[Mesa-stable] Fwd: [PATCH v2] mesa/teximage: Fix S3TC regression due to ASTC interaction

[Nanley Chery]

From: Nanley Chery <nanley.g.chery at intel.com>

A prior, literal reading of the ASTC spec led to the prohibition
of some compressed formats being used against the targets:
TEXTURE_CUBE_MAP_ARRAY and TEXTURE_3D. Since the spec does not specify
interactions with other extensions for specific compressed textures,
remove such interactions.

Fixes the following Piglit tests on Gen9:
piglit.spec.arb_direct_state_access.getcompressedtextureimage
piglit.spec.arb_get_texture_sub_image.arb_get_texture_sub_image-getcompressed
piglit.spec.arb_texture_cube_map_array.fbo-generatemipmap-cubemap array
s3tc_dxt1
piglit.spec.ext_texture_compression_s3tc.getteximage-targets cube_array s3tc

v2. Don't interact with other specific compressed formats (Ian).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91927
Suggested-by: Neil Roberts <neil at linux.intel.com>
Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
---

This patch received an Rb here:
http://lists.freedesktop.org/archives/mesa-dev/2015-November/101066.html

 src/mesa/main/teximage.c | 43 +++++++++++++++----------------------------
 1 file changed, 15 insertions(+), 28 deletions(-)

diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index d9453e3..ac7599f 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -1333,21 +1333,6 @@ _mesa_target_can_be_compressed(const struct
gl_context *ctx, GLenum target,
       break;
    case GL_PROXY_TEXTURE_CUBE_MAP_ARRAY:
    case GL_TEXTURE_CUBE_MAP_ARRAY:
-      /* From section 3.8.6, page 146 of OpenGL ES 3.0 spec:
-       *
-       *    "The ETC2/EAC texture compression algorithm supports only
-       *     two-dimensional images. If internalformat is an ETC2/EAC
format,
-       *     glCompressedTexImage3D will generate an INVALID_OPERATION
error if
-       *     target is not TEXTURE_2D_ARRAY."
-       *
-       * This should also be applicable for glTexStorage3D(). Other
available
-       * targets for these functions are: TEXTURE_3D and
TEXTURE_CUBE_MAP_ARRAY.
-       */
-      if (layout == MESA_FORMAT_LAYOUT_ETC2 && _mesa_is_gles3(ctx))
-            return write_error(error, GL_INVALID_OPERATION);
-
-      target_can_be_compresed = ctx->Extensions.ARB_texture_cube_map_array;
-
       /* From the KHR_texture_compression_astc_hdr spec:
        *
        *     Add a second new column "3D Tex." which is empty for all
non-ASTC
@@ -1368,16 +1353,24 @@ _mesa_target_can_be_compressed(const struct
gl_context *ctx, GLenum target,
        *      8.19 is *not* checked'
        *
        * The instances of <internalformat> above should say <target>.
+       *
+       * ETC2/EAC formats are the only alternative in GLES and thus such
errors
+       * have already been handled by normal ETC2/EAC behavior.
        */

-      /* Throw an INVALID_OPERATION error if the target is
-       * TEXTURE_CUBE_MAP_ARRAY and the format is not ASTC.
+      /* From section 3.8.6, page 146 of OpenGL ES 3.0 spec:
+       *
+       *    "The ETC2/EAC texture compression algorithm supports only
+       *     two-dimensional images. If internalformat is an ETC2/EAC
format,
+       *     glCompressedTexImage3D will generate an INVALID_OPERATION
error if
+       *     target is not TEXTURE_2D_ARRAY."
+       *
+       * This should also be applicable for glTexStorage3D(). Other
available
+       * targets for these functions are: TEXTURE_3D and
TEXTURE_CUBE_MAP_ARRAY.
        */
-      if (target_can_be_compresed &&
-          ctx->Extensions.KHR_texture_compression_astc_ldr &&
-          layout != MESA_FORMAT_LAYOUT_ASTC)
-         return write_error(error, GL_INVALID_OPERATION);
-
+      if (layout == MESA_FORMAT_LAYOUT_ETC2 && _mesa_is_gles3(ctx))
+            return write_error(error, GL_INVALID_OPERATION);
+      target_can_be_compresed = ctx->Extensions.ARB_texture_cube_map_array;
       break;
    case GL_TEXTURE_3D:
       switch (layout) {
@@ -1401,12 +1394,6 @@ _mesa_target_can_be_compressed(const struct
gl_context *ctx, GLenum target,
             return write_error(error, GL_INVALID_OPERATION);
          break;
       default:
-         /* Throw an INVALID_OPERATION error if the target is TEXTURE_3D
and
-          * the format is not ASTC.
-          * See comment in switch case GL_TEXTURE_CUBE_MAP_ARRAY for more
info.
-          */
-         if (ctx->Extensions.KHR_texture_compression_astc_ldr)
-            return write_error(error, GL_INVALID_OPERATION);
          break;
       }
    default:
--
2.6.2
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