EntityAsteroids

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Overview

EntityAsteroids is a simple, open source entity-based game engine with an example space shooter game, written in ActionScript 3 by Iain Lobb.

It accompanies his two-part tutorial series. The first part sets up a bare-bones, component-based entity system and explains why you might build games that way instead of relying on deep class inheritance; the second uses that system to create a simple Asteroids game.

The game is built from six classes: the game logic, the player's ship, the asteroids, the bullets, the gun that fires them, and an enemy ship, a wandering alien that is just there to add some variety to the game.

Made by: Iain Lobb
Released: 2012

Controls guide

Flying

Key	Action
`Left`/`Right`	Rotate the ship
`Up`	Thrust forward
`Down`	Thrust backward
`W`/`A`/`S`/`D`	Same as the arrow keys
`Space`/`Z`	Fire one shot per press

Starting

Key	Action
Click	Start, or start again after you win or lose

Cheatsheet

Objects

Your ship: Takes 6 hits; destroyed on the sixth
Asteroid: 10 at the start; each hit shrinks it and splits off a copy, gone after its third shrink
Enemy ship: Wanders and fires at random; 6 shots to destroy
Bullet: Fades out after under a second
Collision: An asteroid that touches you vanishes and costs you one hit

Rules

Win: Destroy every asteroid and the enemy ship
Lose: Your ship is destroyed
Screen edges: Everything wraps around

Tips

Each starting asteroid takes seven shots to clear (one big, two medium, four small), so 10 asteroids mean about 70 hits; there is no autofire, so tap rather than hold.
Ramming an asteroid removes it whole instead of splitting it, at the cost of one of your six hits. Use it as a last resort to finish the round.
Asteroids never hurt the enemy ship, and only its bullets can hurt you, so keep moving and stay out of its line while you deal with the rocks.
The ship has drag and rotation eases in, so turn early and use short bursts of thrust; Down is a brake as well as a reverse.