[cairo] Per Vertex Color Emulation

Aron Rubin aron.rubin at lmco.com
Fri Aug 29 11:45:17 PDT 2008

Travis Griggs wrote:
> On Aug 29, 2008, at 7:28 AM, Aron Rubin wrote:
>> I have a OpenGL heat map overlay that I need to also render using  
>> cairo. Is
>> there a good way to emulate per vertex color?
> Ideally, you'd like a mesh gradient to do this. A couple of us  
> actually sat around the table yesterday, at the Cairo Summit, and  
> sought for concensus on what the API would look like for supporting  
> Type 7 Tensor-Product gradients. So not yet... but maybe in an  
> experimental build some time soon.

That sounds awesome but I need something that is possible even with cairo 1.4.
Looking at the insides of cairo it looked like per vertex colors should be
do-able but is not exposed by the API in any way. I think you were

I was just thinking maybe I could set the source to a 2x2 pixel surface warped
to fit each quad. That sounds painfully slow though.



ssh aron at rubinium.org cat /dev/brain | grep ^work:

Aron Rubin                       Senior Member, Engineering Staff
Lockheed Martin                  E-Mail: arubin at atl.lmco.com
Advanced Technology Laboratories Phone:  856.792.9865
3 Executive Campus               Fax:    856.792.9930
Cherry Hill, NJ USA 08002        Web:    http://www.atl.lmco.com

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