Okay, I see that OpenGL ES is not yet supported yet in GemRB 0.9.0. I see that PiKiss offers GemRB 0.8.8 using OpenGL ES. So does GemRB 0.8.8 support OpenGL ES on the Raspberry Pi?
Re: So I tried it, it works but not really. I tried it in full screen and windowed mode but the GUI is all garbled. I get the same result when using the PiKiss version.