Re: [Mesa3d-dev] Re: Modularization of software rasterizer

[Keith W. <ke...@va...>]

Brian Paul wrote:
> 
> I am concerned about the performance hit of vertex translation.
> There are some people still using software rendering who are
> concerned about performance.  In one instance, people are running
> the off-screen renderer on large parallel machines and using
> composition to generate complex images. They'd likely notice a
> performance hit if there were one.
> 
> I'll have to think about this more.
> 
> Have you considered adopting Glide's "programmable" vertex format
> idea?  That is, we specify at runtime the offsets into the vertex
> struct for XYZW, colors, texcoords, etc.

I'm providing a RasterSetup stage to do this once per vertex buffer.  A
programmable vertex format is possible but complex.  I'm reluctant to do
anything like that unless translation turned out to be a bottleneck.  As I
said, the hardware drivers all do the same thing and the performance of those
drivers *is not* dominated by this stage.  

Keith