private static extern unsafe void *GenerateStraightSkeleton(Poly *outer, Poly *holes, int holesCount, Poly *straightSkeleton, Poly *spokesResult);
private static extern unsafe void FreePolygonStructMembers(Poly *result);
private static unsafe StraightSkeleton ExtractResult(IReadOnlyList <Vector2> outer, IReadOnlyList <IReadOnlyList <Vector2> > holes, Poly *skeletonResult, Poly *spokesResult, IntPtr handle)
{
//Set of all vertices supplied as input
var inputVertices = new HashSet <Vector2>(outer);
inputVertices.UnionWith(holes.SelectMany(h => h));
//An edge is either:
// - border
// - input -> input
// - spoke
// - input -> skeleton
// - input -> spoke
// - spoke -> skeleton
// - skeleton
// - skeleton -> skeleton
var borders = new HashSet <KeyValuePair <Vector2, Vector2> >();
var spokes = new HashSet <KeyValuePair <Vector2, Vector2> >();
var skeleton = new HashSet <KeyValuePair <Vector2, Vector2> >();
//Extract skeleton edges
for (var i = 0; i < skeletonResult->VerticesLength / 4; i++)
{
skeleton.Add(OrderByHash(
new Vector2(skeletonResult->Vertices[i * 4 + 0], skeletonResult->Vertices[i * 4 + 1]),
new Vector2(skeletonResult->Vertices[i * 4 + 2], skeletonResult->Vertices[i * 4 + 3])
));
}
//Extract spokes
for (int i = 0; i < spokesResult->VerticesLength / 4; i++)
{
spokes.Add(OrderByHash(
new Vector2(spokesResult->Vertices[i * 4 + 0], spokesResult->Vertices[i * 4 + 1]),
new Vector2(spokesResult->Vertices[i * 4 + 2], spokesResult->Vertices[i * 4 + 3])
));
}
//Extract borders
for (int i = 0; i < outer.Count; i++)
{
borders.Add(OrderByHash(
outer[i],
outer[(i + 1) % outer.Count]
));
}
//Extract borders from holes
foreach (var hole in holes)
{
for (int i = 0; i < hole.Count; i++)
{
borders.Add(OrderByHash(
hole[i],
hole[(i + 1) % hole.Count]
));
}
}
return(new StraightSkeleton(inputVertices, borders, spokes, skeleton, handle));
}
