// Dartmouth CS 2, Winter 2009, Chris Bailey-Kellogg
// Notes 18 | Sketch 12

size(800,600);
PImage baker=loadImage("baker.jpg");
loadPixels();
baker.loadPixels();

float[][] kernel = { {-1, -1, -1},
                     {-1, 8, -1},
                     {-1, -1, -1} };

for (int y=1; y<height-1; y++) {
  for (int x=1; x<width/2; x++) {
    // add together the values for all the neighbors,
    // weighted by the corresponding kernel value
    float r=0, g=0, b=0;
    for (int dy=-1; dy<=1; dy++) {
      for (int dx=-1; dx<=1; dx++) {
        color p=baker.pixels[x+dx + (y+dy)*baker.width];
        r += red(p)*kernel[dy+1][dx+1]; 
        g += green(p)*kernel[dy+1][dx+1];
        b += blue(p)*kernel[dy+1][dx+1];
      }
    }
    // set the color
    pixels[x+y*width] = color(r,g,b);
  }
  // show after/before
  for (int x=0; x<width/2; x++)
    pixels[x+width/2+y*width] = baker.pixels[x+y*width];
}
updatePixels();