[Mesa-dev] [PATCH 1/3] r600: Change default behaviour for undefined COLOR0

[Roland Scheidegger]

Am 04.04.2016 um 14:04 schrieb Axel Davy:
> On 03/04/2016 20:41, Roland Scheidegger wrote :
>> Am 03.04.2016 um 10:11 schrieb Axel Davy:
>>> d3d 9 needs COLOR0 to be 1.0 on all channels when
>>> undefined. 0.0 for the others is fine.
>>> GL behaviour is undefined.
>>>
>> Not that I care what drivers use by default for undefined values, but it
>> probably would be better to fix that properly in the state tracker since
>> certainly gallium doesn't impose that default...
>>
>> Roland
>>
> Implementing it properly in the state tracker is a bit annoying,
> because of possible combinations of usage ff pipeline vs non ff pipeline.
> It would be made easier if (0,0,0,0) was defined as the default in gallium,
> so only COLOR0 would have to be checked, else all outputs/inputs have to
> be checked.
> 
> As it seems rather easy to fix in the driver, I chose that way.
Well all zeros might look sane as a default. I have no idea however
which drivers would conform to it - seems a bit unfair to "break" them
by a doc update...
(Though requiring a different default just on color0 input is indeed
insanity on d3d9's part.)

> 
> There seems to be very few games relying on the behaviour.
Yes, hopefully...

Roland