市松模様にズームインする

/**
* zoom in to checkerboard
*
* @author aa_debdeb
* @date 2016/12/12
*/

int LOOP = 300;

void setup(){
  size(500, 500);
  rectMode(CENTER);
}

void draw(){
  background(255);
  float time = frameCount % LOOP;
  float centerX = map(time, 0, LOOP - 1, width * 7.0 / 8.0, width / 2.0);
  float centerY = map(time, 0, LOOP - 1, height * 7.0 / 8.0, height / 2.0);
  float rectSize = map(pow(time / (LOOP - 1), 7), 0, 1, 5, width);

  
  int startX = int(centerX / rectSize) + 1;
  int endX = int((width - centerX) / rectSize) + 1;
  int startY = int(centerY / rectSize) + 1; 
  int endY = int((height - centerY) / rectSize) + 1;
  
  
  
  noStroke();
  fill(0);
  for(int x = -startX; x <= endX; x++){
    for(int y = -startY; y <= endY; y++){
      if((x + y + 1000) % 2 == 1){
        rect(centerX + x * rectSize, centerY + y * rectSize, rectSize, rectSize);
      }
    }
  }
}