func BlendFuncSeparate(sfactorRGB uint32, dfactorRGB uint32, sfactorAlpha uint32, dfactorAlpha uint32) {
	syscall.Syscall6(gpBlendFuncSeparate, 4, uintptr(sfactorRGB), uintptr(dfactorRGB), uintptr(sfactorAlpha), uintptr(dfactorAlpha), 0, 0)
}
func BlendFuncSeparate(sfactorRGB uint32, dfactorRGB uint32, sfactorAlpha uint32, dfactorAlpha uint32) {
	syscall.Syscall6(gpBlendFuncSeparate, 4, uintptr(sfactorRGB), uintptr(dfactorRGB), uintptr(sfactorAlpha), uintptr(dfactorAlpha), 0, 0)
}
// specify pixel arithmetic for RGB and alpha components separately