Re: [Mesa3d-dev] GLSL support in drivers

[Brian P. <bri...@tu...>]

Stephane Marchesin wrote:
> Keith Whitwell wrote:
>> Philipp Klaus Krause wrote:
>>   
>>> Brian Paul schrieb:
>>>
>>>     
>>>> But we might ask ourselves if we really want to expose the shading 
>>>> language in drivers that can't actually run shaders with conditionals, etc.
>>>>
>>>>       
>>> With loop unrolling and use of the SLT instruction it could be possible
>>> to run many shaders on that hardware.
>>>     
>> Yes, there are lots of ways to simulate branches, I don't think we've 
>> really touched on what can be achieved yet.
>>
>> Even on hardware that supports branching, it is probably an optimization 
>> to eliminate them wherever possible.
>>
>>   
> Btw, what's the plan for these optimizations, which are obviously 
> card-dependent (for example one card may perform better with loop 
> unrolling, another one may not). It makes sense to have these be 
> card-specific, but it doesn't really make sense to have the code 
> rewritten 10 times...

Loop unrolling (and various other things) should probably be done in the 
GLSL code generator since it's a device-independent transformation.

Other techniques that are card-specific would be done in the drivers.

I have other priorities for the near future but I encourage others to 
work on optimization techniques.

-Brian