summaryrefslogtreecommitdiff
path: root/src/glx/x11/glxextensions.c
blob: 31f7aee5cc6dd3af37a0c36bdb4e4b325f3c645e (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
/*
 * (C) Copyright IBM Corporation 2002, 2004
 * 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
 * on the rights to use, copy, modify, merge, publish, distribute, sub
 * license, 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 (including the next
 * paragraph) 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 NON-INFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS AND/OR THEIR SUPPLIERS 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.
 */

/**
 * \file glxextensions.c
 *
 * \author Ian Romanick <idr@us.ibm.com>
 */

#include "glxclient.h"
#include <extutil.h>
#include <Xext.h>
#include <string.h>
#include "glapi.h"
#include "glxextensions.h"
#include "simple_list.h"

#define SET_BIT(m,b)   (m[ (b) / 8 ] |=  (1U << ((b) % 8)))
#define CLR_BIT(m,b)   (m[ (b) / 8 ] &= ~(1U << ((b) % 8)))
#define IS_SET(m,b)    ((m[ (b) / 8 ] & (1U << ((b) % 8))) != 0)
#define CONCAT(a,b) a ## b
#define GLX(n) "GLX_" # n, 4 + sizeof( # n ) - 1, CONCAT(n,_bit)
#define GL(n)  "GL_" # n,  3 + sizeof( # n ) - 1, GL_ ## n ## _bit
#define VER(a,b)  a, b
#define Y  1
#define N  0
#define EXT_ENABLED(bit,supported) (IS_SET( supported, bit ))


struct extension_info {
   const char * const name;
   unsigned   name_len;

   unsigned char  bit;

   /* This is the lowest version of GLX that "requires" this extension.
    * For example, GLX 1.3 requires SGIX_fbconfig, SGIX_pbuffer, and
    * SGI_make_current_read.  If the extension is not required by any known
    * version of GLX, use 0, 0.
    */
   unsigned char  version_major;
   unsigned char  version_minor;
   unsigned char  client_support;
   unsigned char  direct_support;
   unsigned char  client_only;       /** Is the extension client-side only? */
   unsigned char  direct_only;       /** Is the extension for direct
				      * contexts only?
				      */
};

static const struct extension_info known_glx_extensions[] = {
   { GLX(ARB_get_proc_address),        VER(1,4), Y, N, Y, N },
   { GLX(ARB_multisample),             VER(1,4), Y, Y, N, N },
   { GLX(ARB_render_texture),          VER(0,0), N, N, N, N },
   { GLX(ATI_pixel_format_float),      VER(0,0), N, N, N, N },
   { GLX(EXT_import_context),          VER(0,0), Y, Y, N, N },
   { GLX(EXT_visual_info),             VER(0,0), Y, Y, N, N },
   { GLX(EXT_visual_rating),           VER(0,0), Y, Y, N, N },
   { GLX(MESA_agp_offset),             VER(0,0), N, N, N, Y }, /* Deprecated */
   { GLX(MESA_allocate_memory),        VER(0,0), Y, N, N, Y },
   { GLX(MESA_copy_sub_buffer),        VER(0,0), N, N, N, N }, /* Deprecated? */
   { GLX(MESA_pixmap_colormap),        VER(0,0), N, N, N, N }, /* Deprecated */
   { GLX(MESA_release_buffers),        VER(0,0), N, N, N, N }, /* Deprecated */
   { GLX(MESA_set_3dfx_mode),          VER(0,0), N, N, N, N }, /* Deprecated */
   { GLX(MESA_swap_control),           VER(0,0), Y, N, N, Y },
   { GLX(MESA_swap_frame_usage),       VER(0,0), Y, N, N, Y },
   { GLX(NV_float_buffer),             VER(0,0), N, N, N, N },
   { GLX(NV_render_depth_texture),     VER(0,0), N, N, N, N },
   { GLX(NV_render_texture_rectangle), VER(0,0), N, N, N, N },
   { GLX(NV_vertex_array_range),       VER(0,0), N, N, N, Y }, /* Deprecated */
   { GLX(OML_swap_method),             VER(0,0), Y, N, N, N },
   { GLX(OML_sync_control),            VER(0,0), Y, N, N, Y },
   { GLX(SGI_cushion),                 VER(0,0), N, N, N, N },
   { GLX(SGI_make_current_read),       VER(1,3), Y, N, N, N },
   { GLX(SGI_swap_control),            VER(0,0), Y, N, N, N },
   { GLX(SGI_video_sync),              VER(0,0), Y, N, N, Y },
   { GLX(SGIS_blended_overlay),        VER(0,0), N, N, N, N },
   { GLX(SGIS_color_range),            VER(0,0), N, N, N, N },
   { GLX(SGIS_multisample),            VER(0,0), Y, Y, N, N },
   { GLX(SGIX_dm_buffer),              VER(0,0), N, N, N, N },
   { GLX(SGIX_fbconfig),               VER(1,3), Y, N, N, N },
   { GLX(SGIX_pbuffer),                VER(1,3), Y, N, N, N },
   { GLX(SGIX_swap_barrier),           VER(0,0), N, N, N, N },
   { GLX(SGIX_swap_group),             VER(0,0), N, N, N, N },
   { GLX(SGIX_video_resize),           VER(0,0), N, N, N, N },
   { GLX(SGIX_video_source),           VER(0,0), N, N, N, N },
   { GLX(SGIX_visual_select_group),    VER(0,0), Y, Y, N, N },
   { GLX(SUN_get_transparent_index),   VER(0,0), N, N, N, N },
   { NULL }
};

static const struct extension_info known_gl_extensions[] = {
   { GL(ARB_depth_texture),              VER(1,4), Y, N, N, N },
   { GL(ARB_draw_buffers),               VER(0,0), Y, N, N, N },
   { GL(ARB_fragment_program),           VER(0,0), Y, N, N, N },
   { GL(ARB_fragment_program_shadow),    VER(0,0), Y, N, N, N },
   { GL(ARB_imaging),                    VER(0,0), Y, N, N, N },
   { GL(ARB_multisample),                VER(1,3), Y, N, N, N },
   { GL(ARB_multitexture),               VER(1,3), Y, N, N, N },
   { GL(ARB_occlusion_query),            VER(1,5), Y, N, N, N },
   { GL(ARB_point_parameters),           VER(1,4), Y, N, N, N },
   { GL(ARB_point_sprite),               VER(0,0), Y, N, N, N },
   { GL(ARB_shadow),                     VER(1,4), Y, N, N, N },
   { GL(ARB_shadow_ambient),             VER(0,0), Y, N, N, N },
   { GL(ARB_texture_border_clamp),       VER(1,3), Y, N, N, N },
   { GL(ARB_texture_compression),        VER(1,3), Y, N, N, N },
   { GL(ARB_texture_cube_map),           VER(1,3), Y, N, N, N },
   { GL(ARB_texture_env_add),            VER(1,3), Y, N, N, N },
   { GL(ARB_texture_env_combine),        VER(1,3), Y, N, N, N },
   { GL(ARB_texture_env_crossbar),       VER(1,4), Y, N, N, N },
   { GL(ARB_texture_env_dot3),           VER(1,3), Y, N, N, N },
   { GL(ARB_texture_mirrored_repeat),    VER(1,4), Y, N, N, N },
   { GL(ARB_texture_non_power_of_two),   VER(1,5), Y, N, N, N },
   { GL(ARB_texture_rectangle),          VER(0,0), Y, N, N, N },
   { GL(ARB_transpose_matrix),           VER(1,3), Y, N, Y, N },
   { GL(ARB_vertex_buffer_object),       VER(1,5), N, N, N, N },
   { GL(ARB_vertex_program),             VER(0,0), Y, N, N, N },
   { GL(ARB_window_pos),                 VER(1,4), Y, N, N, N },
   { GL(EXT_abgr),                       VER(0,0), Y, N, N, N },
   { GL(EXT_bgra),                       VER(1,2), Y, N, N, N },
   { GL(EXT_blend_color),                VER(1,4), Y, N, N, N },
   { GL(EXT_blend_equation_separate),    VER(0,0), N, N, N, N },
   { GL(EXT_blend_func_separate),        VER(1,4), Y, N, N, N },
   { GL(EXT_blend_logic_op),             VER(1,4), Y, N, N, N },
   { GL(EXT_blend_minmax),               VER(1,4), Y, N, N, N },
   { GL(EXT_blend_subtract),             VER(1,4), Y, N, N, N },
   { GL(EXT_clip_volume_hint),           VER(0,0), Y, N, N, N },
   { GL(EXT_compiled_vertex_array),      VER(0,0), N, N, N, N },
   { GL(EXT_convolution),                VER(0,0), N, N, N, N },
   { GL(EXT_copy_texture),               VER(1,1), Y, N, N, N },
   { GL(EXT_cull_vertex),                VER(0,0), N, N, N, N },
   { GL(EXT_depth_bounds_test),          VER(0,0), N, N, N, N },
   { GL(EXT_draw_range_elements),        VER(1,2), Y, N, Y, N },
   { GL(EXT_fog_coord),                  VER(1,4), Y, N, N, N },
   { GL(EXT_multi_draw_arrays),          VER(1,4), Y, N, Y, N },
   { GL(EXT_packed_pixels),              VER(1,2), Y, N, N, N },
   { GL(EXT_paletted_texture),           VER(0,0), Y, N, N, N },
   { GL(EXT_pixel_buffer_object),        VER(0,0), N, N, N, N },
   { GL(EXT_point_parameters),           VER(1,4), Y, N, N, N },
   { GL(EXT_polygon_offset),             VER(1,1), Y, N, N, N },
   { GL(EXT_rescale_normal),             VER(1,2), Y, N, N, N },
   { GL(EXT_secondary_color),            VER(1,4), Y, N, N, N },
   { GL(EXT_separate_specular_color),    VER(1,2), Y, N, N, N },
   { GL(EXT_shadow_funcs),               VER(1,5), Y, N, N, N },
   { GL(EXT_shared_texture_palette),     VER(0,0), Y, N, N, N },
   { GL(EXT_stencil_two_side),           VER(0,0), Y, N, N, N },
   { GL(EXT_stencil_wrap),               VER(1,4), Y, N, N, N },
   { GL(EXT_subtexture),                 VER(1,1), Y, N, N, N },
   { GL(EXT_texture),                    VER(1,1), Y, N, N, N },
   { GL(EXT_texture3D),                  VER(1,2), Y, N, N, N },
   { GL(EXT_texture_compression_dxt1),   VER(0,0), Y, N, N, N },
   { GL(EXT_texture_compression_s3tc),   VER(0,0), Y, N, N, N },
   { GL(EXT_texture_edge_clamp),         VER(1,2), Y, N, N, N },
   { GL(EXT_texture_env_add),            VER(1,3), Y, N, N, N },
   { GL(EXT_texture_env_combine),        VER(1,3), Y, N, N, N },
   { GL(EXT_texture_env_dot3),           VER(0,0), Y, N, N, N },
   { GL(EXT_texture_filter_anisotropic), VER(0,0), Y, N, N, N },
   { GL(EXT_texture_lod),                VER(1,2), Y, N, N, N },
   { GL(EXT_texture_lod_bias),           VER(1,4), Y, N, N, N },
   { GL(EXT_texture_mirror_clamp),       VER(0,0), Y, N, N, N },
   { GL(EXT_texture_object),             VER(1,1), Y, N, N, N },
   { GL(EXT_texture_rectangle),          VER(0,0), Y, N, N, N },
   { GL(EXT_vertex_array),               VER(0,0), Y, N, N, N },
   { GL(3DFX_texture_compression_FXT1),  VER(0,0), Y, N, N, N },
   { GL(APPLE_packed_pixels),            VER(1,2), Y, N, N, N },
   { GL(APPLE_ycbcr_422),                VER(0,0), Y, N, N, N },
   { GL(ATI_draw_buffers),               VER(0,0), Y, N, N, N },
   { GL(ATI_text_fragment_shader),       VER(0,0), Y, N, N, N },
   { GL(ATI_texture_env_combine3),       VER(0,0), Y, N, N, N },
   { GL(ATI_texture_float),              VER(0,0), Y, N, N, N },
   { GL(ATI_texture_mirror_once),        VER(0,0), Y, N, N, N },
   { GL(ATIX_texture_env_combine3),      VER(0,0), Y, N, N, N },
   { GL(HP_convolution_border_modes),    VER(0,0), Y, N, N, N },
   { GL(HP_occlusion_test),              VER(0,0), Y, N, N, N },
   { GL(IBM_cull_vertex),                VER(0,0), Y, N, N, N },
   { GL(IBM_pixel_filter_hint),          VER(0,0), Y, N, N, N },
   { GL(IBM_rasterpos_clip),             VER(0,0), Y, N, N, N },
   { GL(IBM_texture_clamp_nodraw),       VER(0,0), Y, N, N, N },
   { GL(IBM_texture_mirrored_repeat),    VER(0,0), Y, N, N, N },
   { GL(INGR_blend_func_separate),       VER(0,0), Y, N, N, N },
   { GL(INGR_interlace_read),            VER(0,0), Y, N, N, N },
   { GL(MESA_pack_invert),               VER(0,0), Y, N, N, N },
   { GL(MESA_ycbcr_texture),             VER(0,0), Y, N, N, N },
   { GL(NV_blend_square),                VER(1,4), Y, N, N, N },
   { GL(NV_copy_depth_to_color),         VER(0,0), Y, N, N, N },
   { GL(NV_depth_clamp),                 VER(0,0), Y, N, N, N },
   { GL(NV_fog_distance),                VER(0,0), Y, N, N, N },
   { GL(NV_fragment_program),            VER(0,0), Y, N, N, N },
   { GL(NV_fragment_program_option),     VER(0,0), Y, N, N, N },
   { GL(NV_fragment_program2),           VER(0,0), Y, N, N, N },
   { GL(NV_light_max_exponent),          VER(0,0), Y, N, N, N },
   { GL(NV_multisample_filter_hint),     VER(0,0), Y, N, N, N },
   { GL(NV_point_sprite),                VER(0,0), Y, N, N, N },
   { GL(NV_texgen_reflection),           VER(0,0), Y, N, N, N },
   { GL(NV_texture_compression_vtc),     VER(0,0), Y, N, N, N },
   { GL(NV_texture_env_combine4),        VER(0,0), Y, N, N, N },
   { GL(NV_texture_rectangle),           VER(0,0), Y, N, N, N },
   { GL(NV_vertex_program),              VER(0,0), Y, N, N, N },
   { GL(NV_vertex_program1_1),           VER(0,0), Y, N, N, N },
   { GL(NV_vertex_program2),             VER(0,0), Y, N, N, N },
   { GL(NV_vertex_program2_option),      VER(0,0), Y, N, N, N },
   { GL(NV_vertex_program3),             VER(0,0), Y, N, N, N },
   { GL(OES_read_format),                VER(0,0), Y, N, N, N },
   { GL(OES_compressed_paletted_texture),VER(0,0), Y, N, N, N },
   { GL(SGI_color_matrix),               VER(0,0), Y, N, N, N },
   { GL(SGI_texture_color_table),        VER(0,0), Y, N, N, N },
   { GL(SGIS_generate_mipmap),           VER(1,4), Y, N, N, N },
   { GL(SGIS_multisample),               VER(0,0), Y, N, N, N },
   { GL(SGIS_texture_border_clamp),      VER(1,3), Y, N, N, N },
   { GL(SGIS_texture_edge_clamp),        VER(1,2), Y, N, N, N },
   { GL(SGIS_texture_lod),               VER(1,2), Y, N, N, N },
   { GL(SGIX_blend_alpha_minmax),        VER(0,0), Y, N, N, N },
   { GL(SGIX_clipmap),                   VER(0,0), Y, N, N, N },
   { GL(SGIX_depth_texture),             VER(0,0), Y, N, N, N },
   { GL(SGIX_fog_offset),                VER(0,0), Y, N, N, N },
   { GL(SGIX_shadow),                    VER(0,0), Y, N, N, N },
   { GL(SGIX_shadow_ambient),            VER(0,0), Y, N, N, N },
   { GL(SGIX_texture_coordinate_clamp),  VER(0,0), Y, N, N, N },
   { GL(SGIX_texture_lod_bias),          VER(0,0), Y, N, N, N },
   { GL(SGIX_texture_range),             VER(0,0), Y, N, N, N },
   { GL(SGIX_texture_scale_bias),        VER(0,0), Y, N, N, N },
   { GL(SGIX_vertex_preclip),            VER(0,0), Y, N, N, N },
   { GL(SGIX_vertex_preclip_hint),       VER(0,0), Y, N, N, N },
   { GL(SGIX_ycrcb),                     VER(0,0), Y, N, N, N },
   { GL(SUN_convolution_border_modes),   VER(0,0), Y, N, N, N },
   { GL(SUN_multi_draw_arrays),          VER(0,0), Y, N, Y, N },
   { GL(SUN_slice_accum),                VER(0,0), Y, N, N, N },
   { NULL }
};


/* global bit-fields of available extensions and their characteristics */
static unsigned char client_glx_support[8];
static unsigned char client_glx_only[8];
static unsigned char direct_glx_only[8];
static unsigned char client_gl_support[ __GL_EXT_BYTES ];
static unsigned char client_gl_only[ __GL_EXT_BYTES ];

/**
 * Bits representing the set of extensions that are enabled by default in all
 * direct rendering drivers.
 */
static unsigned char direct_glx_support[8];

/**
 * Highest core GL version that can be supported for indirect rendering.
 */
static const unsigned gl_major = 1;
static const unsigned gl_minor = 4;

/* client extensions string */
static const char * __glXGLXClientExtensions = NULL;

static void __glXExtensionsCtr( void );
static void __glXExtensionsCtrScreen( __GLXscreenConfigs *psc );
static void __glXProcessServerString( const struct extension_info * ext,
    const char * server_string, unsigned char * server_support );

/**
 * Set the state of a GLX extension.
 *
 * \param name      Name of the extension.
 * \param name_len  Length, in characters, of the extension name.
 * \param state     New state (either enabled or disabled) of the extension.
 * \param supported Table in which the state of the extension is to be set.
 */
static void
set_glx_extension( const struct extension_info * ext,
		   const char * name, unsigned name_len, GLboolean state,
		   unsigned char * supported )
{
   unsigned   i;


   for ( i = 0 ; ext[i].name != NULL ; i++ ) {
      if ( (name_len == ext[i].name_len)
	   && (strncmp( ext[i].name, name, name_len ) == 0) ) {
	 if ( state ) {
	    SET_BIT( supported, ext[i].bit );
	 }
	 else {
	    CLR_BIT( supported, ext[i].bit );
	 }

	 return;
      }
   }
}


#define NUL '\0'
#define SEPARATOR ' '

/**
 * Convert the server's extension string to a bit-field.
 * 
 * \param server_string   GLX extension string from the server.
 * \param server_support  Bit-field of supported extensions.
 */
static void
__glXProcessServerString( const struct extension_info * ext,
			  const char * server_string,
			  unsigned char * server_support )
{
   unsigned  base;
   unsigned  len;

   (void) memset( server_support, 0, sizeof( server_support ) );
   
   for ( base = 0 ; server_string[ base ] != NUL ; /* empty */ ) {
      /* Determine the length of the next extension name.
       */
      for ( len = 0
	    ; (server_string[ base + len ] != SEPARATOR)
	    && (server_string[ base + len ] != NUL)
	    ; len++ ) {
	 /* empty */
      }

      /* Set the bit for the extension in the server_support table.
       */
      set_glx_extension( ext, & server_string[ base ], len, GL_TRUE,
			 server_support );

 
      /* Advance to the next extension string.  This means that we skip
       * over the previous string and any trialing white-space.
       */
      for ( base += len ;
	    (server_string[ base ] == SEPARATOR)
	    && (server_string[ base ] != NUL)
	    ; base++ ) {
	 /* empty */
      }
   }
}


/**
 * Enable a named GLX extension on a given screen.
 * Drivers should not call this function directly.  They should instead use
 * \c glXGetProcAddress to obtain a pointer to the function.
 *
 * \param psc   Pointer to GLX per-screen record.
 * \param name  Name of the extension to enable.
 *
 * \sa glXGetProcAddress
 *
 * \since Internal API version 20030813.
 */
void
__glXScrEnableExtension( __GLXscreenConfigs *psc, const char * name )
{
   __glXExtensionsCtr();
   __glXExtensionsCtrScreen(psc);
   set_glx_extension( known_glx_extensions, name, strlen( name ), GL_TRUE,
		      psc->direct_support );
}


/**
 * Initialize global extension support tables.
 */

static void
__glXExtensionsCtr( void )
{
   unsigned   i;
   static GLboolean ext_list_first_time = GL_TRUE;


   if ( ext_list_first_time ) {
      ext_list_first_time = GL_FALSE;

      (void) memset( client_glx_support, 0, sizeof( client_glx_support ) );
      (void) memset( direct_glx_support, 0, sizeof( direct_glx_support ) );
      (void) memset( client_glx_only,    0, sizeof( client_glx_only ) );
      (void) memset( direct_glx_only,    0, sizeof( direct_glx_only ) );

      (void) memset( client_gl_support,  0, sizeof( client_gl_support ) );
      (void) memset( client_gl_only,     0, sizeof( client_gl_only ) );

      for ( i = 0 ; known_glx_extensions[i].name != NULL ; i++ ) {
	 const unsigned  bit = known_glx_extensions[i].bit;

	 if ( known_glx_extensions[i].client_support ) {
	    SET_BIT( client_glx_support, bit );
	 }

	 if ( known_glx_extensions[i].direct_support ) {
	    SET_BIT( direct_glx_support, bit );
	 }

	 if ( known_glx_extensions[i].client_only ) {
	    SET_BIT( client_glx_only, bit );
	 }

	 if ( known_glx_extensions[i].direct_only ) {
	    SET_BIT( direct_glx_only, bit );
	 }
      }

      for ( i = 0 ; known_gl_extensions[i].name != NULL ; i++ ) {
	 const unsigned  bit = known_gl_extensions[i].bit;

	 if ( known_gl_extensions[i].client_support ) {
	    SET_BIT( client_gl_support, bit );
	 }

	 if ( known_gl_extensions[i].client_only ) {
	    SET_BIT( client_gl_only, bit );
	 }
      }
      
#if 0
      fprintf( stderr, "[%s:%u] Maximum client library version: %u.%u\n",
	       __func__, __LINE__, gl_major, gl_minor );
#endif
   }
}


/**
 * Make sure that per-screen direct-support table is initialized.
 *
 * \param psc  Pointer to GLX per-screen record.
 */

static void
__glXExtensionsCtrScreen( __GLXscreenConfigs *psc )
{
    if (psc->ext_list_first_time) {
	psc->ext_list_first_time = GL_FALSE;
	(void) memcpy( psc->direct_support, direct_glx_support,
		       sizeof( direct_glx_support ) );
    }
}


/**
 * Check if a certain extension is enabled on a given screen.
 *
 * \param psc  Pointer to GLX per-screen record.
 * \param bit  Bit index in the direct-support table.
 * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
 *          returned.  If the extension bit is not enabled or if \c psc is
 *          \c NULL, then \c GL_FALSE is returned.
 */
GLboolean
__glXExtensionBitIsEnabled( __GLXscreenConfigs *psc, unsigned bit )
{
   GLboolean enabled = GL_FALSE;

   if ( psc != NULL ) {
      __glXExtensionsCtr();
      __glXExtensionsCtrScreen( psc );
      enabled = EXT_ENABLED( bit, psc->direct_support );
   }

   return enabled;
}


/**
 * Check if a certain extension is enabled in a given context.
 *
 */
GLboolean
__glExtensionBitIsEnabled( const __GLXcontext * gc, unsigned bit )
{
   GLboolean enabled = GL_FALSE;

   if ( gc != NULL ) {
      enabled = EXT_ENABLED( bit, gc->gl_extension_bits );
   }

   return enabled;
}



/**
 * Convert a bit-field to a string of supported extensions.
 */
static char *
__glXGetStringFromTable( const struct extension_info * ext,
			 const unsigned char * supported )
{
   unsigned   i;
   unsigned   ext_str_len;
   char * ext_str;
   char * point;


   ext_str_len = 0;
   for ( i = 0 ; ext[i].name != NULL ; i++ ) {
      if ( EXT_ENABLED( ext[i].bit, supported ) ) {
	 ext_str_len += ext[i].name_len + 1;
      }
   }

   ext_str = Xmalloc( ext_str_len + 1 );
   if ( ext_str != NULL ) {
      point = ext_str;

      for ( i = 0 ; ext[i].name != NULL ; i++ ) {
	 if ( EXT_ENABLED( ext[i].bit, supported ) ) {
	    (void) memcpy( point, ext[i].name, ext[i].name_len );
	    point += ext[i].name_len;

	    *point = ' ';
	    point++;
	 }
      }

      *point = '\0';
   }

   return ext_str;
}


/**
 * Get the string of client library supported extensions.
 */
const char *
__glXGetClientExtensions( void )
{
   if ( __glXGLXClientExtensions == NULL ) {
      __glXExtensionsCtr();
      __glXGLXClientExtensions = __glXGetStringFromTable( known_glx_extensions,
							  client_glx_support );
   }

   return __glXGLXClientExtensions;
}


/**
 * Calculate the list of application usable extensions.  The resulting
 * string is stored in \c psc->effectiveGLXexts.
 * 
 * \param psc                        Pointer to GLX per-screen record.
 * \param display_is_direct_capable  True if the display is capable of
 *                                   direct rendering.
 * \param minor_version              GLX minor version from the server.
 */

void
__glXCalculateUsableExtensions( __GLXscreenConfigs *psc,
				GLboolean display_is_direct_capable,
				int minor_version )
{
   unsigned char server_support[8];
   unsigned char usable[8];
   unsigned      i;

   __glXExtensionsCtr();
   __glXExtensionsCtrScreen( psc );
   __glXProcessServerString( known_glx_extensions,
			     psc->serverGLXexts, server_support );


   /* This is a hack.  Some servers support GLX 1.3 but don't export
    * all of the extensions implied by GLX 1.3.  If the server claims
    * support for GLX 1.3, enable support for the extensions that can be
    * "emulated" as well.
    */

   if ( minor_version >= 3 ) {
      SET_BIT( server_support, EXT_visual_info_bit );
      SET_BIT( server_support, EXT_visual_rating_bit );
      SET_BIT( server_support, SGI_make_current_read_bit );
      SET_BIT( server_support, SGIX_fbconfig_bit );
      SET_BIT( server_support, SGIX_pbuffer_bit );
       
      /* This one is a little iffy.  GLX 1.3 doesn't incorporate all of this
       * extension.  However, the only part that is not strictly client-side
       * is shared.  That's the glXQueryContext / glXQueryContextInfoEXT
       * function.
       */

      SET_BIT( server_support, EXT_import_context_bit );
   }


   /* An extension is supported if the client-side (i.e., libGL) supports
    * it and the "server" supports it.  In this case that means that either
    * the true server supports it or it is only for direct-rendering and
    * the direct rendering driver supports it.
    * 
    * If the display is not capable of direct rendering, then the extension
    * is enabled if and only if the client-side library and the server
    * support it.
    */

   if ( display_is_direct_capable ) {
      for ( i = 0 ; i < 8 ; i++ ) {
	 usable[i] = (client_glx_support[i] & client_glx_only[i])
	     | (client_glx_support[i] & psc->direct_support[i] & server_support[i])
	     | (client_glx_support[i] & psc->direct_support[i] & direct_glx_only[i]);
      }
   }
   else {
      for ( i = 0 ; i < 8 ; i++ ) {
	 usable[i] = (client_glx_support[i] & client_glx_only[i])
	     | (client_glx_support[i] & server_support[i]);
      }
   }

   psc->effectiveGLXexts = __glXGetStringFromTable( known_glx_extensions,
						    usable );
}


/**
 * Calculate the list of application usable extensions.  The resulting
 * string is stored in \c gc->extensions.
 * 
 * \param gc             Pointer to GLX context.
 * \param server_string  Extension string from the server.
 * \param major_version  GL major version from the server.
 * \param minor_version  GL minor version from the server.
 */

void
__glXCalculateUsableGLExtensions( __GLXcontext * gc,
				  const char * server_string,
				  int major_version, int minor_version )
{
   unsigned char server_support[ __GL_EXT_BYTES ];
   unsigned char usable[ __GL_EXT_BYTES ];
   unsigned      i;


   __glXExtensionsCtr();

   (void) memset( server_support, 0, sizeof( server_support ) );
   __glXProcessServerString( known_gl_extensions, server_string,
			     server_support );


   /* Handle lazy servers that don't export all the extensions strings that
    * are part of the GL core version that they support.
    */

   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
      if ( (known_gl_extensions[i].version_major != 0)
	   && ((major_version > known_gl_extensions[i].version_major)
	       || ((major_version == known_gl_extensions[i].version_major)
		   && (minor_version >= known_gl_extensions[i].version_minor))) ) {
	 SET_BIT( server_support, known_gl_extensions[i].bit );
      }
   }


   /* An extension is supported if the client-side (i.e., libGL) supports
    * it and the server supports it or the client-side library supports it
    * and it only needs client-side support.
    */

   for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
      usable[i] = (client_gl_support[i] & client_gl_only[i])
	| (client_gl_support[i] & server_support[i]);
   }

   gc->extensions = (unsigned char *) 
     __glXGetStringFromTable( known_gl_extensions, usable );
   (void) memcpy( gc->gl_extension_bits, usable, sizeof( usable ) );
}


/**
 * Calculates the maximum core GL version that can be supported for indirect
 * rendering.
 */
void
__glXGetGLVersion( int * major_version, int * minor_version )
{		   
    __glXExtensionsCtr();
    *major_version = gl_major;
    *minor_version = gl_minor;
}


/**
 * Get a string representing the set of extensions supported by the client
 * library.  This is currently only used to send the list of extensions
 * supported by the client to the server.
 */
char *
__glXGetClientGLExtensionString( void )
{
    __glXExtensionsCtr();
    return __glXGetStringFromTable( known_gl_extensions, client_gl_support );
}