grass fire

//http://what-when-how.com/introduction-to-video-and-image-processing/blob-analysis-introduction-to-video-and-image-processing-part-1/

void burn(int x, int y, int w, int h, int[] image, boolean[] visited, boolean onFire, ArrayList<ArrayList<Integer>> result) {
  int index = y*w+x;

  //if (y < 0 || y >= h || x < 0 || x >= w)
  //  return;
  if(y >= 0 && y < h && x >= 0 && x < w && !visited[index]) {
    visited[index] = true;

    if (image[index] == 1) {
      if(!onFire)
        result.add(new ArrayList<Integer>());
      result.get(result.size()-1).add(index);

      burn(x+1, y, w, h, image, visited, true, result);
      burn(x, y+1, w, h, image, visited, true, result);
      burn(x-1, y, w, h, image, visited, true, result);
      burn(x, y-1, w, h, image, visited, true, result);
    }
  }
  if(!onFire && index+1 < image.length) {
    index++;
    burn(index%w,index/w, w, h, image, visited, false, result);
  }
}

int[] _image = {
  0, 0, 1, 1, 1,
  0, 0, 0, 1, 0,
  0, 0, 0, 1, 0,
  0, 1, 1, 0, 0,
  0, 1, 1, 0, 0,
  0, 1, 1, 0, 0
};
ArrayList<ArrayList<Integer>> _result;
boolean[] _visited;
color[] _rcolor;

void setup() {
  size(500, 600);

  _result = new ArrayList<ArrayList<Integer>>();

  _visited = new boolean[_image.length];
  for (int i=0; i<_visited.length; i++)
    _visited[i] = false;

  _rcolor = new color[100];
  for (int i=0; i<_rcolor.length; i++)
    _rcolor[i] = color((int)random(256),(int)random(256),(int)random(256));

  burn(0, 0, 5, 6, _image, _visited, false, _result);
  println(_result.size());
}

void draw() {
  for (int x=0; x<5; x++) {
    for (int y=0; y<6; y++) {
      int index = y*5+x;
      color c = (_image[index] == 1) ? color(255, 255, 255) : color(127, 127, 127);
      for(int i=0; i<_result.size(); i++) {
        for(int j=0; j<_result.get(i).size(); j++) {
          if(index == _result.get(i).get(j)) {
            c = _rcolor[i];
            break;
          }
        }
      }
      fill(c);
      rect(x*100, y*100, 100, 100);
    }
  }
}