OpenGL and DirectX11 not support FFP, and GFDevice::disableShaders has not the necessary information to decide the shader to be used.
GFDevice::SetupGenericShaders is used instead of GFDevice::disableShaders.
GFDevice::disableShaders will be deprecated on T3D 4.0
- Modified the glow postFX to now respect the current viewport settings.
- This fixes glow rendering for the Oculus Rift and any other time the
glow rendering should be limited to a region of the back buffer.