[Mesa-dev] [PATCH] mesa: do more teximage error checking for generic compressed formats

[Anuj Phogat]

On Thu, Aug 16, 2012 at 10:23 AM, Brian Paul <brianp at vmware.com> wrote:
> On 08/15/2012 02:31 PM, Anuj Phogat wrote:
>>
>> On Tue, May 1, 2012 at 2:07 PM, Brian Paul <brianp at vmware.com
>> <mailto:brianp at vmware.com>> wrote:
>>
>>     When glTexImage or glCopyTexImage is called with internalFormat
>>     being a
>>     generic compressed format (like GL_COMPRESSED_RGB) we need to do
>>     the same
>>     error checks as for specific compressed formats.  In particular,
>>     check if
>>     the texture target is compatible with the format.  None of the texture
>>     compression formats we support so far work with GL_TEXTURE_1D, for
>>     example.
>>
>>     See also https://bugs.freedesktop.org/show_bug.cgi?id=49124
>>
>>
>> Brian, generic texture compression formats with GL_TEXTURE_1D seem to
>> work fine
>> on i965 drivers.
>
>
> Does that wind up using one of the DXT formats?
It uses RGTC for GL_COMPRESSED_RED & GL_COMPRESSED_RG
FXT for GL_COMPRESSED_RGB & GL_COMPRESSED_RGBA

>
>  I verified this by allowing generic texture
>>
>> compression formats for
>> GL_TEXTURE_1D in piglit copyteximage test case and reverting the
>> changes due to
>> this patch on mesa. Is this an issue only on swrast?
>
>
> That's what the bug reported, don't recall testing other drivers.
>
>
>
>> Returning
>> GL_INVALID_ENUM
>> error for generic texture compression formats in glTexImage1D() and
>> glCopyTexImage1D() doesn't seem to follow the OpenGL
>> specification. Spec does allow
>> GL_INVALID_ENUM error for a similar scenario in case
>> of glCompressedTexImage1D().
>> Please correct me if I'm missing something.
>
>
> I guess I'd like to check what either NVIDIA or AMD do in some of these
> cases.
>
> AFAIK, the various DXT, LATC, etc compressed formats are only spec'd to work
> with 2D textures, not 1D.  Since 1D textures are generally pretty small to
> start with, there's not a lot of value in compressed 1D textures.  Plus, if
> a compressed 1D texture uses 4 or 8 bytes to store a 4x1 block of texels,
> there's only 50% or 0% memory savings with compression.
>
> If you can post your patch for the piglit test I can run it with the NVIDIA
> driver and see what it does.
I'll send out a follow up patch for piglit test case which you can use
for testing.

>
> -Brian