// Additive Wave 
// Daniel Shiffman <http://www.shiffman.net> 

int xspacing = 8;   // How far apart should each horizontal location be spaced 
int w;              // Width of entire wave 
int maxwaves = 4;   // total # of waves to add together 
 
float theta = 0.0f; 
float[] amplitude = new float[maxwaves];   // Height of wave 
float[] dx = new float[maxwaves];          // Value for incrementing X, to be calculated as a function of period and xspacing 
float[] yvalues;                           // Using an array to store height values for the wave (not entirely necessary) 
 
void setup() { 
  size(200,200); 
  framerate(30); 
  colorMode(RGB,255,255,255,100); 
  smooth(); 
  w = width+16; 
 
  for (int i = 0; i < maxwaves; i++) { 
    amplitude[i] = random(10,30); 
    float period = random(100,300); // How many pixels before the wave repeats 
    dx[i] = (TWO_PI / period) * xspacing; 
  } 
 
  yvalues = new float[w/xspacing]; 
} 
 
void draw() { 
  background(0); 
  calcWave(); 
  renderWave(); 
} 
 
void calcWave() { 
  // Increment theta (try different values for 'angular velocity' here 
  theta += 0.02; 
 
  // Set all height values to zero 
  for (int i = 0; i < yvalues.length; i++) { 
    yvalues[i] = 0.0f; 
  } 
 
  // Accumulate wave height values 
  for (int j = 0; j < maxwaves; j++) { 
    float x = theta; 
    for (int i = 0; i < yvalues.length; i++) { 
      // Every other wave is cosine instead of sine 
      if (j % 2 == 0)  yvalues[i] += sin(x)*amplitude[j]; 
      else yvalues[i] += cos(x)*amplitude[j]; 
      x+=dx[j]; 
    } 
  } 
} 
 
void renderWave() { 
  // A simple way to draw the wave with an ellipse at each location 
  noStroke(); 
  fill(255,50); 
  ellipseMode(CENTER); 
  for (int x = 0; x < yvalues.length; x++) { 
    ellipse(x*xspacing,width/2+yvalues[x],16,16); 
  } 
}