类: CSG.Polygon

class Polygon

Represents a convex polygon. The vertices used to initialize a polygon must
be coplanar and form a convex loop. They do not have to be `CSG.Vertex`
instances but they must behave similarly (duck typing can be used for
customization).

Each convex polygon has a `shared` property, which is shared between all
polygons that are clones of each other or were split from the same polygon.
This can be used to define per-polygon properties (such as surface color).