/sci/ - Science & Math

I decided to get a hobby and make vidya games but it's been about 8 years since I last did calculus and I'm getting filtered pretty bad.
I don't know how much sense this picture makes, but I've got a function (on the left) that spits out a radian between -[math]\pi[/math] and [math]\pi[/math]. Unfortunately, that doesn't correspond with how the engine (on the right) uses those values.
I think I'm trying to ask how to translate the values on the left into the values on the right.