I learned something about GPUs today

This is one of those bugs that taught me something, so I did this writeup. I hope it's interesting. I tried to write it like a murder mystery, showing you the bug first and then dropping clues until the reveal, so maybe if you're into graphics programming you'll go "aha!" at some point and figure it out before you get to the end.

I am under impression that “do not use floats as ints” is common knowledge.