So the whole point of having a goal is to reach that goal, or at least try to. What this method does is take a list of directions, we'll assume they are already valid directions, and for each of the directions in the list it will calculate the distance from the entity to the goal. Then it returns the direction with the smallest distance. That direction will be chosen instead of choosing a random direction. We find the best direction by calculating the line of sight distance from each direction and just choosing the direction with the shortest line of sight distance. Because we're in a maze, however, the shortest line of sight won't always be the shortest distance the ghost must travel, but it's good enough for now and most importantly it's really fast to figure out. We don't need any fancy A* algorithms here, you can if you want to though. Extra credit if you do!
What you should see after you implement these changes is that the ghost will be moving around in a circle in the upper left corner. This is because the ghost is basically trying to reach the screen's origin which is the upper left corner of the screen, but can't because of the movement restrictions we've placed on it. Remember that it can't ever STOP during the game, so it has to choose a target every time it reaches a node, even if that target takes it further from the goal. But if it is able to choose a target that takes it closer to the goal, it will. What's nice about this is that we can give it any position on or off the screen and it will traverse the maze on its own trying to get to that position. This is the heart behind the ghosts AI. Try giving the ghost a different initial position rather than the first node. The ghost will maneuver around the maze until it reaches the top left corner, at which point it will just move around in a circle forever, or until we exit the game loop. Next we need to understand something called Modes. This will give our ghosts AI more sophistication.
