[Mesa-dev] [Mesa3d-dev] ARB draw buffers + texenv program

[Dave Airlie]

>>> buffers.
>> But you'll have more shader instructions for writing to all these
>> outputs right? I think that could still make a difference, though it
>> might be more theoretical rather than in practice.
>>
>
> Right, I was talking specifically about memory bandwidth. But it would
> take a few extra instructions as well.  I think the major impact will
> be the additional memory bandwidth rather than the added instructions.
>


I also thought about this a bit more, and I'm guessing GPUs use this
to optimise cache usage. If they know they are rendering the same data
to all 1..n render targets they only need to store one copy in the dst
cache.

Dave.