public override double this[double x, double y]
{
get
{
double value = 0.0;
double curPersistence = 1.0;
x *= Frequency;
y *= Frequency;
for (int curOctave = 0; curOctave < OctaveCount; curOctave++)
{
// Make sure that these floating-point values have the same range as a 32-
// bit integer so that we can pass them to the coherent-noise functions.
double nx = NoiseGen.MakeInt32Range(x);
double ny = NoiseGen.MakeInt32Range(y);
// Get the coherent-noise value from the input value and add it to the
// final result.
int localSeed = Seed + curOctave;
double signal = NoiseGen.GradientCoherentNoise2D(nx, ny, localSeed, NoiseQuality);
value += signal * curPersistence;
// Prepare the next octave.
x *= Lacunarity;
y *= Lacunarity;
curPersistence *= Persistence;
}
return(value);
}
}
public override double this[double x, double y]
{
get
{
x *= Frequency;
y *= Frequency;
double value = 0.0;
double weight = 1.0;
// These parameters should be user-defined; they may be exposed in a
// future version of libnoise.
const double offset = 1.0;
const double gain = 2.0;
for (int curOctave = 0; curOctave < OctaveCount; curOctave++)
{
// Make sure that these floating-point values have the same range as a 32-
// bit integer so that we can pass them to the coherent-noise functions.
double nx = NoiseGen.MakeInt32Range(x);
double ny = NoiseGen.MakeInt32Range(y);
// Get the coherent-noise value.
int seed = (Seed + curOctave) & 0x7fffffff;
double signal = NoiseGen.GradientCoherentNoise2D(nx, ny, seed, NoiseQuality);
// Make the ridges.
signal = Math.Abs(signal);
signal = offset - signal;
// Square the signal to increase the sharpness of the ridges.
signal *= signal;
// The weighting from the previous octave is applied to the signal.
// Larger values have higher weights, producing sharp points along the
// ridges.
signal *= weight;
// Weight successive contributions by the previous signal.
weight = signal * gain;
if (weight > 1.0)
{
weight = 1.0;
}
if (weight < 0.0)
{
weight = 0.0;
}
// Add the signal to the output value.
value += (signal * spectralWeights[curOctave]);
// Go to the next octave.
x *= Lacunarity;
y *= Lacunarity;
}
return((value * 1.25) - 1.0);
}
}