st/mesa: fix texture deallocation bug
This fixes a bug reported by Christoph Bumiller on mesa3d-dev.
When a texture is first created as RGBA, then re-defined with
glTexImage(internalFormat=GL_DEPTH_COMPONENT) we failed to deallocate
the original texture. When this texture was bound as a FBO surface,
the depth/Z surface format was RGBA instead of Z. Depending on the
driver this led to a failed assertion or FBO validation failure.
This patch does three things:
1. Remove ancient code that mysteriously tested if we were replacing
the smallest mipmap level and tested if the texture was not a cube map
texture. I can't see any reason for those tests.
2. Move the width=height=depth=0 test to after the code which frees
texture data. Calling glTexImage with width=height=depth=0 and data=NULL
is a way to free a single mipmap level.
3. Update the code comments.
There are no apparent conform, glean or piglit regressions from this change.
(cherry picked from commit 43e4b584227534e30e487e7fb7e99d6501cbcd85)
1 file changed