I don't think there is any need to make monster out of multimap. It should be kept simple as the rest of corona, and instead it should be fixed to work correctly.
Right now, blending is done per channel, which is wrong. Once it's fixed and blending is done in HSV space, then you will be able to randomize hue this way:
- Set item count to 3
- Make item colors R, G and B
- set mode to Instance
- then if you render, you will get entire hue gradient.
- then you will plug your (for example leaf) texture into CoronaMix as bottom map
- plug the CoronaMultiMap as a top map, and set mix operations to Overlay
- Then you can simply use mix amount to define how much the hue randomized MultiMap influences color variation
But as i said, it has to be bugfixed first.
Other things you can do already now, for example randomize saturation:
- create MultiMap and set item count to 2
- in first slot, plug your texture
- create Max's native Mix map, and plug your texture as mix amount. This will convert your texture to grayscale
- Plug this Mix map into second slot
- Now change mix amount. This will randomize saturation across instances.
To randomize value:
- create MultiMap and set item count to 2
- make one item color white, and one black
- plug your texture into CoronaMix map as bottom map
- plug the MultiMap as a top map, and set MultiMap's mix amount to 50%
- In CoronaMix, set Mix operation to overlay, and use Mix amount to define how strong the value (brightness) randomization will be
