如何使用Web Audio Api创建用于创建振荡器节点的功能

Question

我知道这听起来很简单或明显，但我无法做到这一点。

请参阅此代码段：

ctx = new AudioContext();
gain = ctx.createGain();
gain.connect(ctx.destination);
gain.gain.value = 0.5;


osc1 = ctx.createOscillator();
osc1.connect(gain);
osc1.frequency.value = 450;
osc1.start();
osc1.stop(2);

osc2 = ctx.createOscillator();
osc2.connect(gain);
osc2.frequency.value = 500;
osc2.start();
osc2.stop(2);
console.log("playing");

它当时播放两个振荡器没有问题，但它重复代码。如果我尝试将冗余代码放在一个函数中，它就不起作用。

ctx = new AudioContext();
gain = ctx.createGain();
createAndPlayOsc(450);
createAndPlayOsc(500);


function createAndPlayOsc(freq){
    console.log("creating osc with freq " + freq);
    var osc = ctx.createOscillator();
    osc.connect(gain);
    osc.frequency.value = freq;
    osc.start();
    osc.stop(2);
    console.log("playing osc with freq " + freq);
}

即使我发送了AudioContext

ctx = new AudioContext();
gain = ctx.createGain();
createAndPlayOsc(450, ctx);
createAndPlayOsc(500, ctx);


function createAndPlayOsc(freq, context){
    console.log("creating osc with freq " + freq);
    var osc = context.createOscillator();
    osc.connect(gain);
    osc.frequency.value = freq;
    osc.start();
    osc.stop(2);
    console.log("playing osc with freq " + freq);
}

或者gainNode和context

ctx = new AudioContext();
gain = ctx.createGain();
createAndPlayOsc(450, ctx, gain);
createAndPlayOsc(500, ctx, gain);


function createAndPlayOsc(freq, context, gainNode){
    console.log("creating osc with freq " + freq);
    var osc = context.createOscillator();
    osc.connect(gainNode);
    osc.frequency.value = freq;
    osc.start();
    osc.stop(2);
    console.log("playing osc with freq " + freq);
}

我缺少什么？

Answer 1

您忘了将收益连接到上下文：

gain.connect(ctx.destination);