public static Polygon Grid2Cartes(Polygon gPolygon, int gridX, int gridY)
{
PointF[] pointList = gPolygon.ToPointFArray();
List<Point2D> cPointList = new List<Point2D>();
for (int i = 0; i < pointList.Length; i++)
{
Point2D pt = new Point2D(gridX * 256 + pointList[i].X, gridY * 256 + pointList[i].Y);
cPointList.Add(pt);
}
Polygon cPolygon = new Polygon(cPointList);
return cPolygon;
}
public void AddPoint(Point2D pt, int index)
{
pointList.Insert(index, pt);
}
public static Polygon GeneratePolygon(Vector3 scale, Vector3 pos, Quaternion quat)
{
Matrix rotationMat = QuaternionToMatrix(quat);
Matrix transMat = new Matrix(3,1);
transMat[0,0] = pos.X;
transMat[1,0] = pos.Y;
transMat[2,0] = pos.Z;
// generate original Point list
List<Point3D> oriPointList = new List<Point3D>(8);
oriPointList.Add(new Point3D(scale.X / 2, scale.Y / 2, scale.Z / 2));
oriPointList.Add(new Point3D(scale.X / 2, scale.Y / 2, -scale.Z / 2));
oriPointList.Add(new Point3D(scale.X / 2, -scale.Y / 2, scale.Z / 2));
oriPointList.Add(new Point3D(scale.X / 2, -scale.Y / 2, -scale.Z / 2));
oriPointList.Add(new Point3D(-scale.X / 2, scale.Y / 2, scale.Z / 2));
oriPointList.Add(new Point3D(-scale.X / 2, scale.Y / 2, -scale.Z / 2));
oriPointList.Add(new Point3D(-scale.X / 2, -scale.Y / 2, scale.Z / 2));
oriPointList.Add(new Point3D(-scale.X / 2, -scale.Y / 2, -scale.Z / 2));
// rotate the point by the rotationMat
List<Point3D> rotPointList = new List<Point3D>(8);
foreach (var point in oriPointList)
{
Point3D rPoint = new Point3D(Matrix.MatMul(rotationMat, point.ToMatrix()));
rotPointList.Add(rPoint);
}
// translate the point by translatMat
List<Point3D> transPointList = new List<Point3D>(8);
foreach (var point in rotPointList)
{
Point3D tPoint = new Point3D(Matrix.MatAdd(transMat, point.ToMatrix()));
transPointList.Add(tPoint);
}
// project points to xy plane
List<Point2D> point2dList = new List<Point2D>();
foreach (var point3d in transPointList)
{
Point2D point2d = new Point2D(point3d.x, point3d.y);
point2dList.Add(point2d);
}
Polygon polygon = ConvenxHull(point2dList);
return polygon;
}
private static bool TurnLeft(Point2D pt1, Point2D pt2, Point2D pt3)
{
Vector2 vt1 = new Vector2(pt2.x - pt1.x, pt2.y - pt1.y);
Vector2 vt2 = new Vector2(pt3.x - pt2.x, pt3.y - pt2.y);
double det = vt1.X * vt2.Y - vt1.Y * vt2.X;
if (det > 0)
return true;
else
return false;
}
// Calculte the 2Dconvcex hull of the point list on XY plane
private static Polygon ConvenxHull(List<Point2D> pointList)
{
List<Point2D> polyPointList = new List<Point2D>();
pointList.Sort(ComparePointByY);
Point2D p0 = new Point2D(pointList[0].x, pointList[0].y);
polyPointList.Add(p0);
pointList.RemoveAt(0);
tempOrigin = p0;
pointList.Sort(ComparePointByPolarAngle);
//reogranize the pointlist remove duplicate points which have same polar angles
int index = 0;
while (index + 1 < pointList.Count)
{
double rad1 = Radius(pointList[index].x - tempOrigin.x, pointList[index].y - tempOrigin.y);
double rad2 = Radius(pointList[index + 1].x - tempOrigin.x, pointList[index + 1].y - tempOrigin.y);
if (rad1 == rad2)
{
double dist1 = Distance(pointList[index].x - tempOrigin.x, pointList[index].y - tempOrigin.y);
double dist2 = Distance(pointList[index + 1].x - tempOrigin.x, pointList[index + 1].y - tempOrigin.y);
if (dist1 < dist2)
pointList.RemoveAt(index);
else
pointList.RemoveAt(index + 1);
}
else
index++;
}
Point2D p1 = pointList[0]; pointList.RemoveAt(0);
Point2D p2 = pointList[0]; pointList.RemoveAt(0);
polyPointList.Add(p1);
polyPointList.Add(p2);
for (int i = 0; i < pointList.Count; i++)
{
while (TurnLeft(polyPointList[polyPointList.Count - 2], polyPointList[polyPointList.Count - 1], pointList[i]) == false)
polyPointList.RemoveAt(polyPointList.Count - 1);
polyPointList.Add(pointList[i]);
}
return new Polygon(polyPointList);
}
private static int ComparePointByY(Point2D pt1, Point2D pt2)
{
if (pt1.y != pt2.y)
return pt1.y.CompareTo(pt2.y);
else
return pt1.x.CompareTo(pt2.x);
}
private static int ComparePointByPolarAngle(Point2D pt1, Point2D pt2)
{
double rad1 = Radius(pt1.x - tempOrigin.x, pt1.y - tempOrigin.y);
double rad2 = Radius(pt2.x - tempOrigin.x, pt2.y - tempOrigin.y);
return rad1.CompareTo(rad2);
}
