1. “Link All Together” – Linktile 2D game programming
Guanhua Xie
CS 491B
Fall 2008

2. Introduction to the Game
A puzzle game similar to “Mahjong” in China.
Match and eliminate the tiles on board.
Easy to learn but hard to stop from playing.

3. Rule of the Game
Match and link the pairs of the same tiles under time limitations.
The path for the pair elimination should take no more than two turns.

4. Layout of the Game
Blue : Valid Match Red: Invalid Match

5. Deadlock Situation

6. Motivation Interesting game to implement.
Find efficient algorithm to determine the valid match for the two selected tiles and detect deadlock situation.
Design online two user competition mode for this game.

7. Technology Used Programming Language Development Tool
Java 2 Standard Edition 5.0
Development Tool
Eclipse

8. System Component User Visible User Invisible Single user mode
Main Menu
Control Panel
Game Board
Two user online competition mode
User Invisible
Algorithm to determine the valid match
Algorithm to detect the deadlock

9. Algorithm for deadlock detection
Brutal force search (Last quarter)
Inefficiency.
Keep a list of eliminable pairs of tiles
Remove and add tile pair after each elimination.
Check the size of the list.
More time efficient.

10. Extra Features Different tile representation. Game sound and music.
Path display.

11. Online two user competition mode
Simple server
Accepts two clients to form a session
Each session is a thread
Client
Graphical User interface
Pass the user input to the server
Receive game status from the server

12. Transition between each round of the game

13. Gain from the project
A functional version of the single user mode and a working version of online competition mode of the game.
Learn techniques like java sound, networking programming.
Experiences with developing a project.
Learn the technique writing and presentation.

14. Algorithm for Valid Match
Trivial Case
Two tiles are not the same. (Reject)
Two same tiles are adjacent to each other. (Accept)
One of the two tiles are surrounded by other tiles in four directions. (Reject)

15. Algorithm for Valid Match
Generic Situation
Composed of at most three sub-paths.
Find the range of two tiles can freely move in its column or row (Reject if the two ranges do not intersect).
Find a free horizontal or vertical path in the intersection of the two ranges(Reject if no such path exist).