public static void GenerateStretchNoise(float[,] baseNoise, int offsetX, int offsetY, int octave, InterpolationFunction interpolate, ref float[,] result)
{
int width = baseNoise.GetLength(0);
int height = baseNoise.GetLength(1);
if (result == null)
{
result = new float[width, height];
}
Debug.Assert(result.GetLength(0) == width && result.GetLength(1) == height, "Invalid array size");
int samplePeriod = 1 << octave; // calculates 2 ^ k
float sampleFrequency = 1.0f / samplePeriod;
// Wrap the offset around the noise map size (handle negative offset as well).
offsetX = (((offsetX % width) + width) % width) * (width / samplePeriod);
offsetY = (((offsetY % height) + height) % height) * (height / samplePeriod);
for (int i = 0; i < width; i++)
{
// Calculate the horizontal sampling indices
int sample_i0 = (offsetX + i / samplePeriod) % width;
int sample_i1 = (sample_i0 + 1) % width;
float horizontal_blend = (i % samplePeriod) * sampleFrequency;
for (int j = 0; j < height; j++)
{
// Calculate the vertical sampling indices
int sample_j0 = (offsetY + j / samplePeriod) % height;
int sample_j1 = (sample_j0 + 1) % height;
float vertical_blend = (j % samplePeriod) * sampleFrequency;
// Blend the top two corners
float top = interpolate.Invoke(baseNoise[sample_i0, sample_j0], baseNoise[sample_i1, sample_j0], horizontal_blend);
// Blend the bottom two corners
float bottom = interpolate.Invoke(baseNoise[sample_i0, sample_j1], baseNoise[sample_i1, sample_j1], horizontal_blend);
// Final blend
result[i, j] = interpolate.Invoke(top, bottom, vertical_blend);
}
}
}
public static float[,] GenerateSmoothNoise(float[,] baseNoise, int octave, InterpolationFunction interpolate)
{
int width = baseNoise.GetLength(0);
int height = baseNoise.GetLength(1);
float[,] smoothNoise = new float[width, height];
int samplePeriod = 1 << octave; // calculates 2 ^ k
float sampleFrequency = 1.0f / samplePeriod;
for (int i = 0; i < width; i++)
{
// Calculate the horizontal sampling indices
int sample_i0 = (i / samplePeriod) * samplePeriod;
int sample_i1 = (sample_i0 + samplePeriod) % width; // Wrap around
float horizontal_blend = (i - sample_i0) * sampleFrequency;
for (int j = 0; j < height; j++)
{
// Calculate the vertical sampling indices
int sample_j0 = (j / samplePeriod) * samplePeriod;
int sample_j1 = (sample_j0 + samplePeriod) % height; //wrap around
float vertical_blend = (j - sample_j0) * sampleFrequency;
// Blend the top two corners
float top = interpolate.Invoke(baseNoise[sample_i0, sample_j0], baseNoise[sample_i1, sample_j0], horizontal_blend);
// Blend the bottom two corners
float bottom = interpolate.Invoke(baseNoise[sample_i0, sample_j1], baseNoise[sample_i1, sample_j1], horizontal_blend);
// Final blend
smoothNoise[i, j] = interpolate.Invoke(top, bottom, vertical_blend);
}
}
return(smoothNoise);
}
