My first question:
I want to use a sqrt function in my fragment program. Is it really slower than a simple op like + or * ? I mean, does it worth doing a precomputed table I would access when I need a square root, or can I use the sqrt function and don't care about a possible slow down ?
My second question:
What is GLslang ? is it Opengl Shading Language (as described in the spec about "Opengl Shading Language" or is it another language ?
More generally, what do you think about the different languages dealing with fragment programs in opengl ? (like GLslang, Cg, etc..)