Re: gEDA-dev: Faster PCB + GL

[Aapo Tahkola <aet@xxxxxxxxxxxxxx>]

Hi.

On Sat, 21 Jun 2008 23:29:16 +0100
Peter Clifton <pcjc2@xxxxxxxxx> 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). 

-- 
Aapo Tahkola


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