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      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 (at) 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 
     38 #define SET_BIT(m,b)   (m[ (b) / 8 ] |=  (1U << ((b) % 8)))
     39 #define CLR_BIT(m,b)   (m[ (b) / 8 ] &= ~(1U << ((b) % 8)))
     40 #define IS_SET(m,b)    ((m[ (b) / 8 ] & (1U << ((b) % 8))) != 0)
     41 #define CONCAT(a,b) a ## b
     42 #define GLX(n) "GLX_" # n, 4 + sizeof( # n ) - 1, CONCAT(n,_bit)
     43 #define GL(n)  "GL_" # n,  3 + sizeof( # n ) - 1, GL_ ## n ## _bit
     44 #define VER(a,b)  a, b
     45 #define Y  1
     46 #define N  0
     47 #define EXT_ENABLED(bit,supported) (IS_SET( supported, bit ))
     48 
     49 
     50 struct extension_info
     51 {
     52    const char *const name;
     53    unsigned name_len;
     54 
     55    unsigned char bit;
     56 
     57    /* This is the lowest version of GLX that "requires" this extension.
     58     * For example, GLX 1.3 requires SGIX_fbconfig, SGIX_pbuffer, and
     59     * SGI_make_current_read.  If the extension is not required by any known
     60     * version of GLX, use 0, 0.
     61     */
     62    unsigned char version_major;
     63    unsigned char version_minor;
     64 
     65    /**
     66     * The client (i.e., libGL) supports this extension.
     67     *
     68     * Except during bring up, all extensions should have this set to Y.  There
     69     * are a few cases of extensions that have partial (or speculative)
     70     * support, but these are rare.  There also shouldn't be any new ones
     71     * added.
     72     *
     73     * Generally, extensions require server support and ::client_support to be
     74     * enabled.  If the display is capable of direct rendering,
     75     * ::direct_support is also required.
     76     *
     77     * \sa ::client_only
     78     */
     79    unsigned char client_support;
     80 
     81    /**
     82     * The direct-renderer (e.g., i965_dri.so) supports this extension.
     83     *
     84     * For cases where all of the infrastructure to support the extension is a
     85     * required part of the loader/driver interface, this can default to Y.
     86     * For most cases, extended functionality, usually in the form of DRI2
     87     * extensions, is necessary to support the extension.  The loader will set
     88     * the flag true if all the requirements are met.
     89     *
     90     * If the display is capable of direct rendering, ::direct_support is
     91     * required for the extension to be enabled.
     92     */
     93    unsigned char direct_support;
     94 
     95    /**
     96     * The extension depends only on client support.
     97     *
     98     * This is for extensions like GLX_ARB_get_proc_address that are contained
     99     * entirely in the client library.  There is no dependency on the server or
    100     * the direct-renderer.
    101     *
    102     * These extensions will be enabled if ::client_support is set.
    103     *
    104     * \note
    105     * An extension \b cannot be both client-only and direct-only because being
    106     * direct-only implies a dependency on the direct renderer.
    107     *
    108     * \sa ::client_support, ::direct_only
    109     */
    110    unsigned char client_only;
    111 
    112    /**
    113     * The extension only functions with direct-rendering contexts
    114     *
    115     * The extension has no GLX protocol, and, therefore, no explicit
    116     * dependency on the server.  The functionality is contained entirely in
    117     * the client library and the direct renderer.  A few of the swap-related
    118     * extensions are intended to behave this way.
    119     *
    120     * These extensions will be enabled if both ::client_support and
    121     * ::direct_support are set.
    122     *
    123     * \note
    124     * An extension \b cannot be both client-only and direct-only because being
    125     * client-only implies that all functionality is outside the
    126     * direct-renderer.
    127     *
    128     * \sa ::direct_support, ::client_only
    129     */
    130    unsigned char direct_only;
    131 };
    132 
    133 /* *INDENT-OFF* */
    134 static const struct extension_info known_glx_extensions[] = {
    135    { GLX(ARB_create_context),          VER(0,0), Y, N, N, N },
    136    { GLX(ARB_create_context_profile),  VER(0,0), Y, N, N, N },
    137    { GLX(ARB_create_context_robustness), VER(0,0), Y, N, N, N },
    138    { GLX(ARB_fbconfig_float),          VER(0,0), Y, Y, N, N },
    139    { GLX(ARB_framebuffer_sRGB),        VER(0,0), Y, Y, N, N },
    140    { GLX(ARB_get_proc_address),        VER(1,4), Y, N, Y, N },
    141    { GLX(ARB_multisample),             VER(1,4), Y, Y, N, N },
    142    { GLX(ATI_pixel_format_float),      VER(0,0), N, N, N, N },
    143    { GLX(EXT_import_context),          VER(0,0), Y, Y, N, N },
    144    { GLX(EXT_visual_info),             VER(0,0), Y, Y, N, N },
    145    { GLX(EXT_visual_rating),           VER(0,0), Y, Y, N, N },
    146    { GLX(EXT_fbconfig_packed_float),   VER(0,0), Y, Y, N, N },
    147    { GLX(EXT_framebuffer_sRGB),        VER(0,0), Y, Y, N, N },
    148    { GLX(EXT_create_context_es2_profile), VER(0,0), Y, N, N, N },
    149    { GLX(EXT_create_context_es_profile), VER(0,0), Y, N, N, N },
    150    { GLX(MESA_copy_sub_buffer),        VER(0,0), Y, N, N, N },
    151    { GLX(MESA_multithread_makecurrent),VER(0,0), Y, N, Y, N },
    152    { GLX(MESA_query_renderer),         VER(0,0), Y, N, N, Y },
    153    { GLX(MESA_swap_control),           VER(0,0), Y, N, N, Y },
    154    { GLX(NV_float_buffer),             VER(0,0), N, N, N, N },
    155    { GLX(OML_swap_method),             VER(0,0), Y, Y, N, N },
    156    { GLX(OML_sync_control),            VER(0,0), Y, N, N, Y },
    157    { GLX(SGI_make_current_read),       VER(1,3), Y, N, N, N },
    158    { GLX(SGI_swap_control),            VER(0,0), Y, N, N, N },
    159    { GLX(SGI_video_sync),              VER(0,0), Y, N, N, Y },
    160    { GLX(SGIS_multisample),            VER(0,0), Y, Y, N, N },
    161    { GLX(SGIX_fbconfig),               VER(1,3), Y, Y, N, N },
    162    { GLX(SGIX_pbuffer),                VER(1,3), Y, Y, N, N },
    163    { GLX(SGIX_swap_barrier),           VER(0,0), N, N, N, N },
    164    { GLX(SGIX_swap_group),             VER(0,0), N, N, N, N },
    165    { GLX(SGIX_visual_select_group),    VER(0,0), Y, Y, N, N },
    166    { GLX(EXT_texture_from_pixmap),     VER(0,0), Y, N, N, N },
    167    { GLX(INTEL_swap_event),            VER(0,0), Y, N, N, N },
    168    { GLX(EXT_buffer_age),              VER(0,0), Y, N, N, Y },
    169    { NULL }
    170 };
    171 
    172 static const struct extension_info known_gl_extensions[] = {
    173    { GL(ARB_depth_texture),              VER(1,4), Y, N, N, N },
    174    { GL(ARB_draw_buffers),               VER(0,0), Y, N, N, N },
    175    { GL(ARB_fragment_program),           VER(0,0), Y, N, N, N },
    176    { GL(ARB_fragment_program_shadow),    VER(0,0), Y, N, N, N },
    177    { GL(ARB_framebuffer_object),         VER(0,0), Y, N, N, N },
    178    { GL(ARB_imaging),                    VER(0,0), Y, N, N, N },
    179    { GL(ARB_multisample),                VER(1,3), Y, N, N, N },
    180    { GL(ARB_multitexture),               VER(1,3), Y, N, N, N },
    181    { GL(ARB_occlusion_query),            VER(1,5), Y, N, N, N },
    182    { GL(ARB_point_parameters),           VER(1,4), Y, N, N, N },
    183    { GL(ARB_point_sprite),               VER(0,0), Y, N, N, N },
    184    { GL(ARB_shadow),                     VER(1,4), Y, N, N, N },
    185    { GL(ARB_shadow_ambient),             VER(0,0), Y, N, N, N },
    186    { GL(ARB_texture_border_clamp),       VER(1,3), Y, N, N, N },
    187    { GL(ARB_texture_compression),        VER(1,3), Y, N, N, N },
    188    { GL(ARB_texture_cube_map),           VER(1,3), Y, N, N, N },
    189    { GL(ARB_texture_env_add),            VER(1,3), Y, N, N, N },
    190    { GL(ARB_texture_env_combine),        VER(1,3), Y, N, N, N },
    191    { GL(ARB_texture_env_crossbar),       VER(1,4), Y, N, N, N },
    192    { GL(ARB_texture_env_dot3),           VER(1,3), Y, N, N, N },
    193    { GL(ARB_texture_mirrored_repeat),    VER(1,4), Y, N, N, N },
    194    { GL(ARB_texture_non_power_of_two),   VER(1,5), Y, N, N, N },
    195    { GL(ARB_texture_rectangle),          VER(0,0), Y, N, N, N },
    196    { GL(ARB_texture_rg),                 VER(0,0), Y, N, N, N },
    197    { GL(ARB_transpose_matrix),           VER(1,3), Y, N, Y, N },
    198    { GL(ARB_vertex_buffer_object),       VER(1,5), N, N, N, N },
    199    { GL(ARB_vertex_program),             VER(0,0), Y, N, N, N },
    200    { GL(ARB_window_pos),                 VER(1,4), Y, N, N, N },
    201    { GL(EXT_abgr),                       VER(0,0), Y, N, N, N },
    202    { GL(EXT_bgra),                       VER(1,2), Y, N, N, N },
    203    { GL(EXT_blend_color),                VER(1,4), Y, N, N, N },
    204    { GL(EXT_blend_equation_separate),    VER(0,0), Y, N, N, N },
    205    { GL(EXT_blend_func_separate),        VER(1,4), Y, N, N, N },
    206    { GL(EXT_blend_logic_op),             VER(1,4), Y, N, N, N },
    207    { GL(EXT_blend_minmax),               VER(1,4), Y, N, N, N },
    208    { GL(EXT_blend_subtract),             VER(1,4), Y, N, N, N },
    209    { GL(EXT_clip_volume_hint),           VER(0,0), Y, N, N, N },
    210    { GL(EXT_compiled_vertex_array),      VER(0,0), N, N, N, N },
    211    { GL(EXT_convolution),                VER(0,0), N, N, N, N },
    212    { GL(EXT_copy_texture),               VER(1,1), Y, N, N, N },
    213    { GL(EXT_cull_vertex),                VER(0,0), N, N, N, N },
    214    { GL(EXT_depth_bounds_test),          VER(0,0), N, N, N, N },
    215    { GL(EXT_draw_range_elements),        VER(1,2), Y, N, Y, N },
    216    { GL(EXT_fog_coord),                  VER(1,4), Y, N, N, N },
    217    { GL(EXT_framebuffer_blit),           VER(0,0), Y, N, N, N },
    218    { GL(EXT_framebuffer_multisample),    VER(0,0), Y, N, N, N },
    219    { GL(EXT_framebuffer_object),         VER(0,0), Y, N, N, N },
    220    { GL(EXT_framebuffer_sRGB),           VER(0,0), Y, N, N, N },
    221    { GL(EXT_multi_draw_arrays),          VER(1,4), Y, N, Y, N },
    222    { GL(EXT_packed_depth_stencil),       VER(0,0), Y, N, N, N },
    223    { GL(EXT_packed_pixels),              VER(1,2), Y, N, N, N },
    224    { GL(EXT_paletted_texture),           VER(0,0), Y, N, N, N },
    225    { GL(EXT_pixel_buffer_object),        VER(0,0), N, N, N, N },
    226    { GL(EXT_point_parameters),           VER(1,4), Y, N, N, N },
    227    { GL(EXT_polygon_offset),             VER(1,1), Y, N, N, N },
    228    { GL(EXT_rescale_normal),             VER(1,2), Y, N, N, N },
    229    { GL(EXT_secondary_color),            VER(1,4), Y, N, N, N },
    230    { GL(EXT_separate_specular_color),    VER(1,2), Y, N, N, N },
    231    { GL(EXT_shadow_funcs),               VER(1,5), Y, N, N, N },
    232    { GL(EXT_shared_texture_palette),     VER(0,0), Y, N, N, N },
    233    { GL(EXT_stencil_two_side),           VER(0,0), Y, N, N, N },
    234    { GL(EXT_stencil_wrap),               VER(1,4), Y, N, N, N },
    235    { GL(EXT_subtexture),                 VER(1,1), Y, N, N, N },
    236    { GL(EXT_texture),                    VER(1,1), Y, N, N, N },
    237    { GL(EXT_texture3D),                  VER(1,2), Y, N, N, N },
    238    { GL(EXT_texture_compression_dxt1),   VER(0,0), Y, N, N, N },
    239    { GL(EXT_texture_compression_s3tc),   VER(0,0), Y, N, N, N },
    240    { GL(EXT_texture_edge_clamp),         VER(1,2), Y, N, N, N },
    241    { GL(EXT_texture_env_add),            VER(1,3), Y, N, N, N },
    242    { GL(EXT_texture_env_combine),        VER(1,3), Y, N, N, N },
    243    { GL(EXT_texture_env_dot3),           VER(0,0), Y, N, N, N },
    244    { GL(EXT_texture_filter_anisotropic), VER(0,0), Y, N, N, N },
    245    { GL(EXT_texture_integer),            VER(0,0), Y, N, N, N },
    246    { GL(EXT_texture_lod),                VER(1,2), Y, N, N, N },
    247    { GL(EXT_texture_lod_bias),           VER(1,4), Y, N, N, N },
    248    { GL(EXT_texture_mirror_clamp),       VER(0,0), Y, N, N, N },
    249    { GL(EXT_texture_object),             VER(1,1), Y, N, N, N },
    250    { GL(EXT_texture_rectangle),          VER(0,0), Y, N, N, N },
    251    { GL(EXT_vertex_array),               VER(0,0), Y, N, N, N },
    252    { GL(3DFX_texture_compression_FXT1),  VER(0,0), Y, N, N, N },
    253    { GL(APPLE_packed_pixels),            VER(1,2), Y, N, N, N },
    254    { GL(APPLE_ycbcr_422),                VER(0,0), Y, N, N, N },
    255    { GL(ATI_draw_buffers),               VER(0,0), Y, N, N, N },
    256    { GL(ATI_text_fragment_shader),       VER(0,0), Y, N, N, N },
    257    { GL(ATI_texture_env_combine3),       VER(0,0), Y, N, N, N },
    258    { GL(ATI_texture_float),              VER(0,0), Y, N, N, N },
    259    { GL(ATI_texture_mirror_once),        VER(0,0), Y, N, N, N },
    260    { GL(ATIX_texture_env_combine3),      VER(0,0), Y, N, N, N },
    261    { GL(HP_convolution_border_modes),    VER(0,0), Y, N, N, N },
    262    { GL(HP_occlusion_test),              VER(0,0), Y, N, N, N },
    263    { GL(IBM_cull_vertex),                VER(0,0), Y, N, N, N },
    264    { GL(IBM_pixel_filter_hint),          VER(0,0), Y, N, N, N },
    265    { GL(IBM_rasterpos_clip),             VER(0,0), Y, N, N, N },
    266    { GL(IBM_texture_clamp_nodraw),       VER(0,0), Y, N, N, N },
    267    { GL(IBM_texture_mirrored_repeat),    VER(0,0), Y, N, N, N },
    268    { GL(INGR_blend_func_separate),       VER(0,0), Y, N, N, N },
    269    { GL(INGR_interlace_read),            VER(0,0), Y, N, N, N },
    270    { GL(MESA_pack_invert),               VER(0,0), Y, N, N, N },
    271    { GL(MESA_ycbcr_texture),             VER(0,0), Y, N, N, N },
    272    { GL(NV_blend_square),                VER(1,4), Y, N, N, N },
    273    { GL(NV_copy_depth_to_color),         VER(0,0), Y, N, N, N },
    274    { GL(NV_depth_clamp),                 VER(0,0), Y, N, N, N },
    275    { GL(NV_fog_distance),                VER(0,0), Y, N, N, N },
    276    { GL(NV_fragment_program),            VER(0,0), Y, N, N, N },
    277    { GL(NV_fragment_program_option),     VER(0,0), Y, N, N, N },
    278    { GL(NV_fragment_program2),           VER(0,0), Y, N, N, N },
    279    { GL(NV_light_max_exponent),          VER(0,0), Y, N, N, N },
    280    { GL(NV_multisample_filter_hint),     VER(0,0), Y, N, N, N },
    281    { GL(NV_packed_depth_stencil),        VER(0,0), Y, N, N, N },
    282    { GL(NV_point_sprite),                VER(0,0), Y, N, N, N },
    283    { GL(NV_texgen_reflection),           VER(0,0), Y, N, N, N },
    284    { GL(NV_texture_compression_vtc),     VER(0,0), Y, N, N, N },
    285    { GL(NV_texture_env_combine4),        VER(0,0), Y, N, N, N },
    286    { GL(NV_texture_rectangle),           VER(0,0), Y, N, N, N },
    287    { GL(NV_vertex_program),              VER(0,0), Y, N, N, N },
    288    { GL(NV_vertex_program1_1),           VER(0,0), Y, N, N, N },
    289    { GL(NV_vertex_program2),             VER(0,0), Y, N, N, N },
    290    { GL(NV_vertex_program2_option),      VER(0,0), Y, N, N, N },
    291    { GL(NV_vertex_program3),             VER(0,0), Y, N, N, N },
    292    { GL(OES_read_format),                VER(0,0), Y, N, N, N },
    293    { GL(OES_compressed_paletted_texture),VER(0,0), Y, N, N, N },
    294    { GL(SGI_color_matrix),               VER(0,0), Y, N, N, N },
    295    { GL(SGI_color_table),                VER(0,0), Y, N, N, N },
    296    { GL(SGI_texture_color_table),        VER(0,0), Y, N, N, N },
    297    { GL(SGIS_generate_mipmap),           VER(1,4), Y, N, N, N },
    298    { GL(SGIS_multisample),               VER(0,0), Y, N, N, N },
    299    { GL(SGIS_texture_border_clamp),      VER(1,3), Y, N, N, N },
    300    { GL(SGIS_texture_edge_clamp),        VER(1,2), Y, N, N, N },
    301    { GL(SGIS_texture_lod),               VER(1,2), Y, N, N, N },
    302    { GL(SGIX_blend_alpha_minmax),        VER(0,0), Y, N, N, N },
    303    { GL(SGIX_clipmap),                   VER(0,0), Y, N, N, N },
    304    { GL(SGIX_depth_texture),             VER(0,0), Y, N, N, N },
    305    { GL(SGIX_fog_offset),                VER(0,0), Y, N, N, N },
    306    { GL(SGIX_shadow),                    VER(0,0), Y, N, N, N },
    307    { GL(SGIX_shadow_ambient),            VER(0,0), Y, N, N, N },
    308    { GL(SGIX_texture_coordinate_clamp),  VER(0,0), Y, N, N, N },
    309    { GL(SGIX_texture_lod_bias),          VER(0,0), Y, N, N, N },
    310    { GL(SGIX_texture_range),             VER(0,0), Y, N, N, N },
    311    { GL(SGIX_texture_scale_bias),        VER(0,0), Y, N, N, N },
    312    { GL(SGIX_vertex_preclip),            VER(0,0), Y, N, N, N },
    313    { GL(SGIX_vertex_preclip_hint),       VER(0,0), Y, N, N, N },
    314    { GL(SGIX_ycrcb),                     VER(0,0), Y, N, N, N },
    315    { GL(SUN_convolution_border_modes),   VER(0,0), Y, N, N, N },
    316    { GL(SUN_multi_draw_arrays),          VER(0,0), Y, N, Y, N },
    317    { GL(SUN_slice_accum),                VER(0,0), Y, N, N, N },
    318    { NULL }
    319 };
    320 /* *INDENT-ON* */
    321 
    322 
    323 /* global bit-fields of available extensions and their characteristics */
    324 static unsigned char client_glx_support[8];
    325 static unsigned char client_glx_only[8];
    326 static unsigned char direct_glx_only[8];
    327 static unsigned char client_gl_support[__GL_EXT_BYTES];
    328 static unsigned char client_gl_only[__GL_EXT_BYTES];
    329 
    330 /**
    331  * Bits representing the set of extensions that are enabled by default in all
    332  * direct rendering drivers.
    333  */
    334 static unsigned char direct_glx_support[8];
    335 
    336 /**
    337  * Highest core GL version that can be supported for indirect rendering.
    338  */
    339 static const unsigned gl_major = 1;
    340 static const unsigned gl_minor = 4;
    341 
    342 /* client extensions string */
    343 static const char *__glXGLXClientExtensions = NULL;
    344 
    345 static void __glXExtensionsCtr(void);
    346 static void __glXExtensionsCtrScreen(struct glx_screen * psc);
    347 static void __glXProcessServerString(const struct extension_info *ext,
    348                                      const char *server_string,
    349                                      unsigned char *server_support);
    350 
    351 /**
    352  * Set the state of a GLX extension.
    353  *
    354  * \param name      Name of the extension.
    355  * \param name_len  Length, in characters, of the extension name.
    356  * \param state     New state (either enabled or disabled) of the extension.
    357  * \param supported Table in which the state of the extension is to be set.
    358  */
    359 static void
    360 set_glx_extension(const struct extension_info *ext,
    361                   const char *name, unsigned name_len, GLboolean state,
    362                   unsigned char *supported)
    363 {
    364    unsigned i;
    365 
    366 
    367    for (i = 0; ext[i].name != NULL; i++) {
    368       if ((name_len == ext[i].name_len)
    369           && (strncmp(ext[i].name, name, name_len) == 0)) {
    370          if (state) {
    371             SET_BIT(supported, ext[i].bit);
    372          }
    373          else {
    374             CLR_BIT(supported, ext[i].bit);
    375          }
    376 
    377          return;
    378       }
    379    }
    380 }
    381 
    382 
    383 #define NUL '\0'
    384 #define SEPARATOR ' '
    385 
    386 /**
    387  * Convert the server's extension string to a bit-field.
    388  *
    389  * \param server_string   GLX extension string from the server.
    390  * \param server_support  Bit-field of supported extensions.
    391  *
    392  * \note
    393  * This function is used to process both GLX and GL extension strings.  The
    394  * bit-fields used to track each of these have different sizes.  Therefore,
    395  * the data pointed by \c server_support must be preinitialized to zero.
    396  */
    397 static void
    398 __glXProcessServerString(const struct extension_info *ext,
    399                          const char *server_string,
    400                          unsigned char *server_support)
    401 {
    402    unsigned base;
    403    unsigned len;
    404 
    405    for (base = 0; server_string[base] != NUL; /* empty */ ) {
    406       /* Determine the length of the next extension name.
    407        */
    408       for (len = 0; (server_string[base + len] != SEPARATOR)
    409            && (server_string[base + len] != NUL); len++) {
    410          /* empty */
    411       }
    412 
    413       /* Set the bit for the extension in the server_support table.
    414        */
    415       set_glx_extension(ext, &server_string[base], len, GL_TRUE,
    416                         server_support);
    417 
    418 
    419       /* Advance to the next extension string.  This means that we skip
    420        * over the previous string and any trialing white-space.
    421        */
    422       for (base += len; (server_string[base] == SEPARATOR)
    423            && (server_string[base] != NUL); base++) {
    424          /* empty */
    425       }
    426    }
    427 }
    428 
    429 void
    430 __glXEnableDirectExtension(struct glx_screen * psc, const char *name)
    431 {
    432    __glXExtensionsCtr();
    433    __glXExtensionsCtrScreen(psc);
    434 
    435    set_glx_extension(known_glx_extensions,
    436                      name, strlen(name), GL_TRUE, psc->direct_support);
    437 }
    438 
    439 /**
    440  * Initialize global extension support tables.
    441  */
    442 
    443 static void
    444 __glXExtensionsCtr(void)
    445 {
    446    unsigned i;
    447    static GLboolean ext_list_first_time = GL_TRUE;
    448 
    449 
    450    if (ext_list_first_time) {
    451       ext_list_first_time = GL_FALSE;
    452 
    453       (void) memset(client_glx_support, 0, sizeof(client_glx_support));
    454       (void) memset(direct_glx_support, 0, sizeof(direct_glx_support));
    455       (void) memset(client_glx_only, 0, sizeof(client_glx_only));
    456       (void) memset(direct_glx_only, 0, sizeof(direct_glx_only));
    457 
    458       (void) memset(client_gl_support, 0, sizeof(client_gl_support));
    459       (void) memset(client_gl_only, 0, sizeof(client_gl_only));
    460 
    461       for (i = 0; known_glx_extensions[i].name != NULL; i++) {
    462          const unsigned bit = known_glx_extensions[i].bit;
    463 
    464          if (known_glx_extensions[i].client_support) {
    465             SET_BIT(client_glx_support, bit);
    466          }
    467 
    468          if (known_glx_extensions[i].direct_support) {
    469             SET_BIT(direct_glx_support, bit);
    470          }
    471 
    472          if (known_glx_extensions[i].client_only) {
    473             SET_BIT(client_glx_only, bit);
    474          }
    475 
    476          if (known_glx_extensions[i].direct_only) {
    477             SET_BIT(direct_glx_only, bit);
    478          }
    479       }
    480 
    481       for (i = 0; known_gl_extensions[i].name != NULL; i++) {
    482          const unsigned bit = known_gl_extensions[i].bit;
    483 
    484          if (known_gl_extensions[i].client_support) {
    485             SET_BIT(client_gl_support, bit);
    486          }
    487 
    488          if (known_gl_extensions[i].client_only) {
    489             SET_BIT(client_gl_only, bit);
    490          }
    491       }
    492 
    493 #if 0
    494       fprintf(stderr, "[%s:%u] Maximum client library version: %u.%u\n",
    495               __func__, __LINE__, gl_major, gl_minor);
    496 #endif
    497    }
    498 }
    499 
    500 
    501 /**
    502  * Make sure that per-screen direct-support table is initialized.
    503  *
    504  * \param psc  Pointer to GLX per-screen record.
    505  */
    506 
    507 static void
    508 __glXExtensionsCtrScreen(struct glx_screen * psc)
    509 {
    510    if (psc->ext_list_first_time) {
    511       psc->ext_list_first_time = GL_FALSE;
    512       (void) memcpy(psc->direct_support, direct_glx_support,
    513                     sizeof(direct_glx_support));
    514    }
    515 }
    516 
    517 
    518 /**
    519  * Check if a certain extension is enabled on a given screen.
    520  *
    521  * \param psc  Pointer to GLX per-screen record.
    522  * \param bit  Bit index in the direct-support table.
    523  * \returns If the extension bit is enabled for the screen, \c GL_TRUE is
    524  *          returned.  If the extension bit is not enabled or if \c psc is
    525  *          \c NULL, then \c GL_FALSE is returned.
    526  */
    527 GLboolean
    528 __glXExtensionBitIsEnabled(struct glx_screen * psc, unsigned bit)
    529 {
    530    GLboolean enabled = GL_FALSE;
    531 
    532    if (psc != NULL) {
    533       __glXExtensionsCtr();
    534       __glXExtensionsCtrScreen(psc);
    535       enabled = EXT_ENABLED(bit, psc->direct_support);
    536    }
    537 
    538    return enabled;
    539 }
    540 
    541 
    542 /**
    543  * Check if a certain extension is enabled in a given context.
    544  *
    545  */
    546 GLboolean
    547 __glExtensionBitIsEnabled(struct glx_context *gc, unsigned bit)
    548 {
    549    GLboolean enabled = GL_FALSE;
    550 
    551    if (gc != NULL) {
    552       enabled = EXT_ENABLED(bit, gc->gl_extension_bits);
    553    }
    554 
    555    return enabled;
    556 }
    557 
    558 
    559 
    560 /**
    561  * Convert a bit-field to a string of supported extensions.
    562  */
    563 static char *
    564 __glXGetStringFromTable(const struct extension_info *ext,
    565                         const unsigned char *supported)
    566 {
    567    unsigned i;
    568    unsigned ext_str_len;
    569    char *ext_str;
    570    char *point;
    571 
    572 
    573    ext_str_len = 0;
    574    for (i = 0; ext[i].name != NULL; i++) {
    575       if (EXT_ENABLED(ext[i].bit, supported)) {
    576          ext_str_len += ext[i].name_len + 1;
    577       }
    578    }
    579 
    580    ext_str = malloc(ext_str_len + 1);
    581    if (ext_str != NULL) {
    582       point = ext_str;
    583 
    584       for (i = 0; ext[i].name != NULL; i++) {
    585          if (EXT_ENABLED(ext[i].bit, supported)) {
    586             (void) memcpy(point, ext[i].name, ext[i].name_len);
    587             point += ext[i].name_len;
    588 
    589             *point = ' ';
    590             point++;
    591          }
    592       }
    593 
    594       *point = '\0';
    595    }
    596 
    597    return ext_str;
    598 }
    599 
    600 
    601 /**
    602  * Get the string of client library supported extensions.
    603  */
    604 const char *
    605 __glXGetClientExtensions(void)
    606 {
    607    if (__glXGLXClientExtensions == NULL) {
    608       __glXExtensionsCtr();
    609       __glXGLXClientExtensions = __glXGetStringFromTable(known_glx_extensions,
    610                                                          client_glx_support);
    611    }
    612 
    613    return __glXGLXClientExtensions;
    614 }
    615 
    616 
    617 /**
    618  * Calculate the list of application usable extensions.  The resulting
    619  * string is stored in \c psc->effectiveGLXexts.
    620  *
    621  * \param psc                        Pointer to GLX per-screen record.
    622  * \param display_is_direct_capable  True if the display is capable of
    623  *                                   direct rendering.
    624  * \param minor_version              GLX minor version from the server.
    625  */
    626 
    627 void
    628 __glXCalculateUsableExtensions(struct glx_screen * psc,
    629                                GLboolean display_is_direct_capable,
    630                                int minor_version)
    631 {
    632    unsigned char server_support[8];
    633    unsigned char usable[8];
    634    unsigned i;
    635 
    636    __glXExtensionsCtr();
    637    __glXExtensionsCtrScreen(psc);
    638 
    639    (void) memset(server_support, 0, sizeof(server_support));
    640    __glXProcessServerString(known_glx_extensions,
    641                             psc->serverGLXexts, server_support);
    642 
    643 
    644    /* This is a hack.  Some servers support GLX 1.3 but don't export
    645     * all of the extensions implied by GLX 1.3.  If the server claims
    646     * support for GLX 1.3, enable support for the extensions that can be
    647     * "emulated" as well.
    648     */
    649 #ifndef GLX_USE_APPLEGL
    650    if (minor_version >= 3) {
    651       SET_BIT(server_support, EXT_visual_info_bit);
    652       SET_BIT(server_support, EXT_visual_rating_bit);
    653       SET_BIT(server_support, SGI_make_current_read_bit);
    654       SET_BIT(server_support, SGIX_fbconfig_bit);
    655       SET_BIT(server_support, SGIX_pbuffer_bit);
    656 
    657       /* This one is a little iffy.  GLX 1.3 doesn't incorporate all of this
    658        * extension.  However, the only part that is not strictly client-side
    659        * is shared.  That's the glXQueryContext / glXQueryContextInfoEXT
    660        * function.
    661        */
    662 
    663       SET_BIT(server_support, EXT_import_context_bit);
    664    }
    665 #endif
    666 
    667    /* An extension is supported if the client-side (i.e., libGL) supports
    668     * it and the "server" supports it.  In this case that means that either
    669     * the true server supports it or it is only for direct-rendering and
    670     * the direct rendering driver supports it.
    671     *
    672     * If the display is not capable of direct rendering, then the extension
    673     * is enabled if and only if the client-side library and the server
    674     * support it.
    675     */
    676 
    677    if (display_is_direct_capable) {
    678       for (i = 0; i < 8; i++) {
    679          usable[i] = (client_glx_support[i] & client_glx_only[i])
    680             | (client_glx_support[i] & psc->direct_support[i] &
    681                server_support[i])
    682             | (client_glx_support[i] & psc->direct_support[i] &
    683                direct_glx_only[i]);
    684       }
    685    }
    686    else {
    687       for (i = 0; i < 8; i++) {
    688          usable[i] = (client_glx_support[i] & client_glx_only[i])
    689             | (client_glx_support[i] & server_support[i]);
    690       }
    691    }
    692 
    693    psc->effectiveGLXexts = __glXGetStringFromTable(known_glx_extensions,
    694                                                    usable);
    695 }
    696 
    697 
    698 /**
    699  * Calculate the list of application usable extensions.  The resulting
    700  * string is stored in \c gc->extensions.
    701  *
    702  * \param gc             Pointer to GLX context.
    703  * \param server_string  Extension string from the server.
    704  * \param major_version  GL major version from the server.
    705  * \param minor_version  GL minor version from the server.
    706  */
    707 
    708 void
    709 __glXCalculateUsableGLExtensions(struct glx_context * gc,
    710                                  const char *server_string,
    711                                  int major_version, int minor_version)
    712 {
    713    unsigned char server_support[__GL_EXT_BYTES];
    714    unsigned char usable[__GL_EXT_BYTES];
    715    unsigned i;
    716 
    717 
    718    __glXExtensionsCtr();
    719 
    720    (void) memset(server_support, 0, sizeof(server_support));
    721    __glXProcessServerString(known_gl_extensions, server_string,
    722                             server_support);
    723 
    724 
    725    /* Handle lazy servers that don't export all the extensions strings that
    726     * are part of the GL core version that they support.
    727     */
    728 
    729    for (i = 0; i < __GL_EXT_BYTES; i++) {
    730       if ((known_gl_extensions[i].version_major != 0)
    731           && ((major_version > known_gl_extensions[i].version_major)
    732               || ((major_version == known_gl_extensions[i].version_major)
    733                   && (minor_version >=
    734                       known_gl_extensions[i].version_minor)))) {
    735          SET_BIT(server_support, known_gl_extensions[i].bit);
    736       }
    737    }
    738 
    739 
    740    /* An extension is supported if the client-side (i.e., libGL) supports
    741     * it and the server supports it or the client-side library supports it
    742     * and it only needs client-side support.
    743     */
    744 
    745    for (i = 0; i < __GL_EXT_BYTES; i++) {
    746       usable[i] = (client_gl_support[i] & client_gl_only[i])
    747          | (client_gl_support[i] & server_support[i]);
    748    }
    749 
    750    gc->extensions = (unsigned char *)
    751       __glXGetStringFromTable(known_gl_extensions, usable);
    752    (void) memcpy(gc->gl_extension_bits, usable, sizeof(usable));
    753 }
    754 
    755 
    756 /**
    757  * Calculates the maximum core GL version that can be supported for indirect
    758  * rendering.
    759  */
    760 void
    761 __glXGetGLVersion(int *major_version, int *minor_version)
    762 {
    763    __glXExtensionsCtr();
    764    *major_version = gl_major;
    765    *minor_version = gl_minor;
    766 }
    767 
    768 
    769 /**
    770  * Get a string representing the set of extensions supported by the client
    771  * library.  This is currently only used to send the list of extensions
    772  * supported by the client to the server.
    773  */
    774 char *
    775 __glXGetClientGLExtensionString(void)
    776 {
    777    __glXExtensionsCtr();
    778    return __glXGetStringFromTable(known_gl_extensions, client_gl_support);
    779 }
    780