A flowmap Shader for Spark AR.
UPDATE now contains a Flowmap Visualizer Patch which will allow you to visualize any premade or also procedurally generated flowmap.
UPDATE with render passes in Spark AR V92 and this new shader version you can now interactively paint flowmaps directly in Spark!
Some info about what a flowmap is and does http://wiki.polycount.com/wiki/Flow_map
Use FlowMap Painter to generate your flowmap http://teckartist.com/?page_id=107
You can also Use Houdini Game Shelf Tools https://www.sidefx.com/tutorials/flowmap/
Check out a walkthrough of how to use it here https://www.youtube.com/watch?v=5JzOcSb5wuo