Paragraf is a great app to make graphic shaders. It's easy to use touch x/y coordinates and the camera feed as a texture. The results look beautiful on retina

Paragraf is a great app to make graphic shaders. It's easy to use touch x/y coordinates and the camera feed as a texture. The results look beautiful on retina displays. I've gotten several kids hooked on it, even overcoming some of the GLSL syntax hurdles to get their programs to work. I also gave them cheap $5 jeweller's loupes so they could inspect pixels as the program runs. Lots of kids genuinely want to create stuff.