public ConvexHullDlg()
{
InitializeComponent();
points = PointSet.RandomSet(14, new Vector2(), new Vector2(200, 200));
DisplayUpdate();
}
public ConvexHullJarvisAlgorithm(PointSet ps, int maxIterations)
{
// Debug output
Action<int> Output =
(i) => Console.WriteLine("Selected #{0}: ({1}, {2})", i, (int)points[i].x, (int)points[i].y);
set = ps;
points = ps.points;
Console.WriteLine("Running on {0} points...", ps.points.Count);
available = new List<int>(ps.points.Count);
for (int i = 0; i < ps.points.Count; i++)
available.Add(i);
// Pick leftmost point
int pointOnHull = -1;
for (int i = 0; i < points.Count; i++)
if (pointOnHull < 0 || points[i].x < points[pointOnHull].x)
pointOnHull = i;
List<int> hull = new List<int>();
hull.Add(pointOnHull);
// the first point should still be available, to close the loop
// Output(pointOnHull);
int iteration = 0;
do {
if (iteration++ == maxIterations)
break;
// Pick hull candidate
int selectedIndex = -1;
Vector2 org = points[pointOnHull];
for (int i = 0; i < available.Count; i++)
{
if (available[i] == pointOnHull)
continue;
if (selectedIndex < 0) {
selectedIndex = available[i];
// Console.WriteLine("\tBest: {0}", selectedIndex);
}
else
{
Vector2 normal = (points[selectedIndex] - org).Ortho.Normalized;
float d = points[available[i]].Dot(normal) - points[selectedIndex].Dot(normal);
// Console.WriteLine("\t[{1}]: {0}", d, available[i]);
// Test on which side of the plane (normal, dist) point p is located.
if (d < 0)
{
selectedIndex = available[i];
// Console.WriteLine("\tBest: {0}", selectedIndex);
}
}
}
if (selectedIndex < 0)
{
Console.WriteLine("Weird stuff...");
break;
}
// Output(selectedIndex);
pointOnHull = selectedIndex;
hull.Add(pointOnHull);
TakePoint(pointOnHull);
} while (pointOnHull != hull[0] && available.Count>0);
result = hull.ToArray();
}
private void buttonRndGraph_Click(object sender, EventArgs e)
{
points = PointSet.RandomSet(50, new Vector2(), new Vector2(200, 200));
DisplayUpdate();
}
