func StencilFuncSeparate(face uint32, xfunc uint32, ref int32, mask uint32) {
	syscall.Syscall6(gpStencilFuncSeparate, 4, uintptr(face), uintptr(xfunc), uintptr(ref), uintptr(mask), 0, 0)
}
func StencilFuncSeparate(face uint32, xfunc uint32, ref int32, mask uint32) {
	syscall.Syscall6(gpStencilFuncSeparate, 4, uintptr(face), uintptr(xfunc), uintptr(ref), uintptr(mask), 0, 0)
}
func StencilFuncSeparate ( face uint32 , xfunc uint32 , ref int32 , mask uint32 ) { syscall . Syscall6 ( gpStencilFuncSeparate , 4 , uintptr ( face ) , uintptr ( xfunc ) , uintptr ( ref ) , uintptr ( mask ) , 0 , 0 ) }
// set front and/or back function and reference value for stencil testing
set front and / or back function and reference value for stencil testing