How to represent a polygon with hole(s)?

Question

It\'s usually popular to work with polygons with their vertices sorted CW or CCW in vectors(2*1 or 1*2 matrices). However, how to state polygons with holes in vectors?

Answer 1

You can break a polygon with a hole in it into two shapes without a hole. When you're doing contour integration in a complex plane, you can create a "cut" from one edge of the polygon that brings you to the edge of the hole; integrate around one side of the hole and back; then traverse around the other side for the second polygon. You end up with two path integrals along each cut that cancel each other out.

"visibility graph" - is this for a radiation view factor calculation with shading? Or a ray-tracing graphics algorithm?