RGB Rainbow

Apr 5, 2018 • Arne Vogel

For the cyclic cellular automaton I had to get a variable amount of colors around the color circle. This is how I solved that problem.

I split the color wheel into 6 equal parts:

Sector/Color	R	G	B
0	incr.	0	255
1	255	0	decr.
2	255	incr.	0
3	decr.	255	0
4	0	255	incr.
5	0	decr.	255

incr. means the color is increasing and decr. means the color is decreasing going counter clockwise around the circle.

The pseudo code to achieve this:

#get the i'th color, of n colors. 
color(i,n):
	r, g, b = 0
	stepsize = floor((255*6)/n)
	progress = i*stepsize
	switch(floor(progress/255))
		case 0:
			b = 255
			r = progress%255
		case 1:
			r = 255
			b = progress%255
		case 2:
			r = 255
			g = progress%255
		case 3:
			g = 255
			r = progress%255
		case 4:
			g = 255
			b = progress%255
		case 5:
			b = 255
			g = progress%255
	return r, g, b

## Attributions RGB color wheel: https://commons.wikimedia.org/wiki/File:RGB_color_wheel_360.svg