mesa: improve ARB_copy_image internal format compat check

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, whereas the spec gives an explicit table of compatible
formats.

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.
v4: Reformatted spec citations.

Reviewed-by: Jason Ekstrand <[email protected]>

1 files changed, 130 insertions, 21 deletions

diff --git a/src/mesa/main/copyimage.c b/src/mesa/main/copyimage.c
index 455929dc2ff..fd22f28892c 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 +259,124 @@ 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;
+   }
+
+   /*
+    * From ARB_copy_image spec:
+    *    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,           | COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT,|
+    *    |         | RGBA16_SNORM      | COMPRESSED_RED_RGTC1,               |
+    *    |         |                   | COMPRESSED_SIGNED_RED_RGTC1         |
+    *    ---------------------------------------------------------------------
+    */
+
+   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)
+{
+   /*
+    * From ARB_copy_image spec:
+    *    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.
+    */
+
+   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 +389,7 @@ _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 +430,6 @@ _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 +439,11 @@ _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) {