mesa/core: Add definitions and translations for EXT_texture_sRGB_R8

v2: - fix format definition line
    - disable  for desktop GL
    - don't add GL_R8_EXT to glext.h since it is already in
      GLES2/gl2ext.h in glext.h and include this header  where needed
      (all Emil)
v3: - swrast: Fill the function table for sRGB_R8
      The size of the function table is checked at compile time and must
      correspond to the number of mesa texture formats.
      dri/swrast being gles-2.0 doesn't support the extension though
v4: - correct format layout comment (Ilia Mirkin)
    - correct logic for accepting GL_RED only textures (in part Ilia Mirkin)
      EXT_texture_sRGB_R8 requires OpenGL ES 3.0 which includes
      ARB_texture_rg/EXT_texture_rg, so one only must check for the first
      when SR8_EXT is really requested.
v5: - add define for GL_ES8_XT to glheader.h and don't include GLES
      headers  (Ilia Mirkin)

Signed-off-by: Gert Wollny <[email protected]>
Reviewed-by: Ilia Mirkin <[email protected]>

1 files changed, 14 insertions, 3 deletions

diff --git a/src/mesa/main/glformats.c b/src/mesa/main/glformats.c
index f8fc36e9311..6cdc7818756 100644
--- a/src/mesa/main/glformats.c
+++ b/src/mesa/main/glformats.c
@@ -2486,6 +2486,15 @@ _mesa_base_tex_format(const struct gl_context *ctx, GLint internalFormat)
       }
    }
 
+   if (ctx->Extensions.EXT_texture_sRGB_R8) {
+      switch (internalFormat) {
+      case GL_SR8_EXT:
+         return GL_RED;
+      default:
+         ; /* fallthrough */
+      }
+   }
+
    if (ctx->Version >= 30 ||
        ctx->Extensions.EXT_texture_integer) {
       switch (internalFormat) {
@@ -3215,9 +3224,11 @@ _mesa_es3_error_check_format_and_type(const struct gl_context *ctx,
          return GL_INVALID_OPERATION;
       switch (type) {
       case GL_UNSIGNED_BYTE:
-         if (internalFormat != GL_R8)
-            return GL_INVALID_OPERATION;
-         break;
+         if (internalFormat == GL_R8 ||
+             ((internalFormat == GL_SR8_EXT) &&
+              ctx->Extensions.EXT_texture_sRGB_R8))
+            break;
+         return GL_INVALID_OPERATION;
 
       case GL_BYTE:
          if (internalFormat != GL_R8_SNORM)