public override double GetValue(double x, double y)
{
double frequency = Frequency.GetValue(x, y);
x *= frequency;
y *= frequency;
int xInt = (x > 0.0 ? (int)x : (int)x - 1);
int yInt = (y > 0.0 ? (int)y : (int)y - 1);
// Get mode/method:
VoronoiMethod method = (VoronoiMethod)((int)Method.GetValue(x, y));
VoronoiDistance distance = (VoronoiDistance)((int)Distance.GetValue(x, y));
VoronoiDraw drawMode = (VoronoiDraw)((int)DrawMode.GetValue(x, y));
// Get the buffer:
double[] buffer = DistanceBuffer;
int bufferLength = buffer.Length;
// Reset mins:
for (int i = 0; i < bufferLength; i += 2)
{
// Up to max:
buffer[i] = double.MaxValue;
}
// Inside each unit cube, there is a seed point at a random position. Go
// through each of the nearby cubes until we find a cube with a seed point
// that is closest to the specified position.
for (int yCur = yInt - 2; yCur <= yInt + 2; yCur++)
{
for (int xCur = xInt - 2; xCur <= xInt + 2; xCur++)
{
// Calculate the position and distance to the seed point inside of
// this unit cube.
double xPos = xCur + ValueNoiseBasis.ValueNoise(xCur, yCur, Seed);
double yPos = yCur + ValueNoiseBasis.ValueNoise(xCur, yCur, Seed + 1);
double xDist = xPos - x;
double yDist = yPos - y;
double dist;
// Sample and return at the successful point:
int x0 = (xPos > 0.0 ? (int)xPos : (int)xPos - 1);
int y0 = (yPos > 0.0 ? (int)yPos : (int)yPos - 1);
// Min is..
double min = ((double)ValueNoiseBasis.ValueNoise(x0, y0) + 1.0) * 0.5;
switch (distance)
{
default:
case VoronoiDistance.Euclidean:
dist = xDist * xDist + yDist * yDist;
if (drawMode == VoronoiDraw.Normal)
{
dist += 1.0 - min;
}
break;
case VoronoiDistance.Manhattan:
if (yDist < 0)
{
yDist = -yDist;
}
if (xDist < 0)
{
xDist = -xDist;
}
dist = xDist + yDist;
if (drawMode == VoronoiDraw.Normal)
{
dist += 1.0 - min;
}
dist /= 2.0;
break;
case VoronoiDistance.Chebyshev:
if (yDist < 0)
{
yDist = -yDist;
}
if (xDist < 0)
{
xDist = -xDist;
}
if (yDist > xDist)
{
dist = yDist;
}
else
{
dist = xDist;
}
if (drawMode == VoronoiDraw.Normal)
{
if (dist < min)
{
dist = min;
}
}
break;
case VoronoiDistance.Minkowski:
if (yDist < 0)
{
yDist = -yDist;
}
if (xDist < 0)
{
xDist = -xDist;
}
double minkowskiNumber = MinkowskiNumber.GetValue(x, y);
dist = System.Math.Pow((System.Math.Pow(xDist, minkowskiNumber) + System.Math.Pow(yDist, minkowskiNumber)), 1.0 / minkowskiNumber);
if (drawMode == VoronoiDraw.Normal)
{
if (dist < min)
{
dist = min;
}
}
break;
}
// Note: The nearest is at [0].
for (int i = 0; i < bufferLength; i += 2)
{
// Up to max:
if (dist < buffer[i])
{
// This seed point is closer than the one at buffer[i/2].
// Push i onwards over by 2 places as the entry here
// and all after it are now further away.
int offset = i + 2;
if (bufferLength != offset)
{
Array.Copy(buffer, i, buffer, offset, bufferLength - offset);
}
// Write this:
buffer[i] = dist;
buffer[i + 1] = min;
// Stop there.
break;
}
}
}
}
// Buffer now contains n nodes. The nearest one is at the start of the buffer.
double value;
// Special case for euclidean - we used basic lengths for speed:
if (distance == VoronoiDistance.Euclidean)
{
// Must compute the full distance. So, for each one..
for (int i = 0; i < bufferLength; i += 2)
{
// Get complete value:
buffer[i] = (System.Math.Sqrt(buffer[i])) * Math.Sqrt3 - 1.0;
}
}
// Next, compute the point and offset values.
if (drawMode == VoronoiDraw.Solid)
{
switch (method)
{
default:
case VoronoiMethod.F1:
// Best distance was..
value = buffer[1];
break;
case VoronoiMethod.F2:
// 2nd best distance was..
value = buffer[3];
break;
case VoronoiMethod.F3:
// 3rd best distance was..
value = buffer[5];
break;
case VoronoiMethod.F4:
// 4th best distance was..
value = buffer[7];
break;
case VoronoiMethod.F2minusF1:
case VoronoiMethod.F3minusF2:
case VoronoiMethod.F4minusF3:
// fN - fNm1 (but inverted):
value = buffer[bufferLength - 3] - buffer[bufferLength - 1] + 1.0;
break;
case VoronoiMethod.Average2:
case VoronoiMethod.Average3:
case VoronoiMethod.Average4:
// Sum all of them together:
value = 0.0;
for (int i = 1; i < bufferLength; i += 2)
{
value += buffer[i];
}
// Average is then..
value /= (double)bufferLength;
break;
case VoronoiMethod.TwoF3minusF2minusF1:
// 2 * f3 - f2 - f1:
value = 1.0 - ((2.0 * buffer[5]) - buffer[3] - buffer[1]);
break;
}
}
else
{
switch (method)
{
default:
case VoronoiMethod.F1:
// Best distance was..
value = buffer[0];
break;
case VoronoiMethod.F2:
// 2nd best distance was..
value = buffer[2];
break;
case VoronoiMethod.F3:
// 3rd best distance was..
value = buffer[4];
break;
case VoronoiMethod.F4:
// 4th best distance was..
value = buffer[6];
break;
case VoronoiMethod.F2minusF1:
case VoronoiMethod.F3minusF2:
case VoronoiMethod.F4minusF3:
// fN - fNm1 (but inverted):
value = buffer[bufferLength - 4] - buffer[bufferLength - 2] + 1.0;
break;
case VoronoiMethod.Average2:
case VoronoiMethod.Average3:
case VoronoiMethod.Average4:
// Sum all of them together:
value = 0.0;
for (int i = 0; i < bufferLength; i += 2)
{
value += buffer[i];
}
// Average is then..
value /= (double)bufferLength;
break;
case VoronoiMethod.TwoF3minusF2minusF1:
// 2 * f3 - f2 - f1:
value = 1.0 - ((2.0 * buffer[4]) - buffer[2] - buffer[0]);
break;
}
}
// Return the calculated distance.
if (distance == VoronoiDistance.Euclidean)
{
return((1.0 - value) / 2.0);
}
return(1.0 - value);
}