Coordinate Systems
==================

There are 4 coordinate systems:
1. world space
2. view space
3. gl space
4. pixel space

. code-block::
           camera        squash
    world -------> view -------> gl

camera is a user controlled transform. eg used for panning and zooming
squash: squahses the x axis by `aspect ratio`

https://learnopengl.com/Getting-started/Coordinate-Systems

gl: x: [-1, 1], y: [-r, r] where r = 1/aspect_ratio. +ve y is upward. origin at center of screen

pixel space: x: [0, dims.x), y: [0, dims.y). +ve y is downard. origin at top left corner of screen