Render the layer. This method is called once per frame. The implementation should not make any assumptions about the GL state (other than that the correct context is active). It may make changes to the state, and is not required to reset values such as the depth mask, stencil mask, and corresponding test flags to their original values. Make sure that you are drawing your fragments with a z value of 1 to take advantage of the opaque fragment culling in case there are opaque layers above your custom layer.
Parameters
parameters
The `custom layer render parameters` that define the current camera position.