How to debug a shader on iOS?

I have an OpenGL shader that is working fine on desktop (OpenGL, both on Windows and Mac) but it just shows a black screen on iOS.
Is there any way to debug the shader while running on the device? Or is there a way to tell the desktop version to use OpenGL ES 2.0 so that at least it should be a bit easier to debug this issue?


There is an Angle project that uses the Angle OpenGL ES 2.0 emulator for Windows.

Never tried that before. I’ll read about it.
I thought there could be a way to attach Xcode to a running MG game on a real device but it looks like the debugger cannot be attached to a running app that isn’t coming from an Xcode project containing the sources. Or at least I couldn’t find a way to do that. Have you ever tried?