AdrianArroyoCalle/gajse

/**
 * A positional audio based system
 * @module gajse-audio
 */

var storage=require("./gajse-slim-storage");

/**
 * A positional audio system using WebAudio
 * @class gajse-audio
 * @since 0.0.3
 * @static
 * @uses gajse-slim-storage
 */
module.exports={
    /**
     * @property audioContext
     * @type AudioContext
     * @default null
     * @private
    */
    audioContext: "",
    /**
     * @property gainsNodes
     * @type Array
     * @default []
     * @private
    */
    gainsNodes: [],
    audioPos: {x: 0, y: 0, z: 0},
    /** Enables the Audio System
     * @method enableAudio
     * @since 0.0.3
     *  */
    enableAudio: function(){
        window.AudioContext = window.AudioContext || window.webkitAudioContext;
        this.audioContext=new AudioContext();
        document.addEventListener("GAJSE_SetBackgroundMusic",function(evt){
            console.log("SET BACKGROUND MUSIC: "+evt.detail.resource);
            var data=storage.getResource(evt.detail.resource);
            this.audioContext.decodeAudioData(data,function(buffer){
                    var source=this.audioContext.createBufferSource();
                    source.buffer=buffer;
                    source.connect(this.audioContext.destination);
                    source.start(0);
            }.bind(this));
        }.bind(this));
        document.addEventListener("GAJSE_AddPositionalAudio",function(evt){
            var intensity=evt.detail.intensity;
            var position=evt.detail.position;
            var data=storage.getResource(evt.detail.resource);
            this.audioContext.decodeAudioData(data,function(buffer){
                var source=this.audioContext.createBufferSource();
                source.buffer=buffer;
                var node=this.audioContext.createGain();
                source.connect(node);
                node.connect(this.audioContext.destination);
                var gainNode={
                    intensity: intensity,
                    position: position,
                    node: node,
                    source: source
                };
                gainNode.source.start(0);
                this.gainsNodes.push(gainNode);
            }.bind(this));
        }.bind(this));
        document.addEventListener("GAJSE_ResetAudio",function(){

        });
        document.addEventListener("GAJSE_PlaySFX",function(){
            
        });
        document.addEventListener("GASJE_PlayText",function(){

        });
    },
    /**
     * Updates the audio with a new position
     * @method setAudioPosition
     * @since 0.0.3
     * @param {THREE.Vector3} pos The new position
    */
    setAudioPosition: function(pos){
        this.audioPos=pos;
        this.gainsNodes.forEach(function(gainNode){
            var firstOperator=Math.pow(gainNode.position.x-pos.x,2);
            var secondOperator=Math.pow(gainNode.position.y-pos.y,2);
            var square=Math.sqrt(firstOperator+secondOperator)+1;
            var value=(gainNode.intensity/square)+0.001;
            gainNode.node.gain.value=value;
        });
    }
}