Android Open Source - 4est Ring

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Back to project page 4est.

License

The source code is released under:

MIT License

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Java Source Code

package com.wordsaretoys.rise.pattern;
/*from ww  w . j a  va2s .  c  o m*/
import java.util.Random;


/**
 * represent a group of pattern generators
 * that derive from a single linear buffer
 * 
 * provides fast lookups suitable for bitmaps
 */
public class Ring implements Pattern.F2F {

  float[] data;
  int modu;
  
  public Ring(int length) {
    data = new float[length];
    modu = length - 1;
  }
  
  public void generate(Random rng, int minP, int maxP, int minT, int maxT) {
    boolean inPeak = false;
    int count = 0;
    int total = 0;
    float peak0 = 0;
    float peak1 = 0;
    
    for (int i = 0; i < data.length; i++, count++) {
      // if we've reached the end of the current phase
      if (count == total) {
        // flip the phase
        inPeak = !inPeak;
        // derive new period & peak (if necessary)
        if (inPeak) {
          total = minP + rng.nextInt(maxP - minP);
        } else {
          total = minT + rng.nextInt(maxT - minT);
          peak0 = peak1;
          peak1 = rng.nextFloat();
        }
        count = 0;
      }
      // if we're in a peak
      if (inPeak) {
        // give me that peak
        data[i] = peak1;
      } else {
        // otherwise, give me the peak-peak transition
        float mu = (float) count / (float) total;
        float m2 = (float)(1 - Math.cos(mu * Math.PI)) * 0.5f;
        data[i] = (1 - m2) * peak0 + m2 * peak1;
      }
    }
  }

  @Override
  public float get(float x, float y) {
    float fx = data[ (int)(data.length * x) & modu ];
    float fy = data[ (int)(data.length * y) & modu ];
    return data[ (int)(data.length * (fx + fy)) & modu];
  }
}

Java Source Code List