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Old 08-11-04, 02:44 AM   #1
FX 5700
Join Date: May 2003
Posts: 8
Question GLSL and frame buffer reads??


I did some GLSL programming, but quickly came up with a problem: Frame buffer reads do not seem to work at all. I'd like to do custom blending functions where one needs to have access framebuffer color and depth values (gl_FBColor and gl_FBDepth). Based on the GLSL spec I found frame buffer reads are in the experimental end of the GLSL feature set. Thus hardware and drivers may not support it at all.

Does anyone know if this is a HW issue, a driver issue or what?
Should I expect the situation to improve?

Here is an example of a compilation log I get:
(5) : error C1008: undefined variable "gl_FBColor"

And below is a sample fragment shader that would not compile:

void main (void)
gl_FragColor = gl_FBColor + vec4(0.2, 0.1, 0.1, 1.0);

I am using 61.06 drivers with an FX 5700 board.
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