Scratch

This is an overdue post about how to make a PacMan project in Scratch. It is intended purely for educational purposes, as are most of my projects. You can find my unfinished but working PacMan project here... pacman002 but please download it and run it in turbo mode for best usage.


I recreated the original game screen to scale.
Each tile is 8x8 pixels. The entire screen is 28 tiles wide by 36 tiles tall. That is a total of 1008 tiles. But keep in mind, that includes the black areas 'outside' the map as well. That also makes the entire screen 224 x 288 pixels.

You MUST check out the following page if you are serious about understanding/recreating the original gameplay.
http://home.comcast.net/~jpittman2/pacman/pacmandossier.html

Well, you could do a great job of faking it in Scratch using typical Scratch methods, no doubt. But in my opinion, in the long run, if your goal is to clone the original, it will actually be harder to do if you don't use a tile system.
The original game's ghost AI is governed entirely by targeting tiles around PacMan when in Chase mode. The behavior of each ghost is based on how closely each one is allowed to target PacMan. As I mentioned before, collisions occur when 2 sprites occupy the same tile. Each map tile is recorded into memory as either 1) blocks movement or 2) allows movement.
So as you can see, the tile system governs all aspects of game play. There are additional aspects that are not so readily visible. For example, the PacMan uses a special movement feature called "cornering" that allows him to move diagonally around corners. It happens so fast, most people never notice it. This is an important element of gameplay because it gives the player an edge over the ghosts by taking many turns instead of traveling in straight lines.
I watched a video of the original PacMan to see for myself and sure enough, it happens. Another thing I noticed is that even in the original game, Pacman does NOT have 'perfect' movement through the maze. By that, I mean that he is not sized to fit exactly through the maze paths, instead having some pixels worth of distance between him and the maze walls. By imperfect I mean that if you enter and stop moving in the same maze corner from two different directions, he will stop at different places.
But a big part of the game-play is the fast movement and non-stop action so the player stays so busy, they don't notice these things. Working on this project really blew my mind and now I have a ton of respect for the genius of its creator as well as his elegantly simple methods of making it all work. That page I mentioned goes into his history, the development of the game, and all this other stuff in great detail. It is worth reading even if you never intend to make your own PacMan, inspiring stuff!

As for my version, try it (download it) and you can see that I have some of these features implemented. I planned to "cheat" on the dot-eating by stamping over the dots which are drawn onto the background map instead of using sprites. There are a lot of dots! I started on the red ghost's scatter AI but did not finish it and it is currently disabled. I did get PacMan running pretty well, including the cornering feature. However, I later realized that in the real game, PacMan can only anticipate corners from a short distance away whereas mine can currently anticipate them as soon as it makes the turn before it. By anticipate, I mean the player can be going one direction, press an arrow for the next turn and PacMan will continue going straight but will turn automatically when it gets to the next corner.

I also use a long list to store the tile blocks/doesn't block data. Since Scratch will remember saved list data, it is automatically stored in the current project. I also cheated by drawing the maze into the background rather than having the project assemble the screen from a small selection of graphic tiles, as had to be done in the original. Obviously, I have used Scratch's native capabilities in some ways while using the original PacMan game's features (the tile system) to make sure that the whole thing plays and feels correct.

One reason I have stopped working on this is because I have since been told that my scripting methods, specifically using Forever loops as opposed to broadcasting, are slowing down the project. It currently works best in Turbo mode but that messes up costume changes. If I were to continue this, I would re-write everything again using broadcasts to see if I could speed it up enough to run in Normal stepping mode instead of Turbo.

Hope this helps people out    I always intended to make this post and recent Namco-related circumstances have lead me to believe that it is vital. Apparently, some people think that we just wanna play PacMan for free at Scratch. Which is ridiculous because you can download and play the original game with all it's features for free elsewhere. I personally have yet to see a Scratch version that comes close to fully emulating the original. Obviously, I support using this milestone in computer gaming as a method to teach new generations computer programing, which I believe is in line with the whole philosophy behind Scratch in the first place. And I am 39 years old so if Namco should decide to ban my version, I will not give up without a fight unless the Scratch Team itself recommends it which from what I have read so far, they do not. There is far more at stake here than what Namco seems to want us to believe. Peace.