[Mesa-dev] I need some help about OGL extensions (Was Re: About merging pipe-video to master)

[Christoph Bumiller]

On 13.07.2011 12:29, Christian König wrote:
> Hi Henri and everybody else on the list,
>
> Am Dienstag, den 12.07.2011, 19:01 +0200 schrieb Henri Verbeet:
>> I guess my point was mostly that there's not much of a point in doing
>> the clamping both through BLEND_CLAMP and the fragment shader. Also, I
>> guess we need this for EG+ as well.
> Oh, I got quite a problem here: After your mail I created patches to
> push the changes to r600g separately into master. While doing so I also
> checked that there are no piglit regressions, unfortunately the
> "arb_color_buffer_float" test is now failing.
>
> After reading "ARB_color_buffer_float" extension (again) and checking
> that against the r600 documentation, I realized that the behavior of the
> BLEND_CLAMP bit on r600 hardware has nothing todo with clamping the
> fragment color.
>
> As the name of this (well documented) hardware flag already implies: It
> just disabled clamping the output of the fragment shader BEFORE blending
> to a normalized buffer.