1/*
2 * (C) Copyright IBM Corporation 2002, 2004
3 * All Rights Reserved.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * on the rights to use, copy, modify, merge, publish, distribute, sub
9 * license, and/or sell copies of the Software, and to permit persons to whom
10 * the Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
19 * THE COPYRIGHT HOLDERS AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
22 * USE OR OTHER DEALINGS IN THE SOFTWARE.
23 */
24
25/**
26 * \file glxextensions.c
27 *
28 * \author Ian Romanick <idr@us.ibm.com>
29 */
30
31#include "glxclient.h"
32#include <X11/extensions/extutil.h>
33#include <X11/extensions/Xext.h>
34#include <string.h>
35#include "glxextensions.h"
36
37#include "util/driconf.h"
38
39#define SET_BIT(m,b)   (m[ (b) / 8 ] |=  (1U << ((b) % 8)))
40#define CLR_BIT(m,b)   (m[ (b) / 8 ] &= ~(1U << ((b) % 8)))
41#define IS_SET(m,b)    ((m[ (b) / 8 ] & (1U << ((b) % 8))) != 0)
42#define CONCAT(a,b) a ## b
43#define GLX(n) "GLX_" # n, 4 + sizeof( # n ) - 1, CONCAT(n,_bit)
44#define GL(n)  "GL_" # n,  3 + sizeof( # n ) - 1, GL_ ## n ## _bit
45#define Y  1
46#define N  0
47#define EXT_ENABLED(bit,supported) (IS_SET( supported, bit ))
48
49
50struct extension_info
51{
52   const char *const name;
53   unsigned name_len;
54
55   unsigned char bit;
56
57   /**
58    * The direct-renderer (e.g., i965_dri.so) supports this extension.
59    *
60    * For cases where all of the infrastructure to support the extension is a
61    * required part of the loader/driver interface, this can default to Y.
62    * For most cases, extended functionality, usually in the form of DRI2
63    * extensions, is necessary to support the extension.  The loader will set
64    * the flag true if all the requirements are met.
65    *
66    * If the display is capable of direct rendering, ::direct_support is
67    * required for the extension to be enabled.
68    */
69   unsigned char direct_support;
70
71   /**
72    * The extension only functions with direct-rendering contexts
73    *
74    * The extension has no GLX protocol, and, therefore, no explicit
75    * dependency on the server.  The functionality is contained entirely in
76    * the client library and the direct renderer.  A few of the swap-related
77    * extensions are intended to behave this way.
78    */
79   unsigned char direct_only;
80};
81
82/* *INDENT-OFF* */
83static const struct extension_info known_glx_extensions[] = {
84   { GLX(ARB_context_flush_control),      N, N },
85   { GLX(ARB_create_context),             N, N },
86   { GLX(ARB_create_context_no_error),    N, N },
87   { GLX(ARB_create_context_profile),     N, N },
88   { GLX(ARB_create_context_robustness),  N, N },
89   { GLX(ARB_fbconfig_float),             Y, N },
90   { GLX(ARB_framebuffer_sRGB),           Y, N },
91   { GLX(ARB_get_proc_address),           N, N },
92   { GLX(ARB_multisample),                Y, N },
93   { GLX(EXT_buffer_age),                 N, Y },
94   { GLX(EXT_create_context_es2_profile), N, N },
95   { GLX(EXT_create_context_es_profile),  N, N },
96   { GLX(EXT_fbconfig_packed_float),      Y, N },
97   { GLX(EXT_framebuffer_sRGB),           Y, N },
98   { GLX(EXT_import_context),             Y, N },
99   { GLX(EXT_no_config_context),          N, N },
100   { GLX(EXT_swap_control),               N, Y },
101   { GLX(EXT_swap_control_tear),          N, Y },
102   { GLX(EXT_texture_from_pixmap),        N, N },
103   { GLX(EXT_visual_info),                Y, N },
104   { GLX(EXT_visual_rating),              Y, N },
105   { GLX(ATI_pixel_format_float),         N, N },
106   { GLX(INTEL_swap_event),               N, N },
107   { GLX(MESA_copy_sub_buffer),           N, N },
108   { GLX(MESA_multithread_makecurrent),   N, Y },
109   { GLX(MESA_query_renderer),            N, Y },
110   { GLX(MESA_swap_control),              N, Y },
111   { GLX(NV_float_buffer),                N, N },
112   { GLX(OML_swap_method),                Y, N },
113   { GLX(OML_sync_control),               N, Y },
114   { GLX(SGIS_multisample),               Y, N },
115   { GLX(SGIX_fbconfig),                  Y, N },
116   { GLX(SGIX_pbuffer),                   Y, N },
117   { GLX(SGIX_visual_select_group),       Y, N },
118   { GLX(SGI_make_current_read),          N, N },
119   { GLX(SGI_swap_control),               N, N },
120   { GLX(SGI_video_sync),                 N, Y },
121   { NULL }
122};
123
124static const struct extension_info known_gl_extensions[] = {
125   { GL(ARB_depth_texture),               N, N },
126   { GL(ARB_draw_buffers),                N, N },
127   { GL(ARB_fragment_program),            N, N },
128   { GL(ARB_fragment_program_shadow),     N, N },
129   { GL(ARB_framebuffer_object),          N, N },
130   { GL(ARB_imaging),                     N, N },
131   { GL(ARB_multisample),                 N, N },
132   { GL(ARB_multitexture),                N, N },
133   { GL(ARB_occlusion_query),             N, N },
134   { GL(ARB_point_parameters),            N, N },
135   { GL(ARB_point_sprite),                N, N },
136   { GL(ARB_shadow),                      N, N },
137   { GL(ARB_shadow_ambient),              N, N },
138   { GL(ARB_texture_border_clamp),        N, N },
139   { GL(ARB_texture_compression),         N, N },
140   { GL(ARB_texture_cube_map),            N, N },
141   { GL(ARB_texture_env_add),             N, N },
142   { GL(ARB_texture_env_combine),         N, N },
143   { GL(ARB_texture_env_crossbar),        N, N },
144   { GL(ARB_texture_env_dot3),            N, N },
145   { GL(ARB_texture_filter_anisotropic),  N, N },
146   { GL(ARB_texture_mirrored_repeat),     N, N },
147   { GL(ARB_texture_non_power_of_two),    N, N },
148   { GL(ARB_texture_rectangle),           N, N },
149   { GL(ARB_texture_rg),                  N, N },
150   { GL(ARB_transpose_matrix),            N, N },
151   { GL(ARB_vertex_program),              N, N },
152   { GL(ARB_window_pos),                  N, N },
153   { GL(EXT_abgr),                        N, N },
154   { GL(EXT_bgra),                        N, N },
155   { GL(EXT_blend_color),                 N, N },
156   { GL(EXT_blend_equation_separate),     N, N },
157   { GL(EXT_blend_func_separate),         N, N },
158   { GL(EXT_blend_logic_op),              N, N },
159   { GL(EXT_blend_minmax),                N, N },
160   { GL(EXT_blend_subtract),              N, N },
161   { GL(EXT_clip_volume_hint),            N, N },
162   { GL(EXT_copy_texture),                N, N },
163   { GL(EXT_draw_range_elements),         N, N },
164   { GL(EXT_fog_coord),                   N, N },
165   { GL(EXT_framebuffer_blit),            N, N },
166   { GL(EXT_framebuffer_multisample),     N, N },
167   { GL(EXT_framebuffer_object),          N, N },
168   { GL(EXT_framebuffer_sRGB),            N, N },
169   { GL(EXT_multi_draw_arrays),           N, N },
170   { GL(EXT_packed_depth_stencil),        N, N },
171   { GL(EXT_packed_pixels),               N, N },
172   { GL(EXT_paletted_texture),            N, N },
173   { GL(EXT_point_parameters),            N, N },
174   { GL(EXT_polygon_offset),              N, N },
175   { GL(EXT_rescale_normal),              N, N },
176   { GL(EXT_secondary_color),             N, N },
177   { GL(EXT_separate_specular_color),     N, N },
178   { GL(EXT_shadow_funcs),                N, N },
179   { GL(EXT_shared_texture_palette),      N, N },
180   { GL(EXT_stencil_two_side),            N, N },
181   { GL(EXT_stencil_wrap),                N, N },
182   { GL(EXT_subtexture),                  N, N },
183   { GL(EXT_texture),                     N, N },
184   { GL(EXT_texture3D),                   N, N },
185   { GL(EXT_texture_compression_dxt1),    N, N },
186   { GL(EXT_texture_compression_s3tc),    N, N },
187   { GL(EXT_texture_edge_clamp),          N, N },
188   { GL(EXT_texture_env_add),             N, N },
189   { GL(EXT_texture_env_combine),         N, N },
190   { GL(EXT_texture_env_dot3),            N, N },
191   { GL(EXT_texture_filter_anisotropic),  N, N },
192   { GL(EXT_texture_integer),             N, N },
193   { GL(EXT_texture_lod),                 N, N },
194   { GL(EXT_texture_lod_bias),            N, N },
195   { GL(EXT_texture_mirror_clamp),        N, N },
196   { GL(EXT_texture_object),              N, N },
197   { GL(EXT_texture_rectangle),           N, N },
198   { GL(EXT_vertex_array),                N, N },
199   { GL(3DFX_texture_compression_FXT1),   N, N },
200   { GL(APPLE_packed_pixels),             N, N },
201   { GL(APPLE_ycbcr_422),                 N, N },
202   { GL(ATI_draw_buffers),                N, N },
203   { GL(ATI_text_fragment_shader),        N, N },
204   { GL(ATI_texture_env_combine3),        N, N },
205   { GL(ATI_texture_float),               N, N },
206   { GL(ATI_texture_mirror_once),         N, N },
207   { GL(ATIX_texture_env_combine3),       N, N },
208   { GL(HP_convolution_border_modes),     N, N },
209   { GL(HP_occlusion_test),               N, N },
210   { GL(IBM_cull_vertex),                 N, N },
211   { GL(IBM_pixel_filter_hint),           N, N },
212   { GL(IBM_rasterpos_clip),              N, N },
213   { GL(IBM_texture_clamp_nodraw),        N, N },
214   { GL(IBM_texture_mirrored_repeat),     N, N },
215   { GL(INGR_blend_func_separate),        N, N },
216   { GL(INGR_interlace_read),             N, N },
217   { GL(MESA_pack_invert),                N, N },
218   { GL(MESA_ycbcr_texture),              N, N },
219   { GL(NV_blend_square),                 N, N },
220   { GL(NV_copy_depth_to_color),          N, N },
221   { GL(NV_depth_clamp),                  N, N },
222   { GL(NV_fog_distance),                 N, N },
223   { GL(NV_fragment_program),             N, N },
224   { GL(NV_fragment_program_option),      N, N },
225   { GL(NV_fragment_program2),            N, N },
226   { GL(NV_light_max_exponent),           N, N },
227   { GL(NV_multisample_filter_hint),      N, N },
228   { GL(NV_packed_depth_stencil),         N, N },
229   { GL(NV_point_sprite),                 N, N },
230   { GL(NV_texgen_reflection),            N, N },
231   { GL(NV_texture_compression_vtc),      N, N },
232   { GL(NV_texture_env_combine4),         N, N },
233   { GL(NV_texture_rectangle),            N, N },
234   { GL(NV_vertex_program),               N, N },
235   { GL(NV_vertex_program1_1),            N, N },
236   { GL(NV_vertex_program2),              N, N },
237   { GL(NV_vertex_program2_option),       N, N },
238   { GL(NV_vertex_program3),              N, N },
239   { GL(OES_read_format),                 N, N },
240   { GL(OES_compressed_paletted_texture), N, N },
241   { GL(SGI_color_matrix),                N, N },
242   { GL(SGI_color_table),                 N, N },
243   { GL(SGI_texture_color_table),         N, N },
244   { GL(SGIS_generate_mipmap),            N, N },
245   { GL(SGIS_multisample),                N, N },
246   { GL(SGIS_texture_border_clamp),       N, N },
247   { GL(SGIS_texture_edge_clamp),         N, N },
248   { GL(SGIS_texture_lod),                N, N },
249   { GL(SGIX_blend_alpha_minmax),         N, N },
250   { GL(SGIX_clipmap),                    N, N },
251   { GL(SGIX_depth_texture),              N, N },
252   { GL(SGIX_fog_offset),                 N, N },
253   { GL(SGIX_shadow),                     N, N },
254   { GL(SGIX_shadow_ambient),             N, N },
255   { GL(SGIX_texture_coordinate_clamp),   N, N },
256   { GL(SGIX_texture_lod_bias),           N, N },
257   { GL(SGIX_texture_range),              N, N },
258   { GL(SGIX_texture_scale_bias),         N, N },
259   { GL(SGIX_vertex_preclip),             N, N },
260   { GL(SGIX_vertex_preclip_hint),        N, N },
261   { GL(SGIX_ycrcb),                      N, N },
262   { GL(SUN_convolution_border_modes),    N, N },
263   { GL(SUN_multi_draw_arrays),           N, N },
264   { GL(SUN_slice_accum),                 N, N },
265   { NULL }
266};
267/* *INDENT-ON* */
268
269
270/* global bit-fields of available extensions and their characteristics */
271static unsigned char client_glx_only[__GLX_EXT_BYTES];
272static unsigned char direct_glx_only[__GLX_EXT_BYTES];
273
274/**
275 * Bits representing the set of extensions that are enabled by default in all
276 * direct rendering drivers.
277 */
278static unsigned char direct_glx_support[__GLX_EXT_BYTES];
279
280/* client extensions string */
281static const char *__glXGLXClientExtensions = NULL;
282
283static void __glXExtensionsCtr(void);
284static void __glXExtensionsCtrScreen(struct glx_screen * psc);
285static void __glXProcessServerString(const struct extension_info *ext,
286                                     const char *server_string,
287                                     unsigned char *server_support);
288
289/**
290 * Find an extension in the list based on its name.
291 *
292 * \param ext       List of extensions where to search.
293 * \param name      Name of the extension.
294 * \param name_len  Length, in characters, of the extension name.
295 */
296static const struct extension_info *
297find_extension(const struct extension_info *ext, const char *name,
298               unsigned name_len)
299{
300   unsigned i;
301
302   for (i = 0; ext[i].name != NULL; i++) {
303      if ((name_len == ext[i].name_len)
304          && (strncmp(ext[i].name, name, name_len) == 0)) {
305         return &ext[i];
306      }
307   }
308
309   return NULL;
310}
311
312/**
313 * Set the state of a GLX extension.
314 *
315 * \param name      Name of the extension.
316 * \param name_len  Length, in characters, of the extension name.
317 * \param state     New state (either enabled or disabled) of the extension.
318 * \param supported Table in which the state of the extension is to be set.
319 */
320static void
321set_glx_extension(const struct extension_info *ext_list,
322                  const char *name, unsigned name_len, GLboolean state,
323                  unsigned char *supported)
324{
325   const struct extension_info *ext = find_extension(ext_list, name, name_len);
326   if (!ext)
327       return;
328
329   if (state) {
330      SET_BIT(supported, ext->bit);
331   } else {
332      CLR_BIT(supported, ext->bit);
333   }
334}
335
336
337#define NUL '\0'
338#define SEPARATOR ' '
339
340/**
341 * Convert the server's extension string to a bit-field.
342 *
343 * \param server_string   GLX extension string from the server.
344 * \param server_support  Bit-field of supported extensions.
345 *
346 * \note
347 * This function is used to process both GLX and GL extension strings.  The
348 * bit-fields used to track each of these have different sizes.  Therefore,
349 * the data pointed by \c server_support must be preinitialized to zero.
350 */
351static void
352__glXProcessServerString(const struct extension_info *ext,
353                         const char *server_string,
354                         unsigned char *server_support)
355{
356   unsigned base;
357   unsigned len;
358
359   for (base = 0; server_string[base] != NUL; /* empty */ ) {
360      /* Determine the length of the next extension name.
361       */
362      for (len = 0; (server_string[base + len] != SEPARATOR)
363           && (server_string[base + len] != NUL); len++) {
364         /* empty */
365      }
366
367      /* Set the bit for the extension in the server_support table.
368       */
369      set_glx_extension(ext, &server_string[base], len, GL_TRUE,
370                        server_support);
371
372
373      /* Advance to the next extension string.  This means that we skip
374       * over the previous string and any trialing white-space.
375       */
376      for (base += len; (server_string[base] == SEPARATOR)
377           && (server_string[base] != NUL); base++) {
378         /* empty */
379      }
380   }
381}
382
383void
384__glXEnableDirectExtension(struct glx_screen * psc, const char *name)
385{
386   __glXExtensionsCtr();
387   __glXExtensionsCtrScreen(psc);
388
389   set_glx_extension(known_glx_extensions,
390                     name, strlen(name), GL_TRUE, psc->direct_support);
391}
392
393static void
394__ParseExtensionOverride(struct glx_screen *psc,
395                         const struct extension_info *ext_list,
396                         unsigned char *force_enable,
397                         unsigned char *force_disable,
398                         const char *override)
399{
400   const struct extension_info *ext;
401   char *env, *field;
402
403   if (override == NULL)
404       return;
405
406   /* Copy env_const because strtok() is destructive. */
407   env = strdup(override);
408   if (env == NULL)
409      return;
410
411   for (field = strtok(env, " "); field!= NULL; field = strtok(NULL, " ")) {
412      GLboolean enable;
413
414      switch (field[0]) {
415      case '+':
416         enable = GL_TRUE;
417         ++field;
418         break;
419      case '-':
420         enable = GL_FALSE;
421         ++field;
422         break;
423      default:
424         enable = GL_TRUE;
425         break;
426      }
427
428      ext = find_extension(ext_list, field, strlen(field));
429      if (ext) {
430         if (enable)
431            SET_BIT(force_enable, ext->bit);
432         else
433            SET_BIT(force_disable, ext->bit);
434      } else {
435         fprintf(stderr, "WARNING: Trying to %s the unknown extension '%s'\n",
436                 enable ? "enable" : "disable", field);
437      }
438   }
439
440   free(env);
441}
442
443/**
444 * \brief Parse the list of GLX extensions that the user wants to
445 * force-enable/disable by using \c override, and write the results to the
446 * screen's context.
447 *
448 * \param psc        Pointer to GLX per-screen record.
449 * \param override   A space-separated list of extensions to enable or disable.
450 * The list is processed thus:
451 *    - Enable recognized extension names that are prefixed with '+'.
452 *    - Disable recognized extension names that are prefixed with '-'.
453 *    - Enable recognized extension names that are not prefixed.
454 */
455void
456__glXParseExtensionOverride(struct glx_screen *psc, const char *override)
457{
458    __ParseExtensionOverride(psc, known_glx_extensions, psc->glx_force_enabled,
459                             psc->glx_force_disabled, override);
460}
461
462/**
463 * \brief Parse the list of GL extensions that the user wants to
464 * force-enable/disable by using \c override, and write the results to the
465 * screen's context.
466 *
467 * \param psc        Pointer to GLX per-screen record.
468 * \param override   A space-separated list of extensions to enable or disable.
469 * The list is processed thus:
470 *    - Enable recognized extension names that are prefixed with '+'.
471 *    - Disable recognized extension names that are prefixed with '-'.
472 *    - Enable recognized extension names that are not prefixed.
473 */
474void
475__IndirectGlParseExtensionOverride(struct glx_screen *psc, const char *override)
476{
477    __ParseExtensionOverride(psc, known_gl_extensions, psc->gl_force_enabled,
478                             psc->gl_force_disabled, override);
479}
480
481
482/**
483 * Initialize global extension support tables.
484 */
485
486static void
487__glXExtensionsCtr(void)
488{
489   unsigned i;
490   static GLboolean ext_list_first_time = GL_TRUE;
491
492
493   if (ext_list_first_time) {
494      ext_list_first_time = GL_FALSE;
495
496      (void) memset(direct_glx_support, 0, sizeof(direct_glx_support));
497      (void) memset(client_glx_only, 0, sizeof(client_glx_only));
498      (void) memset(direct_glx_only, 0, sizeof(direct_glx_only));
499
500      SET_BIT(client_glx_only, ARB_get_proc_address_bit);
501      for (i = 0; known_glx_extensions[i].name != NULL; i++) {
502         const unsigned bit = known_glx_extensions[i].bit;
503
504         if (known_glx_extensions[i].direct_support) {
505            SET_BIT(direct_glx_support, bit);
506         }
507
508         if (known_glx_extensions[i].direct_only) {
509            SET_BIT(direct_glx_only, bit);
510         }
511      }
512   }
513}
514
515
516/**
517 * Make sure that per-screen direct-support table is initialized.
518 *
519 * \param psc  Pointer to GLX per-screen record.
520 */
521
522static void
523__glXExtensionsCtrScreen(struct glx_screen * psc)
524{
525   if (psc->ext_list_first_time) {
526      psc->ext_list_first_time = GL_FALSE;
527      (void) memcpy(psc->direct_support, direct_glx_support,
528                    sizeof(direct_glx_support));
529      (void) memset(psc->glx_force_enabled, 0,
530                    sizeof(psc->glx_force_enabled));
531      (void) memset(psc->glx_force_disabled, 0,
532                    sizeof(psc->glx_force_disabled));
533      (void) memset(psc->gl_force_enabled, 0,
534                    sizeof(psc->gl_force_enabled));
535      (void) memset(psc->gl_force_disabled, 0,
536                    sizeof(psc->gl_force_disabled));
537   }
538}
539
540
541/**
542 * Check if a certain extension is enabled on a given screen.
543 *
544 * \param psc  Pointer to GLX per-screen record.
545 * \param bit  Bit index in the direct-support table.
546 * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
547 *          returned.  If the extension bit is not enabled or if \c psc is
548 *          \c NULL, then \c GL_FALSE is returned.
549 */
550GLboolean
551__glXExtensionBitIsEnabled(struct glx_screen * psc, unsigned bit)
552{
553   GLboolean enabled = GL_FALSE;
554
555   if (psc != NULL) {
556      __glXExtensionsCtr();
557      __glXExtensionsCtrScreen(psc);
558      enabled = EXT_ENABLED(bit, psc->direct_support);
559   }
560
561   return enabled;
562}
563
564
565/**
566 * Check if a certain extension is enabled in a given context.
567 *
568 */
569GLboolean
570__glExtensionBitIsEnabled(struct glx_context *gc, unsigned bit)
571{
572   GLboolean enabled = GL_FALSE;
573
574   if (gc != NULL) {
575      enabled = EXT_ENABLED(bit, gc->gl_extension_bits);
576   }
577
578   return enabled;
579}
580
581
582
583/**
584 * Convert a bit-field to a string of supported extensions.
585 */
586static char *
587__glXGetStringFromTable(const struct extension_info *ext,
588                        const unsigned char *filter)
589{
590   unsigned i;
591   unsigned ext_str_len;
592   char *ext_str;
593   char *point;
594
595
596   ext_str_len = 0;
597   for (i = 0; ext[i].name != NULL; i++) {
598      if (!filter || EXT_ENABLED(ext[i].bit, filter)) {
599         ext_str_len += ext[i].name_len + 1;
600      }
601   }
602
603   ext_str = malloc(ext_str_len + 1);
604   if (ext_str != NULL) {
605      point = ext_str;
606
607      for (i = 0; ext[i].name != NULL; i++) {
608         if (!filter || EXT_ENABLED(ext[i].bit, filter)) {
609            (void) memcpy(point, ext[i].name, ext[i].name_len);
610            point += ext[i].name_len;
611
612            *point = ' ';
613            point++;
614         }
615      }
616
617      *point = '\0';
618   }
619
620   return ext_str;
621}
622
623
624/**
625 * Get the string of client library supported extensions.
626 */
627const char *
628__glXGetClientExtensions(Display *dpy)
629{
630   if (__glXGLXClientExtensions == NULL) {
631      __glXExtensionsCtr();
632      __glXGLXClientExtensions = __glXGetStringFromTable(known_glx_extensions,
633                                                         NULL);
634   }
635
636   return __glXGLXClientExtensions;
637}
638
639
640/**
641 * Calculate the list of application usable extensions.  The resulting
642 * string is stored in \c psc->effectiveGLXexts.
643 *
644 * \param psc                        Pointer to GLX per-screen record.
645 * \param display_is_direct_capable  True if the display is capable of
646 *                                   direct rendering.
647 */
648
649void
650__glXCalculateUsableExtensions(struct glx_screen * psc,
651                               GLboolean display_is_direct_capable)
652{
653   unsigned char server_support[__GLX_EXT_BYTES];
654   unsigned char usable[__GLX_EXT_BYTES];
655   unsigned i;
656
657   __glXExtensionsCtr();
658   __glXExtensionsCtrScreen(psc);
659
660   (void) memset(server_support, 0, sizeof(server_support));
661   __glXProcessServerString(known_glx_extensions,
662                            psc->serverGLXexts, server_support);
663
664
665   /* An extension is supported if the client-side (i.e., libGL) supports
666    * it and the "server" supports it.  In this case that means that either
667    * the true server supports it or it is only for direct-rendering and
668    * the direct rendering driver supports it.
669    *
670    * If the display is not capable of direct rendering, then the extension
671    * is enabled if and only if the client-side library and the server
672    * support it.
673    */
674
675   if (display_is_direct_capable) {
676      for (i = 0; i < __GLX_EXT_BYTES; i++) {
677         /* Enable extensions that the client supports that only have a client-side
678          * component.
679          */
680         unsigned char u = client_glx_only[i];
681
682         /* Enable extensions that are supported for direct rendering, and either
683          * are supported by the server or only have a direct-rendering component.
684          */
685         u |= psc->direct_support[i] & (server_support[i] | direct_glx_only[i]);
686
687         /* Finally, apply driconf options to force some extension bits either
688          * enabled or disabled.
689          */
690         u |= psc->glx_force_enabled[i];
691         u &= ~psc->glx_force_disabled[i];
692
693         usable[i] = u;
694      }
695   }
696   else {
697      for (i = 0; i < __GLX_EXT_BYTES; i++) {
698         /* Enable extensions that the client supports that only have a
699          * client-side component.
700          */
701         unsigned char u = client_glx_only[i];
702
703         /* Enable extensions that the client and server both support */
704         u |= server_support[i];
705
706         /* Finally, apply driconf options to force some extension bits either
707          * enabled or disabled.
708          */
709         u |= psc->glx_force_enabled[i];
710         u &= ~psc->glx_force_disabled[i];
711
712         usable[i] = u;
713      }
714   }
715
716   psc->effectiveGLXexts = __glXGetStringFromTable(known_glx_extensions,
717                                                   usable);
718}
719
720/**
721 * Calculate the list of application usable extensions.  The resulting
722 * string is stored in \c gc->extensions.
723 *
724 * \param gc             Pointer to GLX context.
725 * \param server_string  Extension string from the server.
726 */
727
728void
729__glXCalculateUsableGLExtensions(struct glx_context * gc,
730                                 const char *server_string)
731{
732   struct glx_screen *psc = gc->psc;
733   unsigned char server_support[__GL_EXT_BYTES];
734   unsigned char usable[__GL_EXT_BYTES];
735   unsigned i;
736
737   (void) memset(server_support, 0, sizeof(server_support));
738   __glXProcessServerString(known_gl_extensions, server_string,
739                            server_support);
740
741   /* These extensions are wholly inside the client-side indirect code */
742   (void) memset(usable, 0, sizeof(usable));
743   SET_BIT(usable, GL_ARB_transpose_matrix_bit);
744   SET_BIT(usable, GL_EXT_draw_range_elements_bit);
745   SET_BIT(usable, GL_EXT_multi_draw_arrays_bit);
746   SET_BIT(usable, GL_SUN_multi_draw_arrays_bit);
747
748   for (i = 0; i < __GL_EXT_BYTES; i++) {
749      /* Usable if the server supports it, or if it's been forced on */
750      usable[i] = server_support[i] | psc->gl_force_enabled[i];
751
752      /* But not if it's been forced off */
753      usable[i] &= ~psc->gl_force_disabled[i];
754   }
755
756   gc->extensions = (unsigned char *)
757      __glXGetStringFromTable(known_gl_extensions, usable);
758   (void) memcpy(gc->gl_extension_bits, usable, sizeof(usable));
759}
760
761/**
762 * Get a string representing the set of extensions supported by the client
763 * library.  This is currently only used to send the list of extensions
764 * supported by the client to the server.
765 */
766char *
767__glXGetClientGLExtensionString(void)
768{
769   return __glXGetStringFromTable(known_gl_extensions, NULL);
770}
771