Alien Invaders

1
Alien Invaders

• Jayne Swank Jillian Murphy

2
Overview

• We plan to create a java version of the game
  Alien Invaders. Evil aliens are coming down from
  space, and the player must save the Earth from
  them. If an alien reaches the ground, the player
  loses a life. Accompanying the aliens are
  radioactive space rays. Beware! If one hits the
  player, points will be deducted from the total
  score. The player is armed with a gun which can
  be used to destroy the alien. The player also has
  the ability to shield himself from the
  radioactive rays. To get past the first round,
  all aliens must be destroyed. The amount of
  aliens and radioactive rays, as well as their
  speed, will increase per level. The player has
  the ability to move the gun both left and right,
  and position it at an angle through keystrokes.
  The game ends when the player loses all lives.

3
Game Design

• Sprites Gun CAG drawing. Shield CAG
  ellipse, transparent color. Bullets Aliens
  image sprite of alien Rays polar sprite
  AddLife levelMessage livesMessage
  scoreMessage aliensLeftMessage
  gameOverMessage (more as needed)

4
Trackers

• GunTracker AliensTracker RaysTracker
  AddLifeTracker

5
Game State Indicators

• Remaining Aliens Each level has an increasing
  number of aliens. Levels when the player kills
  the set number of aliens, they move up a level.
  Lives if an alien hits the ground level, a life
  is lost. If the player catches a 1 sprite, his
  lives increase. Score points are gained when
  the player kills an alien and points are lost
  from rays hitting the player.

6
Sounds Splash Screens

• Bullet shot Hit alien Shield activated Alien
  hits earth (life lost)
• Splash screen in between levels to alert player
  to change.

7
What happens _at_ collisions?

• If a ray collides with the player and the shield
  is not activated, the player will lose points. If
  a ray collides with the player but the shield is
  up, no points are lost. If a bullet hits an
  alien, the alien disappears. If an alien makes it
  to the ground, however, the player loses a life.
  As a bonus, some random 1 sprites will fall
  from the sky. If a player positions the gun so
  the 1 hits it, they will gain a life.

8
Methods Enhancements

• Methods initState() initSprites()
  updateStatus() changeLevels() (more as
  needed)
• Possible Enhancements Making the rays originate
  at the falling aliens. Creating a changing
  background to simulate moving through space.

9
TIMELINE

• Week 1 create all sprites. Write skeleton of
  program including comments. Week 2 work on
  handling collisions updating game states. Week
  3 work on changing levels. Debug. Week 4
  Enhancements, debug, release.