Soundcoder app for iPhone and iPad
Apple provides its own language for writing shaders, the Metal Shading Language (MSL for short) and it can be used for both graphics and compute processing.
Metal Shading Language is a single, unified language based on the C++ programming language that allows integration between the graphics and compute programs.
Soundcoder is an programming environment for real-time audio synthesis and algorithmic composition using Metal Shading Language.