computeCentroid method
Computes the centroid for this polygon.
Implementation
Polygon computeCentroid() {
final centroid = this.centroid;
HalfEdge? edge = this.edge;
int count = 0;
centroid.set( 0, 0, 0 );
do{
centroid.add( edge!.vertex );
count ++;
edge = edge.next;
} while ( edge != this.edge );
centroid.divideScalar( count.toDouble() );
return this;
}