Any difference with 3.0 Pixel Shading?

[imported_Noob]

Is there any difference between 2.0 and 3.0 Pixel Shading in terms of visual quality? I already know it is more efficient.

 

[Shinei]

No. Shader Model 3.0 is identical in featureset to Shader Model 2.x, aside from the efficiency improvements you already know about.
I suspect that nVidia took advantage of that fact so they could squeeze a little more performance out of their NV4x's after the next generation of GPUs hits by letting the older hardware use the newer, more efficient code, while maintaining the same image quality as everything else--not to mention that SM3.0 also lets them upgrade their Cg language (check the nVidia developer site, there's a new version of FX Composer that includes SM3.0 features).

 

[Gamingphreek]

Originally posted by: Shinei
No. Shader Model 3.0 is identical in featureset to Shader Model 2.x, aside from the efficiency improvements you already know about.
I suspect that nVidia took advantage of that fact so they could squeeze a little more performance out of their NV4x's after the next generation of GPUs hits by letting the older hardware use the newer, more efficient code, while maintaining the same image quality as everything else--not to mention that SM3.0 also lets them upgrade their Cg language (check the nVidia developer site, there's a new version of FX Composer that includes SM3.0 features).

Actually there is an advantage it hasn't been used yet though. HW Displacement Mapping is a feature not in SM2.x . Addittionally though not a SM3.0 feature HDR requires 32bit Floating Point precision, which IIRC is a requirement of SM3.

-Kevin

 

[Shinei]

HW is hardware, I'm assuming? I thought that displacement mapping was done at runtime by pixel colorations on the normal map... Or is the benefit that the displacement mapping transformation is handled by the GPU and not the CPU?

Either way, informative post. I didn't know that either of those were included in the SM3.0 spec, I just assumed that they were always features on the GPU since they're included in rendering programs...

 

[Gamingphreek]

Yes HW is Hardware... sorry for the slang

Well im not sure if 32bit FP Precision is a requirement for SM3.0 or not. I need someone wiser than i to verify that. But IIRC it is part of the spec.

-Kevin

 

[Shinei]

I don't think you need a 32-bit floating point buffer, since if I remember correctly, FarCry's OpenEXR method uses the NV40's 16-bit floating point buffer; it's not the precision level of the shader units (which just determines pixel coloration by channel allocation), it's the way the data is stored in the buffer... Or it used 64 bits of color data and stored it in the frame buffer... Or something. Damn, I wish I remembered how OpenEXR was implemented.

 

[BFG10K]

SM 3.0 can collapse multiple SM 2.0 passes into less of them and can make things run faster and more efficiently. Other than that there isn't really anything SM 3.0 can do that SM 2.0 can't.

Far Cry's HDR requires FP16 blending but that has absolutely nothing to do with SM 3.0.

 

[imported_Noob]

Originally posted by: Shinei
I don't think you need a 32-bit floating point buffer, since if I remember correctly, FarCry's OpenEXR method uses the NV40's 16-bit floating point buffer; it's not the precision level of the shader units (which just determines pixel coloration by channel allocation), it's the way the data is stored in the buffer... Or it used 64 bits of color data and stored it in the frame buffer... Or something. Damn, I wish I remembered how OpenEXR was implemented.

So there is an image quality difference?

 

[imported_Noob]

Am I getting this right? There is no image quality difference in 3.0 compared to 2.0 (whether it would be Far Cry, Doom3, etc)?

 

[Drayvn]

There can be an image quality difference.

As PS3 will give better performance, but if you start filling its code registers, and the graphics become more complex to display the quality improves and the performance decreases.

So yes PS3 can improve image quality.