Would it be at all possible to make a shader that has a magma flow?
I am wondering if it would be fast enough? It would be great to be able to return a color based on distances from things etc.
Kind of like the VRay distancetex but with way more flexibility.
R
We already have an Ember texture map which reads a Color channel from the Ember grid and produces a 3D procedural map.
It is not exactly what you are asking for, but a good Proof Of Concept that it is possible and fast enough.
A Magma-based texture map is on the internal wishlist, but it is not on the current roadmap, so we cannot tell when it might happen.
I actually do this very thing (adjust values by object proximity…face direction relative to speed…) by using a gradient map. I adjust a mapping channel to have the U value progress from 0-1 depending on what I want and use a gradient as the texture. it works great. I generally need a lot of verts to get a smooth transition, but it works very well has been fast enough for my needs so far.
But I do want a magma-flow based map too 
Charley, this is very interesting. Could you post an example?
In this case (and most of the time I need this) I only generate one part of the UV (generally the U). But you can easily use this idea to add a V component so you can introduce noise, or using the existing V.
Still think this is a great idea. Not the material IDs by proximity that bobo just cooked up. I could see this as a float value feeding into a blend material of a dozen other ideas along the same lines.
-Michael