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); } }