void Cleanup()
{
for (int i = 0; i < edges.Count; ++i)
{
ConvexHullEdge edge = edges[i];
if (edge.remove)
{
Vector3D point1 = edge.pointA;
Vector3D point2 = edge.pointB;
int keyToEvict = Key2Edge(point1, point2);
edgeMap.Remove(keyToEvict);
edges.RemoveAt(i--);
}
}
for (int i = 0; i < faces.Count; ++i)
{
ConvexHullFace face = faces[i];
if (face.visible)
{
faces.RemoveAt(i--);
}
}
}
public void Erase(ConvexHullFace face)
{
if (adjface2 == face)
{
adjface2 = null;
}
else
{
adjface1 = null;
}
}
private void CreateEdge(Vector3D pointA, Vector3D pointB, ConvexHullFace face)
{
int key = Key2Edge(pointA, pointB);
if (!edgeMap.ContainsKey(key))
{
ConvexHullEdge edge = new ConvexHullEdge(pointA, pointB);
edges.Add(edge);
edgeMap.Add(key, edge);
}
edgeMap[key].LinkAdjFace(face);
}
void AddOneFace(Vector3D pointA, Vector3D pointB, Vector3D pointC, Vector3D innerPoint)
{
faces.Add(new ConvexHullFace(pointA, pointB, pointC));
ConvexHullFace face = faces[faces.Count - 1];
if (VolumeSign(face, innerPoint) < 0)
{
face.Reverse();
}
CreateEdge(pointA, pointB, face);
CreateEdge(pointA, pointC, face);
CreateEdge(pointB, pointC, face);
}
public bool BuildFirstHull(List <Vector3D> points)
{
int pointCount = points.Count;
if (pointCount <= 3)
{
return(false);
}
int i = 2;
while (Colinear(points[i], points[i - 1], points[i - 2]))
{
if (i++ == pointCount - 1)
{
return(false);
}
}
ConvexHullFace face = new ConvexHullFace(points[i], points[i - 1], points[i - 2]);
int j = i;
while (VolumeSign(face, points[j]) == 0)
{
if (j++ == pointCount - 1)
{
return(false);
}
}
Vector3D pointA = points[i];
Vector3D pointB = points[i - 1];
Vector3D pointC = points[i - 2];
Vector3D pointD = points[j];
processedPoints.Add(pointA);
processedPoints.Add(pointB);
processedPoints.Add(pointC);
processedPoints.Add(pointD);
AddOneFace(pointA, pointB, pointC, pointD);
AddOneFace(pointA, pointB, pointD, pointC);
AddOneFace(pointA, pointC, pointD, pointB);
AddOneFace(pointB, pointC, pointD, pointA);
return(true);
}
public void LinkAdjFace(ConvexHullFace face)
{
if (adjface1 != null && adjface2 != null)
{
return;
}
if (adjface1 == null)
{
adjface1 = face;
}
else
{
adjface2 = face;
}
}
Vector3D FindInnerPoint(ConvexHullFace f, ConvexHullEdge e)
{
if (!f.pointA.Equals(e.pointA) && !f.pointA.Equals(e.pointB))
{
return(f.pointA);
}
if (!f.pointB.Equals(e.pointA) && !f.pointB.Equals(e.pointB))
{
return(f.pointB);
}
if (!f.pointC.Equals(e.pointA) && !f.pointC.Equals(e.pointB))
{
return(f.pointC);
}
return(null);
}
void IncrementHull(Vector3D pt)
{
bool vis = false;
foreach (ConvexHullFace face in faces)
{
if (VolumeSign(face, pt) < 0)
{
face.visible = vis = true;
}
}
if (!vis)
{
return;
}
for (int i = 0; i < edges.Count; ++i)
{
ConvexHullEdge edge = edges[i];
ConvexHullFace face1 = edge.adjface1;
ConvexHullFace face2 = edge.adjface2;
if (face1 == null || face2 == null)
{
continue;
}
else if (face1.visible && face2.visible)
{
edge.remove = true;
}
else if (face1.visible || face2.visible)
{
if (face1.visible)
{
ConvexHullFace faceT = face2;
face2 = face1;
face1 = faceT;
}
Vector3D innerPoint = FindInnerPoint(face2, edge);
edge.Erase(face2);
AddOneFace(edge.pointA, edge.pointB, pt, innerPoint);
}
}
}
int VolumeSign(ConvexHullFace face, Vector3D p)
{
double vol;
double ax, ay, az, bx, by, bz, cx, cy, cz;
ax = face.pointA.X - p.X;
ay = face.pointA.Y - p.Y;
az = face.pointA.Z - p.Z;
bx = face.pointB.X - p.X;
by = face.pointB.Y - p.Y;
bz = face.pointB.Z - p.Z;
cx = face.pointC.X - p.X;
cy = face.pointC.Y - p.Y;
cz = face.pointC.Z - p.Z;
vol = ax * (by * cz - bz * cy) +
ay * (bz * cx - bx * cz) +
az * (bx * cy - by * cx);
if (vol == 0)
{
return(0);
}
return(vol < 0 ? -1 : 1);
}
