On Tue, Mar 13, 2007 at 07:05:56PM +0100, Stefan Dösinger wrote:
- Software Vertex Shaders
Not a project for fancy new graphics, but rather to help compatiblity with older cards, for feature completeness and most notably testing. Native DirectX supports Vertex(not pixel) shaders in the CPU, for cards which can't do them, if the application specifically requests this, and for IDirect3DDevice9::ProcessVertices. The use for old cards should be obvious :-) , and ProcessVertices would allow us to test the results of a vertex shader in a more direct way than the visual test does.
This will require a lot of x86 assembler work. For performance reasons the d3d asm should be cross-compiled to x86 mmx instructions and then executed directly. The main challenge will be to overcome the architectural differences between a gpu and a normal cpu.
Why duplicate this? We should be able to use the GLSL or ARB shader software emulation the/a opengl lib might provide. I guess dri+mesa does provide this for cards that don't support shading, but at least the stand alone (non-dri) mesa supports shading.
Jan