Yes, this shader example uses relativity random colors, but if you reduce the given scaling factors for the r,g,b- values the 'linearity' of the mapping will be increased. It's only necessary to distinct the 1-0 jumps for each the color components. But well, this is the laziest mapping for sure (and still used by me
Did you have a mapping in mind and just has problems to casting it into a shader?
Or did you just search a good mapping? The second questions has no answer because the quality of the mapping depends one the input data and the 'target information' which should be accent. Well-known is the jet-mapping.
It exists many websites to this topic, i.e. http://cresspahl.blogspot.de/2012/03/ex ... ormap.html