[Mesa-dev] [PATCH] mesa: fix the compressed TexSubImage size checking code

[Brian Paul]

Before, we'd incorrectly generate an error if we we tried to
replace a non-4x4 block near the edge of a NPOT compressed texture.
For example, if the dest image was 15 texels wide and xoffset=12
and width=3 we'd incorrectly generate GL_INVALID_OPERATION.

Verified with new tests added to piglit s3tc-errors test.

Note: This is a candidate for the stable branches.
---
 src/mesa/main/teximage.c |   12 +++++++++---
 1 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
index 45a13a7..c48b86d 100644
--- a/src/mesa/main/teximage.c
+++ b/src/mesa/main/teximage.c
@@ -1594,14 +1594,20 @@ error_check_subtexture_dimensions(struct gl_context *ctx,
          return GL_TRUE;
       }
 
-      /* size must be multiple of bw by bh or equal to whole texture size */
-      if ((subWidth % bw != 0) && subWidth != (GLint) destImage->Width) {
+      /* The size must be a multiple of bw x bh, or we must be using a
+       * offset+size that exactly hits the edge of the image.  This
+       * is important for small mipmap levels (1x1, 2x1, etc) and for
+       * NPOT textures.
+       */
+      if ((subWidth % bw != 0) &&
+          (xoffset + subWidth != (GLint) destImage->Width)) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "%s%dD(width = %d)", function, dims, subWidth);
          return GL_TRUE;
       }
 
-      if ((subHeight % bh != 0) && subHeight != (GLint) destImage->Height) {
+      if ((subHeight % bh != 0) &&
+          (yoffset + subHeight != (GLint) destImage->Height)) {
          _mesa_error(ctx, GL_INVALID_OPERATION,
                      "%s%dD(height = %d)", function, dims, subHeight);
          return GL_TRUE;
-- 
1.7.3.4