mesa/main: do not check for ARB_texture_buffer_object for GL 3.1

While OpenGL 3.1 does require texture buffer objects, the ARB spec for
this requires support for texture buffers with alpha, luminance,
luminance-alpha and intensity formats in addition to RGBA formats. The
version of texture buffer objects that ended up in the OpenGL spec (even
in the compatibility spec) does not require these formats.

But, we don't even need to check this, because this is already included
in the GLSL 1.40 requirement that's also checked. So this shouldn't make
us expose GL 3.1 in cases where it isn't supported in the first place.

Reviewed-by: Lars-Ivar Hesselberg Simonsen <lars-ivar.simonsen@arm.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38162>

docs/features.txt

@@ -76,7 +76,7 @@ GL 3.1, GLSL 1.40 --- all DONE: freedreno, nv50, nvc0, r600, radeonsi, llvmpipe,
   GL_ARB_copy_buffer (Buffer copying)                   DONE (v3d, vc4, lima, crocus)
   GL_NV_primitive_restart (Primitive restart)           DONE (v3d, crocus)
   16 vertex texture image units                         DONE (v3d)
-  GL_ARB_texture_buffer_object (Texture buffer objs)    DONE (v3d)
+  Texture buffer objs                                   DONE (v3d)
   GL_ARB_texture_rectangle (Rectangular textures)       DONE (v3d, vc4, lima, crocus, etnaviv)
   GL_ARB_uniform_buffer_object (Uniform buffer objs)    DONE (v3d, crocus)
   GL_EXT_texture_snorm (Signed normalized textures)     DONE (v3d, crocus, etnaviv/HALTI1)
@@ -316,6 +316,7 @@ Khronos, ARB, and OES extensions that are not part of any OpenGL or OpenGL ES ve
   GL_ARB_sparse_texture                                 DONE (radeonsi/gfx9+, zink)
   GL_ARB_sparse_texture2                                DONE (radeonsi/gfx9+, zink)
   GL_ARB_sparse_texture_clamp                           DONE (radeonsi/gfx9+, zink)
+  GL_ARB_texture_buffer_object                          DONE (freedreno, nv50, nvc0, r600, radeonsi, llvmpipe, softpipe, virgl, zink, d3d12, panfrost, asahi, iris, crocus/gen6+, v3d)
   GL_ARB_texture_filter_minmax                          DONE (freedreno/a6xx, iris/gen9+, llvmpipe, nvc0/gm200+, zink)
   GL_ARM_shader_framebuffer_fetch_depth_stencil         DONE (llvmpipe)
   GL_EXT_shader_framebuffer_fetch                       DONE (freedreno/a6xx, iris/gen9+, llvmpipe, panfrost, virgl, zink, asahi, v3d)

src/mesa/main/context.h

@@ -487,7 +487,8 @@ static inline bool
 _mesa_has_texture_buffer_object(const struct gl_context *ctx)
 {
    return _mesa_has_ARB_texture_buffer_object(ctx) ||
-          _mesa_has_OES_texture_buffer(ctx);
+          _mesa_has_OES_texture_buffer(ctx) ||
+          (_mesa_is_desktop_gl(ctx) && ctx->Version >= 31);
 }
 
 static inline bool

src/mesa/main/get.c

@@ -214,6 +214,7 @@ enum value_extra {
    EXTRA_EXT_FB_NO_ATTACH_GS,
    EXTRA_EXT_ES_GS,
    EXTRA_EXT_PROVOKING_VERTEX_32,
+   EXTRA_EXT_TBO,
 };
 
 #define NO_EXTRA NULL
@@ -379,7 +380,7 @@ static const int extra_GLSL_130_es3_gpushader4[] = {
 };
 
 static const int extra_texture_buffer_object[] = {
-   EXT(ARB_texture_buffer_object),
+   EXTRA_EXT_TBO,
    EXTRA_END
 };
 
@@ -1582,6 +1583,11 @@ check_extra(struct gl_context *ctx, const char *func, const struct value_desc *d
          if (_mesa_is_desktop_gl_compat(ctx) || version == 32)
             api_found = ctx->Extensions.EXT_provoking_vertex;
          break;
+      case EXTRA_EXT_TBO:
+         api_check = GL_TRUE;
+         if (_mesa_has_texture_buffer_object(ctx))
+            api_found = GL_TRUE;
+         break;
       case EXTRA_END:
          break;
       default: /* *e is a offset into the extension struct */

src/mesa/main/version.c

@@ -291,7 +291,6 @@ compute_version(const struct gl_extensions *extensions,
    const bool ver_3_1 = (ver_3_0 &&
                          consts->GLSLVersion >= 140 &&
                          extensions->ARB_draw_instanced &&
-                         extensions->ARB_texture_buffer_object &&
                          extensions->ARB_uniform_buffer_object &&
                          extensions->EXT_texture_snorm &&
                          extensions->NV_primitive_restart &&

src/mesa/state_tracker/st_extensions.c

@@ -1567,7 +1567,7 @@ void st_init_extensions(struct pipe_screen *screen,
        screen->caps.buffer_sampler_view_rgba_only)
       extensions->ARB_texture_buffer_object = GL_FALSE;
 
-   if (extensions->ARB_texture_buffer_object) {
+   if (screen->caps.texture_buffer_objects) {
       consts->MaxTextureBufferSize =
          screen->caps.max_texel_buffer_elements;
       consts->TextureBufferOffsetAlignment =
@@ -1583,7 +1583,7 @@ void st_init_extensions(struct pipe_screen *screen,
 
    extensions->OES_texture_buffer =
       consts->Program[MESA_SHADER_COMPUTE].MaxImageUniforms &&
-      extensions->ARB_texture_buffer_object &&
+      screen->caps.texture_buffer_objects &&
       extensions->ARB_texture_buffer_range &&
       extensions->ARB_texture_buffer_object_rgb32;