internal/graphicsdriver/opengl/gl/package_windows.go
func AlphaFunc(xfunc uint32, ref float32) {
	syscall.Syscall(gpAlphaFunc, 2, uintptr(xfunc), uintptr(math.Float32bits(ref)), 0)
}
func AlphaFunc(xfunc uint32, ref float32) {
	syscall.Syscall(gpAlphaFunc, 2, uintptr(xfunc), uintptr(math.Float32bits(ref)), 0)
}
// specify the alpha test function