[Mesa-dev] [PATCH] mesa: Correctly handle GL_BGRA_EXT in ES3 format_and_type checks

[Jason Ekstrand]

The EXT_texture_format_BGRA8888 extension (which mesa supports
unconditionally) adds a new format and internal format called GL_BGRA_EXT.
Previously, this was not really handled at all in
_mesa_ex3_error_check_format_and_type.  When the checks were tightened in
commit f15a7f3c, we accidentally tightened things too far and GL_BGRA_EXT
would always cause an error to be thrown.

There were two primary issues here.  First, is that
_mesa_es3_effective_internal_format_for_format_and_type didn't handle the
GL_BGRA_EXT format.  Second is that it blindly uses _mesa_base_tex_format
which returns GL_RGBA for GL_BGRA_EXT.  This commit fixes both of these
issues as well as adds explicit checks that GL_BGRA_EXT is only ever used
with GL_BGRA_EXT and GL_UNSIGNED_BYTE.

Signed-off-by: Jason Ekstrand <jason.ekstrand at intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92265
Cc: Eduardo Lima Mitev <elima at igalia.com>
---
 src/mesa/main/glformats.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/mesa/main/glformats.c b/src/mesa/main/glformats.c
index 7dab33c..843ec02 100644
--- a/src/mesa/main/glformats.c
+++ b/src/mesa/main/glformats.c
@@ -2678,6 +2678,7 @@ _mesa_es3_effective_internal_format_for_format_and_type(GLenum format,
        * internal formats, they do not correspond to GL constants, so the base
        * format is returned instead.
        */
+      case GL_BGRA_EXT:
       case GL_LUMINANCE_ALPHA:
       case GL_LUMINANCE:
       case GL_ALPHA:
@@ -2797,8 +2798,19 @@ _mesa_es3_error_check_format_and_type(const struct gl_context *ctx,
       if (effectiveInternalFormat == GL_NONE)
          return GL_INVALID_OPERATION;
 
-      GLenum baseInternalFormat =
-         _mesa_base_tex_format(ctx, effectiveInternalFormat);
+      GLenum baseInternalFormat;
+      if (internalFormat == GL_BGRA_EXT) {
+         /* Unfortunately, _mesa_base_tex_format returns a base format of
+          * GL_RGBA for GL_BGRA_EXT.  This makes perfect sense if you're
+          * asking the question, "what channels doe this format have?"
+          * However, if we're trying to determine if two internal formats
+          * match in the ES3 sense, we actually want GL_BGRA.
+          */
+         baseInternalFormat = GL_BGRA_EXT;
+      } else {
+         baseInternalFormat =
+            _mesa_base_tex_format(ctx, effectiveInternalFormat);
+      }
 
       if (internalFormat != baseInternalFormat)
          return GL_INVALID_OPERATION;
@@ -2807,6 +2819,11 @@ _mesa_es3_error_check_format_and_type(const struct gl_context *ctx,
    }
 
    switch (format) {
+   case GL_BGRA_EXT:
+      if (type != GL_UNSIGNED_BYTE || internalFormat != GL_BGRA)
+         return GL_INVALID_OPERATION;
+      break;
+
    case GL_RGBA:
       switch (type) {
       case GL_UNSIGNED_BYTE:
-- 
2.5.0.400.gff86faf