js realizes 3D sound effects through audioContext

This article shares the specific code of js to achieve 3D sound effects through audioContext for your reference. The specific content is as follows

Preface

AudioContext's setPosition implements 3D sound effects

Effect display

Code Showcase

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>3D Audio</title>
    <style>
        body, div{
            margin: 0px;
            padding: 0px;
            text-align: center;
        }

        #cav{
            border: 1px solid black;
            border-radius: 4px;
            margin: 10px auto;
        }
    </style>
</head>
<body>
<canvas id="cav" width="320" height="200"></canvas>
</body>
<script>
    let Aud = function (ctx, url) {
        this.ctx = ctx;
        this.url = url;

// source node this.src = ctx.createBufferSource();

//Multiple processing node groups this.pNode = [];
    };

    Aud.prototype = {
        output(){
            for (let i = 0; i < this.pNode.length; i++){
                let tNode = this.src;
                for (let j = 0; j < this.pNode[i].length; j++){
                    tNode.connect(this.pNode[i][j]);
                    tNode = this.pNode[i][j];
                }
                tNode.connect(this.ctx.destination);
            }
        },

        play(loop){
            this.src.loop = loop || false;
            this.output();
            this.src.start(0);
        },

        stop() {
            this.src.stop();
        },

        addNode(node, groupIdx = 0){
            this.pNode[groupIdx] = this.pNode[groupIdx] || [];
            this.pNode[groupIdx].push(node);
        }
    };

    //Set the node type Aud.NODETYPE = {
        GNODE: 0 // represents gainNode node}

    //Aud management object AudManager = {
        urls: [],
        items: [],
        ctx: null,
        init(){
            try{
                this.ctx = new AudioContext();
            }catch (e) {
                console.log(`${e}`);
            }
        },
        load(callback){
            for (let i = 0; i < this.urls.length; i++){
                this.loadSingle(this.urls[i], callback);
            }
        },

        loadSingle(url, callback){
            let req = new XMLHttpRequest();
            req.open('GET', url, true);
            req.responseType = 'arraybuffer';
            let self = this;
            req.onload = function () {
                self.ctx.decodeAudioData(this.response)
                    .then(
                        buf => {
                            let aud = new Aud(self.ctx, url);
                            aud.src.buffer = buf;
                            self.items.push(aud);

                            if (self.items.length == self.urls.length){
                                callback();
                            }
                        },
                        err => {
                            console.log(`decode error:${err}`);
                        }
                    )
            };

            req.send();
        },

        createNode(nodeType, param){
            let node = null;
            switch (nodeType) {
                case 1:
                    node = this.ctx.createPanner();
                    break;
                case 2:
                    node = this.ctx.createScriptProcessor(param[0], param[1], param[2]);
                    break;
                default:
                    node = this.ctx.createGain();
            }
            return node;
        }
    };

    let ctx = document.getElementById('cav').getContext('2d');
// Define the coordinates of the moving point let cX = 190,
        cY = 100,
        deg = 0;

    window.onload = function (){
        init();
    }

    function renderCir(x, y, r, col){
        ctx.save();
        ctx.beginPath();
        ctx.arc(x, y, r, 0, Math.PI*2);
        ctx.closePath();

        ctx.fillStyle = col;
        ctx.fill();
        ctx.restore();
    }

    function renderCenter(){
        renderCir(160, 100, 8, "red");
    }

    function renderCat() {
        renderCir(cX, cY, 8, "blue");
    }

    function init(){
        AudManager.urls = ["test.mp3"];
        AudManager.init();

        AudManager.load(()=>{
            let pNod1 = AudManager.createNode(1);
            let sound1 = AudManager.items[0];

            sound1.addNode(pNod1);
            sound1.play(true);
            timeHandle();
        });
    }

    function timeHandle() {
        window.setInterval(()=>{
            ctx.clearRect(0,0,320,200);
            let rad = Math.PI*deg / 180;
            let sx = 90*Math.cos(rad),
                sy = 90*Math.sin(rad);
            cX = 160 + sx;
            cY = 100 + sy;

            AudManager.items[0].pNode[0][0].setPosition(sx*0.1, -sy*0.1, 0);
            renderCenter();
            renderCat();
            deg++;
        }, 30);
    }
</script>
</html>

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