public List <BoundaryMove> CalcQuickHull(List <BoundaryMove> boundaries)
{
if (boundaries.Count < 3)
{
return(boundaries);
}
int minPoint = -1, maxPoint = -1;
int minX = Int32.MaxValue;
int maxX = Int32.MinValue;
List <BoundaryMove> convexHull = new List <BoundaryMove>();
for (int i = 0; i < boundaries.Count; i++)
{
if (boundaries[i].X < minX)
{
minX = boundaries[i].X;
minPoint = i;
}
if (boundaries[i].X > maxX)
{
maxX = boundaries[i].X;
maxPoint = i;
}
}
BoundaryMove A = boundaries[minPoint];
BoundaryMove B = boundaries[maxPoint];
convexHull.Add(A);
convexHull.Add(B);
boundaries.Remove(A);
boundaries.Remove(B);
List <BoundaryMove> leftSet = new List <BoundaryMove>();
List <BoundaryMove> rightSet = new List <BoundaryMove>();
for (int i = 0; i < boundaries.Count; i++)
{
BoundaryMove p = boundaries[i];
if (pointLocation(A, B, p) == -1)
{
leftSet.Add(p);
}
else
{
rightSet.Add(p);
}
}
hullSet(A, B, rightSet, convexHull);
hullSet(B, A, leftSet, convexHull);
return(convexHull);
}
public int distance(BoundaryMove A, BoundaryMove B, BoundaryMove C)
{
int ABx = B.X - A.X;
int ABy = B.Y - A.Y;
int num = ABx * (A.Y - C.Y) - ABy * (A.X - C.X);
if (num < 0)
{
num = -num;
}
return(num);
}
//return if this veritical & horizontal component are equal to "obj"
public override bool Equals(System.Object obj)
{
// If parameter is null return false.
if (obj == null)
{
return(false);
}
BoundaryMove rhs = (BoundaryMove)obj;
// Return true if the fields match:
return((pixel.X == rhs.X) && (pixel.Y == rhs.Y));
}
public BoundaryMove Move(int val, AdvColor[,] pixels)
{
//figure out the direction to move - left or right never back or forward - forward is handled in calling function
BoundaryMove pt2 = MoveRight();
if (IsValueOnRight(pt2, val, pixels) && pixels[pt2.X, pt2.Y].G != val)
{
return(pt2);
}
pt2 = MoveLeft();
return(pt2);
}
public List <BoundaryMove> WalkShape(int start_i, int start_j, int shape_val)
{
//found the first pixel running face first into it scanning by line. Backup one pixel and set the direction to north so the pixel is on our right
BoundaryMove pt = new BoundaryMove(start_i, --start_j, Direction.eNorth);
List <BoundaryMove> points = new List <BoundaryMove>();
points.Add(pt);
BoundaryMove pt2 = pt.MoveForward();
while (true)
{
if (Equals(pt2, pt))
{
break;
}
points.Add(pt2);
while (IsValueOnRight(pt2, shape_val))
{
BoundaryMove pt3 = pt2.MoveForward();
if (pixels[pt3.X, pt3.Y].G == shape_val)
{
break;
}
pt2 = pt3;
points.Add(pt2);
if (Equals(pt2, pt))
{
break;
}
}
if (Equals(pt2, pt))
{
break;
}
pt2 = pt2.Move(shape_val, pixels);
}
return(points);
}
public void OutlineHull(List <BoundaryMove> hull, AdvColor[,] new_pixels)
{
BresenhamLine line = new BresenhamLine(pixels.GetLength(1), pixels.GetLength(0));
for (int i = 0; i < hull.Count; i++)
{
BoundaryMove p1 = hull[i];
BoundaryMove p2;
if (i == hull.Count - 1)
{
p2 = hull[0];
}
else
{
p2 = hull[i + 1];
}
line.DrawBresenhamLine(new_pixels, p1.X, p1.Y, p2.X, p2.Y, Color.White);
}
}
public void hullSet(BoundaryMove A, BoundaryMove B, List <BoundaryMove> set, List <BoundaryMove> hull)
{
if (set.Count == 0)
{
return;
}
int insertPosition = hull.IndexOf(B);
if (set.Count == 1)
{
BoundaryMove p = set[0];
set.Remove(p);
hull.Insert(insertPosition, p);
return;
}
int dist = Int32.MinValue;
int furthestPoint = -1;
for (int i = 0; i < set.Count; i++)
{
BoundaryMove p = set[i];
int dist2 = distance(A, B, p);
if (dist2 > dist)
{
dist = dist2;
furthestPoint = i;
}
}
BoundaryMove P = set[furthestPoint];
set.RemoveAt(furthestPoint);
hull.Insert(insertPosition, P);
// Determine who's to the left of AP
List <BoundaryMove> leftSetAP = new List <BoundaryMove>();
for (int i = 0; i < set.Count; i++)
{
BoundaryMove M = set[i];
if (pointLocation(A, P, M) == 1)
{
leftSetAP.Add(M);
}
}
// Determine who's to the left of PB
List <BoundaryMove> leftSetPB = new List <BoundaryMove>();
for (int i = 0; i < set.Count; i++)
{
BoundaryMove M = set[i];
if (pointLocation(P, B, M) == 1)
{
leftSetPB.Add(M);
}
}
hullSet(A, P, leftSetAP, hull);
hullSet(P, B, leftSetPB, hull);
}
public int pointLocation(BoundaryMove A, BoundaryMove B, BoundaryMove P)
{
int cp1 = (B.X - A.X) * (P.Y - A.Y) - (B.Y - A.Y) * (P.X - A.X);
return((cp1 > 0) ? 1 : -1);
}
private bool IsValueOnRight(BoundaryMove pt, int val, AdvColor[,] pixels)
{
BoundaryMove pt2 = pt.MoveRight();
return(pt2.X >= 0 && pt2.Y >= 0 && pixels[pt2.X, pt2.Y].G == val);
}
