src/mesa/main/extensions.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 1999-2008  Brian Paul   All Rights Reserved.
   5  * Copyright (C) 2009  VMware, Inc.  All Rights Reserved.
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a
   8  * copy of this software and associated documentation files (the "Software"),
   9  * to deal in the Software without restriction, including without limitation
  10  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11  * and/or sell copies of the Software, and to permit persons to whom the
  12  * Software is furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included
  15  * in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  21  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  22  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  23  * OTHER DEALINGS IN THE SOFTWARE.
  24  */
  25
  26
  27 /**
  28  * \file
  29  * \brief Extension handling
  30  */
  31
  32
  33 #include "glheader.h"
  34 #include "imports.h"
  35 #include "context.h"
  36 #include "extensions.h"
  37 #include "macros.h"
  38 #include "mtypes.h"
  39
  40 struct gl_extensions _mesa_extension_override_enables;
  41 struct gl_extensions _mesa_extension_override_disables;
  42 static char *extra_extensions = NULL;
  43 static char *cant_disable_extensions = NULL;
  44
  45 enum {
  46    DISABLE = 0,
  47    GLL = 1 << API_OPENGL_COMPAT,       /* GL Legacy / Compatibility */
  48    GLC = 1 << API_OPENGL_CORE,  /* GL Core */
  49    GL  = (1 << API_OPENGL_COMPAT) | (1 << API_OPENGL_CORE),
  50    ES1 = 1 << API_OPENGLES,
  51    ES2 = 1 << API_OPENGLES2,
  52    ES3 = 1 << (API_OPENGL_LAST + 1),
  53 };
  54
  55 /**
  56  * \brief An element of the \c extension_table.
  57  */
  58 struct extension {
  59    /** Name of extension, such as "GL_ARB_depth_clamp". */
  60    const char *name;
  61
  62    /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
  63    size_t offset;
  64
  65    /** Set of API's in which the extension exists, as a bitset. */
  66    uint8_t api_set;
  67
  68    /** Year the extension was proposed or approved.  Used to sort the
  69     * extension string chronologically. */
  70    uint16_t year;
  71 };
  72
  73
  74 /**
  75  * Given a member \c x of struct gl_extensions, return offset of
  76  * \c x in bytes.
  77  */
  78 #define o(x) offsetof(struct gl_extensions, x)
  79
  80
  81 /**
  82  * \brief Table of supported OpenGL extensions for all API's.
  83  */
  84 static const struct extension extension_table[] = {
  85    /* ARB Extensions */
  86    { "GL_ARB_ES2_compatibility",                   o(ARB_ES2_compatibility),                   GL,             2009 },
  87    { "GL_ARB_ES3_compatibility",                   o(ARB_ES3_compatibility),                   GL,             2012 },
  88    { "GL_ARB_arrays_of_arrays",                    o(ARB_arrays_of_arrays),                    GL,             2012 },
  89    { "GL_ARB_base_instance",                       o(ARB_base_instance),                       GL,             2011 },
  90    { "GL_ARB_blend_func_extended",                 o(ARB_blend_func_extended),                 GL,             2009 },
  91    { "GL_ARB_buffer_storage",                      o(ARB_buffer_storage),                      GL,             2013 },
  92    { "GL_ARB_clear_buffer_object",                 o(dummy_true),                              GL,             2012 },
  93    { "GL_ARB_clear_texture",                       o(ARB_clear_texture),                       GL,             2013 },
  94    { "GL_ARB_clip_control",                        o(ARB_clip_control),                        GL,             2014 },
  95    { "GL_ARB_color_buffer_float",                  o(ARB_color_buffer_float),                  GL,             2004 },
  96    { "GL_ARB_compressed_texture_pixel_storage",    o(dummy_true),                              GL,             2011 },
  97    { "GL_ARB_compute_shader",                      o(ARB_compute_shader),                      GL,             2012 },
  98    { "GL_ARB_conditional_render_inverted",         o(ARB_conditional_render_inverted),         GL,             2014 },
  99    { "GL_ARB_copy_buffer",                         o(dummy_true),                              GL,             2008 },
 100    { "GL_ARB_copy_image",                          o(ARB_copy_image),                          GL,             2012 },
 101    { "GL_ARB_conservative_depth",                  o(ARB_conservative_depth),                  GL,             2011 },
 102    { "GL_ARB_debug_output",                        o(dummy_true),                              GL,             2009 },
 103    { "GL_ARB_depth_buffer_float",                  o(ARB_depth_buffer_float),                  GL,             2008 },
 104    { "GL_ARB_depth_clamp",                         o(ARB_depth_clamp),                         GL,             2003 },
 105    { "GL_ARB_depth_texture",                       o(ARB_depth_texture),                       GLL,            2001 },
 106    { "GL_ARB_derivative_control",                  o(ARB_derivative_control),                  GL,             2014 },
 107    { "GL_ARB_direct_state_access",                 o(dummy_false),                             GL,             2014 },
 108    { "GL_ARB_draw_buffers",                        o(dummy_true),                              GL,             2002 },
 109    { "GL_ARB_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
 110    { "GL_ARB_draw_elements_base_vertex",           o(ARB_draw_elements_base_vertex),           GL,             2009 },
 111    { "GL_ARB_draw_indirect",                       o(ARB_draw_indirect),                       GLC,            2010 },
 112    { "GL_ARB_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2008 },
 113    { "GL_ARB_explicit_attrib_location",            o(ARB_explicit_attrib_location),            GL,             2009 },
 114    { "GL_ARB_explicit_uniform_location",           o(ARB_explicit_uniform_location),           GL,             2012 },
 115    { "GL_ARB_fragment_coord_conventions",          o(ARB_fragment_coord_conventions),          GL,             2009 },
 116    { "GL_ARB_fragment_layer_viewport",             o(ARB_fragment_layer_viewport),             GLC,            2012 },
 117    { "GL_ARB_fragment_program",                    o(ARB_fragment_program),                    GLL,            2002 },
 118    { "GL_ARB_fragment_program_shadow",             o(ARB_fragment_program_shadow),             GLL,            2003 },
 119    { "GL_ARB_fragment_shader",                     o(ARB_fragment_shader),                     GL,             2002 },
 120    { "GL_ARB_framebuffer_object",                  o(ARB_framebuffer_object),                  GL,             2005 },
 121    { "GL_ARB_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
 122    { "GL_ARB_get_program_binary",                  o(dummy_true),                              GL,             2010 },
 123    { "GL_ARB_gpu_shader5",                         o(ARB_gpu_shader5),                         GLC,            2010 },
 124    { "GL_ARB_half_float_pixel",                    o(dummy_true),                              GL,             2003 },
 125    { "GL_ARB_half_float_vertex",                   o(ARB_half_float_vertex),                   GL,             2008 },
 126    { "GL_ARB_instanced_arrays",                    o(ARB_instanced_arrays),                    GL,             2008 },
 127    { "GL_ARB_internalformat_query",                o(ARB_internalformat_query),                GL,             2011 },
 128    { "GL_ARB_invalidate_subdata",                  o(dummy_true),                              GL,             2012 },
 129    { "GL_ARB_map_buffer_alignment",                o(dummy_true),                              GL,             2011 },
 130    { "GL_ARB_map_buffer_range",                    o(ARB_map_buffer_range),                    GL,             2008 },
 131    { "GL_ARB_multi_bind",                          o(dummy_true),                              GL,             2013 },
 132    { "GL_ARB_multi_draw_indirect",                 o(ARB_draw_indirect),                       GLC,            2012 },
 133    { "GL_ARB_multisample",                         o(dummy_true),                              GLL,            1994 },
 134    { "GL_ARB_multitexture",                        o(dummy_true),                              GLL,            1998 },
 135    { "GL_ARB_occlusion_query2",                    o(ARB_occlusion_query2),                    GL,             2003 },
 136    { "GL_ARB_occlusion_query",                     o(ARB_occlusion_query),                     GLL,            2001 },
 137    { "GL_ARB_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
 138    { "GL_ARB_point_parameters",                    o(EXT_point_parameters),                    GLL,            1997 },
 139    { "GL_ARB_point_sprite",                        o(ARB_point_sprite),                        GL,             2003 },
 140    { "GL_ARB_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
 141    { "GL_ARB_robustness",                          o(dummy_true),                              GL,             2010 },
 142    { "GL_ARB_sample_shading",                      o(ARB_sample_shading),                      GL,             2009 },
 143    { "GL_ARB_sampler_objects",                     o(dummy_true),                              GL,             2009 },
 144    { "GL_ARB_seamless_cube_map",                   o(ARB_seamless_cube_map),                   GL,             2009 },
 145    { "GL_ARB_seamless_cubemap_per_texture",        o(AMD_seamless_cubemap_per_texture),        GL,             2013 },
 146    { "GL_ARB_separate_shader_objects",             o(dummy_true),                              GL,             2010 },
 147    { "GL_ARB_shader_atomic_counters",              o(ARB_shader_atomic_counters),              GL,             2011 },
 148    { "GL_ARB_shader_bit_encoding",                 o(ARB_shader_bit_encoding),                 GL,             2010 },
 149    { "GL_ARB_shader_image_load_store",             o(ARB_shader_image_load_store),             GL,             2011 },
 150    { "GL_ARB_shader_objects",                      o(dummy_true),                              GL,             2002 },
 151    { "GL_ARB_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
 152    { "GL_ARB_shader_texture_lod",                  o(ARB_shader_texture_lod),                  GL,             2009 },
 153    { "GL_ARB_shading_language_100",                o(dummy_true),                              GLL,            2003 },
 154    { "GL_ARB_shading_language_packing",            o(ARB_shading_language_packing),            GL,             2011 },
 155    { "GL_ARB_shading_language_420pack",            o(ARB_shading_language_420pack),            GL,             2011 },
 156    { "GL_ARB_shadow",                              o(ARB_shadow),                              GLL,            2001 },
 157    { "GL_ARB_stencil_texturing",                   o(ARB_stencil_texturing),                   GL,             2012 },
 158    { "GL_ARB_sync",                                o(ARB_sync),                                GL,             2003 },
 159    { "GL_ARB_texture_barrier",                     o(NV_texture_barrier),                      GL,             2014 },
 160    { "GL_ARB_texture_border_clamp",                o(ARB_texture_border_clamp),                GLL,            2000 },
 161    { "GL_ARB_texture_buffer_object",               o(ARB_texture_buffer_object),               GLC,            2008 },
 162    { "GL_ARB_texture_buffer_object_rgb32",         o(ARB_texture_buffer_object_rgb32),         GLC,            2009 },
 163    { "GL_ARB_texture_buffer_range",                o(ARB_texture_buffer_range),                GLC,            2012 },
 164    { "GL_ARB_texture_compression",                 o(dummy_true),                              GLL,            2000 },
 165    { "GL_ARB_texture_compression_bptc",            o(ARB_texture_compression_bptc),            GL,             2010 },
 166    { "GL_ARB_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
 167    { "GL_ARB_texture_cube_map",                    o(ARB_texture_cube_map),                    GLL,            1999 },
 168    { "GL_ARB_texture_cube_map_array",              o(ARB_texture_cube_map_array),              GL,             2009 },
 169    { "GL_ARB_texture_env_add",                     o(dummy_true),                              GLL,            1999 },
 170    { "GL_ARB_texture_env_combine",                 o(ARB_texture_env_combine),                 GLL,            2001 },
 171    { "GL_ARB_texture_env_crossbar",                o(ARB_texture_env_crossbar),                GLL,            2001 },
 172    { "GL_ARB_texture_env_dot3",                    o(ARB_texture_env_dot3),                    GLL,            2001 },
 173    { "GL_ARB_texture_float",                       o(ARB_texture_float),                       GL,             2004 },
 174    { "GL_ARB_texture_gather",                      o(ARB_texture_gather),                      GL,             2009 },
 175    { "GL_ARB_texture_mirrored_repeat",             o(dummy_true),                              GLL,            2001 },
 176    { "GL_ARB_texture_mirror_clamp_to_edge",        o(ARB_texture_mirror_clamp_to_edge),        GL,             2013 },
 177    { "GL_ARB_texture_multisample",                 o(ARB_texture_multisample),                 GL,             2009 },
 178    { "GL_ARB_texture_non_power_of_two",            o(ARB_texture_non_power_of_two),            GL,             2003 },
 179    { "GL_ARB_texture_query_levels",                o(ARB_texture_query_levels),                GL,             2012 },
 180    { "GL_ARB_texture_query_lod",                   o(ARB_texture_query_lod),                   GL,             2009 },
 181    { "GL_ARB_texture_rectangle",                   o(NV_texture_rectangle),                    GL,             2004 },
 182    { "GL_ARB_texture_rgb10_a2ui",                  o(ARB_texture_rgb10_a2ui),                  GL,             2009 },
 183    { "GL_ARB_texture_rg",                          o(ARB_texture_rg),                          GL,             2008 },
 184    { "GL_ARB_texture_storage",                     o(dummy_true),                              GL,             2011 },
 185    { "GL_ARB_texture_storage_multisample",         o(ARB_texture_multisample),                 GL,             2012 },
 186    { "GL_ARB_texture_view",                        o(ARB_texture_view),                        GL,             2012 },
 187    { "GL_ARB_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
 188    { "GL_ARB_timer_query",                         o(ARB_timer_query),                         GL,             2010 },
 189    { "GL_ARB_transform_feedback2",                 o(ARB_transform_feedback2),                 GL,             2010 },
 190    { "GL_ARB_transform_feedback3",                 o(ARB_transform_feedback3),                 GL,             2010 },
 191    { "GL_ARB_transform_feedback_instanced",        o(ARB_transform_feedback_instanced),        GL,             2011 },
 192    { "GL_ARB_transpose_matrix",                    o(dummy_true),                              GLL,            1999 },
 193    { "GL_ARB_uniform_buffer_object",               o(ARB_uniform_buffer_object),               GL,             2009 },
 194    { "GL_ARB_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
 195    { "GL_ARB_vertex_array_object",                 o(dummy_true),                              GL,             2006 },
 196    { "GL_ARB_vertex_attrib_binding",               o(dummy_true),                              GL,             2012 },
 197    { "GL_ARB_vertex_buffer_object",                o(dummy_true),                              GLL,            2003 },
 198    { "GL_ARB_vertex_program",                      o(ARB_vertex_program),                      GLL,            2002 },
 199    { "GL_ARB_vertex_shader",                       o(ARB_vertex_shader),                       GL,             2002 },
 200    { "GL_ARB_vertex_type_10f_11f_11f_rev",         o(ARB_vertex_type_10f_11f_11f_rev),         GL,             2013 },
 201    { "GL_ARB_vertex_type_2_10_10_10_rev",          o(ARB_vertex_type_2_10_10_10_rev),          GL,             2009 },
 202    { "GL_ARB_viewport_array",                      o(ARB_viewport_array),                      GLC,            2010 },
 203    { "GL_ARB_window_pos",                          o(dummy_true),                              GLL,            2001 },
 204    /* EXT extensions */
 205    { "GL_EXT_abgr",                                o(dummy_true),                              GL,             1995 },
 206    { "GL_EXT_bgra",                                o(dummy_true),                              GLL,            1995 },
 207    { "GL_EXT_blend_color",                         o(EXT_blend_color),                         GLL,            1995 },
 208    { "GL_EXT_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
 209    { "GL_EXT_blend_func_separate",                 o(EXT_blend_func_separate),                 GLL,            1999 },
 210    { "GL_EXT_discard_framebuffer",                 o(dummy_true),                                    ES1 | ES2, 2009 },
 211    { "GL_EXT_blend_minmax",                        o(EXT_blend_minmax),                        GLL | ES1 | ES2, 1995 },
 212    { "GL_EXT_blend_subtract",                      o(dummy_true),                              GLL,            1995 },
 213    { "GL_EXT_compiled_vertex_array",               o(dummy_true),                              GLL,            1996 },
 214    { "GL_EXT_copy_texture",                        o(dummy_true),                              GLL,            1995 },
 215    { "GL_EXT_depth_bounds_test",                   o(EXT_depth_bounds_test),                   GL,             2002 },
 216    { "GL_EXT_draw_buffers2",                       o(EXT_draw_buffers2),                       GL,             2006 },
 217    { "GL_EXT_draw_instanced",                      o(ARB_draw_instanced),                      GL,             2006 },
 218    { "GL_EXT_draw_range_elements",                 o(dummy_true),                              GLL,            1997 },
 219    { "GL_EXT_fog_coord",                           o(dummy_true),                              GLL,            1999 },
 220    { "GL_EXT_framebuffer_blit",                    o(dummy_true),                              GL,             2005 },
 221    { "GL_EXT_framebuffer_multisample",             o(EXT_framebuffer_multisample),             GL,             2005 },
 222    { "GL_EXT_framebuffer_multisample_blit_scaled", o(EXT_framebuffer_multisample_blit_scaled), GL,             2011 },
 223    { "GL_EXT_framebuffer_object",                  o(dummy_true),                              GLL,            2000 },
 224    { "GL_EXT_framebuffer_sRGB",                    o(EXT_framebuffer_sRGB),                    GL,             1998 },
 225    { "GL_EXT_gpu_program_parameters",              o(EXT_gpu_program_parameters),              GLL,            2006 },
 226    { "GL_EXT_gpu_shader4",                         o(EXT_gpu_shader4),                         GL,             2006 },
 227    { "GL_EXT_map_buffer_range",                    o(ARB_map_buffer_range),                          ES1 | ES2, 2012 },
 228    { "GL_EXT_multi_draw_arrays",                   o(dummy_true),                              GLL | ES1 | ES2, 1999 },
 229    { "GL_EXT_packed_depth_stencil",                o(dummy_true),                              GL,             2005 },
 230    { "GL_EXT_packed_float",                        o(EXT_packed_float),                        GL,             2004 },
 231    { "GL_EXT_packed_pixels",                       o(dummy_true),                              GLL,            1997 },
 232    { "GL_EXT_pixel_buffer_object",                 o(EXT_pixel_buffer_object),                 GL,             2004 },
 233    { "GL_EXT_point_parameters",                    o(EXT_point_parameters),                    GLL,            1997 },
 234    { "GL_EXT_polygon_offset",                      o(dummy_true),                              GLL,            1995 },
 235    { "GL_EXT_provoking_vertex",                    o(EXT_provoking_vertex),                    GL,             2009 },
 236    { "GL_EXT_rescale_normal",                      o(dummy_true),                              GLL,            1997 },
 237    { "GL_EXT_secondary_color",                     o(dummy_true),                              GLL,            1999 },
 238    { "GL_EXT_separate_shader_objects",             o(dummy_true),                                         ES2, 2013 },
 239    { "GL_EXT_separate_specular_color",             o(dummy_true),                              GLL,            1997 },
 240    { "GL_EXT_shader_integer_mix",                  o(EXT_shader_integer_mix),                  GL       | ES3, 2013 },
 241    { "GL_EXT_shadow_funcs",                        o(ARB_shadow),                              GLL,            2002 },
 242    { "GL_EXT_stencil_two_side",                    o(EXT_stencil_two_side),                    GLL,            2001 },
 243    { "GL_EXT_stencil_wrap",                        o(dummy_true),                              GLL,            2002 },
 244    { "GL_EXT_subtexture",                          o(dummy_true),                              GLL,            1995 },
 245    { "GL_EXT_texture3D",                           o(EXT_texture3D),                           GLL,            1996 },
 246    { "GL_EXT_texture_array",                       o(EXT_texture_array),                       GL,             2006 },
 247    { "GL_EXT_texture_compression_dxt1",            o(ANGLE_texture_compression_dxt),           GL | ES1 | ES2, 2004 },
 248    { "GL_ANGLE_texture_compression_dxt3",          o(ANGLE_texture_compression_dxt),           GL | ES1 | ES2, 2011 },
 249    { "GL_ANGLE_texture_compression_dxt5",          o(ANGLE_texture_compression_dxt),           GL | ES1 | ES2, 2011 },
 250    { "GL_EXT_texture_compression_latc",            o(EXT_texture_compression_latc),            GL,             2006 },
 251    { "GL_EXT_texture_compression_rgtc",            o(ARB_texture_compression_rgtc),            GL,             2004 },
 252    { "GL_EXT_texture_compression_s3tc",            o(EXT_texture_compression_s3tc),            GL,             2000 },
 253    { "GL_EXT_texture_cube_map",                    o(ARB_texture_cube_map),                    GLL,            2001 },
 254    { "GL_EXT_texture_edge_clamp",                  o(dummy_true),                              GLL,            1997 },
 255    { "GL_EXT_texture_env_add",                     o(dummy_true),                              GLL,            1999 },
 256    { "GL_EXT_texture_env_combine",                 o(dummy_true),                              GLL,            2000 },
 257    { "GL_EXT_texture_env_dot3",                    o(EXT_texture_env_dot3),                    GLL,            2000 },
 258    { "GL_EXT_texture_filter_anisotropic",          o(EXT_texture_filter_anisotropic),          GL | ES1 | ES2, 1999 },
 259    { "GL_EXT_texture_format_BGRA8888",             o(dummy_true),                                   ES1 | ES2, 2005 },
 260    { "GL_EXT_texture_rg",                          o(ARB_texture_rg),                                     ES2, 2011 },
 261    { "GL_EXT_read_format_bgra",                    o(dummy_true),                                   ES1 | ES2, 2009 },
 262    { "GL_EXT_texture_integer",                     o(EXT_texture_integer),                     GL,             2006 },
 263    { "GL_EXT_texture_lod_bias",                    o(dummy_true),                              GLL | ES1,      1999 },
 264    { "GL_EXT_texture_mirror_clamp",                o(EXT_texture_mirror_clamp),                GL,             2004 },
 265    { "GL_EXT_texture_object",                      o(dummy_true),                              GLL,            1995 },
 266    { "GL_EXT_texture",                             o(dummy_true),                              GLL,            1996 },
 267    { "GL_EXT_texture_rectangle",                   o(NV_texture_rectangle),                    GLL,            2004 },
 268    { "GL_EXT_texture_shared_exponent",             o(EXT_texture_shared_exponent),             GL,             2004 },
 269    { "GL_EXT_texture_snorm",                       o(EXT_texture_snorm),                       GL,             2009 },
 270    { "GL_EXT_texture_sRGB",                        o(EXT_texture_sRGB),                        GL,             2004 },
 271    { "GL_EXT_texture_sRGB_decode",                 o(EXT_texture_sRGB_decode),                        GL,      2006 },
 272    { "GL_EXT_texture_swizzle",                     o(EXT_texture_swizzle),                     GL,             2008 },
 273    { "GL_EXT_texture_type_2_10_10_10_REV",         o(dummy_true),                                         ES2, 2008 },
 274    { "GL_EXT_timer_query",                         o(EXT_timer_query),                         GL,             2006 },
 275    { "GL_EXT_transform_feedback",                  o(EXT_transform_feedback),                  GL,             2011 },
 276    { "GL_EXT_unpack_subimage",                     o(dummy_true),                                         ES2, 2011 },
 277    { "GL_EXT_vertex_array_bgra",                   o(EXT_vertex_array_bgra),                   GL,             2008 },
 278    { "GL_EXT_vertex_array",                        o(dummy_true),                              GLL,            1995 },
 279    { "GL_EXT_color_buffer_float",                  o(dummy_true),                                         ES3, 2013 },
 280
 281    /* OES extensions */
 282    { "GL_OES_blend_equation_separate",             o(EXT_blend_equation_separate),                  ES1,       2009 },
 283    { "GL_OES_blend_func_separate",                 o(EXT_blend_func_separate),                      ES1,       2009 },
 284    { "GL_OES_blend_subtract",                      o(dummy_true),                                   ES1,       2009 },
 285    { "GL_OES_byte_coordinates",                    o(dummy_true),                                   ES1,       2002 },
 286    { "GL_OES_compressed_ETC1_RGB8_texture",        o(OES_compressed_ETC1_RGB8_texture),             ES1 | ES2, 2005 },
 287    { "GL_OES_compressed_paletted_texture",         o(dummy_true),                                   ES1,       2003 },
 288    { "GL_OES_depth24",                             o(dummy_true),                                   ES1 | ES2, 2005 },
 289    { "GL_OES_depth32",                             o(dummy_false),                     DISABLE,                2005 },
 290    { "GL_OES_depth_texture",                       o(ARB_depth_texture),                                  ES2, 2006 },
 291    { "GL_OES_depth_texture_cube_map",              o(OES_depth_texture_cube_map),                         ES2, 2012 },
 292    { "GL_OES_draw_texture",                        o(OES_draw_texture),                             ES1,       2004 },
 293    /*  FIXME: Mesa expects GL_OES_EGL_image to be available in OpenGL contexts. */
 294    { "GL_OES_EGL_image",                           o(OES_EGL_image),                           GL | ES1 | ES2, 2006 },
 295    { "GL_OES_EGL_image_external",                  o(OES_EGL_image_external),                       ES1 | ES2, 2010 },
 296    { "GL_OES_element_index_uint",                  o(dummy_true),                                   ES1 | ES2, 2005 },
 297    { "GL_OES_fbo_render_mipmap",                   o(dummy_true),                                   ES1 | ES2, 2005 },
 298    { "GL_OES_fixed_point",                         o(dummy_true),                                   ES1,       2002 },
 299    { "GL_OES_framebuffer_object",                  o(dummy_true),                                   ES1,       2005 },
 300    { "GL_OES_get_program_binary",                  o(dummy_true),                                         ES2, 2008 },
 301    { "GL_OES_mapbuffer",                           o(dummy_true),                                   ES1 | ES2, 2005 },
 302    { "GL_OES_packed_depth_stencil",                o(dummy_true),                                   ES1 | ES2, 2007 },
 303    { "GL_OES_point_size_array",                    o(dummy_true),                                   ES1,       2004 },
 304    { "GL_OES_point_sprite",                        o(ARB_point_sprite),                             ES1,       2004 },
 305    { "GL_OES_query_matrix",                        o(dummy_true),                                   ES1,       2003 },
 306    { "GL_OES_read_format",                         o(dummy_true),                              GL | ES1,       2003 },
 307    { "GL_OES_rgb8_rgba8",                          o(dummy_true),                                   ES1 | ES2, 2005 },
 308    { "GL_OES_single_precision",                    o(dummy_true),                                   ES1,       2003 },
 309    { "GL_OES_standard_derivatives",                o(OES_standard_derivatives),                           ES2, 2005 },
 310    { "GL_OES_stencil1",                            o(dummy_false),                     DISABLE,                2005 },
 311    { "GL_OES_stencil4",                            o(dummy_false),                     DISABLE,                2005 },
 312    { "GL_OES_stencil8",                            o(dummy_true),                                   ES1 | ES2, 2005 },
 313    { "GL_OES_stencil_wrap",                        o(dummy_true),                                   ES1,       2002 },
 314    { "GL_OES_surfaceless_context",                 o(dummy_true),                                   ES1 | ES2, 2012 },
 315    { "GL_OES_texture_3D",                          o(EXT_texture3D),                                      ES2, 2005 },
 316    { "GL_OES_texture_cube_map",                    o(ARB_texture_cube_map),                         ES1,       2007 },
 317    { "GL_OES_texture_env_crossbar",                o(ARB_texture_env_crossbar),                     ES1,       2005 },
 318    { "GL_OES_texture_mirrored_repeat",             o(dummy_true),                                   ES1,       2005 },
 319    { "GL_OES_texture_npot",                        o(ARB_texture_non_power_of_two),                 ES1 | ES2, 2005 },
 320    { "GL_OES_vertex_array_object",                 o(dummy_true),                                   ES1 | ES2, 2010 },
 321
 322    /* KHR extensions */
 323    { "GL_KHR_debug",                               o(dummy_true),                              GL,             2012 },
 324    { "GL_KHR_context_flush_control",               o(dummy_true),                              GL       | ES2, 2014 },
 325
 326    /* Vendor extensions */
 327    { "GL_3DFX_texture_compression_FXT1",           o(TDFX_texture_compression_FXT1),           GL,             1999 },
 328    { "GL_AMD_conservative_depth",                  o(ARB_conservative_depth),                  GL,             2009 },
 329    { "GL_AMD_draw_buffers_blend",                  o(ARB_draw_buffers_blend),                  GL,             2009 },
 330    { "GL_AMD_performance_monitor",                 o(AMD_performance_monitor),                 GL,             2007 },
 331    { "GL_AMD_seamless_cubemap_per_texture",        o(AMD_seamless_cubemap_per_texture),        GL,             2009 },
 332    { "GL_AMD_shader_stencil_export",               o(ARB_shader_stencil_export),               GL,             2009 },
 333    { "GL_AMD_shader_trinary_minmax",               o(dummy_true),                              GL,             2012 },
 334    { "GL_AMD_vertex_shader_layer",                 o(AMD_vertex_shader_layer),                 GLC,            2012 },
 335    { "GL_AMD_vertex_shader_viewport_index",        o(AMD_vertex_shader_viewport_index),        GLC,            2012 },
 336    { "GL_APPLE_object_purgeable",                  o(APPLE_object_purgeable),                  GL,             2006 },
 337    { "GL_APPLE_packed_pixels",                     o(dummy_true),                              GLL,            2002 },
 338    { "GL_APPLE_texture_max_level",                 o(dummy_true),                                   ES1 | ES2, 2009 },
 339    { "GL_APPLE_vertex_array_object",               o(dummy_true),                              GLL,            2002 },
 340    { "GL_ATI_blend_equation_separate",             o(EXT_blend_equation_separate),             GL,             2003 },
 341    { "GL_ATI_draw_buffers",                        o(dummy_true),                              GLL,            2002 },
 342    { "GL_ATI_fragment_shader",                     o(ATI_fragment_shader),                     GLL,            2001 },
 343    { "GL_ATI_separate_stencil",                    o(ATI_separate_stencil),                    GLL,            2006 },
 344    { "GL_ATI_texture_compression_3dc",             o(ATI_texture_compression_3dc),             GL,             2004 },
 345    { "GL_ATI_texture_env_combine3",                o(ATI_texture_env_combine3),                GLL,            2002 },
 346    { "GL_ATI_texture_float",                       o(ARB_texture_float),                       GL,             2002 },
 347    { "GL_ATI_texture_mirror_once",                 o(ATI_texture_mirror_once),                 GL,             2006 },
 348    { "GL_IBM_multimode_draw_arrays",               o(dummy_true),                              GL,             1998 },
 349    { "GL_IBM_rasterpos_clip",                      o(dummy_true),                              GLL,            1996 },
 350    { "GL_IBM_texture_mirrored_repeat",             o(dummy_true),                              GLL,            1998 },
 351    { "GL_INGR_blend_func_separate",                o(EXT_blend_func_separate),                 GLL,            1999 },
 352    { "GL_INTEL_performance_query",                 o(INTEL_performance_query),                       GL | ES2, 2013 },
 353    { "GL_MESA_pack_invert",                        o(MESA_pack_invert),                        GL,             2002 },
 354    { "GL_MESA_texture_signed_rgba",                o(EXT_texture_snorm),                       GL,             2009 },
 355    { "GL_MESA_window_pos",                         o(dummy_true),                              GLL,            2000 },
 356    { "GL_MESA_ycbcr_texture",                      o(MESA_ycbcr_texture),                      GL,             2002 },
 357    { "GL_NV_blend_square",                         o(dummy_true),                              GLL,            1999 },
 358    { "GL_NV_conditional_render",                   o(NV_conditional_render),                   GL,             2008 },
 359    { "GL_NV_depth_clamp",                          o(ARB_depth_clamp),                         GL,             2001 },
 360    { "GL_NV_draw_buffers",                         o(dummy_true),                                         ES2, 2011 },
 361    { "GL_NV_fbo_color_attachments",                o(dummy_true),                                         ES2, 2010 },
 362    { "GL_NV_fog_distance",                         o(NV_fog_distance),                         GLL,            2001 },
 363    { "GL_NV_fragment_program_option",              o(NV_fragment_program_option),              GLL,            2005 },
 364    { "GL_NV_light_max_exponent",                   o(dummy_true),                              GLL,            1999 },
 365    { "GL_NV_packed_depth_stencil",                 o(dummy_true),                              GL,             2000 },
 366    { "GL_NV_point_sprite",                         o(NV_point_sprite),                         GL,             2001 },
 367    { "GL_NV_primitive_restart",                    o(NV_primitive_restart),                    GLL,            2002 },
 368    { "GL_NV_read_buffer",                          o(dummy_true),                              ES2,            2011 },
 369    { "GL_NV_texgen_reflection",                    o(dummy_true),                              GLL,            1999 },
 370    { "GL_NV_texture_barrier",                      o(NV_texture_barrier),                      GL,             2009 },
 371    { "GL_NV_texture_env_combine4",                 o(NV_texture_env_combine4),                 GLL,            1999 },
 372    { "GL_NV_texture_rectangle",                    o(NV_texture_rectangle),                    GLL,            2000 },
 373    { "GL_NV_vdpau_interop",                        o(NV_vdpau_interop),                        GL,             2010 },
 374    { "GL_S3_s3tc",                                 o(ANGLE_texture_compression_dxt),           GL,             1999 },
 375    { "GL_SGIS_generate_mipmap",                    o(dummy_true),                              GLL,            1997 },
 376    { "GL_SGIS_texture_border_clamp",               o(ARB_texture_border_clamp),                GLL,            1997 },
 377    { "GL_SGIS_texture_edge_clamp",                 o(dummy_true),                              GLL,            1997 },
 378    { "GL_SGIS_texture_lod",                        o(dummy_true),                              GLL,            1997 },
 379    { "GL_SUN_multi_draw_arrays",                   o(dummy_true),                              GLL,            1999 },
 380
 381    { 0, 0, 0, 0 },
 382 };
 383
 384
 385 /**
 386  * Given an extension name, lookup up the corresponding member of struct
 387  * gl_extensions and return that member's offset (in bytes).  If the name is
 388  * not found in the \c extension_table, return 0.
 389  *
 390  * \param name Name of extension.
 391  * \return Offset of member in struct gl_extensions.
 392  */
 393 static size_t
 394 name_to_offset(const char* name)
 395 {
 396    const struct extension *i;
 397
 398    if (name == 0)
 399       return 0;
 400
 401    for (i = extension_table; i->name != 0; ++i) {
 402       if (strcmp(name, i->name) == 0)
 403          return i->offset;
 404    }
 405
 406    return 0;
 407 }
 408
 409 /**
 410  * Overrides extensions in \c ctx based on the values in
 411  * _mesa_extension_override_enables and _mesa_extension_override_disables.
 412  */
 413 static void
 414 override_extensions_in_context(struct gl_context *ctx)
 415 {
 416    const struct extension *i;
 417    const GLboolean *enables =
 418       (GLboolean*) &_mesa_extension_override_enables;
 419    const GLboolean *disables =
 420       (GLboolean*) &_mesa_extension_override_disables;
 421    GLboolean *ctx_ext = (GLboolean*)&ctx->Extensions;
 422
 423    for (i = extension_table; i->name != 0; ++i) {
 424       size_t offset = i->offset;
 425       assert(!enables[offset] || !disables[offset]);
 426       if (enables[offset]) {
 427          ctx_ext[offset] = 1;
 428       } else if (disables[offset]) {
 429          ctx_ext[offset] = 0;
 430       }
 431    }
 432 }
 433
 434
 435 /**
 436  * Enable all extensions suitable for a software-only renderer.
 437  * This is a convenience function used by the XMesa, OSMesa, GGI drivers, etc.
 438  */
 439 void
 440 _mesa_enable_sw_extensions(struct gl_context *ctx)
 441 {
 442    ctx->Extensions.ARB_depth_clamp = GL_TRUE;
 443    ctx->Extensions.ARB_depth_texture = GL_TRUE;
 444    ctx->Extensions.ARB_draw_elements_base_vertex = GL_TRUE;
 445    ctx->Extensions.ARB_draw_instanced = GL_TRUE;
 446    ctx->Extensions.ARB_explicit_attrib_location = GL_TRUE;
 447    ctx->Extensions.ARB_fragment_coord_conventions = GL_TRUE;
 448    ctx->Extensions.ARB_fragment_program = GL_TRUE;
 449    ctx->Extensions.ARB_fragment_program_shadow = GL_TRUE;
 450    ctx->Extensions.ARB_fragment_shader = GL_TRUE;
 451    ctx->Extensions.ARB_framebuffer_object = GL_TRUE;
 452    ctx->Extensions.ARB_half_float_vertex = GL_TRUE;
 453    ctx->Extensions.ARB_map_buffer_range = GL_TRUE;
 454    ctx->Extensions.ARB_occlusion_query = GL_TRUE;
 455    ctx->Extensions.ARB_occlusion_query2 = GL_TRUE;
 456    ctx->Extensions.ARB_point_sprite = GL_TRUE;
 457    ctx->Extensions.ARB_shadow = GL_TRUE;
 458    ctx->Extensions.ARB_texture_border_clamp = GL_TRUE;
 459    ctx->Extensions.ARB_texture_compression_bptc = GL_TRUE;
 460    ctx->Extensions.ARB_texture_cube_map = GL_TRUE;
 461    ctx->Extensions.ARB_texture_env_combine = GL_TRUE;
 462    ctx->Extensions.ARB_texture_env_crossbar = GL_TRUE;
 463    ctx->Extensions.ARB_texture_env_dot3 = GL_TRUE;
 464 #ifdef TEXTURE_FLOAT_ENABLED
 465    ctx->Extensions.ARB_texture_float = GL_TRUE;
 466 #endif
 467    ctx->Extensions.ARB_texture_mirror_clamp_to_edge = GL_TRUE;
 468    ctx->Extensions.ARB_texture_non_power_of_two = GL_TRUE;
 469    ctx->Extensions.ARB_texture_rg = GL_TRUE;
 470    ctx->Extensions.ARB_texture_compression_rgtc = GL_TRUE;
 471    ctx->Extensions.ARB_vertex_program = GL_TRUE;
 472    ctx->Extensions.ARB_vertex_shader = GL_TRUE;
 473    ctx->Extensions.ARB_sync = GL_TRUE;
 474    ctx->Extensions.APPLE_object_purgeable = GL_TRUE;
 475    ctx->Extensions.ATI_fragment_shader = GL_TRUE;
 476    ctx->Extensions.ATI_texture_compression_3dc = GL_TRUE;
 477    ctx->Extensions.ATI_texture_env_combine3 = GL_TRUE;
 478    ctx->Extensions.ATI_texture_mirror_once = GL_TRUE;
 479    ctx->Extensions.ATI_separate_stencil = GL_TRUE;
 480    ctx->Extensions.EXT_blend_color = GL_TRUE;
 481    ctx->Extensions.EXT_blend_equation_separate = GL_TRUE;
 482    ctx->Extensions.EXT_blend_func_separate = GL_TRUE;
 483    ctx->Extensions.EXT_blend_minmax = GL_TRUE;
 484    ctx->Extensions.EXT_depth_bounds_test = GL_TRUE;
 485    ctx->Extensions.EXT_draw_buffers2 = GL_TRUE;
 486    ctx->Extensions.EXT_pixel_buffer_object = GL_TRUE;
 487    ctx->Extensions.EXT_point_parameters = GL_TRUE;
 488    ctx->Extensions.EXT_provoking_vertex = GL_TRUE;
 489    ctx->Extensions.EXT_stencil_two_side = GL_TRUE;
 490    ctx->Extensions.EXT_texture_array = GL_TRUE;
 491    ctx->Extensions.EXT_texture_compression_latc = GL_TRUE;
 492    ctx->Extensions.EXT_texture_env_dot3 = GL_TRUE;
 493    ctx->Extensions.EXT_texture_filter_anisotropic = GL_TRUE;
 494    ctx->Extensions.EXT_texture_mirror_clamp = GL_TRUE;
 495    ctx->Extensions.EXT_texture_shared_exponent = GL_TRUE;
 496    ctx->Extensions.EXT_texture_sRGB = GL_TRUE;
 497    ctx->Extensions.EXT_texture_sRGB_decode = GL_TRUE;
 498    ctx->Extensions.EXT_texture_swizzle = GL_TRUE;
 499    /*ctx->Extensions.EXT_transform_feedback = GL_TRUE;*/
 500    ctx->Extensions.EXT_vertex_array_bgra = GL_TRUE;
 501    ctx->Extensions.MESA_pack_invert = GL_TRUE;
 502    ctx->Extensions.MESA_ycbcr_texture = GL_TRUE;
 503    ctx->Extensions.NV_conditional_render = GL_TRUE;
 504    ctx->Extensions.NV_point_sprite = GL_TRUE;
 505    ctx->Extensions.NV_texture_env_combine4 = GL_TRUE;
 506    ctx->Extensions.NV_texture_rectangle = GL_TRUE;
 507    ctx->Extensions.NV_fragment_program_option = GL_TRUE;
 508    ctx->Extensions.EXT_gpu_program_parameters = GL_TRUE;
 509    ctx->Extensions.OES_standard_derivatives = GL_TRUE;
 510    ctx->Extensions.TDFX_texture_compression_FXT1 = GL_TRUE;
 511    if (ctx->Mesa_DXTn) {
 512       ctx->Extensions.ANGLE_texture_compression_dxt = GL_TRUE;
 513       ctx->Extensions.EXT_texture_compression_s3tc = GL_TRUE;
 514    }
 515 }
 516
 517 /**
 518  * Either enable or disable the named extension.
 519  * \return offset of extensions withint `ext' or 0 if extension is not known
 520  */
 521 static size_t
 522 set_extension(struct gl_extensions *ext, const char *name, GLboolean state)
 523 {
 524    size_t offset;
 525
 526    offset = name_to_offset(name);
 527    if (offset != 0 && (offset != o(dummy_true) || state != GL_FALSE)) {
 528       ((GLboolean *) ext)[offset] = state;
 529    }
 530
 531    return offset;
 532 }
 533
 534 /**
 535  * \brief Apply the \c MESA_EXTENSION_OVERRIDE environment variable.
 536  *
 537  * \c MESA_EXTENSION_OVERRIDE is a space-separated list of extensions to
 538  * enable or disable. The list is processed thus:
 539  *    - Enable recognized extension names that are prefixed with '+'.
 540  *    - Disable recognized extension names that are prefixed with '-'.
 541  *    - Enable recognized extension names that are not prefixed.
 542  *    - Collect unrecognized extension names in a new string.
 543  *
 544  * \c MESA_EXTENSION_OVERRIDE was previously parsed during
 545  * _mesa_one_time_init_extension_overrides. We just use the results of that
 546  * parsing in this function.
 547  *
 548  * \return Space-separated list of unrecognized extension names (which must
 549  *    be freed). Does not return \c NULL.
 550  */
 551 static char *
 552 get_extension_override( struct gl_context *ctx )
 553 {
 554    override_extensions_in_context(ctx);
 555
 556    if (cant_disable_extensions != NULL) {
 557       _mesa_problem(ctx,
 558                     "Trying to disable permanently enabled extensions: %s",
 559                     cant_disable_extensions);
 560    }
 561
 562    if (extra_extensions == NULL) {
 563       return calloc(1, sizeof(char));
 564    } else {
 565       _mesa_problem(ctx, "Trying to enable unknown extensions: %s",
 566                     extra_extensions);
 567       return strdup(extra_extensions);
 568    }
 569 }
 570
 571
 572 /**
 573  * \brief Free extra_extensions and cant_disable_extensions strings
 574  *
 575  * These strings are allocated early during the first context creation by
 576  * _mesa_one_time_init_extension_overrides.
 577  */
 578 static void
 579 free_unknown_extensions_strings(void)
 580 {
 581    free(extra_extensions);
 582    free(cant_disable_extensions);
 583 }
 584
 585
 586 /**
 587  * \brief Initialize extension override tables.
 588  *
 589  * This should be called one time early during first context initialization.
 590  */
 591 void
 592 _mesa_one_time_init_extension_overrides(void)
 593 {
 594    const char *env_const = getenv("MESA_EXTENSION_OVERRIDE");
 595    char *env;
 596    char *ext;
 597    int len;
 598    size_t offset;
 599
 600    atexit(free_unknown_extensions_strings);
 601
 602    memset(&_mesa_extension_override_enables, 0, sizeof(struct gl_extensions));
 603    memset(&_mesa_extension_override_disables, 0, sizeof(struct gl_extensions));
 604
 605    if (env_const == NULL) {
 606       return;
 607    }
 608
 609    /* extra_exts: List of unrecognized extensions. */
 610    extra_extensions = calloc(ALIGN(strlen(env_const) + 2, 4), sizeof(char));
 611    cant_disable_extensions = calloc(ALIGN(strlen(env_const) + 2, 4), sizeof(char));
 612
 613    /* Copy env_const because strtok() is destructive. */
 614    env = strdup(env_const);
 615
 616    if (env == NULL || extra_extensions == NULL ||
 617            cant_disable_extensions == NULL) {
 618        free(env);
 619        free(extra_extensions);
 620        free(cant_disable_extensions);
 621        return;
 622    }
 623
 624    for (ext = strtok(env, " "); ext != NULL; ext = strtok(NULL, " ")) {
 625       int enable;
 626       bool recognized;
 627       switch (ext[0]) {
 628       case '+':
 629          enable = 1;
 630          ++ext;
 631          break;
 632       case '-':
 633          enable = 0;
 634          ++ext;
 635          break;
 636       default:
 637          enable = 1;
 638          break;
 639       }
 640
 641       offset = set_extension(&_mesa_extension_override_enables, ext, enable);
 642       if (offset != 0 && (offset != o(dummy_true) || enable != GL_FALSE)) {
 643          ((GLboolean *) &_mesa_extension_override_disables)[offset] = !enable;
 644          recognized = true;
 645       } else {
 646          recognized = false;
 647       }
 648
 649       if (!recognized) {
 650          if (enable) {
 651             strcat(extra_extensions, ext);
 652             strcat(extra_extensions, " ");
 653          } else if (offset == o(dummy_true)) {
 654             strcat(cant_disable_extensions, ext);
 655             strcat(cant_disable_extensions, " ");
 656          }
 657       }
 658    }
 659
 660    free(env);
 661
 662    /* Remove trailing space, and free if unused. */
 663    len = strlen(extra_extensions);
 664    if (len == 0) {
 665       free(extra_extensions);
 666       extra_extensions = NULL;
 667    } else if (extra_extensions[len - 1] == ' ') {
 668       extra_extensions[len - 1] = '\0';
 669    }
 670    len = strlen(cant_disable_extensions);
 671    if (len == 0) {
 672       free(cant_disable_extensions);
 673       cant_disable_extensions = NULL;
 674    } else if (cant_disable_extensions[len - 1] == ' ') {
 675       cant_disable_extensions[len - 1] = '\0';
 676    }
 677 }
 678
 679
 680 /**
 681  * \brief Initialize extension tables and enable default extensions.
 682  *
 683  * This should be called during context initialization.
 684  * Note: Sets gl_extensions.dummy_true to true.
 685  */
 686 void
 687 _mesa_init_extensions(struct gl_extensions *extensions)
 688 {
 689    GLboolean *base = (GLboolean *) extensions;
 690    GLboolean *sentinel = base + o(extension_sentinel);
 691    GLboolean *i;
 692
 693    /* First, turn all extensions off. */
 694    for (i = base; i != sentinel; ++i)
 695       *i = GL_FALSE;
 696
 697    /* Then, selectively turn default extensions on. */
 698    extensions->dummy_true = GL_TRUE;
 699    extensions->EXT_texture3D = GL_TRUE;
 700 }
 701
 702
 703 typedef unsigned short extension_index;
 704
 705
 706 /**
 707  * Compare two entries of the extensions table.  Sorts first by year,
 708  * then by name.
 709  *
 710  * Arguments are indices into extension_table.
 711  */
 712 static int
 713 extension_compare(const void *p1, const void *p2)
 714 {
 715    extension_index i1 = * (const extension_index *) p1;
 716    extension_index i2 = * (const extension_index *) p2;
 717    const struct extension *e1 = &extension_table[i1];
 718    const struct extension *e2 = &extension_table[i2];
 719    int res;
 720
 721    res = (int)e1->year - (int)e2->year;
 722
 723    if (res == 0) {
 724       res = strcmp(e1->name, e2->name);
 725    }
 726
 727    return res;
 728 }
 729
 730
 731 /**
 732  * Construct the GL_EXTENSIONS string.  Called the first time that
 733  * glGetString(GL_EXTENSIONS) is called.
 734  */
 735 GLubyte*
 736 _mesa_make_extension_string(struct gl_context *ctx)
 737 {
 738    /* The extension string. */
 739    char *exts = 0;
 740    /* Length of extension string. */
 741    size_t length = 0;
 742    /* Number of extensions */
 743    unsigned count;
 744    /* Indices of the extensions sorted by year */
 745    extension_index *extension_indices;
 746    /* String of extra extensions. */
 747    char *extra_extensions = get_extension_override(ctx);
 748    GLboolean *base = (GLboolean *) &ctx->Extensions;
 749    const struct extension *i;
 750    unsigned j;
 751    unsigned maxYear = ~0;
 752    unsigned api_set = (1 << ctx->API);
 753    if (_mesa_is_gles3(ctx))
 754       api_set |= ES3;
 755
 756    /* Check if the MESA_EXTENSION_MAX_YEAR env var is set */
 757    {
 758       const char *env = getenv("MESA_EXTENSION_MAX_YEAR");
 759       if (env) {
 760          maxYear = atoi(env);
 761          _mesa_debug(ctx, "Note: limiting GL extensions to %u or earlier\n",
 762                      maxYear);
 763       }
 764    }
 765
 766    /* Compute length of the extension string. */
 767    count = 0;
 768    for (i = extension_table; i->name != 0; ++i) {
 769       if (base[i->offset] &&
 770           i->year <= maxYear &&
 771           (i->api_set & api_set)) {
 772          length += strlen(i->name) + 1; /* +1 for space */
 773          ++count;
 774       }
 775    }
 776    if (extra_extensions != NULL)
 777       length += 1 + strlen(extra_extensions); /* +1 for space */
 778
 779    exts = calloc(ALIGN(length + 1, 4), sizeof(char));
 780    if (exts == NULL) {
 781       free(extra_extensions);
 782       return NULL;
 783    }
 784
 785    extension_indices = malloc(count * sizeof(extension_index));
 786    if (extension_indices == NULL) {
 787       free(exts);
 788       free(extra_extensions);
 789       return NULL;
 790    }
 791
 792    /* Sort extensions in chronological order because certain old applications
 793     * (e.g., Quake3 demo) store the extension list in a static size buffer so
 794     * chronologically order ensure that the extensions that such applications
 795     * expect will fit into that buffer.
 796     */
 797    j = 0;
 798    for (i = extension_table; i->name != 0; ++i) {
 799       if (base[i->offset] &&
 800           i->year <= maxYear &&
 801           (i->api_set & api_set)) {
 802          extension_indices[j++] = i - extension_table;
 803       }
 804    }
 805    assert(j == count);
 806    qsort(extension_indices, count,
 807          sizeof *extension_indices, extension_compare);
 808
 809    /* Build the extension string.*/
 810    for (j = 0; j < count; ++j) {
 811       i = &extension_table[extension_indices[j]];
 812       assert(base[i->offset] && (i->api_set & api_set));
 813       strcat(exts, i->name);
 814       strcat(exts, " ");
 815    }
 816    free(extension_indices);
 817    if (extra_extensions != 0) {
 818       strcat(exts, extra_extensions);
 819       free(extra_extensions);
 820    }
 821
 822    return (GLubyte *) exts;
 823 }
 824
 825 /**
 826  * Return number of enabled extensions.
 827  */
 828 GLuint
 829 _mesa_get_extension_count(struct gl_context *ctx)
 830 {
 831    GLboolean *base;
 832    const struct extension *i;
 833    unsigned api_set = (1 << ctx->API);
 834    if (_mesa_is_gles3(ctx))
 835       api_set |= ES3;
 836
 837    /* only count once */
 838    if (ctx->Extensions.Count != 0)
 839       return ctx->Extensions.Count;
 840
 841    base = (GLboolean *) &ctx->Extensions;
 842    for (i = extension_table; i->name != 0; ++i) {
 843       if (base[i->offset] && (i->api_set & api_set)) {
 844          ctx->Extensions.Count++;
 845       }
 846    }
 847    return ctx->Extensions.Count;
 848 }
 849
 850 /**
 851  * Return name of i-th enabled extension
 852  */
 853 const GLubyte *
 854 _mesa_get_enabled_extension(struct gl_context *ctx, GLuint index)
 855 {
 856    const GLboolean *base;
 857    size_t n;
 858    const struct extension *i;
 859    unsigned api_set = (1 << ctx->API);
 860    if (_mesa_is_gles3(ctx))
 861       api_set |= ES3;
 862
 863    base = (GLboolean*) &ctx->Extensions;
 864    n = 0;
 865    for (i = extension_table; i->name != 0; ++i) {
 866       if (base[i->offset] && (i->api_set & api_set)) {
 867          if (n == index)
 868             return (const GLubyte*) i->name;
 869          else
 870             ++n;
 871       }
 872    }
 873
 874    return NULL;
 875 }