Should IHVs write their own MS HLSL compilers?

[MrGaribaldi]

AFAIK ATI/Valve have more or less implemented a suggestion that Colorless made - I think they have created a special texture type and ATI recognises these textures for centroid sampling - so it doesn't detect the application, it just looks out for these textures.

Thanks for the info

I thought there might be a way for the app to tell the drivers to use centroid sampling instead of the driver detecting the app, but had no idea on how they'd do it...

 

[Clootie]

Yep, for ATI R3xx chips in PS_2_0: 'dcl_pp t0' == 'dcl_centroid t0'

But that can not work for all shaders - what happens to those shaders which do not want centroid sampling but are using _pp, assuming R3xx will ignore it, and nv will use it? There also has to be the dreaded app detection built into the R3xx drivers, no?

According to DX docs setting _pp modifier for texture coordinates and using them later for non-dependent texture reads (from tXX registers not from rXX) have no meaning. So all chips read texture data at full precision here.

I'm afraid you are mistaken.

Why? Has it changed by now?