I've never written shaders before, and now I'm trying to implement SSAO with SceneKit on OS X and iOS. I'm trying different SSAO shaders that I find, e.g. from Three.js, this one, and this one.
On OS X they all work as they should, but on iPhone all of them giving me the same artefacts (images show SSAO pass only). The lines move when I move the camera. So it must be because of some differences of OpenGL ES. Anyone knows what's wrong?