Expansion Engine Sound

"use strict";
this.name	= "engine_sound";
this.author	= "Norby";
this.copyright	= "2015 Norby";
this.description= "The tone of engine sound follow the speed of your ship.";
this.licence	= "CC BY-NC-SA 4.0";

//internal properties, should not touch
this.$Last = 1; //last played sound
this.$Pause = false; //no sound in pause
this.$S = []; //sound objects storing sound files
this.$SS = null; //soundsource

//worldscript events
this.startUp = function() {
	for(var i=1; i<26; i++) {
		this.$S[i] = Sound.load("bgs-m_ambi_engine1-"+i+".ogg");
	}
	
	this.$SS = new SoundSource;
	this.$SS.sound = this.$S[1];
	this.$SS.loop = true;

	this.$T =  new Timer(this, this.$Play, 0, 0.25);
	this.$T2 =  new Timer(this, this.$Play, 0.125, 0.25);
}


this.startUpComplete = function() {
	var b = worldScripts["BGS-M"];
//	if( b ) b.ambientSounds = false; //turn off BGS engine sound but chatter too
}

this.gamePaused = this.shipDockedWithStation = this.shipDied = this.shipWillEnterWitchspace = function() {
	this.$SS.volume = 0;
	this.$Pause = true;
}

this.gameResumed = this.shipWillLaunchFromStation  = this.shipExitedWitchspace = function() {
	this.$Pause = false; 
}

//engine sound methods
this.$Play = function() {
	var p = player.ship;
	if( !p || !p.isValid || p.docked || p.speed < 1 || p.torusEngaged
		|| p.speed > 8 * p.maxSpeed + 1
		|| !this.$SS || this.$Pause ) {
		this.$SS.volume = 0;
		return;
	}

	var s = p.speed;
	if( !p.injectorsEngaged && s > p.maxSpeed ) s = p.maxSpeed;
	var l = Math.ceil( s/20 );
	if( !this.$S[ l ] ) l = 25; //speed over 500
	this.$SS.volume = 0.2 + l / 250; //from 0.2 to 0.3

	if( this.$Last != l ) {
		this.$Last = l;
		this.$SS.sound = this.$S[ l ];
		this.$SS.play();
	}
}