private NativeArray <ECHoleData> GetHolesDataSortedByMaxX()
{
NativeArray <ECHoleData> holesData = new NativeArray <ECHoleData>(Polygon.HolesNum, Allocator.Temp);
for (int hi = 0; hi < Polygon.HolesNum; ++hi)
{
var hole = Polygon.GetPolygonHole(hi);
int indexMaxX = -1;
float maxX = float.MinValue;
for (int hvi = 0; hvi < hole.Length; ++hvi)
{
if (maxX < hole[hvi].Point.x)
{
maxX = hole[hvi].Point.x;
indexMaxX = hole[hvi].Index;
}
}
holesData[hi] = new ECHoleData
{
HoleIndex = hi,
HoleFirstIndex = hole[0].Index,
HoleLength = hole.Length,
BridgePointIndex = indexMaxX,
BridgePoint = Polygon[indexMaxX]
};
}
holesData.Sort();
return(holesData);
}
public void Execute()
{
NativeLinkedList <int> hullVertices = StorePolygonContourAsLinkedList();
#region Removing Holes
//create the array containing the holes data
NativeArray <ECHoleData> holes = GetHolesDataSortedByMaxX();
//remove holes
for (int hi = 0; hi < holes.Length; ++hi)
{
ECHoleData hole = holes[hi];
var intersectionEdgeP0 = hullVertices.GetEnumerator();
var intersectionEdgeP1 = hullVertices.GetEnumerator();
float2 intersectionPoint = new float2(float.MaxValue, hole.BridgePoint.y);
for (var currentHullVertex = hullVertices.Head; currentHullVertex.IsValid; currentHullVertex.MoveNext())
{
var nextHullVertex = (currentHullVertex.Next.IsValid) ? currentHullVertex.Next : hullVertices.Head;
float2 currPoint = Polygon[currentHullVertex.Value];
float2 nextPoint = Polygon[nextHullVertex.Value];
//M is to the left of the line containing the edge (M is inside the outer polygon)
bool isMOnLeftOfEdgeLine = (Math2DUtils.LineSide(hole.BridgePoint, currPoint, nextPoint) < 0f);
if (isMOnLeftOfEdgeLine)
{
continue;
}
// at least one point must be to right of the hole bridge point for intersection with ray to be possible
if (currPoint.x < hole.BridgePoint.x && nextPoint.x < hole.BridgePoint.x)
{
continue;
}
if (currPoint.y > hole.BridgePoint.y == nextPoint.y > hole.BridgePoint.y)
{
continue;
}
float intersectionX = nextPoint.x; // if line p0,p1 is vertical
if (math.abs(currPoint.x - nextPoint.x) > float.Epsilon)
{
float intersectY = hole.BridgePoint.y;
float gradient = (currPoint.y - nextPoint.y) / (currPoint.x - nextPoint.x);
float c = nextPoint.y - gradient * nextPoint.x;
intersectionX = (intersectY - c) / gradient;
}
if (intersectionX < intersectionPoint.x)
{
intersectionPoint.x = intersectionX;
intersectionEdgeP0 = currentHullVertex;
intersectionEdgeP1 = nextHullVertex;
}
}
var selectedHullBridgePoint = hullVertices.GetEnumerator();
//If I is a vertex of the outer polygon, then M and I are mutually visible
if (Math2DUtils.SamePoints(intersectionPoint, Polygon[intersectionEdgeP0.Value]))
{
selectedHullBridgePoint = intersectionEdgeP0;
}
else if (Math2DUtils.SamePoints(intersectionPoint, Polygon[intersectionEdgeP1.Value]))
{
selectedHullBridgePoint = intersectionEdgeP1;
}
else
{
//Select P to be the endpoint of maximum x-value for this edge
var P = (Polygon[intersectionEdgeP0.Value].x > Polygon[intersectionEdgeP1.Value].x) ? intersectionEdgeP0 : intersectionEdgeP1;
bool existReflexVertexInsideMIP = false;
float minAngle = float.MaxValue;
float minDist = float.MaxValue;
for (var currOuterPolygonVertex = hullVertices.Head; currOuterPolygonVertex.IsValid; currOuterPolygonVertex.MoveNext())
{
if (currOuterPolygonVertex.Value == P.Value)
{
continue;
}
var nextOuterPolygonVertex = (currOuterPolygonVertex.Next.IsValid) ? currOuterPolygonVertex.Next : hullVertices.Head;
var prevOuterPolygonVertex = (currOuterPolygonVertex.Prev.IsValid) ? currOuterPolygonVertex.Prev : hullVertices.Tail;
if (Math2DUtils.IsVertexReflex(
Polygon[prevOuterPolygonVertex.Value],
Polygon[currOuterPolygonVertex.Value],
Polygon[nextOuterPolygonVertex.Value],
true))
{
bool isInsideMIPTriangle = Math2DUtils.IsInsideTriangle(Polygon[currOuterPolygonVertex.Value],
hole.BridgePoint,
intersectionPoint,
Polygon[P.Value]);
existReflexVertexInsideMIP |= isInsideMIPTriangle;
if (isInsideMIPTriangle)
{
//search for the reflex vertex R that minimizes the angle between (1,0) and the line segment M-R
float2 MR = Polygon[currOuterPolygonVertex.Value] - hole.BridgePoint;
float angleMRI = math.atan2(MR.y, MR.x);
if (angleMRI < minAngle)
{
selectedHullBridgePoint = currOuterPolygonVertex;
minAngle = angleMRI;
}
else if (math.abs(angleMRI - minAngle) <= float.Epsilon)
{
//same angle
float lengthMR = math.length(MR);
if (lengthMR < minDist)
{
selectedHullBridgePoint = currOuterPolygonVertex;
minDist = lengthMR;
}
}
}
}
if (!existReflexVertexInsideMIP)
{
selectedHullBridgePoint = P;
}
}
}
hullVertices.InsertAfter(selectedHullBridgePoint, selectedHullBridgePoint.Value);
for (int i = hole.BridgePointIndex - hole.HoleFirstIndex, count = 0;
count < hole.HoleLength;
i = (i + hole.HoleLength - 1) % hole.HoleLength, ++count)
{
hullVertices.InsertAfter(selectedHullBridgePoint, i + hole.HoleFirstIndex);
}
hullVertices.InsertAfter(selectedHullBridgePoint, hole.BridgePointIndex);
}
holes.Dispose();
#endregion
Triangulate(hullVertices);
hullVertices.Dispose();
}