All I know is, what I'm trying to do has been around since before pixel shaders were invented, and worked just fine without slowing everything down. (And on computers that are much less powerful than we've got today.) So obviously there's another way. I just don't know what it is, and in fact it's far enough out of my area of expertise that I don't know where to start looking.

I downloaded FX Composer--a program for building shaders--and read through the "basic quick start tutorial," and nothing in it made any sense to me. It came with a built-in library, including a RGB-to-HSL-transform shader. I tried to place that into a sample project, and it gave error messages with no explanations for them. Simply put, I'm trying to program something, and I don't know where to start, and all the "help" I've gotten from people in the past has been--to my level of knowledge, at least--supremely unhelpful gibberish.

That's my situation. Is anyone actually able to help out?