Rock.js

// ====
// ROCK
// ====

"use strict";

/* jshint browser: true, devel: true, globalstrict: true */

/*
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*/


// A generic contructor which accepts an arbitrary descriptor object
function Rock(descr) {

	// Common inherited setup logic from Entity
	this.setup(descr);

	this.randomisePosition();
	this.randomiseVelocity();
	  
	// Default sprite and scale, if not otherwise specified
	this.sprite = this.sprite || g_sprites.rock;
	this.scale  = this.scale  || 1;

/*
	// Diagnostics to check inheritance stuff
	this._rockProperty = true;
	console.dir(this);
*/

};

Rock.prototype = new Entity();

Rock.prototype.randomisePosition = function () {
	// Rock randomisation defaults (if nothing otherwise specified)
	this.cx = this.cx || Math.random() * g_canvas.width;
	this.cy = this.cy || Math.random() * g_canvas.height;
	this.rotation = this.rotation || 0;
};

Rock.prototype.randomiseVelocity = function () {
	var MIN_SPEED = 20,
		MAX_SPEED = 70;

	var speed = util.randRange(MIN_SPEED, MAX_SPEED) / SECS_TO_NOMINALS;
	var dirn = Math.random() * consts.FULL_CIRCLE;

	this.velX = this.velX || speed * Math.cos(dirn);
	this.velY = this.velY || speed * Math.sin(dirn);

	var MIN_ROT_SPEED = 0.5,
		MAX_ROT_SPEED = 2.5;

	this.velRot = this.velRot ||
		util.randRange(MIN_ROT_SPEED, MAX_ROT_SPEED) / SECS_TO_NOMINALS;
};

Rock.prototype.update = function (du) {

	// TODO: YOUR STUFF HERE! --- Unregister and check for death

	this.cx += this.velX * du;
	this.cy += this.velY * du;

	this.rotation += 1 * this.velRot;
	this.rotation = util.wrapRange(this.rotation,
								   0, consts.FULL_CIRCLE);

	this.wrapPosition();
	
	// TODO: YOUR STUFF HERE! --- (Re-)Register

};

Rock.prototype.getRadius = function () {
	return this.scale * (this.sprite.width / 2) * 0.9;
};

// HACKED-IN AUDIO (no preloading)
Rock.prototype.splitSound = new Audio(
  "sounds/rockSplit.ogg");
Rock.prototype.evaporateSound = new Audio(
  "sounds/rockEvaporate.ogg");

Rock.prototype.takeWireHit = function () {
	this.kill();
	
	if (this.scale > 0.25) {
		this._spawnFragment();
		this._spawnFragment();
		
		this.splitSound.play();
	} else {
		this.evaporateSound.play();
	}
};

Rock.prototype._spawnFragment = function () {
	entityManager.generateRock({
		cx : this.cx,
		cy : this.cy,
		scale : this.scale /2
	});
};

Rock.prototype.render = function (ctx) {
	var origScale = this.sprite.scale;
	// pass my scale into the sprite, for drawing
	this.sprite.scale = this.scale;
	this.sprite.drawWrappedCentredAt(
		ctx, this.cx, this.cy, this.rotation
	);
};