[Mesa-dev] Uploading PIPE_FORMAT_B8G8R8A8_UNORM to pixmap texture in PIPE_FORMAT_B8G8R8X8_UNORM

Jerome Glisse j.glisse at gmail.com
Wed Dec 15 11:25:42 PST 2010

On Wed, Dec 15, 2010 at 2:20 PM, Christoph Bumiller
<e0425955 at student.tuwien.ac.at> wrote:
> On 12/15/2010 07:55 PM, Jerome Glisse wrote:
>> Hi,
>> I am facing an issue which i am not sure what is the proper things to
>> do about. piglit tfp test try to upload PIPE_FORMAT_B8G8R8A8_UNORM to
>> texture pixmap which is  PIPE_FORMAT_B8G8R8X8_UNORM r600g assert in
>> blitter util because format are not compatible. Should all pixmap
>> texture considered with A8 ? Should i just disable the assert in case
>> of A->X convertion ? Other answer ?
> 1. The assertion is in the wrong place, since util_blitter_copy_region's
> description reads:
> "You can copy from any color format to any other color format provided
> the former can be sampled and the latter can be rendered to. Otherwise,
> a software fallback path is taken and both surfaces must be of the same
> format."
> 2. The arguments to util_is_format_compatible in the assertion are
> reversed:
> "Whether the src format can be blitted to destation format with a simple
> memcpy." - this is true for A8 -> X8, only X8 -> A8 cannot be done with
> memcpy.
> assert(util_is_format_compatible(util_format_description(dst->format),
> util_format_description(src->format)));
> boolean util_is_format_compatible(const struct util_format_description
> *src_desc, const struct util_format_description *dst_desc);
> Christoph

I agree with that but the root issue remain, what is the expected
result of X8 pixmap when uploading A8 channel.


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