I'm writing a game engine, and when I use a perspective camera I get a black screen. I am not going to ask exactly why this is because there would be a lot of code to share and, frankly, I think that's a bit petty a question even to bother you all with.
The trouble is that I don't know how to debug it. All that changes is my projection matrix, and if my projection matrix looks fine, I don't know why it doesn't work. Ideally I'd print out the values of various things as the shader did its calculations, but GLSL inconveniently doesn't have a printf() function.
So my question is: how do I debug my problem? The only thing I can think of is checking as many values as I can client-side and then programming by permutation, but I've done that and gotten nowhere. Is there a way I can see what's happening in the video card? Is there a completely different technique I could be using?
I'm using GLSL version 420 (and features specific to that version), so I don't think that glslDevil is an option, considering that it was last updated in 2010.
I managed to solve my problem through some completely unrelated debugging.