I have some code that uses glBlendFuncSeparateOES and glBendEquationSeparateOES in order to render onto framebuffers with alpha.
However, I've found that a couple of my target devices do NOT appear to support these functions. They fail silently, and all that happens is that your render mode doesn't get set. My Kinda Fire cheapie tablet and an older Samsung both exhibit this behavior.
Is there a good way, on android, to query if they're actually implemented? I have tried eglGetProcAddress, but it returns an address for any string you throw at it!!!!!
Currently, I just have the game, on startup, do a quick render on a small FBO to see if the transparency is correct or if it has artifacts. It works, but it's a very kludgy method.
I'd much prefer if there was something like glIsBlendFuncSeparateSupported().
You can get a list of all available extensions using glGetString(GL_EXTENSIONS). This returns a space-separated list of supported extensions. For more details see Khronos specification.