mesa/st: Disable OES_texture_3D for PIPE_CAP_MAX_TEXTURE_3D_LEVELS==0.

This will be used for vc4, where incorrectly exposing 3D textures accounts
for most of the GLES2 conformance failures it has.  This leaves
EXT_texture3d exposed in the (already non-conformant) GL2.1 support it
exposes, which has always been a best-effort thing.

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/17350>

src/compiler/glsl/standalone_scaffolding.cpp

@@ -218,6 +218,7 @@ void initialize_context_to_defaults(struct gl_context *ctx, gl_api api)
 
    ctx->Extensions.OES_EGL_image_external = true;
    ctx->Extensions.OES_standard_derivatives = true;
+   ctx->Extensions.OES_texture_3D = true;
 
    ctx->Extensions.EXT_gpu_shader4 = true;
    ctx->Extensions.EXT_shader_integer_mix = true;

src/mesa/main/consts_exts.h

@@ -286,6 +286,7 @@ struct gl_extensions
    GLboolean OES_draw_texture;
    GLboolean OES_depth_texture_cube_map;
    GLboolean OES_EGL_image_external;
+   GLboolean OES_texture_3D;
    GLboolean OES_texture_float;
    GLboolean OES_texture_float_linear;
    GLboolean OES_texture_half_float;

src/mesa/main/extensions_table.h

@@ -471,7 +471,7 @@ EXT(OES_stencil_wrap                        , dummy_true
 EXT(OES_surfaceless_context                 , dummy_true                             ,  x ,  x , ES1, ES2, 2012)
 EXT(OES_tessellation_point_size             , ARB_tessellation_shader                ,  x ,  x ,  x ,  31, 2014)
 EXT(OES_tessellation_shader                 , ARB_tessellation_shader                ,  x ,  x ,  x ,  31, 2014)
-EXT(OES_texture_3D                          , dummy_true                             ,  x ,  x ,  x , ES2, 2005)
+EXT(OES_texture_3D                          , OES_texture_3D                         ,  x ,  x ,  x , ES2, 2005)
 EXT(OES_texture_border_clamp                , dummy_true                             ,  x ,  x ,  x , ES2, 2014)
 EXT(OES_texture_buffer                      , OES_texture_buffer                     ,  x ,  x ,  x ,  31, 2014)
 EXT(OES_texture_compression_astc            , OES_texture_compression_astc           ,  x ,  x , ES1, ES2, 2015)

src/mesa/main/fbobject.c

@@ -3797,7 +3797,8 @@ check_textarget(struct gl_context *ctx, int dims, GLenum target,
       err = dims != 2;
       break;
    case GL_TEXTURE_3D:
-      err = dims != 3;
+      err = dims != 3 ||
+            (ctx->API == API_OPENGLES2 && !ctx->Extensions.OES_texture_3D);
       break;
    default:
       _mesa_error(ctx, GL_INVALID_ENUM,

src/mesa/main/get.c

@@ -2464,7 +2464,9 @@ tex_binding_to_index(const struct gl_context *ctx, GLenum binding)
    case GL_TEXTURE_BINDING_2D:
       return TEXTURE_2D_INDEX;
    case GL_TEXTURE_BINDING_3D:
-      return ctx->API != API_OPENGLES ? TEXTURE_3D_INDEX : -1;
+      return (ctx->API != API_OPENGLES &&
+              !(ctx->API == API_OPENGLES2 && !ctx->Extensions.OES_texture_3D))
+         ? TEXTURE_3D_INDEX : -1;
    case GL_TEXTURE_BINDING_CUBE_MAP:
       return TEXTURE_CUBE_INDEX;
    case GL_TEXTURE_BINDING_RECTANGLE:

src/mesa/main/teximage.c

@@ -497,7 +497,8 @@ _mesa_max_texture_levels(const struct gl_context *ctx, GLenum target)
       return ffs(util_next_power_of_two(ctx->Const.MaxTextureSize));
    case GL_TEXTURE_3D:
    case GL_PROXY_TEXTURE_3D:
-      return ctx->Const.Max3DTextureLevels;
+      return !(ctx->API == API_OPENGLES2 && !ctx->Extensions.OES_texture_3D)
+         ? ctx->Const.Max3DTextureLevels : 0;
    case GL_TEXTURE_CUBE_MAP:
    case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
    case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:

src/mesa/main/texobj.c

@@ -169,7 +169,8 @@ _mesa_get_current_tex_object(struct gl_context *ctx, GLenum target)
       case GL_TEXTURE_3D:
          return texUnit->CurrentTex[TEXTURE_3D_INDEX];
       case GL_PROXY_TEXTURE_3D:
-         return ctx->Texture.ProxyTex[TEXTURE_3D_INDEX];
+         return !(ctx->API == API_OPENGLES2 && !ctx->Extensions.OES_texture_3D)
+             ? ctx->Texture.ProxyTex[TEXTURE_3D_INDEX] : NULL;
       case GL_TEXTURE_CUBE_MAP_POSITIVE_X:
       case GL_TEXTURE_CUBE_MAP_NEGATIVE_X:
       case GL_TEXTURE_CUBE_MAP_POSITIVE_Y:
@@ -1537,7 +1538,9 @@ _mesa_tex_target_to_index(const struct gl_context *ctx, GLenum target)
    case GL_TEXTURE_2D:
       return TEXTURE_2D_INDEX;
    case GL_TEXTURE_3D:
-      return ctx->API != API_OPENGLES ? TEXTURE_3D_INDEX : -1;
+      return (ctx->API != API_OPENGLES &&
+              !(ctx->API == API_OPENGLES2 && !ctx->Extensions.OES_texture_3D))
+         ? TEXTURE_3D_INDEX : -1;
    case GL_TEXTURE_CUBE_MAP:
       return TEXTURE_CUBE_INDEX;
    case GL_TEXTURE_RECTANGLE:

src/mesa/state_tracker/st_extensions.c

@@ -94,6 +94,7 @@ void st_init_limits(struct pipe_screen *screen,
    c->Max3DTextureLevels
       = _min(screen->get_param(screen, PIPE_CAP_MAX_TEXTURE_3D_LEVELS),
             MAX_TEXTURE_LEVELS);
+   extensions->OES_texture_3D = c->Max3DTextureLevels != 0;
 
    c->MaxCubeTextureLevels
       = _min(screen->get_param(screen, PIPE_CAP_MAX_TEXTURE_CUBE_LEVELS),