Perlin 噪声不会随着八度音阶的增加而增加深度

Question

我不熟悉 Perlin 噪音，但遇到了障碍。我从 C++ 翻译的 perlin 噪声函数似乎在一个八度音程上可以正常工作，但是我发现较低八度音程的噪声没有添加到原始的 Perlin 噪声中。这是我的代码：

public class Perlin {
    float[][] generateWhiteNoise(int width, int height) {
        Random random = new Random(0);
        float[][] noise = new float[width][height];

        for (int i = 0; i < noise.length; i++) {
            for (int j = 0; j < noise[i].length; j++){
                noise[i][j] = (float)random.nextDouble();
            }
        }

        return noise;
    }

    float[][] generateSmoothNoise(float[][] baseNoise, int octave){
        int width = baseNoise.length;
        int height = baseNoise[0].length;

        float[][] smoothNoise = baseNoise;

        int samplePeriod = (int) Math.pow(2,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(baseNoise[sample_i0][sample_j0],
                baseNoise[sample_i1][sample_j0], horizontal_blend);

             //blend the bottom two corners
             float bottom = interpolate(baseNoise[sample_i0][sample_j1],
                baseNoise[sample_i1][sample_j1], horizontal_blend);

             //final blend
             smoothNoise[i][j] = interpolate(top, bottom, vertical_blend);
          }
       }

       return smoothNoise;
    }

    float interpolate(float x0, float x1, float alpha){
        return (float) ((float)(x0) * (float)(1 - alpha) + (float)(alpha * x1));
    }

    float[][] generatePerlinNoise(float[][] baseNoise, int octaveCount) {
       int width = baseNoise.length;
       int height = baseNoise[0].length;

       float[][][] smoothNoise = new float[octaveCount][][]; //an array of 2D arrays containing

       float persistance = .5f;

       //generate smooth noise
       for (int i = 0; i<octaveCount; i++) {
           System.out.println("Generating Smooth Noise: " + i);
           smoothNoise[i] = generateSmoothNoise(baseNoise, i);
       }

        float[][] perlinNoise = new float[width][height];
        float amplitude = 1.0f;
        float totalAmplitude = 0.0f;

        //blend noise together
        for (int octave = octaveCount - 1; octave >= 0; octave--) {
           amplitude *= persistance;
           totalAmplitude += amplitude;
           System.out.println("Adding smooth noise for octave: " + octave + " at amplitude: " + amplitude);
           for (int i = 0; i < width; i++) {
              for (int j = 0; j < height; j++) {
                 perlinNoise[i][j] += smoothNoise[octave][i][j] * amplitude;
              }
           }
        }

       //normalization
       for (int i = 0; i < width; i++) {
          for (int j = 0; j < height; j++) {
             perlinNoise[i][j] /= totalAmplitude;
          }
       }
       return perlinNoise;
    }

    public float[][] printVals(float[][] baseNoise){
        baseNoise = generatePerlinNoise(generateWhiteNoise(800,800),6);
        for(int i = 0; i<baseNoise.length; i++){
            String row = "";
            for(int j = 0; j<baseNoise[i].length;j++){
                row+= (int)(baseNoise[i][j]*255) + " ";
            }
            System.out.println(row);
        }
        return baseNoise;
    }
}

这是我用来获取值的代码：

baseNoise = generatePerlinNoise(generateWhiteNoise(800,800),6);

这里是八度音阶 1、2、3 和 4 的输出

任何帮助将不胜感激！

编辑： 通过反复试验，我发现最有可能出现问题的区域是generatePerlinNoise() 函数。如果我改变八度音阶，我会得到想要的噪音水平，这就是我想要的。这也意味着generateWhiteNoise() 和generateSmoothNoise() 有效。因此，generatePerlinNoise() 混合中的某处存在问题，但它似乎应该可以工作。

Answer 1

我找到了答案。我原以为generateSmoothNoise() 命令会给我带来多倍频程的柏林噪音。然而，我意识到我需要构建另一个类似于平滑噪声混合的命令来混合我不同八度音阶的柏林噪声。

public float[][] generateMultiOctavePerlinNoise(int octaves, double persistence, double dropoff, int width, int height){
        float[][][]noise = new float[octaves][width][height];
        for(int i = octaves - 1; i > 0;i--){
            noise[i] = generatePerlinNoise(generateWhiteNoise(width,height),octaves - i);
        }

        float[][] multiOctave = new float[width][height];

        for(int a= 0; a<noise.length; a++){
            persistence*= dropoff;
            for(int i = 0; i<multiOctave.length; i++){
                for(int j = 0; j<multiOctave[i].length; j++){
                    multiOctave[i][j] += noise[a][i][j]*persistence;
                }
            }
        }
        return multiOctave;

    }