On Mon, 2008-06-30 at 08:36 +0300, Aapo Tahkola wrote:
> Hi.
> 
> On Sat, 21 Jun 2008 23:29:16 +0100
> Peter Clifton <[EMAIL PROTECTED]> wrote:
> 
> > This attempt uses an array of triangle primatives for lines, line caps
> > and filled circles. These are flushed if the colour changes, the
> > triangle array fills up, and after rendering completes.
> 
> Implementing a vertex buffer cache for circles and other heavily
> tesselated objects might be a cheap and easy way to get more speed.
> It's a good idea to place the color in seperate array with 0 stride as
> most drivers are smart enough not to "generate" new color for each
> vertex. Also, mixing immediate mode with non-immediate in one
> rendering operation might make some drivers to stupid things(like
> replicating the color for each vertex) so it's better to use
> gl*Pointer all the way.
> 
> If you can, please avoid using smooth points and line stipple as these
> are currently software rendered by open source r300 driver(radeon 9500
> and up). 

Thanks for the pointers. I'm away at the moment, so am not doing
anything on this coding at the moment, but your tips will be useful when
I get back.

Vertex buffer caches should be useful for repeated geometry, but
unfortunately PCB's drawing model doesn't easily let you know you're
drawing the same object again later. Might have to make some kind of
cache.

Best wishes,

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)



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