[Mesa-dev] [PATCH] mesa: Don't override S3TC internalFormat if data is pre-compressed.

[Jordan Justen]

No more speckled zombies. :)

For gen7:
Tested-by: Jordan Justen <jordan.l.justen at intel.com>

Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

On Wed, Sep 19, 2012 at 12:01 PM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> Commit 42723d88d intended to override an S3TC internalFormat to a
> generic compressed format when the application requested online
> compression of uncompressed data.  Unfortunately, it also broke
> pre-compressed textures when libtxc_dxtn isn't installed but the
> extensions are forced on.
>
> Both glCompressedTexImage2D() and glTexImage2D() call teximage(), which
> calls _mesa_choose_texture_format(), hitting this override code.  If we
> have actual S3TC source data, we can't treat it as any other format, and
> need to avoid the override.
>
> Since glCompressedTexImage2D() passes in a format of GL_NONE (which is
> illegal for glTexImage), we can use that to detect the pre-compressed
> case and avoid the overrides.
>
> Fixes a regression since 42723d88d370a7599398cc1c2349aeb951ba1c57.
>
> NOTE: This is a candidate for the 9.0 branch.
>
> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
> Cc: Ian Romanick <idr at freedesktop.org>
> Cc: Jordan Justen <jljusten at gmail.com>
> ---
>  src/mesa/main/teximage.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/src/mesa/main/teximage.c b/src/mesa/main/teximage.c
> index da8fbcd..dff50ca 100644
> --- a/src/mesa/main/teximage.c
> +++ b/src/mesa/main/teximage.c
> @@ -2806,7 +2806,7 @@ _mesa_choose_texture_format(struct gl_context *ctx,
>     /* If the application requested compression to an S3TC format but we don't
>      * have the DTXn library, force a generic compressed format instead.
>      */
> -   if (internalFormat != format) {
> +   if (internalFormat != format && format != GL_NONE) {
>        const GLenum before = internalFormat;
>
>        switch (internalFormat) {
> --
> 1.7.11.4
>