疎密波

/**
* compressional wave
* 
* @author aa_debdeb
* @date 2016/08/20
*/

void setup(){
  size(640, 480);
  rectMode(CENTER);
  noStroke();
  fill(0);
}

void draw(){
  background(255);
  translate(width / 2, height / 2);
  for(float x = -200; x <= 200; x += 5){
    float angle = x * 0.02 + frameCount * 0.03;  
    float amp = map(sin(angle), -1, 1, -15, 15);
    rect(x + amp, 0, 2, 250);
  }
}