[Mesa-dev] [PATCH 6/7] softpipe: add dual source blending support

[Dave Airlie]

On Wed, Apr 4, 2012 at 4:16 PM, Brian Paul <brianp at vmware.com> wrote:
> On 04/03/2012 07:16 AM, Dave Airlie wrote:
>>
>> From: Dave Airlie<airlied at redhat.com>
>>
>> This adds support for a single dual source blending MRT to softpipe.
>
>
> Why can't we do dual-source blending to all RTs?

The problem is currently TGSI can't encode (location, index) color
shader outputs,

So the shader outputs would have to be mapped from a 1 dimensional
array to something 2 dimensional,
either defining alternate output colors as primary/secondary, or the
secondary color as being an array after the primary color outputs.

So I checked the hw, and none of it does this, they all report 1 dual
source MRT, so I see no reason to make gallium care until someone
creates hw that cares.

Dave.

>
> -Brian
>