func StencilMaskSeparate(face uint32, mask uint32) {
	syscall.Syscall(gpStencilMaskSeparate, 2, uintptr(face), uintptr(mask), 0)
}
func StencilMaskSeparate(face uint32, mask uint32) {
	syscall.Syscall(gpStencilMaskSeparate, 2, uintptr(face), uintptr(mask), 0)
}
// control the front and/or back writing of individual bits in the stencil planes