public void QuickHull()
{
var ltl = CGUtils.LowestThenLeftmost(points);
var htr = CGUtils.HighestThenRightmost(points);
List <CGPoint> leftPoints = new List <CGPoint>();
List <CGPoint> rightPoints = new List <CGPoint>();
leftPoints.Add(ltl);
rightPoints.Add(htr);
for (int i = 0; i < points.Count; i++)
{
if (points[i] != ltl && points[i] != htr)
{
if (CGUtils.ToLeft(ltl, htr, points[i]))
{
leftPoints.Add(points[i]);
}
else
{
rightPoints.Add(points[i]);
}
}
}
leftPoints.Add(htr);
rightPoints.Add(ltl);
QuickHull(leftPoints, 0, leftPoints.Count - 1);
QuickHull(rightPoints, 0, rightPoints.Count - 1);
}
public void GrahamScan()
{
Reset();
if (points.Count < 3)
{
return;
}
CGPoint ltl = CGUtils.LowestThenLeftmost(points);
int ltlIndex = points.FindIndex(o => o == ltl);
if (ltlIndex > 0)
{
CGPoint temp = points[ltlIndex];
points[ltlIndex] = points[0];
points[0] = temp;
}
PolarAnglePointCompare compare = new PolarAnglePointCompare()
{
piovt = ltl
};
points.Sort(1, points.Count - 1, compare);
Stack <CGPoint> t = new Stack <CGPoint>();
Stack <CGPoint> s = new Stack <CGPoint>();
s.Push(points[0]);
s.Push(points[1]);
for (int i = points.Count - 1; i > 1; i--)
{
t.Push(points[i]);
}
while (t.Count != 0)
{
var topOfS = s.Pop();
if (CGUtils.ToLeft(s.Peek(), topOfS, t.Peek()))
{
s.Push(topOfS);
s.Push(t.Pop());
}
}
var last = s.Peek();
CGPoint curr = null;
while (s.Count > 0)
{
curr = s.Pop();
curr.isExtreme = true;
if (s.Count == 0)
{
break;
}
curr.pred = s.Peek();
s.Peek().succ = curr;
}
last.succ = curr;
curr.pred = last;
}
public override void DrawResult()
{
var ltl = CGUtils.LowestThenLeftmost(WinManager.Instance.data.points);
var curr = ltl;
do
{
Draw.DrawLine(curr, curr.succ);
curr = curr.succ;
} while (ltl != curr);
Draw.DrawImage();
}
void InitLeftRightChain()
{
var htr = CGUtils.HighestThenRightmost(p.vertices);
var ltl = CGUtils.LowestThenLeftmost(p.vertices);
int index = 0;
var leftCurr = htr;
while (leftCurr != ltl)
{
leftChain.Add(index++, leftCurr);
leftCurr = leftCurr.succ;
}
leftChain.Add(index++, ltl);
var rightCurr = htr.pred;
while (rightCurr != ltl)
{
rightChain.Add(index++, rightCurr);
rightCurr = rightCurr.pred;
}
}
public void JarvisMarch()
{
Reset();
CGPoint ltl = CGUtils.LowestThenLeftmost(points);
CGPoint curr = ltl;
CGPoint next = null;
do
{
curr.isExtreme = true;
next = null;
for (int i = 0; i < points.Count; i++)
{
if (points[i] != curr && (next == null || !CGUtils.ToLeft(curr, next, points[i])))
{
next = points[i];
}
}
curr.succ = next;
next.pred = curr;
curr = next;
} while (ltl != curr);
}
