private static PolySet Inset(ICollection <Polygon> polygons, IList <Vector3> vertices, PolySet polys, float insetDistance)
{
PolySet stitchedPolys = StitchPolys(polygons, vertices, polys, out EdgeSet stitchedEdge);
Dictionary <int, Vector3> inwardDirections = EdgeSet.GetInwardDirections(stitchedEdge, vertices);
// Push each vertex inwards, then correct
// it's height so that it's as far from the center of
// the planet as it was before.
foreach (KeyValuePair <int, Vector3> kvp in inwardDirections)
{
int vertIndex = kvp.Key;
Vector3 inwardDirection = kvp.Value;
Vector3 vertex = vertices[vertIndex];
float originalHeight = vertex.magnitude;
vertex += inwardDirection * insetDistance;
vertex = vertex.normalized * originalHeight;
vertices[vertIndex] = vertex;
}
return(stitchedPolys);
}