+ # Center of the top of the screen, at z = 0
+ fun top: Point3d[Float] do return new Point3d[Float](position.x + width / 2.0, position.y, 0.0)
+
+ # Center of the bottom of the screen, at z = 0
+ fun bottom: Point3d[Float] do return new Point3d[Float](position.x + width / 2.0, position.y - height, 0.0)
+
+ # Center of the left border of the screen, at z = 0
+ fun left: Point3d[Float] do return new Point3d[Float](position.x, position.y - height / 2.0, 0.0)
+
+ # Center of the right border of the screen, at z = 0
+ fun right: Point3d[Float] do return new Point3d[Float](position.x + width, position.y - height / 2.0, 0.0)
+
+ # Top left corner of the screen, at z = 0