Pacman README
Overview:
My PacMan app has a PacMan that moves around and can change directions via
the arrow keys (up/down/left/right). There are also four ghosts that move around.
If the ghosts are in Chase mode, they run after Pacman; in Scatter mode, they
run after a corner of the maze; in Frightened mode, they move randomly.
The game alternates between 20 seconds of Chase mode and 7 seconds of Scatter mode.
The Frightened mode can be started by PacMan eating an energizer and it lasts 7 seconds.
The ghosts are released from the pen every 3 seconds, if there is any ghost left.
The goal of the game is to control PacMan to eat dots and energizers, and to avoid
ghosts in Chase and Scatter mode and to eat ghosts in Frightened mode.
There are in total eight classes: Game, PacMan, Ghost, Map, MazeSquare, BoardCoordinates,
Dot, and Energizer. There are two enum classes: GhostMode, Direction, and GhostName. They interact
in the following way:
- The Game class contains PacMan, Ghost, and Map class.
- The Map class contains MazeSquare, BoardCoordinates, Dot, and Energizer class.
- GhostMode provides different enums to represent modes of the ghosts (CHASE, SCATTER, FRIGHTENED)
- GhostName provides different enums to represent different ghosts (BLINKY, PINKY, INKY, CLYDE)
Design Choices:
Since all four ghosts have the same functionality (e.g. moving around, colliding with PacMan)
but different properties (e.g. color, initial location, the order to leave the pen), I decided to
write a single Ghost class to represent four ghosts, and passed in their different properties
in the parameters.
Also, ghosts, dots, and energizers can all collide with PacMan and update the current score,
but they have different ways of doing it. For example, after a collision, ghosts need to
return to the pen whereas dots need to removed from the maze. So I decided to write a
Collidable interface.
In addition, I wrote a breadth-first-search method to help Pacman find the quickest direction
to get to the target. The method first uses a for-loop to iterate all four directions,
enqueues the valid board coordinates in a queue, and documents the corresponding directions in
a 2-D array. Then it dequeues the first coordinate as the currentCell and adds new
valid coordinates of the currentCell to the queue. The method continues this process of
enqueuing and dequeuing until the whole board is gone through and the square closest to the
target is found. The direction that was documented in the 2-D array in that square is
returned.
To decide the random direction to turn for ghosts in the Frightened mode, I wrote an
arrayList called validDirections because the number of valid directions it can move
is not fixed depending on the current location of the ghost. I iterate through all
four directions, adds the valid directions to the arrayList and generates a random
index in the arrayList to become the new direction.
When ghosts are released from the ghost pen in Frightened mode, they need to be released in
a "first in, first out" order. So I wrote a queue to document and release the ghosts in the pen.
Known Bugs:
None.
Debugging Collaborators:
No.