Compiz rendering - excellent performnce, but not with XRende

[topblue]

When I use compiz I can get a window transparently blended with another, and the performance I am seeing is great (ATI graphicscard using radeon driver on FC6). Now here's the problem. When I try to to the same thing myself without a compositing window manager (using metacity) and implement the alpha blending with XRender extensions, the performance on the same hardware is miserable. Evidently, compiz is not using XRender.

Can somebody enlighten me as to why there is a different here in the two approaches?

Dave

[RYX]

Hi Dave!

I can't give you any technical details, but as far as I know compiz is using more than just XRender to achieve its performance. Many things are done through OpenGL and (since recently) through the new fragment-system and GLSL. You could ask this question on the official compiz-mailinglist, there you will likely get the most technical answer.

:)