func StencilOp(fail uint32, zfail uint32, zpass uint32) {
	syscall.Syscall(gpStencilOp, 3, uintptr(fail), uintptr(zfail), uintptr(zpass))
}
func StencilOp(fail uint32, zfail uint32, zpass uint32) {
	syscall.Syscall(gpStencilOp, 3, uintptr(fail), uintptr(zfail), uintptr(zpass))
}
func StencilOp ( fail uint32 , zfail uint32 , zpass uint32 ) { syscall . Syscall ( gpStencilOp , 3 , uintptr ( fail ) , uintptr ( zfail ) , uintptr ( zpass ) ) }
// set front and back stencil test actions
set front and back stencil test actions