Homeworld Effects Manual: setAddColorDist()
setAddColorDist(float red, float green, float blue)
Default values: (0,0,0)
Adds color uncertainty to a texture.
setAddColorDist() adds an amount of red, green, and blue to every pixel in the textures on an object. The amount of color is random, and the parameters indicate exactly how much deviation is allowed. Say a certain pixel has a red component of 64. If red is 96, the red component of that pixel may be anything between 0 and 160. (The red component can't be -32, that doesn't mean anything) Values are clamped at 1.0, so setAddColorDist(128, 3.5, 65534.9) is the same as setAddColorDist(1,1,1).
setAddColor() is disabled by setLighting(1).
For the maximum color randomness, use these two lines: setAddColor(0.5,0.5,0.5) and setAddColorDist(0.5,0.5,0.5). If you only use setAddColorDist(1,1,1) and no setAddColor(), the colors will vary between (-255,-255,-255) and (255,255,255). Half of that range is invalid and is replaced by (0,0,0), so half of your objects won't change color.
setAddColor(0.8,0.23,0.6), setAddColorDist(0,0,0)
setAddColor(1,0,0), setAddColorDist(0,0.5,0)
setAddColor(0,0,0), setAddColorDist(1,1,1)