I am using glslDevil for shader debugging. I had to buy a certain videocard to be able to do that though.
The vertex shader debugging is very good and actually is much better than I expected.
However I seem not to be able to inspect varying variables when debugging a fragment shader. Nor I can inspect variables that are calculated based on varying variables.
The varying variables in question are set correctly - the shader works, but only when I am not debugging it. When I do step through debugger such variables show either zero or NAN and the whole fragment is colored black.
Is is a design feature or I am doing something wrong ?
See the attache image. The vertex shader shows correct direction.x = 1, while the fragment shader shows it as 0.
It also can show NAN.