Function orthographic 

pub fn orthographic(
    left: f64,
    right: f64,
    bottom: f64,
    top: f64,
    near: f64,
    far: f64,
) -> DMat4

Creates an orthographic projection matrix for use with OpenGL.

Expects a right-handed Y-up view space input. Outputs NDC with Z in [-1, 1] and Y-up.

This is the OpenGL glOrtho equivalent.