https://github.com/lispgames/mathkit.git

```
git clone 'https://github.com/lispgames/mathkit.git'
```

(ql:quickload :mathkit)

★6

This is a purely math-related utility kit, providing functions which can be useful for games, 3D, and GL in general. Right now this includes additional matrix functionality by @3b on top of sb-cga.

`ortho-matrix LEFT RIGHT BOTTOM TOP NEAR FAR`

: Construct an orthographic matrix like`glOrtho`

from OpenGL 2.1.`frustum LEFT RIGHT BOTTOM TOP NEAR FAR`

: Construct a perspective matrix from the given parameters, like`glFrustum`

from OpenGL 2.1.`perspective-matrix FOVY-DEGREES ASPECT Z-NEAR Z-FAR`

: Construct a perspective matrix from the given parameters, like`gluPerspective`

from OpenGL 2.1.`look-at EYE TARGET UP`

: Where`EYE`

,`TARGET`

, and`UP`

are vectors, construct a viewing matrix much like`gluLookAt`

from OpenGL 2.1.

**Note:** These merely *create* native Lisp matrices; they do **not**
*multiply* them like the similar GL functions or in any way set them
as GL state like the old fixed-function pipeline.

Additionally:

`copy-matrix M`

: Create a copy of`M`

.`deg-to-rad D`

: Convert`D`

degrees to radians.