// Learning Processing
  // Daniel Shiffman
  // http://www.learningprocessing.com
  
  // Example 15-10: Brightness threshold
  
  PImage source;      // Source image
  PImage destination; // Destination image
  
  void setup() {
    size(200,200);
    source = loadImage("sunflower.jpg");
    destination = createImage(source.width, source.height, RGB);
  }
  
  void draw() {
    float threshold = 127;
    
    // We are going to look at both image's pixels
    source.loadPixels();
    destination.loadPixels();
    
    for (int x = 0; x < source.width; x++ ) {
      for (int y = 0; y < source.height; y++ ) {
        int loc = x + y*source.width;
        // Test the brightness against the threshold
        if (brightness(source.pixels[loc]) > threshold){
          destination.pixels[loc] = color(255); // White
        } else {
          destination.pixels[loc] = color(0);   // Black
        }
      }
    }
    
    // We changed the pixels in destination
    destination.updatePixels();
    // Display the destination
    image(destination,0,0);
  }