05-830, User Interface Software, Spring, 1998.

Battleship Game Benchmark Description

Ann Sluzhevsky

Introduction

This is a simple interface for playing the Battleship game. It features direct manipulation, simple animation and simple sound.

The interface allows the user to play the Battleship game with the computer as the opponent. All user actions and commands are issued with the help of a mouse. This is a rather simple game similar to Minesweeper on MS Windows or Macintosh. (I was only able to find some non-commercial Java implementations of Battleship on the WWW).

This benchmark was chosen for several reasons. It features direct manipulation by allowinng the user to drag and drop ships onto the playfield. The drag and drop feature must have a constraint of being able to "snap" the ship on the grid of the field. The user should not just be able to place the ship starting in the middle of a cell. This constraint is representative of many other direct manipulation interfaces, such as the "Snap to Grid" options on drawing packages such as ClarisDraw.

Other features are animation and sound. When a ship is hit, the user sees the cell explode and when a ship is drowned there is a bigger explosion. These explosions are accompanied by sound..

Description

Rules of the Game

There are 2 players in this game: the user and the computer. The goal of the game is to sink all your opponent's ships before your opponent sinks yours. There are two playfields displayed. Each playfield is 10x10 cells. The user's fields the one on the left and the computer's is the one on the right. Each player has five ships, each of which occupies a certain number of squares on the playfield:

• Destroyer (2 squares)
• Submarine (3 squares)
• Cruiser (3 squares)
• BattleShip (4 squares)
• Aircraft Carrier (5 squares)
• At the start of the game, the user places the ships onto the playfield. The user starts the game by making the first move. The user and the computer take turns shooting at each other's ships. The user shoots by clicking one of the squares on the right-hand playfield which haven't been already tried. If a ship is hit, an explosion is displayed. To sink a ship, the user must score a hit on each of the squares occupied by the ship. If you lose, the locations of the enemy ships are displayed.

  Computer's Strategy

  • The computer places the ships using a random number, but such that no ships overlap or go out of bound.
  • When there are no ships which have been hit (but yet unsunk) the computer picks cells to try randomly
  • When there is a ship which has been hit, the computer should "finish off" the ship by trying the cells around the hit cell in 4 directions.

    Interface Features

    • The ships are located on a tool bar, on the left.
    • The ships can be displayed either vertically or horizontally, depending on the selections of (vertical/horizontal) radio buttons.
    • To the right of the toolbar, there are 2 playfield areas. Both are 10x10 grids. The user's field is the one the left.
    • The user places ships on the field by dragging them onto the field. The ships "snap" into the grid, matching the leftmost or topmost cell to the front of the ship. In the case where the ships closest cell will place the end of the ship out of bounds, the ship is shifted to the left or to the top. The same shifting is applied when there is a ship overlapping. No overlapping is allowed.
    • The user can also change the location of the ship, by dragging them again.
    • When the user takes the ship our the horizontal view, that ship will no longer be available in the vertical view.
    • The user has to place all the ships on the field, before being able to start playing. The user starts the game by making the first move.
    • The user makes a move, by clicking the cell of his choice on the enemy field. Once the user, makes the first move, he/she can no longer move the ships around on the field.
    • The cells on both playfields are marked according to their status:
      • Untouched
      • Guessed, but missed a ship
      • Hit
      • Shot down (part of drowned ship)
    • When a computer's ship is hit, there is an explosion in that cell and a sound. When a computer's ship is drowned, there is a different animation and sound.
    • The way the cells are marked to distinquish their status is up to the implementation. It could include either coloring them a different color, or displaying a picture of a mine in a cell.
    • When the game is over, a message of the outcome is displayed.
    • If the users looses, the enemies ships are displayed
    • At all times, he user has an option to restart the game and to exit out of the game. Exiting and restarting is acheived by clicking on appropriate buttons

  Prototype Drawing

  This an example of what the game looks like at the start of the game.