# Immutable relative anchors for reference points on `camera`
private class CameraAnchor
	super IPoint3d[Float]

	# Reference camera
	var camera: UICamera

	# Reference position, the top left of the screen
	var ref: Point3d[Float] = camera.position is lazy

	# X position as proportion of the screen width
	var relative_x: Float

	# Y position as proportion of the screen height
	var relative_y: Float

	redef fun x do return ref.x + relative_x*camera.width
	redef fun y do return ref.y + relative_y*camera.height
	redef fun z do return ref.z

	redef fun offset(x, y, z) do return new OffsetPoint3d(self, x.to_f, y.to_f, z.to_f)
end