Sine Surface Movement

/**
* Sine Surface Movement
*
* @author aa_debdeb
* @date 2015/09/03
*/

float BLOCK_SIZE = 5;
int BLOCK_NUM = 100;

float radian = 0.0;
float radianStep = PI / 100;

void setup(){
  size(501, 501);
  smooth();
  frameRate(30);
}

void draw(){
  
  stroke(128);
  strokeWeight(1.0);
  for(int w = 0; w < BLOCK_NUM; w++){
    fill(255.0 * sin(radian + ((float)w / BLOCK_NUM) * PI));
    for(int h = 0; h < BLOCK_NUM; h++){
      rect(w * BLOCK_SIZE, h * BLOCK_SIZE, BLOCK_SIZE, BLOCK_SIZE);
    }
  }
  
  radian += radianStep;
  if(radian >= 2.0 * PI){
    radian -= 2.0 * PI;
  }
}