Pac-Man in JavaFX

The O'Reilly InsideRIA site has published an interesting series of articles by Haining Henry Zhang titled "Writing the Pac-Man Game in JavaFX." This is yet another illustration of the power of JavaFX, exemplifying the richness and variety of capabilities the framework provides.

To date, four JavaFX Pac-Man articles have been published. The current version of the application can be run in Part 4 of the series. And the source code is available for download.

In "Writing the Pac-Man Game in JavaFX - Part 1, Haining outlines the logical and data structure behind his implementation of the game.

When designing a data model, I usually consider two aspects: performance and space. Performance means that the data should be accessed via an efficient approach. For example, a hash table is usually faster than a linked list when a keyword-based search is performed. Performance is an important consideration for games that are constantly taking a player's input and updating graphical objects. Games like Pac-Man or Space Invaders fall into this category.

Haining notes that "the ability to leverage Java from within JavaFX is one of the very powerful features of JavaFX," and he puts this to use in the application. The article demonstrates the code for drawing the Pac-Man maze and concludes with a runnable JavaFX demo.

In Part 2, Haining tackles some of the Pac-Man animation requirements, including the chomping Pac-Man himself. This is designed looking ahead to the subsequent need to create the "ghosts" later on. Haining creates a MovingObject class with a moveOneStep() function that is called every 200 milliseconds. The Pac-Man is inserted into the maze, and code for letting the user control the Pac-Man's motion via the keyboard is implemented, followed by code to let the Pac-Man grab the dots it passes through. At this point, the program is an interesting toy, but there isn't much challenge in playing it.

Part 3 of the article series brings in those frightening Pac-Man ghosts. The programming challenge is to create the different state representations of the ghosts (normal, hollow, and flashing), and correctly manifest the transitions between the states. This part of the article ends with the ghosts roaming the maze along with the Pac-Man, but these are nice ghosts that don't yet try to eat the Pac-Man.

Writing the Pac-Man Game in JavaFX - Part 4 provides the interactions between the Pac-Man and the ghosts (if the Pac-Man has recently gobbled a dot, he can eat the ghosts; if not, then they can eat him). First, the distance between the Pac-Man and the ghosts is calcuated. A threshold is applied, defining when the Pac-Man and a ghost are considered to be "touching" (in which case somebody is destroyed). Haining also implements the classical death throes of the Pac-Man, when he is eaten by a ghost (his circle unwraps until he disappears). To do this, he creates a DyingPacMan class. Whenever the Pac-Man is eaten by a ghost, an instance of DyingPacMan is inserted into the maze at the appropriate locations, it does its visual activity, and the game ends.

It looks like there will be a Part 5 article, since near the end of Part 4 Haining says:

As we mentioned in previous article, the ghosts are moving in a random fashion. This makes the game less challenging. In the next article, we will discuss a better algorithm of the ghost's moving behavior.

Haining's "Pac-Man in JavaFX" series is an interesting tutorial on JavaFX, worthy of study if you're looking for a fun way to introduce yourself to JavaFX.