By Richard Maxwell
I wrote this because all the OpenGL and DirectX tutorials on the net and stackoverflow are all confusing and needlessly complicated. Conflating row and column matrices with matrix storage in computer memory, pre and post multiplication, right hand and left hand coordinates, and unexplained mathematical shortcuts and reader assumptions. It means it's hard to get anything right first time. So I wrote this document while I figured it all out myself, so that I could have a reference for myself later.