explosions.js

function ExplosionFactory() {
	this.explosions = [];
	this.randomExplosion = function() {
		return randomPick(this.explosions);
	}
	this.generateExplosion = function() {
		var explosion = newCanvas(EXPLOSION_SIZE, EXPLOSION_SIZE);
		explosion_ctx = explosion.getContext("2d");
		var DRAW_GROUND = true;
		if (DRAW_GROUND) {
			
			var groundColor = function() {
				return [181, 109, 16, irand(255)];
			}
			for (var i=0 ; i<3 ; ++i) {
				var ground = newCanvas(EXPLOSION_SIZE, EXPLOSION_SIZE);
				perlin_noise(ground, groundColor);
				circle_alpha(ground);
				var ox = (explosion.width - ground.width)/2;
				var oy = (explosion.height - ground.height)/2;
				explosion_ctx.drawImage(ground, ox, oy, ground.width, ground.width);
			}
		}
		var black = function() {
				return [0,0,0, irand(255)];
		};
		var scortchMark = newCanvas(EXPLOSION_SIZE, EXPLOSION_SIZE);
		perlin_noise(scortchMark, black);
		circle_alpha(scortchMark);
		var ox = (explosion.width - scortchMark.width)/2;
		var oy = (explosion.height - scortchMark.height)/2;
		explosion_ctx.drawImage(scortchMark, ox, oy, scortchMark.width, scortchMark.width);
		return explosion;
	}

	for (var i=0 ; i<5 ; ++i) {
		this.explosions.push(this.generateExplosion());
	}
}