public static void EdgeFinder(PointTester tester, double x0, double y0, double x1, double y1,
int recursionSteps, out double x, out double y)
{
var xc = (x0 + x1) * 0.5;
var yc = (y0 + y1) * 0.5;
x = xc;
y = yc;
if (recursionSteps == 0)
{
return;
}
var val0 = tester(x0, y0);
var valC = tester(xc, yc);
if (val0 != valC)
{
EdgeFinder(tester, x0, y0, xc, yc, recursionSteps - 1, out x, out y);
}
else
{
var val1 = tester(x1, y1);
if (val1 != valC)
{
EdgeFinder(tester, xc, yc, x1, y1, recursionSteps - 1, out x, out y);
}
else
{
return;
}
}
}
static public double Calc(PointTester tester, double dx = 1, double dy = 1, double xs = 0, double ys = 0)
{
int cnt = 0;
var rnd = new System.Random();
for (int i = 0; i < Samples; i++)
{
Point2 pt;
pt.x = rnd.NextDouble() * dx + xs;
pt.y = rnd.NextDouble() * dy + ys;
bool b = tester(pt);
if (Log)
{
Console.WriteLine(String.Format("({0}, {1}) -> {2}", pt.x, pt.y, b));
}
if (b)
{
cnt++;
}
}
double maxa = dx * dy;
return(maxa * cnt / Samples);
}
public static void EdgeFinder(PointTester tester, double x0, double y0, double x1, double y1,
int recursionSteps, out double x, out double y)
{
var xc = (x0 + x1)*0.5;
var yc = (y0 + y1)*0.5;
x = xc;
y = yc;
if(recursionSteps==0)
return;
var val0 = tester(x0,y0);
var valC = tester(xc,yc);
if (val0 != valC)
EdgeFinder(tester, x0, y0, xc, yc, recursionSteps - 1, out x, out y);
else
{
var val1 = tester(x1, y1);
if (val1 != valC)
EdgeFinder(tester, xc, yc, x1, y1, recursionSteps - 1, out x, out y);
else
return;
}
}
public static List <Triangle> PointsTriangulation(int count, Func <int, Point> xy, Func <bool> cancel)
{
List <Triangle> Triangles = new List <Triangle>();
if (count >= 3)
{
List <int> indices = new List <int>()
{
Capacity = count
};
for (int i = 0; i < count; ++i)
{
indices.Add(i);
}
Comparison <int> comparison = (a, b) => xy(a).X <xy(b).X? -1 : xy(a).X> xy(b).X ? 1 : xy(a).Y.CompareTo(xy(b).Y);
indices.Sort(comparison);
#region add super triangle vertices
double xmin = xy(indices[0]).X;
double xmax = xy(indices[count - 1]).X;
double ymin = xy(indices[0]).Y;
double ymax = ymin;
for (int i = 1; i < count; i++)
{
ymin = Math.Min(ymin, xy(indices[i]).Y);
ymax = Math.Max(ymax, xy(indices[i]).Y);
}
double dx = xmax - xmin;
double dy = ymax - ymin;
double dmax = Math.Max(dx, dy);
double xmid = (xmax + xmin) / 2;
double ymid = (ymax + ymin) / 2;
Point s0 = new Point(xmid - 20 * dmax, ymid - dmax);
Point s1 = new Point(xmid, ymid + 20 * dmax);
Point s2 = new Point(xmid + 20 * dmax, ymid - dmax);
#endregion
Triangle[] triangleBuffer = new Triangle[4 * count];
bool[] complete = new bool[triangleBuffer.Length];
HalfEdgeSet edgeBuffer = new HalfEdgeSet();
PointTester pointTester = new PointTester();
int triangleCount = 0;
#region add super triangle and initial triangle buffer
triangleBuffer[0] = new Triangle()
{
v0 = count, v1 = count + 1, v2 = count + 2
};
complete[0] = false;
for (int i = 1; i < triangleBuffer.Length; ++i)
{
triangleBuffer[i] = new Triangle();
complete[i] = false;
}
;
++triangleCount;
#endregion
#region point getter delegate
Func <int, Point> XY = (i) =>
{
if (i < count)
{
return(xy(indices[i]));
}
if (i == count)
{
return(s0);
}
if (i == count + 1)
{
return(s1);
}
return(s2);
};
#endregion
#region triangulate
for (int i = 0; i < count; ++i)
{
if (cancel != null && cancel())
{
return(null);
}
edgeBuffer.Clear();
for (int j = 0; j < triangleCount; ++j)
{
if (complete[j])
{
continue;
}
pointTester.Test(XY(i), XY(triangleBuffer[j].v0), XY(triangleBuffer[j].v1), XY(triangleBuffer[j].v2));
complete[j] = pointTester.Complete;
if (pointTester.Inside)
{
HalfEdge e;
e = new HalfEdge(triangleBuffer[j].v0, triangleBuffer[j].v1);
if (edgeBuffer.Contains(e))
{
edgeBuffer.Remove(e);
}
else
{
edgeBuffer.Add(e);
}
e = new HalfEdge(triangleBuffer[j].v1, triangleBuffer[j].v2);
if (edgeBuffer.Contains(e))
{
edgeBuffer.Remove(e);
}
else
{
edgeBuffer.Add(e);
}
e = new HalfEdge(triangleBuffer[j].v2, triangleBuffer[j].v0);
if (edgeBuffer.Contains(e))
{
edgeBuffer.Remove(e);
}
else
{
edgeBuffer.Add(e);
}
triangleBuffer[j].v0 = triangleBuffer[triangleCount - 1].v0;
triangleBuffer[j].v1 = triangleBuffer[triangleCount - 1].v1;
triangleBuffer[j].v2 = triangleBuffer[triangleCount - 1].v2;
complete[j] = complete[triangleCount - 1];
--triangleCount;
--j;
}
}
// (re)create triangles
foreach (HalfEdge edge in edgeBuffer)
{
triangleBuffer[triangleCount].v0 = edge.B;
triangleBuffer[triangleCount].v1 = edge.E;
triangleBuffer[triangleCount].v2 = i;
complete[triangleCount] = false;
++triangleCount;
}
}
#endregion
#region save permanent mesh
for (int i = 0; i < triangleCount; ++i)
{
if (triangleBuffer[i].v0 < count && triangleBuffer[i].v1 < count && triangleBuffer[i].v2 < count)
{
Triangles.Add(new Triangle()
{
v0 = indices[triangleBuffer[i].v0], v1 = indices[triangleBuffer[i].v1], v2 = indices[triangleBuffer[i].v2]
}); //triangleBuffer[i]);
}
}
#endregion
}
return(Triangles);
}
