
791      case '-':
792         enable = 0;
793         ++ext;
794         break;
795      default:
796         enable = 1;
797         break;
798      }
799      recognized = set_extension(ctx, ext, enable);
800      if (!recognized) {
801         strcat(extra_exts, ext);
802         strcat(extra_exts, " ");
803      }
804   }
805
806   /* Remove trailing space. */
807   len = strlen(extra_exts);
808   if (extra_exts[len - 1] == ' ')
809      extra_exts[len - 1] = '\0';
810
811   return extra_exts;
812}
813
814
815/**
816 * \brief Initialize extension tables and enable default extensions.
817 *
818 * This should be called during context initialization.
819 * Note: Sets gl_extensions.dummy_true to true.
820 */
821void
822_mesa_init_extensions( struct gl_context *ctx )
823{
824   GLboolean *base = (GLboolean *) &ctx->Extensions;
825   GLboolean *sentinel = base + o(extension_sentinel);
826   GLboolean *i;
827   const size_t *j;
828
829   /* First, turn all extensions off. */
830   for (i = base; i != sentinel; ++i)
831      *i = GL_FALSE;
832
833   /* Then, selectively turn default extensions on. */
834   ctx->Extensions.dummy_true = GL_TRUE;
835   for (j = default_extensions; *j != 0; ++j)
836      base[*j] = GL_TRUE;
837}
838
839
840typedef unsigned short extension_index;
841
842
843/**
844 * Compare two entries of the extensions table.  Sorts first by year,
845 * then by name.
846 *
847 * Arguments are indices into extension_table.
848 */
849static int
850extension_compare(const void *p1, const void *p2)
851{
852   extension_index i1 = * (const extension_index *) p1;
853   extension_index i2 = * (const extension_index *) p2;
854   const struct extension *e1 = &extension_table[i1];
855   const struct extension *e2 = &extension_table[i2];
856   int res;
857
858   res = (int)e1->year - (int)e2->year;
859
860   if (res == 0) {
861      res = strcmp(e1->name, e2->name);
862   }
863
864   return res;
865}
866
867
868/**
869 * Construct the GL_EXTENSIONS string.  Called the first time that
870 * glGetString(GL_EXTENSIONS) is called.
871 */
872GLubyte*
873_mesa_make_extension_string(struct gl_context *ctx)
874{
875   /* The extension string. */
876   char *exts = 0;
877   /* Length of extension string. */
878   size_t length = 0;
879   /* Number of extensions */
880   unsigned count;
881   /* Indices of the extensions sorted by year */
882   extension_index *extension_indices;
883   /* String of extra extensions. */
884   char *extra_extensions = get_extension_override(ctx);
885   GLboolean *base = (GLboolean *) &ctx->Extensions;
886   const struct extension *i;
887   unsigned j;
888   unsigned maxYear = ~0;
889
890   /* Check if the MESA_EXTENSION_MAX_YEAR env var is set */
891   {
892      const char *env = getenv("MESA_EXTENSION_MAX_YEAR");
893      if (env) {
894         maxYear = atoi(env);
895         _mesa_debug(ctx, "Note: limiting GL extensions to %u or earlier\n",
896                     maxYear);
897      }
898   }
899
900   /* Compute length of the extension string. */
901   count = 0;
902   for (i = extension_table; i->name != 0; ++i) {
903      if (base[i->offset] &&
904          i->year <= maxYear &&
905          (i->api_set & (1 << ctx->API))) {
906	 length += strlen(i->name) + 1; /* +1 for space */
907	 ++count;
908      }
909   }
910   if (extra_extensions != NULL)
911      length += 1 + strlen(extra_extensions); /* +1 for space */
912
913   exts = (char *) calloc(length + 1, sizeof(char));
914   if (exts == NULL) {
915      free(extra_extensions);
916      return NULL;
917   }
918
919   extension_indices = malloc(count * sizeof(extension_index));
920   if (extension_indices == NULL) {
921      free(exts);
922      free(extra_extensions);
923      return NULL;
924   }
925
926   /* Sort extensions in chronological order because certain old applications (e.g.,
927    * Quake3 demo) store the extension list in a static size buffer so chronologically
928    * order ensure that the extensions that such applications expect will fit into
929    * that buffer.
930    */
931   j = 0;
932   for (i = extension_table; i->name != 0; ++i) {
933      if (base[i->offset] &&
934          i->year <= maxYear &&
935          (i->api_set & (1 << ctx->API))) {
936         extension_indices[j++] = i - extension_table;
937      }
938   }
939   assert(j == count);
940   qsort(extension_indices, count, sizeof *extension_indices, extension_compare);
941
942   /* Build the extension string.*/
943   for (j = 0; j < count; ++j) {
944      i = &extension_table[extension_indices[j]];
945      assert(base[i->offset] && (i->api_set & (1 << ctx->API)));
946      strcat(exts, i->name);
947      strcat(exts, " ");
948   }
949   free(extension_indices);
950   if (extra_extensions != 0) {
951      strcat(exts, extra_extensions);
952      free(extra_extensions);
953   }
954
955   return (GLubyte *) exts;
956}
957
958/**
959 * Return number of enabled extensions.
960 */
961GLuint
962_mesa_get_extension_count(struct gl_context *ctx)
963{
964   GLboolean *base;
965   const struct extension *i;
966
967   /* only count once */
968   if (ctx->Extensions.Count != 0)
969      return ctx->Extensions.Count;
970
971   base = (GLboolean *) &ctx->Extensions;
972   for (i = extension_table; i->name != 0; ++i) {
973      if (base[i->offset]) {
974	 ctx->Extensions.Count++;
975      }
976   }
977   return ctx->Extensions.Count;
978}
979
980/**
981 * Return name of i-th enabled extension
982 */
983const GLubyte *
984_mesa_get_enabled_extension(struct gl_context *ctx, GLuint index)
985{
986   const GLboolean *base;
987   size_t n;
988   const struct extension *i;
989
990   if (index < 0)
991      return NULL;
992
993   base = (GLboolean*) &ctx->Extensions;
994   n = 0;
995   for (i = extension_table; i->name != 0; ++i) {
996      if (n == index && base[i->offset]) {
997	 return (GLubyte*) i->name;
998      } else if (base[i->offset]) {
999	 ++n;
1000      }
1001   }
1002
1003   return NULL;
1004}
1005