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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 
40 #define ALIGN(value, alignment)  (((value) + alignment - 1) & ~(alignment - 1))
41 
42 enum {
43    DISABLE = 0,
44    GLL = 1 << API_OPENGL,       /* GL Legacy / Compatibility */
45    GLC = 1 << API_OPENGL_CORE,  /* GL Core */
46    GL  = (1 << API_OPENGL) | (1 << API_OPENGL_CORE),
47    ES1 = 1 << API_OPENGLES,
48    ES2 = 1 << API_OPENGLES2,
49 };
50 
51 /**
52  * \brief An element of the \c extension_table.
53  */
54 struct extension {
55    /** Name of extension, such as "GL_ARB_depth_clamp". */
56    const char *name;
57 
58    /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
59    size_t offset;
60 
61    /** Set of API's in which the extension exists, as a bitset. */
62    uint8_t api_set;
63 
64    /** Year the extension was proposed or approved.  Used to sort the
65     * extension string chronologically. */
66    uint16_t year;
67 };
68 
69 
70 /**
71  * Given a member \c x of struct gl_extensions, return offset of
72  * \c x in bytes.
73  */
74 #define o(x) offsetof(struct gl_extensions, x)
75 
76 
77 /**
78  * \brief Table of supported OpenGL extensions for all API's.
79  */
80 static const struct extension extension_table[] = {
81    /* ARB Extensions */
82    { "GL_ARB_ES2_compatibility",                   o(ARB_ES2_compatibility),                   GL,             2009 },
83    { "GL_ARB_base_instance",                       o(ARB_base_instance),                       GL,             2011 },
84    { "GL_ARB_blend_func_extended",                 o(ARB_blend_func_extended),                 GL,             2009 },
85    { "GL_ARB_color_buffer_float",                  o(ARB_color_buffer_float),                  GL,             2004 },
86    { "GL_ARB_copy_buffer",                         o(ARB_copy_buffer),                         GL,             2008 },
87    { "GL_ARB_conservative_depth",                  o(ARB_conservative_depth),                  GL,             2011 },
88    { "GL_ARB_debug_output",                        o(dummy_true),                              GL,             2009 },
89    { "GL_ARB_depth_buffer_float",                  o(ARB_depth_buffer_float),                  GL,             2008 },
90    { "GL_ARB_depth_clamp",                         o(ARB_depth_clamp),                         GL,             2003 },
91    { "GL_ARB_depth_texture",                       o(ARB_depth_texture),                       GLL,            2001 },
92    { "GL_ARB_draw_buffers",                        o(dummy_true),                              GL,             2002 },
93    { "GL_ARB_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
94    { "GL_ARB_draw_elements_base_vertex",           o(ARB_draw_elements_base_vertex),           GL,             2009 },
95    { "GL_ARB_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2008 },
96    { "GL_ARB_explicit_attrib_location",            o(ARB_explicit_attrib_location),            GL,             2009 },
97    { "GL_ARB_fragment_coord_conventions",          o(ARB_fragment_coord_conventions),          GL,             2009 },
98    { "GL_ARB_fragment_program",                    o(ARB_fragment_program),                    GLL,            2002 },
99    { "GL_ARB_fragment_program_shadow",             o(ARB_fragment_program_shadow),             GLL,            2003 },
100    { "GL_ARB_fragment_shader",                     o(ARB_fragment_shader),                     GL,             2002 },
101    { "GL_ARB_framebuffer_object",                  o(ARB_framebuffer_object),                  GL,             2005 },
102    { "GL_ARB_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
103    { "GL_ARB_half_float_pixel",                    o(ARB_half_float_pixel),                    GL,             2003 },
104    { "GL_ARB_half_float_vertex",                   o(ARB_half_float_vertex),                   GL,             2008 },
105    { "GL_ARB_instanced_arrays",                    o(ARB_instanced_arrays),                    GL,             2008 },
106    { "GL_ARB_invalidate_subdata",                  o(dummy_true),                              GL,             2012 },
107    { "GL_ARB_map_buffer_range",                    o(ARB_map_buffer_range),                    GL,             2008 },
108    { "GL_ARB_multisample",                         o(dummy_true),                              GLL,            1994 },
109    { "GL_ARB_multitexture",                        o(dummy_true),                              GLL,            1998 },
110    { "GL_ARB_occlusion_query2",                    o(ARB_occlusion_query2),                    GL,             2003 },
111    { "GL_ARB_occlusion_query",                     o(ARB_occlusion_query),                     GLL,            2001 },
112    { "GL_ARB_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
113    { "GL_ARB_point_parameters",                    o(EXT_point_parameters),                    GLL,            1997 },
114    { "GL_ARB_point_sprite",                        o(ARB_point_sprite),                        GL,             2003 },
115    { "GL_ARB_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
116    { "GL_ARB_robustness",                          o(dummy_true),                              GL,             2010 },
117    { "GL_ARB_sampler_objects",                     o(dummy_true),                              GL,             2009 },
118    { "GL_ARB_seamless_cube_map",                   o(ARB_seamless_cube_map),                   GL,             2009 },
119    { "GL_ARB_shader_bit_encoding",                 o(ARB_shader_bit_encoding),                 GL,             2010 },
120    { "GL_ARB_shader_objects",                      o(ARB_shader_objects),                      GL,             2002 },
121    { "GL_ARB_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
122    { "GL_ARB_shader_texture_lod",                  o(ARB_shader_texture_lod),                  GL,             2009 },
123    { "GL_ARB_shading_language_100",                o(ARB_shading_language_100),                GLL,            2003 },
124    { "GL_ARB_shadow",                              o(ARB_shadow),                              GLL,            2001 },
125    { "GL_ARB_sync",                                o(ARB_sync),                                GL,             2003 },
126    { "GL_ARB_texture_border_clamp",                o(ARB_texture_border_clamp),                GLL,            2000 },
127    { "GL_ARB_texture_buffer_object",               o(ARB_texture_buffer_object),               GL,             2008 },
128    { "GL_ARB_texture_compression",                 o(dummy_true),                              GLL,            2000 },
129    { "GL_ARB_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
130    { "GL_ARB_texture_cube_map",                    o(ARB_texture_cube_map),                    GLL,            1999 },
131    { "GL_ARB_texture_env_add",                     o(dummy_true),                              GLL,            1999 },
132    { "GL_ARB_texture_env_combine",                 o(ARB_texture_env_combine),                 GLL,            2001 },
133    { "GL_ARB_texture_env_crossbar",                o(ARB_texture_env_crossbar),                GLL,            2001 },
134    { "GL_ARB_texture_env_dot3",                    o(ARB_texture_env_dot3),                    GLL,            2001 },
135    { "GL_ARB_texture_float",                       o(ARB_texture_float),                       GL,             2004 },
136    { "GL_ARB_texture_mirrored_repeat",             o(dummy_true),                              GLL,            2001 },
137    { "GL_ARB_texture_multisample",                 o(ARB_texture_multisample),                 GL,             2009 },
138    { "GL_ARB_texture_non_power_of_two",            o(ARB_texture_non_power_of_two),            GL,             2003 },
139    { "GL_ARB_texture_rectangle",                   o(NV_texture_rectangle),                    GL,             2004 },
140    { "GL_ARB_texture_rgb10_a2ui",                  o(ARB_texture_rgb10_a2ui),                  GL,             2009 },
141    { "GL_ARB_texture_rg",                          o(ARB_texture_rg),                          GL,             2008 },
142    { "GL_ARB_texture_storage",                     o(ARB_texture_storage),                     GL,             2011 },
143    { "GL_ARB_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
144    { "GL_ARB_timer_query",                         o(ARB_timer_query),                         GL,             2010 },
145    { "GL_ARB_transform_feedback2",                 o(ARB_transform_feedback2),                 GL,             2010 },
146    { "GL_ARB_transform_feedback3",                 o(ARB_transform_feedback3),                 GL,             2010 },
147    { "GL_ARB_transform_feedback_instanced",        o(ARB_transform_feedback_instanced),        GL,             2011 },
148    { "GL_ARB_transpose_matrix",                    o(ARB_transpose_matrix),                    GLL,            1999 },
149    { "GL_ARB_uniform_buffer_object",               o(ARB_uniform_buffer_object),               GL,             2009 },
150    { "GL_ARB_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
151    { "GL_ARB_vertex_array_object",                 o(dummy_true),                              GL,             2006 },
152    { "GL_ARB_vertex_buffer_object",                o(dummy_true),                              GLL,            2003 },
153    { "GL_ARB_vertex_program",                      o(ARB_vertex_program),                      GLL,            2002 },
154    { "GL_ARB_vertex_shader",                       o(ARB_vertex_shader),                       GL,             2002 },
155    { "GL_ARB_vertex_type_2_10_10_10_rev",          o(ARB_vertex_type_2_10_10_10_rev),          GL,             2009 },
156    { "GL_ARB_window_pos",                          o(ARB_window_pos),                          GLL,            2001 },
157    /* EXT extensions */
158    { "GL_EXT_abgr",                                o(dummy_true),                              GL,             1995 },
159    { "GL_EXT_bgra",                                o(dummy_true),                              GLL,            1995 },
160    { "GL_EXT_blend_color",                         o(EXT_blend_color),                         GLL,            1995 },
161    { "GL_EXT_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
162    { "GL_EXT_blend_func_separate",                 o(EXT_blend_func_separate),                 GLL,            1999 },
163    { "GL_EXT_blend_minmax",                        o(EXT_blend_minmax),                        GLL | ES1 | ES2, 1995 },
164    { "GL_EXT_blend_subtract",                      o(dummy_true),                              GLL,            1995 },
165    { "GL_EXT_clip_volume_hint",                    o(EXT_clip_volume_hint),                    GL,             1996 },
166    { "GL_EXT_compiled_vertex_array",               o(EXT_compiled_vertex_array),               GLL,            1996 },
167    { "GL_EXT_copy_texture",                        o(dummy_true),                              GLL,            1995 },
168    { "GL_EXT_depth_bounds_test",                   o(EXT_depth_bounds_test),                   GL,             2002 },
169    { "GL_EXT_draw_buffers2",                       o(EXT_draw_buffers2),                       GL,             2006 },
170    { "GL_EXT_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2006 },
171    { "GL_EXT_draw_range_elements",                 o(EXT_draw_range_elements),                 GLL,            1997 },
172    { "GL_EXT_fog_coord",                           o(EXT_fog_coord),                           GLL,            1999 },
173    { "GL_EXT_framebuffer_blit",                    o(EXT_framebuffer_blit),                    GL,             2005 },
174    { "GL_EXT_framebuffer_multisample",             o(EXT_framebuffer_multisample),             GL,             2005 },
175    { "GL_EXT_framebuffer_object",                  o(EXT_framebuffer_object),                  GL,             2000 },
176    { "GL_EXT_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
177    { "GL_EXT_gpu_program_parameters",              o(EXT_gpu_program_parameters),              GLL,            2006 },
178    { "GL_EXT_gpu_shader4",                         o(EXT_gpu_shader4),                         GL,             2006 },
179    { "GL_EXT_multi_draw_arrays",                   o(dummy_true),                              GLL | ES1 | ES2, 1999 },
180    { "GL_EXT_packed_depth_stencil",                o(EXT_packed_depth_stencil),                GL,             2005 },
181    { "GL_EXT_packed_float",                        o(EXT_packed_float),                        GL,             2004 },
182    { "GL_EXT_packed_pixels",                       o(EXT_packed_pixels),                       GLL,            1997 },
183    { "GL_EXT_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
184    { "GL_EXT_point_parameters",                    o(EXT_point_parameters),                    GLL,            1997 },
185    { "GL_EXT_polygon_offset",                      o(dummy_true),                              GLL,            1995 },
186    { "GL_EXT_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
187    { "GL_EXT_rescale_normal",                      o(EXT_rescale_normal),                      GLL,            1997 },
188    { "GL_EXT_secondary_color",                     o(EXT_secondary_color),                     GLL,            1999 },
189    { "GL_EXT_separate_shader_objects",             o(EXT_separate_shader_objects),             GLL,            2008 },
190    { "GL_EXT_separate_specular_color",             o(EXT_separate_specular_color),             GLL,            1997 },
191    { "GL_EXT_shadow_funcs",                        o(EXT_shadow_funcs),                        GLL,            2002 },
192    { "GL_EXT_stencil_two_side",                    o(EXT_stencil_two_side),                    GLL,            2001 },
193    { "GL_EXT_stencil_wrap",                        o(dummy_true),                              GLL,            2002 },
194    { "GL_EXT_subtexture",                          o(dummy_true),                              GLL,            1995 },
195    { "GL_EXT_texture3D",                           o(EXT_texture3D),                           GLL,            1996 },
196    { "GL_EXT_texture_array",                       o(EXT_texture_array),                       GL,             2006 },
197    { "GL_EXT_texture_compression_dxt1",            o(EXT_texture_compression_s3tc),            GL | ES1 | ES2, 2004 },
198    { "GL_EXT_texture_compression_latc",            o(EXT_texture_compression_latc),            GL,             2006 },
199    { "GL_EXT_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
200    { "GL_EXT_texture_compression_s3tc",            o(EXT_texture_compression_s3tc),            GL,             2000 },
201    { "GL_EXT_texture_cube_map",                    o(ARB_texture_cube_map),                    GLL,            2001 },
202    { "GL_EXT_texture_edge_clamp",                  o(dummy_true),                              GLL,            1997 },
203    { "GL_EXT_texture_env_add",                     o(dummy_true),                              GLL,            1999 },
204    { "GL_EXT_texture_env_combine",                 o(dummy_true),                              GLL,            2000 },
205    { "GL_EXT_texture_env_dot3",                    o(EXT_texture_env_dot3),                    GLL,            2000 },
206    { "GL_EXT_texture_filter_anisotropic",          o(EXT_texture_filter_anisotropic),          GL | ES1 | ES2, 1999 },
207    { "GL_EXT_texture_format_BGRA8888",             o(dummy_true),                                   ES1 | ES2, 2005 },
208    { "GL_EXT_texture_rg",                          o(ARB_texture_rg),                                     ES2, 2011 },
209    { "GL_EXT_read_format_bgra",                    o(dummy_true),                                   ES1 | ES2, 2009 },
210    { "GL_EXT_texture_integer",                     o(EXT_texture_integer),                     GL,             2006 },
211    { "GL_EXT_texture_lod_bias",                    o(dummy_true),                              GLL | ES1,      1999 },
212    { "GL_EXT_texture_mirror_clamp",                o(EXT_texture_mirror_clamp),                GL,             2004 },
213    { "GL_EXT_texture_object",                      o(dummy_true),                              GLL,            1995 },
214    { "GL_EXT_texture",                             o(dummy_true),                              GLL,            1996 },
215    { "GL_EXT_texture_rectangle",                   o(NV_texture_rectangle),                    GLL,            2004 },
216    { "GL_EXT_texture_shared_exponent",             o(EXT_texture_shared_exponent),             GL,             2004 },
217    { "GL_EXT_texture_snorm",                       o(EXT_texture_snorm),                       GL,             2009 },
218    { "GL_EXT_texture_sRGB",                        o(EXT_texture_sRGB),                        GL,             2004 },
219    { "GL_EXT_texture_sRGB_decode",                 o(EXT_texture_sRGB_decode),                        GL,      2006 },
220    { "GL_EXT_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
221    { "GL_EXT_texture_type_2_10_10_10_REV",         o(dummy_true),                                         ES2, 2008 },
222    { "GL_EXT_timer_query",                         o(EXT_timer_query),                         GL,             2006 },
223    { "GL_EXT_transform_feedback",                  o(EXT_transform_feedback),                  GL,             2011 },
224    { "GL_EXT_unpack_subimage",                     o(dummy_true),                                         ES2, 2011 },
225    { "GL_EXT_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
226    { "GL_EXT_vertex_array",                        o(dummy_true),                              GLL,            1995 },
227 
228    /* OES extensions */
229    { "GL_OES_blend_equation_separate",             o(EXT_blend_equation_separate),                  ES1,       2009 },
230    { "GL_OES_blend_func_separate",                 o(EXT_blend_func_separate),                      ES1,       2009 },
231    { "GL_OES_blend_subtract",                      o(dummy_true),                                   ES1,       2009 },
232    { "GL_OES_byte_coordinates",                    o(dummy_true),                                   ES1,       2002 },
233    { "GL_OES_compressed_ETC1_RGB8_texture",        o(OES_compressed_ETC1_RGB8_texture),             ES1 | ES2, 2005 },
234    { "GL_OES_compressed_paletted_texture",         o(dummy_true),                                   ES1,       2003 },
235    { "GL_OES_depth24",                             o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
236    { "GL_OES_depth32",                             o(dummy_false),                     DISABLE,                2005 },
237    { "GL_OES_depth_texture",                       o(ARB_depth_texture),                                  ES2, 2006 },
238 #if FEATURE_OES_draw_texture
239    { "GL_OES_draw_texture",                        o(OES_draw_texture),                             ES1,       2004 },
240 #endif
241 #if FEATURE_OES_EGL_image
242    /*  FIXME: Mesa expects GL_OES_EGL_image to be available in OpenGL contexts. */
243    { "GL_OES_EGL_image",                           o(OES_EGL_image),                           GL | ES1 | ES2, 2006 },
244    { "GL_OES_EGL_image_external",                  o(OES_EGL_image_external),                       ES1 | ES2, 2010 },
245 #endif
246    { "GL_OES_element_index_uint",                  o(dummy_true),                                   ES1 | ES2, 2005 },
247    { "GL_OES_fbo_render_mipmap",                   o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
248    { "GL_OES_fixed_point",                         o(dummy_true),                                   ES1,       2002 },
249    { "GL_OES_framebuffer_object",                  o(EXT_framebuffer_object),                       ES1,       2005 },
250    { "GL_OES_mapbuffer",                           o(dummy_true),                                   ES1 | ES2, 2005 },
251    { "GL_OES_matrix_get",                          o(dummy_true),                                   ES1,       2004 },
252    { "GL_OES_packed_depth_stencil",                o(EXT_packed_depth_stencil),                     ES1 | ES2, 2007 },
253    { "GL_OES_point_size_array",                    o(dummy_true),                                   ES1,       2004 },
254    { "GL_OES_point_sprite",                        o(ARB_point_sprite),                             ES1,       2004 },
255    { "GL_OES_query_matrix",                        o(dummy_true),                                   ES1,       2003 },
256    { "GL_OES_read_format",                         o(dummy_true),                              GL | ES1,       2003 },
257    { "GL_OES_rgb8_rgba8",                          o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
258    { "GL_OES_single_precision",                    o(dummy_true),                                   ES1,       2003 },
259    { "GL_OES_standard_derivatives",                o(OES_standard_derivatives),                           ES2, 2005 },
260    { "GL_OES_stencil1",                            o(dummy_false),                     DISABLE,                2005 },
261    { "GL_OES_stencil4",                            o(dummy_false),                     DISABLE,                2005 },
262    { "GL_OES_stencil8",                            o(EXT_framebuffer_object),                       ES1 | ES2, 2005 },
263    { "GL_OES_stencil_wrap",                        o(dummy_true),                                   ES1,       2002 },
264    { "GL_OES_texture_3D",                          o(EXT_texture3D),                                      ES2, 2005 },
265    { "GL_OES_texture_cube_map",                    o(ARB_texture_cube_map),                         ES1,       2007 },
266    { "GL_OES_texture_env_crossbar",                o(ARB_texture_env_crossbar),                     ES1,       2005 },
267    { "GL_OES_texture_mirrored_repeat",             o(dummy_true),                                   ES1,       2005 },
268    { "GL_OES_texture_npot",                        o(ARB_texture_non_power_of_two),                       ES2, 2005 },
269    { "GL_OES_vertex_array_object",                 o(dummy_true),                                   ES1 | ES2, 2010 },
270 
271    /* Vendor extensions */
272    { "GL_3DFX_texture_compression_FXT1",           o(TDFX_texture_compression_FXT1),           GL,             1999 },
273    { "GL_AMD_conservative_depth",                  o(ARB_conservative_depth),                  GL,             2009 },
274    { "GL_AMD_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
275    { "GL_AMD_seamless_cubemap_per_texture",        o(AMD_seamless_cubemap_per_texture),        GL,             2009 },
276    { "GL_AMD_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
277    { "GL_APPLE_object_purgeable",                  o(APPLE_object_purgeable),                  GL,             2006 },
278    { "GL_APPLE_packed_pixels",                     o(APPLE_packed_pixels),                     GLL,            2002 },
279    { "GL_APPLE_texture_max_level",                 o(dummy_true),                                   ES1 | ES2, 2009 },
280    { "GL_APPLE_vertex_array_object",               o(dummy_true),                              GLL,            2002 },
281    { "GL_ATI_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
282    { "GL_ATI_draw_buffers",                        o(dummy_true),                              GLL,            2002 },
283    { "GL_ATI_envmap_bumpmap",                      o(ATI_envmap_bumpmap),                      GLL,            2001 },
284    { "GL_ATI_fragment_shader",                     o(ATI_fragment_shader),                     GLL,            2001 },
285    { "GL_ATI_separate_stencil",                    o(ATI_separate_stencil),                    GLL,            2006 },
286    { "GL_ATI_texture_compression_3dc",             o(ATI_texture_compression_3dc),             GL,             2004 },
287    { "GL_ATI_texture_env_combine3",                o(ATI_texture_env_combine3),                GLL,            2002 },
288    { "GL_ATI_texture_float",                       o(ARB_texture_float),                       GL,             2002 },
289    { "GL_ATI_texture_mirror_once",                 o(ATI_texture_mirror_once),                 GL,             2006 },
290    { "GL_IBM_multimode_draw_arrays",               o(IBM_multimode_draw_arrays),               GL,             1998 },
291    { "GL_IBM_rasterpos_clip",                      o(IBM_rasterpos_clip),                      GLL,            1996 },
292    { "GL_IBM_texture_mirrored_repeat",             o(dummy_true),                              GLL,            1998 },
293    { "GL_INGR_blend_func_separate",                o(EXT_blend_func_separate),                 GLL,            1999 },
294    { "GL_MESA_pack_invert",                        o(MESA_pack_invert),                        GL,             2002 },
295    { "GL_MESA_resize_buffers",                     o(MESA_resize_buffers),                     GL,             1999 },
296    { "GL_MESA_texture_array",                      o(MESA_texture_array),                      GLL,            2007 },
297    { "GL_MESA_texture_signed_rgba",                o(EXT_texture_snorm),                       GL,             2009 },
298    { "GL_MESA_window_pos",                         o(ARB_window_pos),                          GLL,            2000 },
299    { "GL_MESA_ycbcr_texture",                      o(MESA_ycbcr_texture),                      GL,             2002 },
300    { "GL_NV_blend_square",                         o(NV_blend_square),                         GLL,            1999 },
301    { "GL_NV_conditional_render",                   o(NV_conditional_render),                   GL,             2008 },
302    { "GL_NV_depth_clamp",                          o(ARB_depth_clamp),                         GL,             2001 },
303    { "GL_NV_draw_buffers",                         o(dummy_true),                                         ES2, 2011 },
304    { "GL_NV_fbo_color_attachments",                o(EXT_framebuffer_object),                             ES2, 2010 },
305    { "GL_NV_fog_distance",                         o(NV_fog_distance),                         GLL,            2001 },
306    { "GL_NV_fragment_program",                     o(NV_fragment_program),                     GLL,            2001 },
307    { "GL_NV_fragment_program_option",              o(NV_fragment_program_option),              GLL,            2005 },
308    { "GL_NV_light_max_exponent",                   o(NV_light_max_exponent),                   GLL,            1999 },
309    { "GL_NV_packed_depth_stencil",                 o(EXT_packed_depth_stencil),                GL,             2000 },
310    { "GL_NV_point_sprite",                         o(NV_point_sprite),                         GL,             2001 },
311    { "GL_NV_primitive_restart",                    o(NV_primitive_restart),                    GLL,            2002 },
312    { "GL_NV_read_buffer",                          o(dummy_true),                              ES2,            2011 },
313    { "GL_NV_texgen_reflection",                    o(NV_texgen_reflection),                    GLL,            1999 },
314    { "GL_NV_texture_barrier",                      o(NV_texture_barrier),                      GL,             2009 },
315    { "GL_NV_texture_env_combine4",                 o(NV_texture_env_combine4),                 GLL,            1999 },
316    { "GL_NV_texture_rectangle",                    o(NV_texture_rectangle),                    GLL,            2000 },
317    { "GL_NV_vertex_program1_1",                    o(NV_vertex_program1_1),                    GLL,            2001 },
318    { "GL_NV_vertex_program",                       o(NV_vertex_program),                       GLL,            2000 },
319    { "GL_S3_s3tc",                                 o(S3_s3tc),                                 GL,             1999 },
320    { "GL_SGIS_generate_mipmap",                    o(dummy_true),                              GLL,            1997 },
321    { "GL_SGIS_texture_border_clamp",               o(ARB_texture_border_clamp),                GLL,            1997 },
322    { "GL_SGIS_texture_edge_clamp",                 o(dummy_true),                              GLL,            1997 },
323    { "GL_SGIS_texture_lod",                        o(SGIS_texture_lod),                        GLL,            1997 },
324    { "GL_SUN_multi_draw_arrays",                   o(dummy_true),                              GLL,            1999 },
325 
326    { 0, 0, 0, 0 },
327 };
328 
329 
330 /**
331  * Given an extension name, lookup up the corresponding member of struct
332  * gl_extensions and return that member's offset (in bytes).  If the name is
333  * not found in the \c extension_table, return 0.
334  *
335  * \param name Name of extension.
336  * \return Offset of member in struct gl_extensions.
337  */
338 static size_t
name_to_offset(const char * name)339 name_to_offset(const char* name)
340 {
341    const struct extension *i;
342 
343    if (name == 0)
344       return 0;
345 
346    for (i = extension_table; i->name != 0; ++i) {
347       if (strcmp(name, i->name) == 0)
348 	 return i->offset;
349    }
350 
351    return 0;
352 }
353 
354 
355 /**
356  * \brief Extensions enabled by default.
357  *
358  * These extensions are enabled by _mesa_init_extensions().
359  *
360  * XXX: Should these defaults also apply to GLES?
361  */
362 static const size_t default_extensions[] = {
363    o(ARB_copy_buffer),
364    o(ARB_transpose_matrix),
365    o(ARB_window_pos),
366 
367    o(EXT_compiled_vertex_array),
368    o(EXT_draw_range_elements),
369    o(EXT_packed_pixels),
370    o(EXT_rescale_normal),
371    o(EXT_separate_specular_color),
372    o(EXT_texture3D),
373 
374    o(OES_standard_derivatives),
375 
376    /* Vendor Extensions */
377    o(APPLE_packed_pixels),
378    o(IBM_multimode_draw_arrays),
379    o(IBM_rasterpos_clip),
380    o(NV_light_max_exponent),
381    o(NV_texgen_reflection),
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  */
392 void
_mesa_enable_sw_extensions(struct gl_context * ctx)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_elements_base_vertex = GL_TRUE;
399    ctx->Extensions.ARB_draw_instanced = GL_TRUE;
400    ctx->Extensions.ARB_explicit_attrib_location = GL_TRUE;
401    ctx->Extensions.ARB_fragment_coord_conventions = GL_TRUE;
402 #if FEATURE_ARB_fragment_program
403    ctx->Extensions.ARB_fragment_program = GL_TRUE;
404    ctx->Extensions.ARB_fragment_program_shadow = GL_TRUE;
405 #endif
406 #if FEATURE_ARB_fragment_shader
407    ctx->Extensions.ARB_fragment_shader = GL_TRUE;
408 #endif
409 #if FEATURE_ARB_framebuffer_object
410    ctx->Extensions.ARB_framebuffer_object = GL_TRUE;
411 #endif
412 #if FEATURE_ARB_geometry_shader4 && 0
413    /* XXX re-enable when GLSL compiler again supports geometry shaders */
414    ctx->Extensions.ARB_geometry_shader4 = GL_TRUE;
415 #endif
416    ctx->Extensions.ARB_half_float_pixel = GL_TRUE;
417    ctx->Extensions.ARB_half_float_vertex = GL_TRUE;
418    ctx->Extensions.ARB_map_buffer_range = GL_TRUE;
419 #if FEATURE_queryobj
420    ctx->Extensions.ARB_occlusion_query = GL_TRUE;
421    ctx->Extensions.ARB_occlusion_query2 = GL_TRUE;
422 #endif
423    ctx->Extensions.ARB_point_sprite = GL_TRUE;
424 #if FEATURE_ARB_shader_objects
425    ctx->Extensions.ARB_shader_objects = GL_TRUE;
426    ctx->Extensions.EXT_separate_shader_objects = GL_TRUE;
427 #endif
428 #if FEATURE_ARB_shading_language_100
429    ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
430 #endif
431    ctx->Extensions.ARB_shadow = GL_TRUE;
432    ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
433    ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
434    ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
435    ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
436    ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
437    /*ctx->Extensions.ARB_texture_float = GL_TRUE;*/
438    ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
439    ctx->Extensions.ARB_texture_rg = GL_TRUE;
440    ctx->Extensions.ARB_texture_compression_rgtc = GL_TRUE;
441    ctx->Extensions.ARB_texture_storage = GL_TRUE;
442 #if FEATURE_ARB_vertex_program
443    ctx->Extensions.ARB_vertex_program = GL_TRUE;
444 #endif
445 #if FEATURE_ARB_vertex_shader
446    ctx->Extensions.ARB_vertex_shader = GL_TRUE;
447 #endif
448 #if FEATURE_ARB_sync
449    ctx->Extensions.ARB_sync = GL_TRUE;
450 #endif
451 #if FEATURE_APPLE_object_purgeable
452    ctx->Extensions.APPLE_object_purgeable = GL_TRUE;
453 #endif
454    ctx->Extensions.ATI_envmap_bumpmap = GL_TRUE;
455 #if FEATURE_ATI_fragment_shader
456    ctx->Extensions.ATI_fragment_shader = GL_TRUE;
457 #endif
458    ctx->Extensions.ATI_texture_compression_3dc = GL_TRUE;
459    ctx->Extensions.ATI_texture_env_combine3 = GL_TRUE;
460    ctx->Extensions.ATI_texture_mirror_once = GL_TRUE;
461    ctx->Extensions.ATI_separate_stencil = GL_TRUE;
462    ctx->Extensions.EXT_blend_color = GL_TRUE;
463    ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
464    ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
465    ctx->Extensions.EXT_blend_minmax = GL_TRUE;
466    ctx->Extensions.EXT_depth_bounds_test = GL_TRUE;
467    ctx->Extensions.EXT_draw_buffers2 = GL_TRUE;
468    ctx->Extensions.EXT_fog_coord = GL_TRUE;
469 #if FEATURE_EXT_framebuffer_object
470    ctx->Extensions.EXT_framebuffer_object = GL_TRUE;
471 #endif
472 #if FEATURE_EXT_framebuffer_blit
473    ctx->Extensions.EXT_framebuffer_blit = GL_TRUE;
474 #endif
475    ctx->Extensions.EXT_packed_depth_stencil = GL_TRUE;
476 #if FEATURE_EXT_pixel_buffer_object
477    ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
478 #endif
479    ctx->Extensions.EXT_point_parameters = GL_TRUE;
480    ctx->Extensions.EXT_provoking_vertex = GL_TRUE;
481    ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
482    ctx->Extensions.EXT_secondary_color = GL_TRUE;
483    ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
484    ctx->Extensions.EXT_texture_array = GL_TRUE;
485    ctx->Extensions.EXT_texture_compression_latc = GL_TRUE;
486    ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
487    ctx->Extensions.EXT_texture_filter_anisotropic = GL_TRUE;
488    ctx->Extensions.EXT_texture_mirror_clamp = GL_TRUE;
489    ctx->Extensions.EXT_texture_shared_exponent = GL_TRUE;
490 #if FEATURE_EXT_texture_sRGB
491    ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
492    ctx->Extensions.EXT_texture_sRGB_decode = GL_TRUE;
493 #endif
494    ctx->Extensions.EXT_texture_swizzle = GL_TRUE;
495 #if FEATURE_EXT_transform_feedback
496    /*ctx->Extensions.EXT_transform_feedback = GL_TRUE;*/
497 #endif
498    ctx->Extensions.EXT_vertex_array_bgra = GL_TRUE;
499    /*ctx->Extensions.IBM_multimode_draw_arrays = GL_TRUE;*/
500    ctx->Extensions.MESA_pack_invert = GL_TRUE;
501    ctx->Extensions.MESA_resize_buffers = GL_TRUE;
502    ctx->Extensions.MESA_texture_array = GL_TRUE;
503    ctx->Extensions.MESA_ycbcr_texture = GL_TRUE;
504    ctx->Extensions.NV_blend_square = GL_TRUE;
505    ctx->Extensions.NV_conditional_render = GL_TRUE;
506    /*ctx->Extensions.NV_light_max_exponent = GL_TRUE;*/
507    ctx->Extensions.NV_point_sprite = GL_TRUE;
508    ctx->Extensions.NV_texture_env_combine4 = GL_TRUE;
509    ctx->Extensions.NV_texture_rectangle = GL_TRUE;
510    /*ctx->Extensions.NV_texgen_reflection = GL_TRUE;*/
511 #if FEATURE_NV_vertex_program
512    ctx->Extensions.NV_vertex_program = GL_TRUE;
513    ctx->Extensions.NV_vertex_program1_1 = GL_TRUE;
514 #endif
515 #if FEATURE_NV_fragment_program
516    ctx->Extensions.NV_fragment_program = GL_TRUE;
517 #endif
518 #if FEATURE_NV_fragment_program && FEATURE_ARB_fragment_program
519    ctx->Extensions.NV_fragment_program_option = GL_TRUE;
520 #endif
521 #if FEATURE_ARB_vertex_program || FEATURE_ARB_fragment_program
522    ctx->Extensions.EXT_gpu_program_parameters = GL_TRUE;
523 #endif
524 #if FEATURE_texture_fxt1
525    _mesa_enable_extension(ctx, "GL_3DFX_texture_compression_FXT1");
526 #endif
527 #if FEATURE_texture_s3tc
528    if (ctx->Mesa_DXTn) {
529       _mesa_enable_extension(ctx, "GL_EXT_texture_compression_s3tc");
530       _mesa_enable_extension(ctx, "GL_S3_s3tc");
531    }
532 #endif
533 }
534 
535 
536 /**
537  * Enable all OpenGL 1.3 features and extensions.
538  * A convenience function to be called by drivers.
539  */
540 void
_mesa_enable_1_3_extensions(struct gl_context * ctx)541 _mesa_enable_1_3_extensions(struct gl_context *ctx)
542 {
543    ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
544    ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
545    ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
546    ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
547    /*ctx->Extensions.ARB_transpose_matrix = GL_TRUE;*/
548 }
549 
550 
551 
552 /**
553  * Enable all OpenGL 1.4 features and extensions.
554  * A convenience function to be called by drivers.
555  */
556 void
_mesa_enable_1_4_extensions(struct gl_context * ctx)557 _mesa_enable_1_4_extensions(struct gl_context *ctx)
558 {
559    ctx->Extensions.ARB_depth_texture = GL_TRUE;
560    ctx->Extensions.ARB_shadow = GL_TRUE;
561    ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
562    ctx->Extensions.ARB_window_pos = GL_TRUE;
563    ctx->Extensions.EXT_blend_color = GL_TRUE;
564    ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
565    ctx->Extensions.EXT_blend_minmax = GL_TRUE;
566    ctx->Extensions.EXT_fog_coord = GL_TRUE;
567    ctx->Extensions.EXT_point_parameters = GL_TRUE;
568    ctx->Extensions.EXT_secondary_color = GL_TRUE;
569 }
570 
571 
572 /**
573  * Enable all OpenGL 1.5 features and extensions.
574  * A convenience function to be called by drivers.
575  */
576 void
_mesa_enable_1_5_extensions(struct gl_context * ctx)577 _mesa_enable_1_5_extensions(struct gl_context *ctx)
578 {
579    ctx->Extensions.ARB_occlusion_query = GL_TRUE;
580    ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
581 }
582 
583 
584 /**
585  * Enable all OpenGL 2.0 features and extensions.
586  * A convenience function to be called by drivers.
587  */
588 void
_mesa_enable_2_0_extensions(struct gl_context * ctx)589 _mesa_enable_2_0_extensions(struct gl_context *ctx)
590 {
591 #if FEATURE_ARB_fragment_shader
592    ctx->Extensions.ARB_fragment_shader = GL_TRUE;
593 #endif
594    ctx->Extensions.ARB_point_sprite = GL_TRUE;
595    ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
596    ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
597 #if FEATURE_ARB_shader_objects
598    ctx->Extensions.ARB_shader_objects = GL_TRUE;
599 #endif
600 #if FEATURE_ARB_shading_language_100
601    ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
602 #endif
603    ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
604 #if FEATURE_ARB_vertex_shader
605    ctx->Extensions.ARB_vertex_shader = GL_TRUE;
606 #endif
607 }
608 
609 
610 /**
611  * Enable all OpenGL 2.1 features and extensions.
612  * A convenience function to be called by drivers.
613  */
614 void
_mesa_enable_2_1_extensions(struct gl_context * ctx)615 _mesa_enable_2_1_extensions(struct gl_context *ctx)
616 {
617 #if FEATURE_EXT_pixel_buffer_object
618    ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
619 #endif
620 #if FEATURE_EXT_texture_sRGB
621    ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
622 #endif
623 }
624 
625 
626 /**
627  * Either enable or disable the named extension.
628  * \return GL_TRUE for success, GL_FALSE if invalid extension name
629  */
630 static GLboolean
set_extension(struct gl_context * ctx,const char * name,GLboolean state)631 set_extension( struct gl_context *ctx, const char *name, GLboolean state )
632 {
633    size_t offset;
634 
635    if (ctx->Extensions.String) {
636       /* The string was already queried - can't change it now! */
637       _mesa_problem(ctx, "Trying to enable/disable extension after glGetString(GL_EXTENSIONS): %s", name);
638       return GL_FALSE;
639    }
640 
641    offset = name_to_offset(name);
642    if (offset == 0) {
643       _mesa_problem(ctx, "Trying to enable/disable unknown extension %s",
644 	            name);
645       return GL_FALSE;
646    } else if (offset == o(dummy_true) && state == GL_FALSE) {
647       _mesa_problem(ctx, "Trying to disable a permanently enabled extension: "
648 	                  "%s", name);
649       return GL_FALSE;
650    } else {
651       GLboolean *base = (GLboolean *) &ctx->Extensions;
652       base[offset] = state;
653       return GL_TRUE;
654    }
655 }
656 
657 
658 /**
659  * Enable the named extension.
660  * Typically called by drivers.
661  */
662 void
_mesa_enable_extension(struct gl_context * ctx,const char * name)663 _mesa_enable_extension( struct gl_context *ctx, const char *name )
664 {
665    if (!set_extension(ctx, name, GL_TRUE))
666       _mesa_problem(ctx, "Trying to enable unknown extension: %s", name);
667 }
668 
669 
670 /**
671  * Disable the named extension.
672  * XXX is this really needed???
673  */
674 void
_mesa_disable_extension(struct gl_context * ctx,const char * name)675 _mesa_disable_extension( struct gl_context *ctx, const char *name )
676 {
677    if (!set_extension(ctx, name, GL_FALSE))
678       _mesa_problem(ctx, "Trying to disable unknown extension: %s", name);
679 }
680 
681 
682 /**
683  * Test if the named extension is enabled in this context.
684  */
685 GLboolean
_mesa_extension_is_enabled(struct gl_context * ctx,const char * name)686 _mesa_extension_is_enabled( struct gl_context *ctx, const char *name )
687 {
688    size_t offset;
689    GLboolean *base;
690 
691    if (name == 0)
692       return GL_FALSE;
693 
694    offset = name_to_offset(name);
695    if (offset == 0)
696       return GL_FALSE;
697    base = (GLboolean *) &ctx->Extensions;
698    return base[offset];
699 }
700 
701 
702 /**
703  * \brief Apply the \c MESA_EXTENSION_OVERRIDE environment variable.
704  *
705  * \c MESA_EXTENSION_OVERRIDE is a space-separated list of extensions to
706  * enable or disable. The list is processed thus:
707  *    - Enable recognized extension names that are prefixed with '+'.
708  *    - Disable recognized extension names that are prefixed with '-'.
709  *    - Enable recognized extension names that are not prefixed.
710  *    - Collect unrecognized extension names in a new string.
711  *
712  * \return Space-separated list of unrecognized extension names (which must
713  *    be freed). Does not return \c NULL.
714  */
715 static char *
get_extension_override(struct gl_context * ctx)716 get_extension_override( struct gl_context *ctx )
717 {
718    const char *env_const = _mesa_getenv("MESA_EXTENSION_OVERRIDE");
719    char *env;
720    char *ext;
721    char *extra_exts;
722    int len;
723 
724    if (env_const == NULL) {
725       /* Return the empty string rather than NULL. This simplifies the logic
726        * of client functions. */
727       return calloc(4, sizeof(char));
728    }
729 
730    /* extra_exts: List of unrecognized extensions. */
731    extra_exts = calloc(ALIGN(strlen(env_const) + 2, 4), sizeof(char));
732 
733    /* Copy env_const because strtok() is destructive. */
734    env = strdup(env_const);
735    for (ext = strtok(env, " "); ext != NULL; ext = strtok(NULL, " ")) {
736       int enable;
737       int recognized;
738       switch (ext[0]) {
739       case '+':
740          enable = 1;
741          ++ext;
742          break;
743       case '-':
744          enable = 0;
745          ++ext;
746          break;
747       default:
748          enable = 1;
749          break;
750       }
751       recognized = set_extension(ctx, ext, enable);
752       if (!recognized) {
753          strcat(extra_exts, ext);
754          strcat(extra_exts, " ");
755       }
756    }
757 
758    free(env);
759 
760    /* Remove trailing space. */
761    len = strlen(extra_exts);
762    if (len > 0 && extra_exts[len - 1] == ' ')
763       extra_exts[len - 1] = '\0';
764 
765    return extra_exts;
766 }
767 
768 
769 /**
770  * \brief Initialize extension tables and enable default extensions.
771  *
772  * This should be called during context initialization.
773  * Note: Sets gl_extensions.dummy_true to true.
774  */
775 void
_mesa_init_extensions(struct gl_context * ctx)776 _mesa_init_extensions( struct gl_context *ctx )
777 {
778    GLboolean *base = (GLboolean *) &ctx->Extensions;
779    GLboolean *sentinel = base + o(extension_sentinel);
780    GLboolean *i;
781    const size_t *j;
782 
783    /* First, turn all extensions off. */
784    for (i = base; i != sentinel; ++i)
785       *i = GL_FALSE;
786 
787    /* Then, selectively turn default extensions on. */
788    ctx->Extensions.dummy_true = GL_TRUE;
789    for (j = default_extensions; *j != 0; ++j)
790       base[*j] = GL_TRUE;
791 }
792 
793 
794 typedef unsigned short extension_index;
795 
796 
797 /**
798  * Compare two entries of the extensions table.  Sorts first by year,
799  * then by name.
800  *
801  * Arguments are indices into extension_table.
802  */
803 static int
extension_compare(const void * p1,const void * p2)804 extension_compare(const void *p1, const void *p2)
805 {
806    extension_index i1 = * (const extension_index *) p1;
807    extension_index i2 = * (const extension_index *) p2;
808    const struct extension *e1 = &extension_table[i1];
809    const struct extension *e2 = &extension_table[i2];
810    int res;
811 
812    res = (int)e1->year - (int)e2->year;
813 
814    if (res == 0) {
815       res = strcmp(e1->name, e2->name);
816    }
817 
818    return res;
819 }
820 
821 
822 /**
823  * Construct the GL_EXTENSIONS string.  Called the first time that
824  * glGetString(GL_EXTENSIONS) is called.
825  */
826 GLubyte*
_mesa_make_extension_string(struct gl_context * ctx)827 _mesa_make_extension_string(struct gl_context *ctx)
828 {
829    /* The extension string. */
830    char *exts = 0;
831    /* Length of extension string. */
832    size_t length = 0;
833    /* Number of extensions */
834    unsigned count;
835    /* Indices of the extensions sorted by year */
836    extension_index *extension_indices;
837    /* String of extra extensions. */
838    char *extra_extensions = get_extension_override(ctx);
839    GLboolean *base = (GLboolean *) &ctx->Extensions;
840    const struct extension *i;
841    unsigned j;
842    unsigned maxYear = ~0;
843 
844    /* Check if the MESA_EXTENSION_MAX_YEAR env var is set */
845    {
846       const char *env = getenv("MESA_EXTENSION_MAX_YEAR");
847       if (env) {
848          maxYear = atoi(env);
849          _mesa_debug(ctx, "Note: limiting GL extensions to %u or earlier\n",
850                      maxYear);
851       }
852    }
853 
854    /* Compute length of the extension string. */
855    count = 0;
856    for (i = extension_table; i->name != 0; ++i) {
857       if (base[i->offset] &&
858           i->year <= maxYear &&
859           (i->api_set & (1 << ctx->API))) {
860 	 length += strlen(i->name) + 1; /* +1 for space */
861 	 ++count;
862       }
863    }
864    if (extra_extensions != NULL)
865       length += 1 + strlen(extra_extensions); /* +1 for space */
866 
867    exts = (char *) calloc(ALIGN(length + 1, 4), sizeof(char));
868    if (exts == NULL) {
869       free(extra_extensions);
870       return NULL;
871    }
872 
873    extension_indices = malloc(count * sizeof(extension_index));
874    if (extension_indices == NULL) {
875       free(exts);
876       free(extra_extensions);
877       return NULL;
878    }
879 
880    /* Sort extensions in chronological order because certain old applications (e.g.,
881     * Quake3 demo) store the extension list in a static size buffer so chronologically
882     * order ensure that the extensions that such applications expect will fit into
883     * that buffer.
884     */
885    j = 0;
886    for (i = extension_table; i->name != 0; ++i) {
887       if (base[i->offset] &&
888           i->year <= maxYear &&
889           (i->api_set & (1 << ctx->API))) {
890          extension_indices[j++] = i - extension_table;
891       }
892    }
893    assert(j == count);
894    qsort(extension_indices, count, sizeof *extension_indices, extension_compare);
895 
896    /* Build the extension string.*/
897    for (j = 0; j < count; ++j) {
898       i = &extension_table[extension_indices[j]];
899       assert(base[i->offset] && (i->api_set & (1 << ctx->API)));
900       strcat(exts, i->name);
901       strcat(exts, " ");
902    }
903    free(extension_indices);
904    if (extra_extensions != 0) {
905       strcat(exts, extra_extensions);
906       free(extra_extensions);
907    }
908 
909    return (GLubyte *) exts;
910 }
911 
912 /**
913  * Return number of enabled extensions.
914  */
915 GLuint
_mesa_get_extension_count(struct gl_context * ctx)916 _mesa_get_extension_count(struct gl_context *ctx)
917 {
918    GLboolean *base;
919    const struct extension *i;
920 
921    /* only count once */
922    if (ctx->Extensions.Count != 0)
923       return ctx->Extensions.Count;
924 
925    base = (GLboolean *) &ctx->Extensions;
926    for (i = extension_table; i->name != 0; ++i) {
927       if (base[i->offset] && (i->api_set & (1 << ctx->API))) {
928 	 ctx->Extensions.Count++;
929       }
930    }
931    return ctx->Extensions.Count;
932 }
933 
934 /**
935  * Return name of i-th enabled extension
936  */
937 const GLubyte *
_mesa_get_enabled_extension(struct gl_context * ctx,GLuint index)938 _mesa_get_enabled_extension(struct gl_context *ctx, GLuint index)
939 {
940    const GLboolean *base;
941    size_t n;
942    const struct extension *i;
943 
944    base = (GLboolean*) &ctx->Extensions;
945    n = 0;
946    for (i = extension_table; i->name != 0; ++i) {
947       if (base[i->offset] && (i->api_set & (1 << ctx->API))) {
948          if (n == index)
949             return (const GLubyte*) i->name;
950          else
951             ++n;
952       }
953    }
954 
955    return NULL;
956 }
957