Rui Wang @ Tsinghua University
(To watch the full demo, please visit its GitHub page)
The game is composed of three main pages. The index page, the game page, and the resume page.
The index page is where a user can select levels and custom difficulty according to a .txt file. Users can also quit the game from this page.
The game page is the main body of this game. There is a cannon that can shoot a ball on clicking. The next ball to be shot is placed under the cannon (half-exposed), while the next next ball is placed to the left of the cannon. There is a timer that starts at 60 seconds. The balls will bounce off if it collides with a side wall. Apart from the basic functions, the game also offers four additional tools.
- The bomb. The bomb will eliminate all balls next to it.
- The rainbow. The rainbow will randomly turn into the color of a ball next to it.
- The laser. The laser will let all balls that are not on the ceiling fall
- The gold. The gold will add 10 seconds.
The balls are eliminated if there are more than 3 of the same color connected together. If a ball is not connected to the ceiling any more after other balls eliminate, it falls to the ground.
You win when: the total number of balls left < 5.
You lose when: any ball reaches below the death line.
The code can be broken into three major classes. Index, GameInterface, and LogicGame. GameInterface defines different JPanels within the game page including the timer, the balls, the pause button, and so on.
The major body of the program is insider LogicGame.java, where the game itself is implemented. Actually both the logic representation and graphics are implemented in this file. The mouse listener detects the user's input and use a different thread to render the ball launching procedure. It also determines when the balls are eliminated, fall, or the user wins or loses.
Throughout the program we use a single frame so that the window will not move by itself. The only thing we change is the JPanel within this frame. We DO NOT create a new frame each time the user restarts the game.
The most difficult part is to let the cannon rotate with the mouse. This is hard because java does not have an embedded method for icon rotation. Therefore, I had to rotate the image first and set it as an icon. Also, special attention has to be paid in order to let the image rotate around a certain point and fix that point inside the window.