[Mesa-dev] [PATCH v3] mesa: improve ARB_copy_image internal format compat check

Jason Ekstrand jason at jlekstrand.net
Sat Mar 7 15:05:26 PST 2015


On Sat, Mar 7, 2015 at 2:10 PM, Sean Burke <leftmostcat at gmail.com> wrote:

> The memory layout of compatible internal formats may differ in bytes per
> block, so TexFormat is not a reliable measure of compatibility. For
> example,
> GL_RGB8 and GL_RGB8UI are compatible formats, but GL_RGB8 may be laid out
> in
> memory as B8G8R8X8. If GL_RGB8UI has a 3 byte-per-block memory layout, the
> existing compatibility check will fail.
>
> Additionally, the current check allows any two compressed textures which
> share
> block size to be used, which is in violation of the spec.
>

Rather than simply saying "which is in violation of the spec", perhaps it
would be better to say "whereas the spec gives an explicit table of
compatible formats".  I think the original check actually worked because
mesa doesn't support anything not in that table.  However, doing it
explicitly is probably better.


>
> v2: Use a switch instead of array iteration for block class and show the
>     correct GL error when internal formats are mismatched.
> v3: Include spec citations for new compatibility checks, rearrange check
>     order to ensure that compressed, view-compatible formats return the
>     correct result, and make style fixes. Original commit message amended
>     for clarity.
> ---
>  src/mesa/main/copyimage.c | 148
> +++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 127 insertions(+), 21 deletions(-)
>
> diff --git a/src/mesa/main/copyimage.c b/src/mesa/main/copyimage.c
> index 455929d..9fc9c82 100644
> --- a/src/mesa/main/copyimage.c
> +++ b/src/mesa/main/copyimage.c
> @@ -33,6 +33,12 @@
>  #include "texobj.h"
>  #include "fbobject.h"
>  #include "textureview.h"
> +#include "glformats.h"
> +
> +enum mesa_block_class {
> +   BLOCK_CLASS_128_BITS,
> +   BLOCK_CLASS_64_BITS
> +};
>
>  static bool
>  prepare_target(struct gl_context *ctx, GLuint name, GLenum *target, int
> level,
> @@ -253,6 +259,121 @@ check_region_bounds(struct gl_context *ctx,
> struct gl_texture_image *tex_image,
>     return true;
>  }
>
> +static bool
> +compressed_format_compatible(struct gl_context *ctx,
> +                             GLenum compressedFormat, GLenum otherFormat)
> +{
> +   enum mesa_block_class compressedClass, otherClass;
> +
> +   /* Two view-incompatible compressed formats are never compatible. */
> +   if (_mesa_is_compressed_format(ctx, otherFormat)) {
> +      return false;
> +   }
> +
> +   /* Table 4.X.1 (Compatible internal formats for copying between
> compressed
> +    *              and uncompressed internal formats)
> +    *
> ------------------------------------------------------------------------
> +    * | Texel / | Uncompressed         |
>    |
> +    * | Block   | internal format      | Compressed internal format
>     |
> +    * | size    |                      |
>    |
> +    *
> ------------------------------------------------------------------------
> +    * | 128-bit | RGBA32UI,            | COMPRESSED_RGBA_S3TC_DXT3_EXT,
>     |
> +    * |         | RGBA32I,             |
> COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT,|
> +    * |         | RGBA32F              | COMPRESSED_RGBA_S3TC_DXT5_EXT,
>     |
> +    * |         |                      |
> COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT,|
> +    * |         |                      | COMPRESSED_RG_RGTC2,
>     |
> +    * |         |                      | COMPRESSED_SIGNED_RG_RGTC2,
>    |
> +    * |         |                      | COMPRESSED_RGBA_BPTC_UNORM,
>    |
> +    * |         |                      |
> COMPRESSED_SRGB_ALPHA_BPTC_UNORM,   |
> +    * |         |                      |
> COMPRESSED_RGB_BPTC_SIGNED_FLOAT,   |
> +    * |         |                      |
> COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT  |
> +    *
> ------------------------------------------------------------------------
> +    * | 64-bit  | RGBA16F, RG32F,      | COMPRESSED_RGB_S3TC_DXT1_EXT,
>    |
> +    * |         | RGBA16UI, RG32UI,    | COMPRESSED_SRGB_S3TC_DXT1_EXT,
>     |
> +    * |         | RGBA16I, RG32I,      | COMPRESSED_RGBA_S3TC_DXT1_EXT,
>     |
> +    * |         | RGBA16, RGBA16_SNORM |
> COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT,|
> +    * |         |                      | COMPRESSED_RED_RGTC1,
>    |
> +    * |         |                      | COMPRESSED_SIGNED_RED_RGTC1
>    |
> +    *
> ------------------------------------------------------------------------
> +    */
>

Spec references should cite a spec version and page number or, if pulled
form the extension spec say as much.  For instance:

>From the OpenGL specification version 4.4 core, p. 125:

blah

That way the reader knows exactly what document to go look at.  Also, spec
citations are usually done as a block quite where the quoted text is
indented another 3 spaces from the rest of the comment.


> +
> +   switch (compressedFormat) {
> +      case GL_COMPRESSED_RGBA_S3TC_DXT3_EXT:
> +      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT:
> +      case GL_COMPRESSED_RGBA_S3TC_DXT5_EXT:
> +      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT:
> +      case GL_COMPRESSED_RG_RGTC2:
> +      case GL_COMPRESSED_SIGNED_RG_RGTC2:
> +      case GL_COMPRESSED_RGBA_BPTC_UNORM:
> +      case GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM:
> +      case GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT:
> +      case GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT:
> +         compressedClass = BLOCK_CLASS_128_BITS;
> +         break;
> +      case GL_COMPRESSED_RGB_S3TC_DXT1_EXT:
> +      case GL_COMPRESSED_SRGB_S3TC_DXT1_EXT:
> +      case GL_COMPRESSED_RGBA_S3TC_DXT1_EXT:
> +      case GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT:
> +      case GL_COMPRESSED_RED_RGTC1:
> +      case GL_COMPRESSED_SIGNED_RED_RGTC1:
> +         compressedClass = BLOCK_CLASS_64_BITS;
> +         break;
> +      default:
> +         return false;
> +   }
> +
> +   switch (otherFormat) {
> +      case GL_RGBA32UI:
> +      case GL_RGBA32I:
> +      case GL_RGBA32F:
> +         otherClass = BLOCK_CLASS_128_BITS;
> +         break;
> +      case GL_RGBA16F:
> +      case GL_RG32F:
> +      case GL_RGBA16UI:
> +      case GL_RG32UI:
> +      case GL_RGBA16I:
> +      case GL_RG32I:
> +      case GL_RGBA16:
> +      case GL_RGBA16_SNORM:
> +         otherClass = BLOCK_CLASS_64_BITS;
> +         break;
> +      default:
> +         return false;
> +   }
> +
> +   return compressedClass == otherClass;
> +}
> +
> +static bool
> +copy_format_compatible(struct gl_context *ctx,
> +                                GLenum srcFormat, GLenum dstFormat)
> +{
> +   /*
>
+    * For the purposes of CopyImageSubData, two internal formats
> +    * are considered compatible if any of the following conditions are
> +    * met:
> +    * * the formats are the same,
> +    * * the formats are considered compatible according to the
> +    *   compatibility rules used for texture views as defined in
> +    *   section 3.9.X. In particular, if both internal formats are listed
> +    *   in the same entry of Table 3.X.2, they are considered compatible,
> or
> +    * * one format is compressed and the other is uncompressed and
> +    *   Table 4.X.1 lists the two formats in the same row.
> +    */
>


Same here.

With those comments fixed,
Reviewed-by: Jason Ekstrand <jason.ekstrand at intel.com>


> +
> +   if (_mesa_texture_view_compatible_format(ctx, srcFormat, dstFormat)) {
> +      /* Also checks if formats are equal. */
> +      return true;
> +   } else if (_mesa_is_compressed_format(ctx, srcFormat)) {
> +      return compressed_format_compatible(ctx, srcFormat, dstFormat);
> +   } else if (_mesa_is_compressed_format(ctx, dstFormat)) {
> +      return compressed_format_compatible(ctx, dstFormat, srcFormat);
> +   }
> +
> +   return false;
> +}
> +
>  void GLAPIENTRY
>  _mesa_CopyImageSubData(GLuint srcName, GLenum srcTarget, GLint srcLevel,
>                         GLint srcX, GLint srcY, GLint srcZ,
> @@ -265,7 +386,7 @@ _mesa_CopyImageSubData(GLuint srcName, GLenum
> srcTarget, GLint srcLevel,
>     struct gl_texture_object *srcTexObj, *dstTexObj;
>     struct gl_texture_image *srcTexImage, *dstTexImage;
>     GLuint src_bw, src_bh, dst_bw, dst_bh;
> -   int i, srcNewZ, dstNewZ, Bpt;
> +   int i, srcNewZ, dstNewZ;
>
>     if (MESA_VERBOSE & VERBOSE_API)
>        _mesa_debug(ctx, "glCopyImageSubData(%u, %s, %d, %d, %d, %d, "
> @@ -306,15 +427,6 @@ _mesa_CopyImageSubData(GLuint srcName, GLenum
> srcTarget, GLint srcLevel,
>        goto cleanup;
>     }
>
> -   /* Very simple sanity check.  This is sufficient if one of the textures
> -    * is compressed. */
> -   Bpt = _mesa_get_format_bytes(srcTexImage->TexFormat);
> -   if (_mesa_get_format_bytes(dstTexImage->TexFormat) != Bpt) {
> -      _mesa_error(ctx, GL_INVALID_VALUE,
> -                  "glCopyImageSubData(internalFormat mismatch)");
> -      goto cleanup;
> -   }
> -
>     if (!check_region_bounds(ctx, srcTexImage, srcX, srcY, srcZ,
>                              srcWidth, srcHeight, srcDepth, "src"))
>        goto cleanup;
> @@ -324,17 +436,11 @@ _mesa_CopyImageSubData(GLuint srcName, GLenum
> srcTarget, GLint srcLevel,
>                              (srcHeight / src_bh) * dst_bh, srcDepth,
> "dst"))
>        goto cleanup;
>
> -   if (_mesa_is_format_compressed(srcTexImage->TexFormat)) {
> -      /* XXX: Technically, we should probaby do some more specific
> checking
> -       * here.  However, this should be sufficient for all compressed
> -       * formats that mesa supports since it is a direct memory copy.
> -       */
> -   } else if (_mesa_is_format_compressed(dstTexImage->TexFormat)) {
> -   } else if (_mesa_texture_view_compatible_format(ctx,
> -
>  srcTexImage->InternalFormat,
> -
> dstTexImage->InternalFormat)) {
> -   } else {
> -      return; /* Error logged by _mesa_texture_view_compatible_format */
> +   if (!copy_format_compatible(ctx, srcTexImage->InternalFormat,
> +                               dstTexImage->InternalFormat)) {
> +      _mesa_error(ctx, GL_INVALID_OPERATION,
> +                  "glCopyImageSubData(internalFormat mismatch)");
> +      goto cleanup;
>     }
>
>     for (i = 0; i < srcDepth; ++i) {
> --
> 2.1.0
>
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