src/glx/x11/glxextensions.c

   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 /* $XFree86: xc/lib/GL/glx/glxextensions.c,v 1.1 2003/09/28 20:15:03 alanh Exp $ */
  31
  32 #include "glxclient.h"
  33 #include <extutil.h>
  34 #include <Xext.h>
  35 #include <string.h>
  36 #include "glapi.h"
  37 #include "glxextensions.h"
  38 #include "simple_list.h"
  39
  40 #define SET_BIT(m,b)   (m[ (b) / 8 ] |=  (1U << ((b) % 8)))
  41 #define CLR_BIT(m,b)   (m[ (b) / 8 ] &= ~(1U << ((b) % 8)))
  42 #define IS_SET(m,b)    ((m[ (b) / 8 ] & (1U << ((b) % 8))) != 0)
  43 #define CONCAT(a,b) a ## b
  44 #define GLX(n) "GLX_" # n, 4 + sizeof( # n ) - 1, CONCAT(n,_bit)
  45 #define GL(n)  "GL_" # n,  3 + sizeof( # n ) - 1, GL_ ## n ## _bit
  46 #define VER(a,b)  a, b
  47 #define Y  1
  48 #define N  0
  49 #define EXT_ENABLED(bit,supported) (IS_SET( supported, bit ))
  50
  51
  52 struct extension_info {
  53    const char * const name;
  54    unsigned   name_len;
  55
  56    unsigned char  bit;
  57
  58    /* This is the lowest version of GLX that "requires" this extension.
  59     * For example, GLX 1.3 requires SGIX_fbconfig, SGIX_pbuffer, and
  60     * SGI_make_current_read.  If the extension is not required by any known
  61     * version of GLX, use 0, 0.
  62     */
  63    unsigned char  version_major;
  64    unsigned char  version_minor;
  65    unsigned char  client_support;
  66    unsigned char  direct_support;
  67    unsigned char  client_only;       /** Is the extension client-side only? */
  68    unsigned char  direct_only;       /** Is the extension for direct
  69                                       * contexts only?
  70                                       */
  71 };
  72
  73 static const struct extension_info known_glx_extensions[] = {
  74    { GLX(ARB_get_proc_address),        VER(1,4), Y, N, Y, N },
  75    { GLX(ARB_multisample),             VER(1,4), Y, Y, N, N },
  76    { GLX(ARB_render_texture),          VER(0,0), N, N, N, N },
  77    { GLX(ATI_pixel_format_float),      VER(0,0), N, N, N, N },
  78    { GLX(EXT_import_context),          VER(0,0), Y, Y, N, N },
  79    { GLX(EXT_visual_info),             VER(0,0), Y, Y, N, N },
  80    { GLX(EXT_visual_rating),           VER(0,0), Y, Y, N, N },
  81    { GLX(MESA_agp_offset),             VER(0,0), N, N, N, Y }, /* Deprecated */
  82    { GLX(MESA_allocate_memory),        VER(0,0), Y, N, N, Y },
  83    { GLX(MESA_copy_sub_buffer),        VER(0,0), N, N, N, N }, /* Deprecated? */
  84    { GLX(MESA_pixmap_colormap),        VER(0,0), N, N, N, N }, /* Deprecated */
  85    { GLX(MESA_release_buffers),        VER(0,0), N, N, N, N }, /* Deprecated */
  86    { GLX(MESA_set_3dfx_mode),          VER(0,0), N, N, N, N }, /* Deprecated */
  87    { GLX(MESA_swap_control),           VER(0,0), Y, N, N, Y },
  88    { GLX(MESA_swap_frame_usage),       VER(0,0), Y, N, N, Y },
  89    { GLX(NV_float_buffer),             VER(0,0), N, N, N, N },
  90    { GLX(NV_render_depth_texture),     VER(0,0), N, N, N, N },
  91    { GLX(NV_render_texture_rectangle), VER(0,0), N, N, N, N },
  92    { GLX(NV_vertex_array_range),       VER(0,0), N, N, N, Y }, /* Deprecated */
  93    { GLX(OML_swap_method),             VER(0,0), Y, N, N, N },
  94    { GLX(OML_sync_control),            VER(0,0), Y, N, N, Y },
  95    { GLX(SGI_cushion),                 VER(0,0), N, N, N, N },
  96    { GLX(SGI_make_current_read),       VER(1,3), Y, N, N, N },
  97    { GLX(SGI_swap_control),            VER(0,0), Y, N, N, N },
  98    { GLX(SGI_video_sync),              VER(0,0), Y, N, N, Y },
  99    { GLX(SGIS_blended_overlay),        VER(0,0), N, N, N, N },
 100    { GLX(SGIS_color_range),            VER(0,0), N, N, N, N },
 101    { GLX(SGIS_multisample),            VER(0,0), Y, Y, N, N },
 102    { GLX(SGIX_dm_buffer),              VER(0,0), N, N, N, N },
 103    { GLX(SGIX_fbconfig),               VER(1,3), Y, N, N, N },
 104    { GLX(SGIX_pbuffer),                VER(1,3), Y, N, N, N },
 105    { GLX(SGIX_swap_barrier),           VER(0,0), N, N, N, N },
 106    { GLX(SGIX_swap_group),             VER(0,0), N, N, N, N },
 107    { GLX(SGIX_video_resize),           VER(0,0), N, N, N, N },
 108    { GLX(SGIX_video_source),           VER(0,0), N, N, N, N },
 109    { GLX(SGIX_visual_select_group),    VER(0,0), Y, Y, N, N },
 110    { GLX(SUN_get_transparent_index),   VER(0,0), N, N, N, N },
 111    { NULL }
 112 };
 113
 114 static const struct extension_info known_gl_extensions[] = {
 115    { GL(ARB_depth_texture),              VER(1,4), Y, N, N, N },
 116    { GL(ARB_fragment_program),           VER(0,0), N, N, N, N },
 117    { GL(ARB_imaging),                    VER(0,0), Y, N, N, N },
 118    { GL(ARB_multisample),                VER(1,3), Y, N, N, N },
 119    { GL(ARB_multitexture),               VER(1,3), Y, N, N, N },
 120    { GL(ARB_occlusion_query),            VER(1,5), N, N, N, N },
 121    { GL(ARB_point_parameters),           VER(1,4), Y, N, N, N },
 122    { GL(ARB_point_sprite),               VER(0,0), Y, N, N, N },
 123    { GL(ARB_shadow),                     VER(1,4), Y, N, N, N },
 124    { GL(ARB_shadow_ambient),             VER(0,0), Y, N, N, N },
 125    { GL(ARB_texture_border_clamp),       VER(1,3), Y, N, N, N },
 126    { GL(ARB_texture_compression),        VER(1,3), N, N, N, N },
 127    { GL(ARB_texture_cube_map),           VER(1,3), Y, N, N, N },
 128    { GL(ARB_texture_env_add),            VER(1,3), Y, N, N, N },
 129    { GL(ARB_texture_env_combine),        VER(1,3), Y, N, N, N },
 130    { GL(ARB_texture_env_crossbar),       VER(1,4), Y, N, N, N },
 131    { GL(ARB_texture_env_dot3),           VER(1,3), Y, N, N, N },
 132    { GL(ARB_texture_mirrored_repeat),    VER(1,4), Y, N, N, N },
 133    { GL(ARB_texture_non_power_of_two),   VER(1,5), Y, N, N, N },
 134    { GL(ARB_texture_rectangle),          VER(0,0), Y, N, N, N },
 135    { GL(ARB_transpose_matrix),           VER(1,3), Y, N, Y, N },
 136    { GL(ARB_vertex_buffer_object),       VER(1,5), N, N, N, N },
 137    { GL(ARB_window_pos),                 VER(1,4), Y, N, N, N },
 138    { GL(EXT_abgr),                       VER(0,0), Y, N, N, N },
 139    { GL(EXT_bgra),                       VER(1,2), Y, N, N, N },
 140    { GL(EXT_blend_color),                VER(1,4), Y, N, N, N },
 141    { GL(EXT_blend_equation_separate),    VER(0,0), N, N, N, N },
 142    { GL(EXT_blend_func_separate),        VER(1,4), Y, N, N, N },
 143    { GL(EXT_blend_logic_op),             VER(1,4), Y, N, N, N },
 144    { GL(EXT_blend_minmax),               VER(1,4), Y, N, N, N },
 145    { GL(EXT_blend_subtract),             VER(1,4), Y, N, N, N },
 146    { GL(EXT_clip_volume_hint),           VER(0,0), Y, N, N, N },
 147    { GL(EXT_compiled_vertex_array),      VER(0,0), N, N, N, N },
 148    { GL(EXT_convolution),                VER(0,0), N, N, N, N },
 149    { GL(EXT_copy_texture),               VER(1,1), Y, N, N, N },
 150    { GL(EXT_cull_vertex),                VER(0,0), N, N, N, N },
 151    { GL(EXT_depth_bounds_test),          VER(0,0), N, N, N, N },
 152    { GL(EXT_draw_range_elements),        VER(1,2), Y, N, Y, N },
 153    { GL(EXT_fog_coord),                  VER(1,4), Y, N, N, N },
 154    { GL(EXT_multi_draw_arrays),          VER(1,4), Y, N, Y, N },
 155    { GL(EXT_packed_pixels),              VER(1,2), Y, N, N, N },
 156    { GL(EXT_paletted_texture),           VER(0,0), Y, N, N, N },
 157    { GL(EXT_pixel_buffer_object),        VER(0,0), N, N, N, N },
 158    { GL(EXT_point_parameters),           VER(1,4), Y, N, N, N },
 159    { GL(EXT_polygon_offset),             VER(1,1), Y, N, N, N },
 160    { GL(EXT_rescale_normal),             VER(1,2), Y, N, N, N },
 161    { GL(EXT_secondary_color),            VER(1,4), Y, N, N, N },
 162    { GL(EXT_separate_specular_color),    VER(1,2), Y, N, N, N },
 163    { GL(EXT_shadow_funcs),               VER(1,5), Y, N, N, N },
 164    { GL(EXT_shared_texture_palette),     VER(0,0), Y, N, N, N },
 165    { GL(EXT_stencil_two_side),           VER(0,0), Y, N, N, N },
 166    { GL(EXT_stencil_wrap),               VER(1,4), Y, N, N, N },
 167    { GL(EXT_subtexture),                 VER(1,1), Y, N, N, N },
 168    { GL(EXT_texture),                    VER(1,1), Y, N, N, N },
 169    { GL(EXT_texture3D),                  VER(1,2), Y, N, N, N },
 170    { GL(EXT_texture_compression_s3tc),   VER(0,0), N, N, N, N },
 171    { GL(EXT_texture_edge_clamp),         VER(1,2), Y, N, N, N },
 172    { GL(EXT_texture_env_add),            VER(1,3), Y, N, N, N },
 173    { GL(EXT_texture_env_combine),        VER(1,3), Y, N, N, N },
 174    { GL(EXT_texture_env_dot3),           VER(0,0), Y, N, N, N },
 175    { GL(EXT_texture_filter_anisotropic), VER(0,0), Y, N, N, N },
 176    { GL(EXT_texture_lod),                VER(1,2), Y, N, N, N },
 177    { GL(EXT_texture_lod_bias),           VER(1,4), Y, N, N, N },
 178    { GL(EXT_texture_mirror_clamp),       VER(0,0), Y, N, N, N },
 179    { GL(EXT_texture_object),             VER(1,1), Y, N, N, N },
 180    { GL(EXT_texture_rectangle),          VER(0,0), Y, N, N, N },
 181    { GL(EXT_vertex_array),               VER(0,0), Y, N, N, N },
 182    { GL(3DFX_texture_compression_FXT1),  VER(0,0), N, N, N, N },
 183    { GL(APPLE_packed_pixels),            VER(1,2), Y, N, N, N },
 184    { GL(APPLE_ycbcr_422),                VER(0,0), Y, N, N, N },
 185    { GL(ATI_texture_env_combine3),       VER(0,0), Y, N, N, N },
 186    { GL(ATI_texture_float),              VER(0,0), Y, N, N, N },
 187    { GL(ATI_texture_mirror_once),        VER(0,0), Y, N, N, N },
 188    { GL(ATIX_texture_env_combine3),      VER(0,0), Y, N, N, N },
 189    { GL(HP_convolution_border_modes),    VER(0,0), Y, N, N, N },
 190    { GL(HP_occlusion_test),              VER(0,0), Y, N, N, N },
 191    { GL(IBM_cull_vertex),                VER(0,0), Y, N, N, N },
 192    { GL(IBM_pixel_filter_hint),          VER(0,0), Y, N, N, N },
 193    { GL(IBM_rasterpos_clip),             VER(0,0), Y, N, N, N },
 194    { GL(IBM_texture_clamp_nodraw),       VER(0,0), Y, N, N, N },
 195    { GL(IBM_texture_mirrored_repeat),    VER(0,0), Y, N, N, N },
 196    { GL(INGR_blend_func_separate),       VER(0,0), Y, N, N, N },
 197    { GL(INGR_interlace_read),            VER(0,0), Y, N, N, N },
 198    { GL(MESA_pack_invert),               VER(0,0), Y, N, N, N },
 199    { GL(MESA_ycbcr_texture),             VER(0,0), Y, N, N, N },
 200    { GL(NV_blend_square),                VER(1,4), Y, N, N, N },
 201    { GL(NV_copy_depth_to_color),         VER(0,0), Y, N, N, N },
 202    { GL(NV_depth_clamp),                 VER(0,0), Y, N, N, N },
 203    { GL(NV_fog_distance),                VER(0,0), Y, N, N, N },
 204    { GL(NV_light_max_exponent),          VER(0,0), Y, N, N, N },
 205    { GL(NV_multisample_filter_hint),     VER(0,0), Y, N, N, N },
 206    { GL(NV_point_sprite),                VER(0,0), Y, N, N, N },
 207    { GL(NV_texgen_reflection),           VER(0,0), Y, N, N, N },
 208    { GL(NV_texture_compression_vtc),     VER(0,0), N, N, N, N },
 209    { GL(NV_texture_env_combine4),        VER(0,0), Y, N, N, N },
 210    { GL(NV_texture_rectangle),           VER(0,0), Y, N, N, N },
 211    { GL(OES_read_format),                VER(0,0), Y, N, N, N },
 212    { GL(SGIS_generate_mipmap),           VER(1,4), Y, N, N, N },
 213    { GL(SGIS_multisample),               VER(0,0), Y, N, N, N },
 214    { GL(SGIS_texture_border_clamp),      VER(1,3), Y, N, N, N },
 215    { GL(SGIS_texture_edge_clamp),        VER(1,2), Y, N, N, N },
 216    { GL(SGIS_texture_lod),               VER(1,2), Y, N, N, N },
 217    { GL(SGIX_blend_alpha_minmax),        VER(0,0), Y, N, N, N },
 218    { GL(SGIX_clipmap),                   VER(0,0), Y, N, N, N },
 219    { GL(SGIX_depth_texture),             VER(0,0), Y, N, N, N },
 220    { GL(SGIX_fog_offset),                VER(0,0), Y, N, N, N },
 221    { GL(SGIX_shadow),                    VER(0,0), Y, N, N, N },
 222    { GL(SGIX_shadow_ambient),            VER(0,0), Y, N, N, N },
 223    { GL(SGIX_texture_coordinate_clamp),  VER(0,0), Y, N, N, N },
 224    { GL(SGIX_texture_lod_bias),          VER(0,0), Y, N, N, N },
 225    { GL(SGIX_texture_range),             VER(0,0), Y, N, N, N },
 226    { GL(SGIX_texture_scale_bias),        VER(0,0), Y, N, N, N },
 227    { GL(SGIX_vertex_preclip),            VER(0,0), Y, N, N, N },
 228    { GL(SGIX_vertex_preclip_hint),       VER(0,0), Y, N, N, N },
 229    { GL(SGIX_ycrcb),                     VER(0,0), Y, N, N, N },
 230    { GL(SUN_convolution_border_modes),   VER(0,0), Y, N, N, N },
 231    { GL(SUN_multi_draw_arrays),          VER(0,0), Y, N, Y, N },
 232    { GL(SUN_slice_accum),                VER(0,0), Y, N, N, N },
 233    { NULL }
 234 };
 235
 236
 237 #define __GL_EXT_BYTES   ((__NUM_GL_EXTS + 7) / 8)
 238
 239 /* global bit-fields of available extensions and their characteristics */
 240 static unsigned char client_glx_support[8];
 241 static unsigned char client_glx_only[8];
 242 static unsigned char direct_glx_only[8];
 243 static unsigned char client_gl_support[ __GL_EXT_BYTES ];
 244 static unsigned char client_gl_only[ __GL_EXT_BYTES ];
 245
 246 /**
 247  * Bits representing the set of extensions that are enabled by default in all
 248  * direct rendering drivers.
 249  */
 250 static unsigned char direct_glx_support[8];
 251
 252 /**
 253  * Highest core GL version that can be supported for indirect rendering.
 254  */
 255 static unsigned gl_major = 0;
 256 static unsigned gl_minor = 0;
 257
 258 /* client extensions string */
 259 static const char * __glXGLXClientExtensions = NULL;
 260
 261 static void __glXExtensionsCtr( void );
 262 static void __glXExtensionsCtrScreen( __GLXscreenConfigs *psc );
 263 static void __glXProcessServerString( const struct extension_info * ext,
 264     const char * server_string, unsigned char * server_support );
 265
 266 /**
 267  * Set the state of a GLX extension.
 268  *
 269  * \param name      Name of the extension.
 270  * \param name_len  Length, in characters, of the extension name.
 271  * \param state     New state (either enabled or disabled) of the extension.
 272  * \param supported Table in which the state of the extension is to be set.
 273  */
 274 static void
 275 set_glx_extension( const struct extension_info * ext,
 276                    const char * name, unsigned name_len, GLboolean state,
 277                    unsigned char * supported )
 278 {
 279    unsigned   i;
 280
 281
 282    for ( i = 0 ; ext[i].name != NULL ; i++ ) {
 283       if ( (name_len == ext[i].name_len)
 284            && (strncmp( ext[i].name, name, name_len ) == 0) ) {
 285          if ( state ) {
 286             SET_BIT( supported, ext[i].bit );
 287          }
 288          else {
 289             CLR_BIT( supported, ext[i].bit );
 290          }
 291
 292          return;
 293       }
 294    }
 295 }
 296
 297
 298 #define NUL '\0'
 299 #define SEPARATOR ' '
 300
 301 /**
 302  * Convert the server's extension string to a bit-field.
 303  *
 304  * \param server_string   GLX extension string from the server.
 305  * \param server_support  Bit-field of supported extensions.
 306  */
 307 static void
 308 __glXProcessServerString( const struct extension_info * ext,
 309                           const char * server_string,
 310                           unsigned char * server_support )
 311 {
 312    unsigned  base;
 313    unsigned  len;
 314
 315    (void) memset( server_support, 0, sizeof( server_support ) );
 316
 317    for ( base = 0 ; server_string[ base ] != NUL ; /* empty */ ) {
 318       /* Determine the length of the next extension name.
 319        */
 320       for ( len = 0
 321             ; (server_string[ base + len ] != SEPARATOR)
 322             && (server_string[ base + len ] != NUL)
 323             ; len++ ) {
 324          /* empty */
 325       }
 326
 327       /* Set the bit for the extension in the server_support table.
 328        */
 329       set_glx_extension( ext, & server_string[ base ], len, GL_TRUE,
 330                          server_support );
 331
 332
 333       /* Advance to the next extension string.  This means that we skip
 334        * over the previous string and any trialing white-space.
 335        */
 336       for ( base += len ;
 337             (server_string[ base ] == SEPARATOR)
 338             && (server_string[ base ] != NUL)
 339             ; base++ ) {
 340          /* empty */
 341       }
 342    }
 343 }
 344
 345
 346 /**
 347  * Enable a named GLX extension on a given screen.
 348  * Drivers should not call this function directly.  They should instead use
 349  * \c glXGetProcAddress to obtain a pointer to the function.
 350  *
 351  * \param psc   Pointer to GLX per-screen record.
 352  * \param name  Name of the extension to enable.
 353  *
 354  * \sa glXGetProcAddress
 355  *
 356  * \since Internal API version 20030813.
 357  */
 358 void
 359 __glXScrEnableExtension( __GLXscreenConfigs *psc, const char * name )
 360 {
 361    __glXExtensionsCtr();
 362    __glXExtensionsCtrScreen(psc);
 363    set_glx_extension( known_glx_extensions, name, strlen( name ), GL_TRUE,
 364                       psc->direct_support );
 365 }
 366
 367
 368 /**
 369  * Initialize global extension support tables.
 370  */
 371
 372 static void
 373 __glXExtensionsCtr( void )
 374 {
 375    static const char major_table[32] = { 1, 1, 1, 1, 1, 1, 2, };
 376    static const char minor_table[32] = { 0, 1, 2, 3, 4, 5, 0, };
 377    unsigned   i;
 378    static GLboolean ext_list_first_time = GL_TRUE;
 379    unsigned   full_support = ~0;
 380
 381
 382    if ( ext_list_first_time ) {
 383       ext_list_first_time = GL_FALSE;
 384
 385       (void) memset( client_glx_support, 0, sizeof( client_glx_support ) );
 386       (void) memset( direct_glx_support, 0, sizeof( direct_glx_support ) );
 387       (void) memset( client_glx_only,    0, sizeof( client_glx_only ) );
 388       (void) memset( direct_glx_only,    0, sizeof( direct_glx_only ) );
 389
 390       (void) memset( client_gl_support,  0, sizeof( client_gl_support ) );
 391       (void) memset( client_gl_only,     0, sizeof( client_gl_only ) );
 392
 393       for ( i = 0 ; known_glx_extensions[i].name != NULL ; i++ ) {
 394          const unsigned  bit = known_glx_extensions[i].bit;
 395
 396          if ( known_glx_extensions[i].client_support ) {
 397             SET_BIT( client_glx_support, bit );
 398          }
 399
 400          if ( known_glx_extensions[i].direct_support ) {
 401             SET_BIT( direct_glx_support, bit );
 402          }
 403
 404          if ( known_glx_extensions[i].client_only ) {
 405             SET_BIT( client_glx_only, bit );
 406          }
 407
 408          if ( known_glx_extensions[i].direct_only ) {
 409             SET_BIT( direct_glx_only, bit );
 410          }
 411       }
 412
 413       for ( i = 0 ; known_gl_extensions[i].name != NULL ; i++ ) {
 414          const unsigned  bit = known_gl_extensions[i].bit;
 415
 416          if ( known_gl_extensions[i].client_support ) {
 417             SET_BIT( client_gl_support, bit );
 418          }
 419          else if ( known_gl_extensions[i].version_major != 0 ) {
 420             /* If an extension that is required for some core GL version is
 421              * not supported, clear the bit for that core GL version as well.
 422              */
 423
 424             unsigned ver_bit = (6 * (known_gl_extensions[i].version_major - 1))
 425               + (known_gl_extensions[i].version_minor);
 426
 427             full_support &= ~(1U << ver_bit);
 428          }
 429
 430          if ( known_gl_extensions[i].client_only ) {
 431             SET_BIT( client_gl_only, bit );
 432          }
 433       }
 434
 435       /* Determine the lowest unsupported core GL version.  The version before
 436        * that is, therefore, the highest supported core GL version.
 437        */
 438       for ( i = 0 ; (full_support & (1 << i)) != 0 ; i++ )
 439          /* empty */ ;
 440
 441       i--;
 442       gl_major = major_table[i];
 443       gl_minor = minor_table[i];
 444 #if 0
 445       fprintf( stderr, "[%s:%u] Maximum client library version: %u.%u\n",
 446                __func__, __LINE__, gl_major, gl_minor );
 447 #endif
 448    }
 449 }
 450
 451
 452 /**
 453  * Make sure that per-screen direct-support table is initialized.
 454  *
 455  * \param psc  Pointer to GLX per-screen record.
 456  */
 457
 458 static void
 459 __glXExtensionsCtrScreen( __GLXscreenConfigs *psc )
 460 {
 461     if (psc->ext_list_first_time) {
 462         psc->ext_list_first_time = GL_FALSE;
 463         (void) memcpy( psc->direct_support, direct_glx_support,
 464                        sizeof( direct_glx_support ) );
 465     }
 466 }
 467
 468
 469 /**
 470  * Check if a certain extension is enabled on a given screen.
 471  *
 472  * \param psc  Pointer to GLX per-screen record.
 473  * \param bit  Bit index in the direct-support table.
 474  * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
 475  *          returned.  If the extension bit is not enabled or if \c psc is
 476  *          \c NULL, then \c GL_FALSE is returned.
 477  */
 478 GLboolean
 479 __glXExtensionBitIsEnabled( __GLXscreenConfigs *psc, unsigned bit )
 480 {
 481    GLboolean enabled = GL_FALSE;
 482
 483    if ( psc != NULL ) {
 484       __glXExtensionsCtr();
 485       __glXExtensionsCtrScreen( psc );
 486       enabled = EXT_ENABLED( bit, psc->direct_support );
 487    }
 488
 489    return enabled;
 490 }
 491
 492
 493 /**
 494  * Convert a bit-field to a string of supported extensions.
 495  */
 496 static char *
 497 __glXGetStringFromTable( const struct extension_info * ext,
 498                          const unsigned char * supported )
 499 {
 500    unsigned   i;
 501    unsigned   ext_str_len;
 502    char * ext_str;
 503    char * point;
 504
 505
 506    ext_str_len = 0;
 507    for ( i = 0 ; ext[i].name != NULL ; i++ ) {
 508       if ( EXT_ENABLED( ext[i].bit, supported ) ) {
 509          ext_str_len += ext[i].name_len + 1;
 510       }
 511    }
 512
 513    ext_str = Xmalloc( ext_str_len + 1 );
 514    if ( ext_str != NULL ) {
 515       point = ext_str;
 516
 517       for ( i = 0 ; ext[i].name != NULL ; i++ ) {
 518          if ( EXT_ENABLED( ext[i].bit, supported ) ) {
 519             (void) memcpy( point, ext[i].name, ext[i].name_len );
 520             point += ext[i].name_len;
 521
 522             *point = ' ';
 523             point++;
 524          }
 525       }
 526
 527       *point = '\0';
 528    }
 529
 530    return ext_str;
 531 }
 532
 533
 534 /**
 535  * Get the string of client library supported extensions.
 536  */
 537 const char *
 538 __glXGetClientExtensions( void )
 539 {
 540    if ( __glXGLXClientExtensions == NULL ) {
 541       __glXExtensionsCtr();
 542       __glXGLXClientExtensions = __glXGetStringFromTable( known_glx_extensions,
 543                                                           client_glx_support );
 544    }
 545
 546    return __glXGLXClientExtensions;
 547 }
 548
 549
 550 /**
 551  * Calculate the list of application usable extensions.  The resulting
 552  * string is stored in \c psc->effectiveGLXexts.
 553  *
 554  * \param psc                        Pointer to GLX per-screen record.
 555  * \param display_is_direct_capable  True if the display is capable of
 556  *                                   direct rendering.
 557  * \param minor_version              GLX minor version from the server.
 558  */
 559
 560 void
 561 __glXCalculateUsableExtensions( __GLXscreenConfigs *psc,
 562                                 GLboolean display_is_direct_capable,
 563                                 int minor_version )
 564 {
 565    unsigned char server_support[8];
 566    unsigned char usable[8];
 567    unsigned      i;
 568
 569    __glXExtensionsCtr();
 570    __glXExtensionsCtrScreen( psc );
 571    __glXProcessServerString( known_glx_extensions,
 572                              psc->serverGLXexts, server_support );
 573
 574
 575    /* This is a hack.  Some servers support GLX 1.3 but don't export
 576     * all of the extensions implied by GLX 1.3.  If the server claims
 577     * support for GLX 1.3, enable support for the extensions that can be
 578     * "emulated" as well.
 579     */
 580
 581    if ( minor_version >= 3 ) {
 582       SET_BIT( server_support, EXT_visual_info_bit );
 583       SET_BIT( server_support, EXT_visual_rating_bit );
 584       SET_BIT( server_support, SGI_make_current_read_bit );
 585       SET_BIT( server_support, SGIX_fbconfig_bit );
 586       SET_BIT( server_support, SGIX_pbuffer_bit );
 587
 588       /* This one is a little iffy.  GLX 1.3 doesn't incorporate all of this
 589        * extension.  However, the only part that is not strictly client-side
 590        * is shared.  That's the glXQueryContext / glXQueryContextInfoEXT
 591        * function.
 592        */
 593
 594       SET_BIT( server_support, EXT_import_context_bit );
 595    }
 596
 597
 598    /* An extension is supported if the client-side (i.e., libGL) supports
 599     * it and the "server" supports it.  In this case that means that either
 600     * the true server supports it or it is only for direct-rendering and
 601     * the direct rendering driver supports it.
 602     *
 603     * If the display is not capable of direct rendering, then the extension
 604     * is enabled if and only if the client-side library and the server
 605     * support it.
 606     */
 607
 608    if ( display_is_direct_capable ) {
 609       for ( i = 0 ; i < 8 ; i++ ) {
 610          usable[i] = (client_glx_support[i] & client_glx_only[i])
 611              | (client_glx_support[i] & psc->direct_support[i] & server_support[i])
 612              | (client_glx_support[i] & psc->direct_support[i] & direct_glx_only[i]);
 613       }
 614    }
 615    else {
 616       for ( i = 0 ; i < 8 ; i++ ) {
 617          usable[i] = (client_glx_support[i] & client_glx_only[i])
 618              | (client_glx_support[i] & server_support[i]);
 619       }
 620    }
 621
 622    psc->effectiveGLXexts = __glXGetStringFromTable( known_glx_extensions,
 623                                                     usable );
 624 }
 625
 626
 627 /**
 628  * Calculate the list of application usable extensions.  The resulting
 629  * string is stored in \c gc->extensions.
 630  *
 631  * \param gc             Pointer to GLX context.
 632  * \param server_string  Extension string from the server.
 633  * \param major_version  GL major version from the server.
 634  * \param minor_version  GL minor version from the server.
 635  */
 636
 637 void
 638 __glXCalculateUsableGLExtensions( __GLXcontext * gc,
 639                                   const char * server_string,
 640                                   int major_version, int minor_version )
 641 {
 642    unsigned char server_support[ __GL_EXT_BYTES ];
 643    unsigned char usable[ __GL_EXT_BYTES ];
 644    unsigned      i;
 645
 646
 647    __glXExtensionsCtr();
 648
 649    (void) memset( server_support, 0, sizeof( server_support ) );
 650    __glXProcessServerString( known_gl_extensions, server_string,
 651                              server_support );
 652
 653
 654    /* Handle lazy servers that don't export all the extensions strings that
 655     * are part of the GL core version that they support.
 656     */
 657
 658    for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
 659       if ( (known_gl_extensions[i].version_major != 0)
 660            && ((major_version > known_gl_extensions[i].version_major)
 661                || ((major_version == known_gl_extensions[i].version_major)
 662                    && (minor_version >= known_gl_extensions[i].version_minor))) ) {
 663          SET_BIT( server_support, known_gl_extensions[i].bit );
 664       }
 665    }
 666
 667
 668    /* An extension is supported if the client-side (i.e., libGL) supports
 669     * it and the server supports it or the client-side library supports it
 670     * and it only needs client-side support.
 671     */
 672
 673    for ( i = 0 ; i < __GL_EXT_BYTES ; i++ ) {
 674       usable[i] = (client_gl_support[i] & client_gl_only[i])
 675         | (client_gl_support[i] & server_support[i]);
 676    }
 677
 678    gc->extensions = (unsigned char *)
 679      __glXGetStringFromTable( known_gl_extensions, usable );
 680 }
 681
 682
 683 /**
 684  * Calculates the maximum core GL version that can be supported for indirect
 685  * rendering.
 686  */
 687 void
 688 __glXGetGLVersion( int * major_version, int * minor_version )
 689 {
 690     __glXExtensionsCtr();
 691     *major_version = gl_major;
 692     *minor_version = gl_minor;
 693 }
 694
 695
 696 /**
 697  * Get a string representing the set of extensions supported by the client
 698  * library.  This is currently only used to send the list of extensions
 699  * supported by the client to the server.
 700  */
 701 char *
 702 __glXGetClientGLExtensionString( void )
 703 {
 704     __glXExtensionsCtr();
 705     return __glXGetStringFromTable( known_gl_extensions, client_gl_support );
 706 }