Backwards compatiblity is another issue. But as far as pix shaders 2.0 go(It's easy to test what shaders are supported on a gpu) you can really do a TON you can't with pix shaders 1.
iirc with pix shaders 1.0 you can look up textures and do simple multiply etc, basically texture combiners with script like access. definitely useful, but pix shaders2.0+ can be much more complex. I did a per-pixel lighting routine entirely in a pixel shader for example, without using normal maps/dot3.
iirc with pix shaders 1.0 you can look up textures and do simple multiply etc, basically texture combiners with script like access. definitely useful, but pix shaders2.0+ can be much more complex. I did a per-pixel lighting routine entirely in a pixel shader for example, without using normal maps/dot3.