HTML5 Canvas, 2nd Edition

Our Game’s Design

We are not going to assume that everyone who reads this chapter knows of or understands Atari’s classic arcade game Asteroids. So let’s start by taking a peek at the Asteroids game-play elements.

Asteroids, designed by Ed Logg and Lyle Rains, was released by Atari in 1979. The game pitted a lone triangular two-dimensional vector spaceship (the player ship) against screen after screen of asteroid rocks that needed to be dodged and destroyed. Every so often a space saucer would enter the screen attempting to destroy the player ship.

All asteroids started the game as large rocks; when they were hit, they would split into two medium-sized rocks. When hit by a player missile, these medium-sized rocks would then split into two small rocks. The small rocks would simply be destroyed when hit. (Small was the final size for all asteroids.)

When the player destroyed all the asteroids, a new screen of more and slightly faster asteroids would appear. This went on until the player exhausted his three ships. At each 10,000-point score mark, the player was awarded an extra ship.

All of the game objects moved (thrusting, rotating, and/or floating) freely across the entire screen, which represented a slice of space as a flat plane. When an object went off the side of the screen, it would reappear on the opposite side, in warp-like fashion.