sketch.pde

import processing.video.*;

Capture capture;
int[] pastPixels;

void setup(){
  size(1280, 720);
  String[] cameras = Capture.list();
  print(cameras[0]);
  capture = new Capture(this, cameras[0]);
  capture.start();
  frameRate(15);
  pastPixels = new int[width*height];
}

int[] getColor(int col){
  int red   = (col >> 16) & 0xFF;
  int green = (col >> 8)  & 0xFF;
  int blue  =  col        & 0xFF;
  int[] colors = {red,green,blue};
  return colors;
}

int checkColor(int color1,int color2){
  int diff = color1 - color2;
  return abs(diff);
}

boolean checkRGB(int color1,int color2){
  int[] col1 = getColor(color1);
  int[] col2 = getColor(color2);
  int allow = 20;
  int diff = 0;
  for(int i=0;i<3;i++){
    diff += checkColor(col1[i],col2[i]);
  }
  if(diff < allow){
    return true;
  }else{
    return false;
  }
}

void draw(){
  background(0);
  if (capture.available()){
    capture.read();
    capture.loadPixels();

    int d = 20;
    for(int y = d/2; y < height; y += d){
      for(int x = d/2; x < width; x += d){
        int px = y*width + x;


        if(!checkRGB(pastPixels[px], capture.pixels[px])){
          fill(capture.pixels[px]);
          rect(x,y,d,d);        
        }
      }
    }
    pastPixels = capture.pixels;
  }
}