summaryrefslogtreecommitdiff
path: root/src/mesa/main/extensions.c
blob: b71afdd61f35323c2530ead1bc68cde13af62b7b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
/*
 * Mesa 3-D graphics library
 * Version:  7.6
 *
 * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
 * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */


#include "glheader.h"
#include "imports.h"
#include "context.h"
#include "extensions.h"
#include "mtypes.h"


#define F(x) offsetof(struct gl_extensions, x)
#define ON GL_TRUE
#define OFF GL_FALSE


/*
 * Note: The GL_MESAX_* extensions are placeholders for future ARB extensions.
 */
static const struct {
   GLboolean enabled;
   const char *name;
   int flag_offset;
} default_extensions[] = {
   { OFF, "GL_ARB_blend_func_extended",        F(ARB_blend_func_extended) },
   { ON,  "GL_ARB_copy_buffer",                F(ARB_copy_buffer) },
   { OFF, "GL_ARB_depth_buffer_float",         F(ARB_depth_buffer_float) },
   { OFF, "GL_ARB_depth_clamp",                F(ARB_depth_clamp) },
   { OFF, "GL_ARB_depth_texture",              F(ARB_depth_texture) },
   { ON,  "GL_ARB_draw_buffers",               F(ARB_draw_buffers) },
   { OFF, "GL_ARB_draw_elements_base_vertex",  F(ARB_draw_elements_base_vertex) },
   { OFF, "GL_ARB_draw_instanced",             F(ARB_draw_instanced) },
   { OFF, "GL_ARB_explicit_attrib_location",   F(ARB_explicit_attrib_location) },
   { OFF, "GL_ARB_fragment_coord_conventions", F(ARB_fragment_coord_conventions) },
   { OFF, "GL_ARB_fragment_program",           F(ARB_fragment_program) },
   { OFF, "GL_ARB_fragment_program_shadow",    F(ARB_fragment_program_shadow) },
   { OFF, "GL_ARB_fragment_shader",            F(ARB_fragment_shader) },
   { OFF, "GL_ARB_framebuffer_object",         F(ARB_framebuffer_object) },
   /* TODO: reenable this when the new GLSL compiler actually supports them */
   /* { OFF, "GL_ARB_geometry_shader4",           F(ARB_geometry_shader4) }, */
   { OFF, "GL_ARB_half_float_pixel",           F(ARB_half_float_pixel) },
   { OFF, "GL_ARB_half_float_vertex",          F(ARB_half_float_vertex) },
   { OFF, "GL_ARB_instanced_arrays",           F(ARB_instanced_arrays) },
   { OFF, "GL_ARB_map_buffer_range",           F(ARB_map_buffer_range) },
   { ON,  "GL_ARB_multisample",                F(ARB_multisample) },
   { OFF, "GL_ARB_multitexture",               F(ARB_multitexture) },
   { OFF, "GL_ARB_occlusion_query",            F(ARB_occlusion_query) },
   { OFF, "GL_ARB_occlusion_query2",           F(ARB_occlusion_query2) },
   { OFF, "GL_ARB_pixel_buffer_object",        F(EXT_pixel_buffer_object) },
   { OFF, "GL_ARB_point_parameters",           F(EXT_point_parameters) },
   { OFF, "GL_ARB_point_sprite",               F(ARB_point_sprite) },
   { OFF, "GL_ARB_provoking_vertex",           F(EXT_provoking_vertex) },
   { OFF, "GL_ARB_sampler_objects",            F(ARB_sampler_objects) },
   { OFF, "GL_ARB_seamless_cube_map",          F(ARB_seamless_cube_map) },
   { OFF, "GL_ARB_shader_objects",             F(ARB_shader_objects) },
   { OFF, "GL_ARB_shader_stencil_export",      F(ARB_shader_stencil_export) },
   { OFF, "GL_ARB_shading_language_100",       F(ARB_shading_language_100) },
   { OFF, "GL_ARB_shadow",                     F(ARB_shadow) },
   { OFF, "GL_ARB_shadow_ambient",             F(ARB_shadow_ambient) },
   { OFF, "GL_ARB_sync",                       F(ARB_sync) },
   { OFF, "GL_ARB_texture_border_clamp",       F(ARB_texture_border_clamp) },
   { OFF, "GL_ARB_texture_buffer_object",      F(ARB_texture_buffer_object) },
   { ON,  "GL_ARB_texture_compression",        F(ARB_texture_compression) },
   { OFF, "GL_ARB_texture_compression_rgtc",   F(ARB_texture_compression_rgtc) },
   { OFF, "GL_ARB_texture_cube_map",           F(ARB_texture_cube_map) },
   { OFF, "GL_ARB_texture_env_add",            F(EXT_texture_env_add) },
   { OFF, "GL_ARB_texture_env_combine",        F(ARB_texture_env_combine) },
   { OFF, "GL_ARB_texture_env_crossbar",       F(ARB_texture_env_crossbar) },
   { OFF, "GL_ARB_texture_env_dot3",           F(ARB_texture_env_dot3) },
   { OFF, "GL_MESAX_texture_float",            F(ARB_texture_float) },
   { OFF, "GL_ARB_texture_mirrored_repeat",    F(ARB_texture_mirrored_repeat)},
   { OFF, "GL_ARB_texture_multisample",        F(ARB_texture_multisample) },
   { OFF, "GL_ARB_texture_non_power_of_two",   F(ARB_texture_non_power_of_two)},
   { OFF, "GL_ARB_texture_rectangle",          F(NV_texture_rectangle) },
   { OFF, "GL_ARB_texture_rg",                 F(ARB_texture_rg) },
   { OFF, "GL_ARB_texture_rgb10_a2ui",         F(ARB_texture_rgb10_a2ui) },
   { OFF, "GL_ARB_texture_swizzle",            F(EXT_texture_swizzle) },
   { ON,  "GL_ARB_transpose_matrix",           F(ARB_transpose_matrix) },
   { OFF, "GL_ARB_transform_feedback2",        F(ARB_transform_feedback2) },
   { OFF, "GL_ARB_uniform_buffer_object",      F(ARB_uniform_buffer_object) },
   { OFF, "GL_ARB_vertex_array_bgra",          F(EXT_vertex_array_bgra) },
   { OFF, "GL_ARB_vertex_array_object",        F(ARB_vertex_array_object) },
   { ON,  "GL_ARB_vertex_buffer_object",       F(ARB_vertex_buffer_object) },
   { OFF, "GL_ARB_vertex_program",             F(ARB_vertex_program) },
   { OFF, "GL_ARB_vertex_shader",              F(ARB_vertex_shader) },
   { OFF, "GL_ARB_vertex_type_2_10_10_10_rev", F(ARB_vertex_type_2_10_10_10_rev) },
   { ON,  "GL_ARB_window_pos",                 F(ARB_window_pos) },
   { ON,  "GL_EXT_abgr",                       F(EXT_abgr) },
   { ON,  "GL_EXT_bgra",                       F(EXT_bgra) },
   { OFF, "GL_EXT_blend_color",                F(EXT_blend_color) },
   { OFF, "GL_EXT_blend_equation_separate",    F(EXT_blend_equation_separate) },
   { OFF, "GL_EXT_blend_func_separate",        F(EXT_blend_func_separate) },
   { OFF, "GL_EXT_blend_logic_op",             F(EXT_blend_logic_op) },
   { OFF, "GL_EXT_blend_minmax",               F(EXT_blend_minmax) },
   { OFF, "GL_EXT_blend_subtract",             F(EXT_blend_subtract) },
   { OFF, "GL_EXT_clip_volume_hint",           F(EXT_clip_volume_hint) },
   { ON,  "GL_EXT_compiled_vertex_array",      F(EXT_compiled_vertex_array) },
   { ON,  "GL_EXT_copy_texture",               F(EXT_copy_texture) },
   { OFF, "GL_EXT_depth_bounds_test",          F(EXT_depth_bounds_test) },
   { OFF, "GL_EXT_draw_buffers2",              F(EXT_draw_buffers2) },
   { OFF, "GL_EXT_draw_instanced",             F(ARB_draw_instanced) },
   { ON,  "GL_EXT_draw_range_elements",        F(EXT_draw_range_elements) },
   { OFF, "GL_EXT_framebuffer_blit",           F(EXT_framebuffer_blit) },
   { OFF, "GL_EXT_framebuffer_multisample",    F(EXT_framebuffer_multisample) },
   { OFF, "GL_EXT_framebuffer_object",         F(EXT_framebuffer_object) },
   { OFF, "GL_EXT_framebuffer_sRGB",           F(EXT_framebuffer_sRGB) },
   { OFF, "GL_EXT_fog_coord",                  F(EXT_fog_coord) },
   { OFF, "GL_EXT_gpu_program_parameters",     F(EXT_gpu_program_parameters) },
   { OFF, "GL_EXT_gpu_shader4",                F(EXT_gpu_shader4) },
   { ON,  "GL_EXT_multi_draw_arrays",          F(EXT_multi_draw_arrays) },
   { OFF, "GL_EXT_packed_depth_stencil",       F(EXT_packed_depth_stencil) },
   { OFF, "GL_EXT_packed_float",               F(EXT_packed_float) },
   { ON,  "GL_EXT_packed_pixels",              F(EXT_packed_pixels) },
   { OFF, "GL_EXT_paletted_texture",           F(EXT_paletted_texture) },
   { OFF, "GL_EXT_pixel_buffer_object",        F(EXT_pixel_buffer_object) },
   { OFF, "GL_EXT_point_parameters",           F(EXT_point_parameters) },
   { ON,  "GL_EXT_polygon_offset",             F(EXT_polygon_offset) },
   { OFF, "GL_EXT_provoking_vertex",           F(EXT_provoking_vertex) },
   { ON,  "GL_EXT_rescale_normal",             F(EXT_rescale_normal) },
   { OFF, "GL_EXT_secondary_color",            F(EXT_secondary_color) },
   { OFF, "GL_EXT_separate_shader_objects",    F(EXT_separate_shader_objects) },
   { ON,  "GL_EXT_separate_specular_color",    F(EXT_separate_specular_color) },
   { OFF, "GL_EXT_shadow_funcs",               F(EXT_shadow_funcs) },
   { OFF, "GL_EXT_shared_texture_palette",     F(EXT_shared_texture_palette) },
   { OFF, "GL_EXT_stencil_two_side",           F(EXT_stencil_two_side) },
   { OFF, "GL_EXT_stencil_wrap",               F(EXT_stencil_wrap) },
   { ON,  "GL_EXT_subtexture",                 F(EXT_subtexture) },
   { ON,  "GL_EXT_texture",                    F(EXT_texture) },
   { ON,  "GL_EXT_texture3D",                  F(EXT_texture3D) },
   { OFF, "GL_EXT_texture_array",              F(EXT_texture_array) },
   { OFF, "GL_EXT_texture_compression_s3tc",   F(EXT_texture_compression_s3tc) },
   { OFF, "GL_EXT_texture_compression_rgtc",   F(ARB_texture_compression_rgtc) },
   { OFF, "GL_EXT_texture_cube_map",           F(ARB_texture_cube_map) },
   { ON,  "GL_EXT_texture_edge_clamp",         F(SGIS_texture_edge_clamp) },
   { OFF, "GL_EXT_texture_env_add",            F(EXT_texture_env_add) },
   { OFF, "GL_EXT_texture_env_combine",        F(EXT_texture_env_combine) },
   { OFF, "GL_EXT_texture_env_dot3",           F(EXT_texture_env_dot3) },
   { OFF, "GL_EXT_texture_filter_anisotropic", F(EXT_texture_filter_anisotropic) },
   { OFF, "GL_EXT_texture_integer",            F(EXT_texture_integer) },
   { OFF, "GL_EXT_texture_lod_bias",           F(EXT_texture_lod_bias) },
   { OFF, "GL_EXT_texture_mirror_clamp",       F(EXT_texture_mirror_clamp) },
   { ON,  "GL_EXT_texture_object",             F(EXT_texture_object) },
   { OFF, "GL_EXT_texture_rectangle",          F(NV_texture_rectangle) },
   { OFF, "GL_EXT_texture_shared_exponent",    F(EXT_texture_shared_exponent) },
   { OFF, "GL_EXT_texture_sRGB",               F(EXT_texture_sRGB) },
   { OFF, "GL_EXT_texture_swizzle",            F(EXT_texture_swizzle) },
   { OFF, "GL_EXT_timer_query",                F(EXT_timer_query) },
   { OFF, "GL_EXT_transform_feedback",         F(EXT_transform_feedback) },
   { ON,  "GL_EXT_vertex_array",               F(EXT_vertex_array) },
   { OFF, "GL_EXT_vertex_array_bgra",          F(EXT_vertex_array_bgra) },
   { OFF, "GL_EXT_vertex_array_set",           F(EXT_vertex_array_set) },
   { OFF, "GL_3DFX_texture_compression_FXT1",  F(TDFX_texture_compression_FXT1) },
   { OFF, "GL_APPLE_client_storage",           F(APPLE_client_storage) },
   { ON,  "GL_APPLE_packed_pixels",            F(APPLE_packed_pixels) },
   { OFF, "GL_APPLE_vertex_array_object",      F(APPLE_vertex_array_object) },
   { OFF, "GL_APPLE_object_purgeable",         F(APPLE_object_purgeable) },
   { OFF, "GL_ATI_blend_equation_separate",    F(EXT_blend_equation_separate) },
   { OFF, "GL_ATI_envmap_bumpmap",             F(ATI_envmap_bumpmap) },
   { OFF, "GL_ATI_texture_env_combine3",       F(ATI_texture_env_combine3)},
   { OFF, "GL_ATI_texture_mirror_once",        F(ATI_texture_mirror_once)},
   { OFF, "GL_ATI_fragment_shader",            F(ATI_fragment_shader)},
   { OFF, "GL_ATI_separate_stencil",           F(ATI_separate_stencil)},
   { ON,  "GL_IBM_multimode_draw_arrays",      F(IBM_multimode_draw_arrays) },
   { ON,  "GL_IBM_rasterpos_clip",             F(IBM_rasterpos_clip) },
   { OFF, "GL_IBM_texture_mirrored_repeat",    F(ARB_texture_mirrored_repeat)},
   { OFF, "GL_INGR_blend_func_separate",       F(EXT_blend_func_separate) },
   { OFF, "GL_MESA_pack_invert",               F(MESA_pack_invert) },
   { OFF, "GL_MESA_resize_buffers",            F(MESA_resize_buffers) },
   { OFF, "GL_MESA_texture_array",             F(MESA_texture_array) },
   { OFF, "GL_MESA_texture_signed_rgba",       F(MESA_texture_signed_rgba) },
   { OFF, "GL_MESA_ycbcr_texture",             F(MESA_ycbcr_texture) },
   { ON,  "GL_MESA_window_pos",                F(ARB_window_pos) },
   { OFF, "GL_NV_blend_square",                F(NV_blend_square) },
   { OFF, "GL_NV_conditional_render",          F(NV_conditional_render) },
   { OFF, "GL_NV_depth_clamp",                 F(ARB_depth_clamp) },
   { OFF, "GL_NV_fragment_program",            F(NV_fragment_program) },
   { OFF, "GL_NV_fragment_program_option",     F(NV_fragment_program_option) },
   { ON,  "GL_NV_light_max_exponent",          F(NV_light_max_exponent) },
   { OFF, "GL_NV_packed_depth_stencil",        F(EXT_packed_depth_stencil) },
   { OFF, "GL_NV_point_sprite",                F(NV_point_sprite) },
   { OFF, "GL_NV_primitive_restart",           F(NV_primitive_restart) },
   { ON,  "GL_NV_texgen_reflection",           F(NV_texgen_reflection) },
   { OFF, "GL_NV_texture_env_combine4",        F(NV_texture_env_combine4) },
   { OFF, "GL_NV_texture_rectangle",           F(NV_texture_rectangle) },
   { OFF, "GL_NV_vertex_program",              F(NV_vertex_program) },
   { OFF, "GL_NV_vertex_program1_1",           F(NV_vertex_program1_1) },
   { ON,  "GL_OES_read_format",                F(OES_read_format) },
   { OFF, "GL_SGI_texture_color_table",        F(SGI_texture_color_table) },
   { ON,  "GL_SGIS_generate_mipmap",           F(SGIS_generate_mipmap) },
   { OFF, "GL_SGIS_texture_border_clamp",      F(ARB_texture_border_clamp) },
   { ON,  "GL_SGIS_texture_edge_clamp",        F(SGIS_texture_edge_clamp) },
   { ON,  "GL_SGIS_texture_lod",               F(SGIS_texture_lod) },
   { ON,  "GL_SUN_multi_draw_arrays",          F(EXT_multi_draw_arrays) },
   { OFF, "GL_S3_s3tc",                        F(S3_s3tc) },
   { OFF, "GL_EXT_texture_format_BGRA8888",    F(EXT_texture_format_BGRA8888) },
#if FEATURE_OES_EGL_image
   { OFF, "GL_OES_EGL_image",                  F(OES_EGL_image) },
#endif
#if FEATURE_OES_draw_texture
   { OFF, "GL_OES_draw_texture",               F(OES_draw_texture) },
#endif /* FEATURE_OES_draw_texture */
};



/**
 * Enable all extensions suitable for a software-only renderer.
 * This is a convenience function used by the XMesa, OSMesa, GGI drivers, etc.
 */
void
_mesa_enable_sw_extensions(struct gl_context *ctx)
{
   /*ctx->Extensions.ARB_copy_buffer = GL_TRUE;*/
   ctx->Extensions.ARB_depth_clamp = GL_TRUE;
   ctx->Extensions.ARB_depth_texture = GL_TRUE;
   /*ctx->Extensions.ARB_draw_buffers = GL_TRUE;*/
   ctx->Extensions.ARB_draw_elements_base_vertex = GL_TRUE;
   ctx->Extensions.ARB_explicit_attrib_location = GL_TRUE;
   ctx->Extensions.ARB_fragment_coord_conventions = GL_TRUE;
#if FEATURE_ARB_fragment_program
   ctx->Extensions.ARB_fragment_program = GL_TRUE;
   ctx->Extensions.ARB_fragment_program_shadow = GL_TRUE;
#endif
#if FEATURE_ARB_fragment_shader
   ctx->Extensions.ARB_fragment_shader = GL_TRUE;
#endif
#if FEATURE_ARB_framebuffer_object
   ctx->Extensions.ARB_framebuffer_object = GL_TRUE;
#endif
#if FEATURE_ARB_geometry_shader4
   ctx->Extensions.ARB_geometry_shader4 = GL_TRUE;
#endif
   ctx->Extensions.ARB_half_float_pixel = GL_TRUE;
   ctx->Extensions.ARB_half_float_vertex = GL_TRUE;
   ctx->Extensions.ARB_map_buffer_range = GL_TRUE;
   ctx->Extensions.ARB_multitexture = GL_TRUE;
#if FEATURE_queryobj
   ctx->Extensions.ARB_occlusion_query = GL_TRUE;
#endif
   ctx->Extensions.ARB_point_sprite = GL_TRUE;
#if FEATURE_ARB_shader_objects
   ctx->Extensions.ARB_shader_objects = GL_TRUE;
   ctx->Extensions.EXT_separate_shader_objects = GL_TRUE;
#endif
#if FEATURE_ARB_shading_language_100
   ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
#endif
   ctx->Extensions.ARB_shadow = GL_TRUE;
   ctx->Extensions.ARB_shadow_ambient = GL_TRUE;
   ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
   ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
   ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
   ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
   ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
   /*ctx->Extensions.ARB_texture_float = GL_TRUE;*/
   ctx->Extensions.ARB_texture_mirrored_repeat = GL_TRUE;
   ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
   ctx->Extensions.ARB_texture_rg = GL_TRUE;
   ctx->Extensions.ARB_vertex_array_object = GL_TRUE;
#if FEATURE_ARB_vertex_program
   ctx->Extensions.ARB_vertex_program = GL_TRUE;
#endif
#if FEATURE_ARB_vertex_shader
   ctx->Extensions.ARB_vertex_shader = GL_TRUE;
#endif
#if FEATURE_ARB_vertex_buffer_object
   /*ctx->Extensions.ARB_vertex_buffer_object = GL_TRUE;*/
#endif
#if FEATURE_ARB_sync
   ctx->Extensions.ARB_sync = GL_TRUE;
#endif
   ctx->Extensions.APPLE_vertex_array_object = GL_TRUE;
#if FEATURE_APPLE_object_purgeable
   ctx->Extensions.APPLE_object_purgeable = GL_TRUE;
#endif
   ctx->Extensions.ATI_envmap_bumpmap = GL_TRUE;
#if FEATURE_ATI_fragment_shader
   ctx->Extensions.ATI_fragment_shader = GL_TRUE;
#endif
   ctx->Extensions.ATI_texture_env_combine3 = GL_TRUE;
   ctx->Extensions.ATI_texture_mirror_once = GL_TRUE;
   ctx->Extensions.ATI_separate_stencil = GL_TRUE;
   ctx->Extensions.EXT_blend_color = GL_TRUE;
   ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
   ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
   ctx->Extensions.EXT_blend_logic_op = GL_TRUE;
   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
   ctx->Extensions.EXT_depth_bounds_test = GL_TRUE;
   ctx->Extensions.EXT_draw_buffers2 = GL_TRUE;
   ctx->Extensions.EXT_fog_coord = GL_TRUE;
#if FEATURE_EXT_framebuffer_object
   ctx->Extensions.EXT_framebuffer_object = GL_TRUE;
#endif
#if FEATURE_EXT_framebuffer_blit
   ctx->Extensions.EXT_framebuffer_blit = GL_TRUE;
#endif
#if FEATURE_ARB_framebuffer_object
   ctx->Extensions.EXT_framebuffer_multisample = GL_TRUE;
#endif
   /*ctx->Extensions.EXT_multi_draw_arrays = GL_TRUE;*/
   ctx->Extensions.EXT_packed_depth_stencil = GL_TRUE;
   ctx->Extensions.EXT_paletted_texture = GL_TRUE;
#if FEATURE_EXT_pixel_buffer_object
   ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
#endif
   ctx->Extensions.EXT_point_parameters = GL_TRUE;
   ctx->Extensions.EXT_provoking_vertex = GL_TRUE;
   ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
   ctx->Extensions.EXT_secondary_color = GL_TRUE;
   ctx->Extensions.EXT_shared_texture_palette = GL_TRUE;
   ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
   ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
   ctx->Extensions.EXT_texture_array = GL_TRUE;
   ctx->Extensions.EXT_texture_env_add = GL_TRUE;
   ctx->Extensions.EXT_texture_env_combine = GL_TRUE;
   ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
   ctx->Extensions.EXT_texture_mirror_clamp = GL_TRUE;
   ctx->Extensions.EXT_texture_lod_bias = GL_TRUE;
#if FEATURE_EXT_texture_sRGB
   ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
#endif
   ctx->Extensions.EXT_texture_swizzle = GL_TRUE;
#if FEATURE_EXT_transform_feedback
   /*ctx->Extensions.EXT_transform_feedback = GL_TRUE;*/
#endif
   ctx->Extensions.EXT_vertex_array_bgra = GL_TRUE;
   /*ctx->Extensions.IBM_multimode_draw_arrays = GL_TRUE;*/
   ctx->Extensions.MESA_pack_invert = GL_TRUE;
   ctx->Extensions.MESA_resize_buffers = GL_TRUE;
   ctx->Extensions.MESA_texture_array = GL_TRUE;
   ctx->Extensions.MESA_ycbcr_texture = GL_TRUE;
   ctx->Extensions.NV_blend_square = GL_TRUE;
   ctx->Extensions.NV_conditional_render = GL_TRUE;
   /*ctx->Extensions.NV_light_max_exponent = GL_TRUE;*/
   ctx->Extensions.NV_point_sprite = GL_TRUE;
   ctx->Extensions.NV_texture_env_combine4 = GL_TRUE;
   ctx->Extensions.NV_texture_rectangle = GL_TRUE;
   /*ctx->Extensions.NV_texgen_reflection = GL_TRUE;*/
#if FEATURE_NV_vertex_program
   ctx->Extensions.NV_vertex_program = GL_TRUE;
   ctx->Extensions.NV_vertex_program1_1 = GL_TRUE;
#endif
#if FEATURE_NV_fragment_program
   ctx->Extensions.NV_fragment_program = GL_TRUE;
#endif
#if FEATURE_NV_fragment_program && FEATURE_ARB_fragment_program
   ctx->Extensions.NV_fragment_program_option = GL_TRUE;
#endif
   ctx->Extensions.SGI_texture_color_table = GL_TRUE;
   /*ctx->Extensions.SGIS_generate_mipmap = GL_TRUE;*/
   ctx->Extensions.SGIS_texture_edge_clamp = GL_TRUE;
#if FEATURE_ARB_vertex_program || FEATURE_ARB_fragment_program
   ctx->Extensions.EXT_gpu_program_parameters = GL_TRUE;
#endif
#if FEATURE_texture_fxt1
   _mesa_enable_extension(ctx, "GL_3DFX_texture_compression_FXT1");
#endif
#if FEATURE_texture_s3tc
   if (ctx->Mesa_DXTn) {
      _mesa_enable_extension(ctx, "GL_EXT_texture_compression_s3tc");
      _mesa_enable_extension(ctx, "GL_S3_s3tc");
   }
#endif
}


/**
 * Enable common EXT extensions in the ARB_imaging subset.
 */
void
_mesa_enable_imaging_extensions(struct gl_context *ctx)
{
   ctx->Extensions.EXT_blend_color = GL_TRUE;
   ctx->Extensions.EXT_blend_logic_op = GL_TRUE;
   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
}



/**
 * Enable all OpenGL 1.3 features and extensions.
 * A convenience function to be called by drivers.
 */
void
_mesa_enable_1_3_extensions(struct gl_context *ctx)
{
   /*ctx->Extensions.ARB_multisample = GL_TRUE;*/
   ctx->Extensions.ARB_multitexture = GL_TRUE;
   ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
   /*ctx->Extensions.ARB_texture_compression = GL_TRUE;*/
   ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
   ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
   ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
   ctx->Extensions.EXT_texture_env_add = GL_TRUE;
   /*ctx->Extensions.ARB_transpose_matrix = GL_TRUE;*/
}



/**
 * Enable all OpenGL 1.4 features and extensions.
 * A convenience function to be called by drivers.
 */
void
_mesa_enable_1_4_extensions(struct gl_context *ctx)
{
   ctx->Extensions.ARB_depth_texture = GL_TRUE;
   ctx->Extensions.ARB_shadow = GL_TRUE;
   ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
   ctx->Extensions.ARB_texture_mirrored_repeat = GL_TRUE;
   ctx->Extensions.ARB_window_pos = GL_TRUE;
   ctx->Extensions.EXT_blend_color = GL_TRUE;
   ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
   ctx->Extensions.EXT_blend_minmax = GL_TRUE;
   ctx->Extensions.EXT_blend_subtract = GL_TRUE;
   ctx->Extensions.EXT_fog_coord = GL_TRUE;
   /*ctx->Extensions.EXT_multi_draw_arrays = GL_TRUE;*/
   ctx->Extensions.EXT_point_parameters = GL_TRUE;
   ctx->Extensions.EXT_secondary_color = GL_TRUE;
   ctx->Extensions.EXT_stencil_wrap = GL_TRUE;
   ctx->Extensions.EXT_texture_lod_bias = GL_TRUE;
   /*ctx->Extensions.SGIS_generate_mipmap = GL_TRUE;*/
}


/**
 * Enable all OpenGL 1.5 features and extensions.
 * A convenience function to be called by drivers.
 */
void
_mesa_enable_1_5_extensions(struct gl_context *ctx)
{
   ctx->Extensions.ARB_occlusion_query = GL_TRUE;
   /*ctx->Extensions.ARB_vertex_buffer_object = GL_TRUE;*/
   ctx->Extensions.EXT_shadow_funcs = GL_TRUE;
}


/**
 * Enable all OpenGL 2.0 features and extensions.
 * A convenience function to be called by drivers.
 */
void
_mesa_enable_2_0_extensions(struct gl_context *ctx)
{
   /*ctx->Extensions.ARB_draw_buffers = GL_TRUE;*/
#if FEATURE_ARB_fragment_shader
   ctx->Extensions.ARB_fragment_shader = GL_TRUE;
#endif
   ctx->Extensions.ARB_point_sprite = GL_TRUE;
   ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
   ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
#if FEATURE_ARB_shader_objects
   ctx->Extensions.ARB_shader_objects = GL_TRUE;
#endif
#if FEATURE_ARB_shading_language_100
   ctx->Extensions.ARB_shading_language_100 = GL_TRUE;
#endif
   ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
#if FEATURE_ARB_vertex_shader
   ctx->Extensions.ARB_vertex_shader = GL_TRUE;
#endif
}


/**
 * Enable all OpenGL 2.1 features and extensions.
 * A convenience function to be called by drivers.
 */
void
_mesa_enable_2_1_extensions(struct gl_context *ctx)
{
#if FEATURE_EXT_pixel_buffer_object
   ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
#endif
#if FEATURE_EXT_texture_sRGB
   ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
#endif
}


/**
 * Either enable or disable the named extension.
 * \return GL_TRUE for success, GL_FALSE if invalid extension name
 */
static GLboolean
set_extension( struct gl_context *ctx, const char *name, GLboolean state )
{
   GLboolean *base = (GLboolean *) &ctx->Extensions;
   GLuint i;

   if (ctx->Extensions.String) {
      /* The string was already queried - can't change it now! */
      _mesa_problem(ctx, "Trying to enable/disable extension after glGetString(GL_EXTENSIONS): %s", name);
      return GL_FALSE;
   }

   for (i = 0 ; i < Elements(default_extensions) ; i++) {
      if (strcmp(default_extensions[i].name, name) == 0) {
         if (default_extensions[i].flag_offset) {
            GLboolean *enabled = base + default_extensions[i].flag_offset;
            *enabled = state;
         }
         return GL_TRUE;
      }
   }
   return GL_FALSE;
}


/**
 * Enable the named extension.
 * Typically called by drivers.
 */
void
_mesa_enable_extension( struct gl_context *ctx, const char *name )
{
   if (!set_extension(ctx, name, GL_TRUE))
      _mesa_problem(ctx, "Trying to enable unknown extension: %s", name);
}


/**
 * Disable the named extension.
 * XXX is this really needed???
 */
void
_mesa_disable_extension( struct gl_context *ctx, const char *name )
{
   if (!set_extension(ctx, name, GL_FALSE))
      _mesa_problem(ctx, "Trying to disable unknown extension: %s", name);
}


/**
 * Check if the i-th extension is enabled.
 */
static GLboolean
extension_enabled(struct gl_context *ctx, GLuint index)
{
   const GLboolean *base = (const GLboolean *) &ctx->Extensions;
   if (!default_extensions[index].flag_offset ||
       *(base + default_extensions[index].flag_offset)) {
      return GL_TRUE;
   }
   else {
      return GL_FALSE;
   }
}


/**
 * Test if the named extension is enabled in this context.
 */
GLboolean
_mesa_extension_is_enabled( struct gl_context *ctx, const char *name )
{
   GLuint i;

   for (i = 0 ; i < Elements(default_extensions) ; i++) {
      if (strcmp(default_extensions[i].name, name) == 0) {
         return extension_enabled(ctx, i);
      }
   }
   return GL_FALSE;
}


/**
 * Append string 'b' onto string 'a'.  Free 'a' and return new string.
 */
static char *
append(const char *a, const char *b)
{
   const GLuint aLen = a ? strlen(a) : 0;
   const GLuint bLen = b ? strlen(b) : 0;
   char *s = calloc(1, aLen + bLen + 1);
   if (s) {
      if (a)
         memcpy(s, a, aLen);
      if (b)
         memcpy(s + aLen, b, bLen);
      s[aLen + bLen] = '\0';
   }
   if (a)
      free((void *) a);
   return s;
}


/**
 * Check the MESA_EXTENSION_OVERRIDE env var.
 * For extension names that are recognized, turn them on.  For extension
 * names that are recognized and prefixed with '-', turn them off.
 * Return a string of the unknown/leftover names.
 */
static const char *
get_extension_override( struct gl_context *ctx )
{
   const char *envExt = _mesa_getenv("MESA_EXTENSION_OVERRIDE");
   char *extraExt = NULL;
   char ext[1000];
   GLuint extLen = 0;
   GLuint i;
   GLboolean disableExt = GL_FALSE;

   if (!envExt)
      return NULL;

   for (i = 0; ; i++) {
      if (envExt[i] == '\0' || envExt[i] == ' ') {
         /* terminate/process 'ext' if extLen > 0 */
         if (extLen > 0) {
            assert(extLen < sizeof(ext));
            /* enable extension named by 'ext' */
            ext[extLen] = 0;
            if (!set_extension(ctx, ext, !disableExt)) {
               /* unknown extension name, append it to extraExt */
               if (extraExt) {
                  extraExt = append(extraExt, " ");
               }
               extraExt = append(extraExt, ext);
            }
            extLen = 0;
            disableExt = GL_FALSE;
         }
         if (envExt[i] == '\0')
            break;
      }
      else if (envExt[i] == '-') {
         disableExt = GL_TRUE;
      }
      else {
         /* accumulate this non-space character */
         ext[extLen++] = envExt[i];
      }
   }

   return extraExt;
}


/**
 * Run through the default_extensions array above and set the
 * ctx->Extensions.ARB/EXT_* flags accordingly.
 * To be called during context initialization.
 */
void
_mesa_init_extensions( struct gl_context *ctx )
{
   GLboolean *base = (GLboolean *) &ctx->Extensions;
   GLuint i;

   for (i = 0 ; i < Elements(default_extensions) ; i++) {
      if (default_extensions[i].enabled &&
          default_extensions[i].flag_offset) {
         *(base + default_extensions[i].flag_offset) = GL_TRUE;
      }
   }
}


/**
 * Construct the GL_EXTENSIONS string.  Called the first time that
 * glGetString(GL_EXTENSIONS) is called.
 */
static GLubyte *
compute_extensions( struct gl_context *ctx )
{
   const char *extraExt = get_extension_override(ctx);
   GLuint extStrLen = 0;
   char *s;
   GLuint i;

   /* first, compute length of the extension string */
   for (i = 0 ; i < Elements(default_extensions) ; i++) {
      if (extension_enabled(ctx, i)) {
         extStrLen += (GLuint) strlen(default_extensions[i].name) + 1;
      }
   }

   if (extraExt)
      extStrLen += strlen(extraExt) + 1; /* +1 for space */

   /* allocate the extension string */
   s = (char *) malloc(extStrLen);
   if (!s)
      return NULL;

   /* second, build the extension string */
   extStrLen = 0;
   for (i = 0 ; i < Elements(default_extensions) ; i++) {
      if (extension_enabled(ctx, i)) {
         GLuint len = (GLuint) strlen(default_extensions[i].name);
         memcpy(s + extStrLen, default_extensions[i].name, len);
         extStrLen += len;
         s[extStrLen] = ' ';
         extStrLen++;
      }
   }
   ASSERT(extStrLen > 0);

   s[extStrLen - 1] = 0; /* -1 to overwrite trailing the ' ' */

   if (extraExt) {
      s = append(s, " ");
      s = append(s, extraExt);
   }

   return (GLubyte *) s;
}

static size_t
append_extension(GLubyte **str, const char *ext)
{
   GLubyte *s = *str;
   size_t len = strlen(ext);

   if (s) {
      memcpy(s, ext, len);
      s[len++] = ' ';
      s[len] = '\0';

      *str += len;
   }
   else {
      len++;
   }

   return len;
}


static size_t
make_extension_string_es1(const struct gl_context *ctx, GLubyte *str)
{
   size_t len = 0;

   /* Core additions */
   len += append_extension(&str, "GL_OES_byte_coordinates");
   len += append_extension(&str, "GL_OES_fixed_point");
   len += append_extension(&str, "GL_OES_single_precision");
   len += append_extension(&str, "GL_OES_matrix_get");

   /* 1.1 required extensions */
   len += append_extension(&str, "GL_OES_read_format");
   len += append_extension(&str, "GL_OES_compressed_paletted_texture");
   len += append_extension(&str, "GL_OES_point_size_array");
   len += append_extension(&str, "GL_OES_point_sprite");

   /* 1.1 deprecated extensions */
   len += append_extension(&str, "GL_OES_query_matrix");

#if FEATURE_OES_draw_texture
   if (ctx->Extensions.OES_draw_texture)
      len += append_extension(&str, "GL_OES_draw_texture");
#endif

   if (ctx->Extensions.EXT_blend_equation_separate)
      len += append_extension(&str, "GL_OES_blend_equation_separate");
   if (ctx->Extensions.EXT_blend_func_separate)
      len += append_extension(&str, "GL_OES_blend_func_separate");
   if (ctx->Extensions.EXT_blend_subtract)
      len += append_extension(&str, "GL_OES_blend_subtract");

   if (ctx->Extensions.EXT_stencil_wrap)
      len += append_extension(&str, "GL_OES_stencil_wrap");

   if (ctx->Extensions.ARB_texture_cube_map)
      len += append_extension(&str, "GL_OES_texture_cube_map");
   if (ctx->Extensions.ARB_texture_env_crossbar)
      len += append_extension(&str, "GL_OES_texture_env_crossbar");
   if (ctx->Extensions.ARB_texture_mirrored_repeat)
      len += append_extension(&str, "GL_OES_texture_mirrored_repeat");

   if (ctx->Extensions.ARB_framebuffer_object) {
      len += append_extension(&str, "GL_OES_framebuffer_object");
      len += append_extension(&str, "GL_OES_depth24");
      len += append_extension(&str, "GL_OES_depth32");
      len += append_extension(&str, "GL_OES_fbo_render_mipmap");
      len += append_extension(&str, "GL_OES_rgb8_rgba8");
      len += append_extension(&str, "GL_OES_stencil1");
      len += append_extension(&str, "GL_OES_stencil4");
      len += append_extension(&str, "GL_OES_stencil8");
   }

   if (ctx->Extensions.EXT_vertex_array)
      len += append_extension(&str, "GL_OES_element_index_uint");
   if (ctx->Extensions.ARB_vertex_buffer_object)
      len += append_extension(&str, "GL_OES_mapbuffer");
   if (ctx->Extensions.EXT_texture_filter_anisotropic)
      len += append_extension(&str, "GL_EXT_texture_filter_anisotropic");

   /* some applications check this for NPOT support */
   if (ctx->Extensions.ARB_texture_non_power_of_two)
      len += append_extension(&str, "GL_ARB_texture_non_power_of_two");

   if (ctx->Extensions.EXT_texture_compression_s3tc)
      len += append_extension(&str, "GL_EXT_texture_compression_dxt1");
   if (ctx->Extensions.EXT_texture_lod_bias)
      len += append_extension(&str, "GL_EXT_texture_lod_bias");
   if (ctx->Extensions.EXT_blend_minmax)
      len += append_extension(&str, "GL_EXT_blend_minmax");
   if (ctx->Extensions.EXT_multi_draw_arrays)
      len += append_extension(&str, "GL_EXT_multi_draw_arrays");

#if FEATURE_OES_EGL_image
   if (ctx->Extensions.OES_EGL_image)
      len += append_extension(&str, "GL_OES_EGL_image");
#endif

   return len;
}


static GLubyte *
compute_extensions_es1(const struct gl_context *ctx)
{
   GLubyte *s;
   unsigned int len;
   
   len = make_extension_string_es1(ctx, NULL);
   s = malloc(len + 1);
   if (!s)
      return NULL;
   make_extension_string_es1(ctx, s);
   
   return s;
}

static size_t
make_extension_string_es2(const struct gl_context *ctx, GLubyte *str)
{
   size_t len = 0;

   len += append_extension(&str, "GL_OES_compressed_paletted_texture");

   if (ctx->Extensions.ARB_framebuffer_object) {
      len += append_extension(&str, "GL_OES_depth24");
      len += append_extension(&str, "GL_OES_depth32");
      len += append_extension(&str, "GL_OES_fbo_render_mipmap");
      len += append_extension(&str, "GL_OES_rgb8_rgba8");
      len += append_extension(&str, "GL_OES_stencil1");
      len += append_extension(&str, "GL_OES_stencil4");
   }

   if (ctx->Extensions.EXT_vertex_array)
      len += append_extension(&str, "GL_OES_element_index_uint");
   if (ctx->Extensions.ARB_vertex_buffer_object)
      len += append_extension(&str, "GL_OES_mapbuffer");

#if 0
   /* disabled because of missing GLSL support */
   if (ctx->Extensions.EXT_texture3D)
      len += append_extension(&str, "GL_OES_texture_3D");
#endif

   if (ctx->Extensions.ARB_texture_non_power_of_two)
      len += append_extension(&str, "GL_OES_texture_npot");
   if (ctx->Extensions.EXT_texture_filter_anisotropic)
      len += append_extension(&str, "GL_EXT_texture_filter_anisotropic");

   len += append_extension(&str, "GL_EXT_texture_type_2_10_10_10_REV");
   if (ctx->Extensions.ARB_depth_texture)
      len += append_extension(&str, "GL_OES_depth_texture");
   if (ctx->Extensions.EXT_packed_depth_stencil)
      len += append_extension(&str, "GL_OES_packed_depth_stencil");
   if (ctx->Extensions.ARB_fragment_shader)
      len += append_extension(&str, "GL_OES_standard_derivatives");

   if (ctx->Extensions.EXT_texture_compression_s3tc)
      len += append_extension(&str, "GL_EXT_texture_compression_dxt1");
   if (ctx->Extensions.EXT_blend_minmax)
      len += append_extension(&str, "GL_EXT_blend_minmax");
   if (ctx->Extensions.EXT_multi_draw_arrays)
      len += append_extension(&str, "GL_EXT_multi_draw_arrays");

#if FEATURE_OES_EGL_image
   if (ctx->Extensions.OES_EGL_image)
      len += append_extension(&str, "GL_OES_EGL_image");
#endif

   if (ctx->Extensions.EXT_texture_format_BGRA8888)
      len += append_extension(&str, "GL_EXT_texture_format_BGRA8888");

   return len;
}

static GLubyte *
compute_extensions_es2(struct gl_context *ctx)
{
   GLubyte *s;
   unsigned int len;

   len = make_extension_string_es2(ctx, NULL);
   s = malloc(len + 1);
   if (!s)
      return NULL;
   make_extension_string_es2(ctx, s);
   
   return s;
}


GLubyte *
_mesa_make_extension_string(struct gl_context *ctx)
{
   switch (ctx->API) {
   case API_OPENGL:
      return compute_extensions(ctx);
   case API_OPENGLES2:
      return compute_extensions_es2(ctx);
   case API_OPENGLES:
      return compute_extensions_es1(ctx);
   default:
      assert(0);
      return NULL;
   }
}

/**
 * Return number of enabled extensions.
 */
GLuint
_mesa_get_extension_count(struct gl_context *ctx)
{
   GLuint i;

   /* only count once */
   if (!ctx->Extensions.Count) {
      for (i = 0; i < Elements(default_extensions); i++) {
         if (extension_enabled(ctx, i)) {
            ctx->Extensions.Count++;
         }
      }
   }

   if (0)
      _mesa_debug(ctx, "%u of %d extensions enabled\n", ctx->Extensions.Count,
                  (int) Elements(default_extensions));

   return ctx->Extensions.Count;
}


/**
 * Return name of i-th enabled extension
 */
const GLubyte *
_mesa_get_enabled_extension(struct gl_context *ctx, GLuint index)
{
   GLuint i;

   for (i = 0; i < Elements(default_extensions); i++) {
      if (extension_enabled(ctx, i)) {
         if (index == 0)
            return (const GLubyte *) default_extensions[i].name;
         index--;
      }
   }

   return NULL;
}