docs: public int getIndexForColor(int rgb) {
  		int red = (rgb >> 16) & 0xff;
  		int green = (rgb >> 8) & 0xff;
  		int blue = rgb & 0xff;
  
  		OctTreeNode node = root;
  
  		for (int level = 0; level <= MAX_LEVEL; level++) {
  			OctTreeNode child;
  			int bit = 0x80 >> level;
  
  			int index = 0;
  			if ((red & bit) != 0)
  				index += 4;
  			if ((green & bit) != 0)
  				index += 2;
  			if ((blue & bit) != 0)
  				index += 1;
  
  			child = node.leaf[index];
  
  			if (child == null)
  				return node.index;
  			else if (child.isLeaf)
  				return child.index;
  			else
  				node = child;
  		}
  		System.out.println("getIndexForColor failed");
  		return 0;
  	}