Chris Orona

1

• Chris Orona
• CS 491B
• June 2, 2005

2
Game Components

• Introduction
• Storyline
• Objective
• System
• Game threads
• Scheduling
• Characters
• Player ships and weapons
• Enemies and paths
• Software Issues
• Technical Background
• Technical Issues
• Deployment

3
Storyline Introduction

• Aliens are attacking Earth! Last time, a lone
  space ship attempted to save mankind from aliens.
  Now the aliens are back with reinforcements. Now
  its up to you to eradicate this threat to
  humanity once and for all!

4
Gameplay

• Player earns points by defeating enemies.
• Player starts with 4 lives, when hit by an enemy,
  the player loses a life.
• Lose all your lives, and the game is over.
• Pickup powerup weapons to improve your
  destructive powers.

5
Game Threads
Wait for next event
Keyboard
Mouse
Run next event
Cheats
Any more events?
Yes
No
Scheduler Thread
Update Thread
Input Thread
6
Game Threads (cont.)

• Level Threads

Score Panel
Action Panel
Background Panel

• Character Threads

7
Level Scheduler Design

• How the scheduler works
• Implemented using a PriorityQueue
• Inserts objects in a tree sorted by run time
• Schedules the introduction of enemies, powerups,
  or the end of timed levels
• Some enemies schedule events when they die

8
Powerups

• Weapon Cycling
• Each ship has certain weapons it may use
• Additional Lives
• Shielding
• Protects from enemy attacks for a short while

9
Collision Detection

• bounding box

hit detected

• Bounding Box check
• x, y, height, width of shots are compared to the
  enemies coordinates.

10
Enemies

• Equipped weapon
• Some enemies will fire at the player, these shots
  are considered enemies.
• Enemy Health
• Amount of hits required to destroy the enemy
• Corporeality
• Some enemies should not be allowed to be hit!
  This includes enemy shots, explosions, and
  powerups.
• Defeat
• Award points, and special death events
• Path
• Movement pattern assigned to an enemy.

11
Enemy paths

• Paths
• Collection of points for movement
• Different paths can be plugged into any object
  (except the ship)
• Basic Types
• Straight Line
• Oscillating
• Random

12
Shot Paths
(x0, y0)
(x1, y1)
?y y1- y0 ?x x1- x0 Is ?y aspect
?x? (y1 - y0) (?y / ?x)(x1 - x0)
(x1, y1)
13
Zigzag Paths
(x3, y3)
(x2, y2)
(x1, y1)
(x0, y0)
14
Technical Background

• Language
• Uses Java for cross-platform compatibility
• Minimum version is Java 5
• Java 2D API and Java Sound API
• Based on an earlier project
• Java 1.2 with limited capability

15
Technical Issues

• Using Java2D shapes is much faster than bitmap
  images.
• Objects are reused whenever possible.
• Sprite and Sound caches
• Lowering the refresh rate of threads improves
  performance.

16
Java Web Start

• Deploy Java programs online using Java
  applications rather than applets
• Enables automatic updates by checking the web
  server for a more recent version
• Can be accessed as a shortcut on the desktop
• Configured through the use of a JNLP file (which
  is XML format)
• MIME type application/x-java-jnlp-file

17
Java Web Start Configuration File

• du/corona/cs491/"
• hrefDeepSpace2.jnlp"
• Deep Space 2
• C. O.
• cs491/" /
• Deep Space 2 - the
  game
• height"50" /
• /
• ager" /

18
References