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

[Brian P. <br...@va...>]

Keith Whitwell wrote:
> 
> 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.

OK.  A little benchmarking will let us know if we have anything
to worry about.

-Brian