mesa: Add condition in glGetTexImage for zero size textures

TestMipMaps() function in src/OGLconform/textureNPOT.c calls glTexImage2D()
with width = 0. Texture with zero size skips miptree allocation due to a
condition in function _mesa_store_teximage3d(). While calling glGetTexImage()
it results in assertion failure in intel_map_texture_image() due to null mt
pointer.

This patch fixes the issue by detecting the zero size texture early in
glGetTexImage and glGetCompressedTexImage functions. In such a case function
simply returns doing nothing.
Verified that below mentioned bug is fixed by this patch.

https://bugs.freedesktop.org/show_bug.cgi?id=42334

NOTE: This is a candidate for stable branches

Signed-off-by: Anuj Phogat <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

1 files changed, 8 insertions, 1 deletions

diff --git a/src/mesa/main/teximage.h b/src/mesa/main/teximage.h
index 12af0e6d6d5..e2bdaca0150 100644
--- a/src/mesa/main/teximage.h
+++ b/src/mesa/main/teximage.h
@@ -44,7 +44,14 @@ _mesa_is_cube_face(GLenum target)
            target <= GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB);
 }
 
-
+/** Is any of the dimensions of given texture equal to zero? */
+static inline GLboolean
+_mesa_is_zero_size_texture(const struct gl_texture_image *texImage)
+{
+   return (texImage->Width == 0 ||
+           texImage->Height == 0 ||
+           texImage->Depth == 0);
+}
 
 /** \name Internal functions */
 /*@{*/