How to debug a GLSL shader?

Question

I need to debug a GLSL program but I don\'t know how to output intermediate result. Is it possible to make some debug traces (like with printf) with GLSL ?

Answer 1

I have found Transform Feedback to be a useful tool for debugging vertex shaders. You can use this to capture the values of VS outputs, and read them back on the CPU side, without having to go through the rasterizer.

Here is another link to a tutorial on Transform Feedback.