public static List <List <Vector2> > Simplify(List <Vector2> vertices)
{
var polygons = new List <List <Vector2> >();
var vertexCount = vertices.Count;
for (var edgeOneIndex = 0; edgeOneIndex < vertexCount - 2; edgeOneIndex++)
{
var lastEdgeIndex = vertexCount - 1;
var edgeOne = new Segment(vertices[edgeOneIndex], vertices[(edgeOneIndex + 1) % vertexCount]);
//First index is neighbor with last index
if (edgeOneIndex == 0)
{
lastEdgeIndex--;
}
for (var edgeTwoIndex = edgeOneIndex + 2; edgeTwoIndex <= lastEdgeIndex; edgeTwoIndex++)
{
var edgeTwo = new Segment(vertices[edgeTwoIndex], vertices[(edgeTwoIndex + 1) % vertexCount]);
if (Segment.Intersect(edgeOne, edgeTwo, out var intersectionPoint))
{
var subPolygonOne = new List <Vector2>();
for (var i = 0; i <= edgeOneIndex; i++)
{
subPolygonOne.Add(vertices[i]);
}
subPolygonOne.Add(intersectionPoint);
for (var i = edgeTwoIndex + 1; i < vertexCount; i++)
{
subPolygonOne.Add(vertices[i]);
}
var subPolygonTwo = new List <Vector2>();
subPolygonTwo.Add(intersectionPoint);
for (var i = edgeOneIndex + 1; i <= edgeTwoIndex; i++)
{
subPolygonTwo.Add(vertices[i]);
}
var simplifiedSubPolygonOne = Simplify(subPolygonOne);
var simplifiedSubPolygonTwo = Simplify(subPolygonTwo);
for (var i = 0; i < simplifiedSubPolygonOne.Count; i++)
{
polygons.Add(simplifiedSubPolygonOne[i]);
}
for (var i = 0; i < simplifiedSubPolygonTwo.Count; i++)
{
polygons.Add(simplifiedSubPolygonTwo[i]);
}
return(polygons);
}
}
}
polygons.Add(vertices);
return(polygons);
}
private static bool TryFindASurgerySegment(List <Vector2> vertices, List <List <Vector2> > holes, int holeIndex, ref int holeVertexIndex,
Segment otherSurgerySegment, HashSet <int> vertexIndexSet, out SurgerySegment surgerySegment)
{
var holeCount = holes.Count;
var hole = holes[holeIndex];
var holeVertexCount = hole.Count;
for (; holeVertexIndex < holeVertexCount; holeVertexIndex++)
{
var holeVertex = hole[holeVertexIndex];
var vertexCount = vertices.Count;
for (var vertIndex = 0; vertIndex < vertexCount; vertIndex++)
{
if (vertexIndexSet.Contains(vertIndex))
{
continue;
}
var vertex = vertices[vertIndex];
var segment = new Segment(holeVertex, vertex);
var intersection = Segment.Intersect(segment, otherSurgerySegment);
if (intersection)
{
continue;
}
var nextHoleVertexIndex = (holeVertexIndex + 1) % holeVertexCount;
for (var j = 0; j < holeVertexCount - 2; j++)
{
var index = (nextHoleVertexIndex + j) % holeVertexCount;
var comparedSegment = new Segment(hole[index], hole[(index + 1) % holeVertexCount]);
if (Segment.Intersect(segment, comparedSegment))
{
intersection = true;
break;
}
}
if (intersection)
{
continue;
}
for (var j = 0; j < holeCount; j++)
{
if (j == holeIndex)
{
continue;
}
var comparedHole = holes[j];
if (Segment.Intersect(segment, comparedHole))
{
intersection = true;
break;
}
}
if (intersection)
{
continue;
}
var nextVertexIndex = (vertIndex + 1) % vertexCount;
for (var j = 0; j < vertexCount - 2; j++)
{
var index = (nextVertexIndex + j) % vertexCount;
var comparedSegment = new Segment(vertices[index], vertices[(index + 1) % vertexCount]);
if (Segment.Intersect(segment, comparedSegment))
{
intersection = true;
break;
}
}
if (!intersection)
{
// Debug.DrawLine(segment.p, segment.q, Color.red, 10);
vertexIndexSet.Add(vertIndex);
surgerySegment = new SurgerySegment(holeVertexIndex, vertIndex);
return(true);
}
}
}
surgerySegment = new SurgerySegment();
return(false);
}