playing with glsl fragment shaders
can be run in your browser:
https://0xcafed00d.github.io/glsl/index.html?frag=1.frag
https://0xcafed00d.github.io/glsl/index.html?frag=2.colour_wheel.frag
https://0xcafed00d.github.io/glsl/index.html?frag=3.mandelbrot.frag