Jaz*_*att 2 html audio canvas html5-audio
我想做的是一个“addEventListener”函数。单击画布并出现雨滴时，会发出晃动的声音。因此，无论您单击多少次，声音都会始终播放。
我不知道它叫什么，是我的教授建议的。然而，当我梳理google时，我发现的只是按钮点击或Jquery的东西。我不想要按钮，也不被允许使用 Jquery。
一如既往，我只寻求正确方向的推动。
感谢你们迄今为止给予我的所有帮助。
var canvas;
var context;
var drops = [];
var squares = [];
function Drop(x,y,color){
this.x = x;
this.y = y;
this.color = color;
this.dy = Math.random();
}
function Square(x,y,w,color){
this.sx = x;
this.sy = y;
this.sw = w;
this.color = color;
this.qy = Math.random();
}
function init(){
canvas = document.getElementById('canvas');
context = canvas.getContext('2d');
alert("Hello!\nClick on the screen for rain drops!");
window.addEventListener('resize', resizeCanvas, false);
window.addEventListener('orientationchange', resizeCanvas, false);
resizeCanvas();
canvas.onclick = function(event){
handleClick(event.clientX, event.clientY);
};
setInterval(handleClick,5);
}
function handleClick(x,y,w){
var found = false;
for(var i = 0; i<drops.length; i++){
d = Math.sqrt((drops[i].x-x)*(drops[i].x-x) + (drops[i].y-y)*(drops[i].y-y));
if(d<=5){
drops.splice(i,1);
found = true;
}
}
fillBackgroundColor();
if(!found){
var colors = ["#000080", "#add8e6", "blue"];
var color = colors[Math.floor(Math.random()*colors.length)];
drops.push(new Drop(x,y,color));
squares.push(new Square(x,y,w,color));
}
for(var i = 0; i<drops.length; i++){
drawDrop(drops[i]);
}
for(var i = 0; i<squares.length; i++){
drawSquare(squares[i]);
}
}
function drawDrop(drop){
context.beginPath();
context.arc(drop.x, drop.y, 5, 0, Math.PI);
context.fillStyle = drop.color;
context.moveTo(drop.x - 5, drop.y);
context.lineTo(drop.x, drop.y - 7);
context.lineTo(drop.x + 5, drop.y);
context.closePath();
context.fill();
if (drop.y + drop.dy > canvas.height || drop.y + drop.dy < 0)
drop.dy != -drop.dy;
drop.y += drop.dy;
};
function drawSquare(square){
var sw = Math.floor(4);
var sx = Math.floor(Math.random() * canvas.width);
var sy = Math.floor(Math.random() * canvas.height);
context.beginPath();
context.rect(sx, sy, sw, sw);
context.fillStyle = '#add8e6';
context.fill();
};
function fillBackgroundColor(){
context.fillStyle = 'gray';
context.fillRect(0,0,canvas.width,canvas.height);
}
function resizeCanvas(){
canvas.width = window.innerWidth - 20;
canvas.height = window.innerHeight - 20;
fillBackgroundColor();
for(var i = 0; i<drops.length; i++){
drawDrop(drops[i]);
}
for(var i = 0; i<squares.length; i++){
drawSquare(squares[i]);
}
}
function degreesToRadians(degrees) {
return (degrees * Math.PI)/180;
}
window.onload = init;
</script>
</head>
<body>
<canvas id='canvas' width=500 height=500></canvas>
</body>
单击画布或任何元素
要将事件侦听器添加到画布，您只需要元素，您可以通过多种方式从 DOM 获取它，我已经使用了getElementById它的唯一 id。然后，要添加click事件，只需附加侦听器和要调用的函数即可。
每次单击画布时都会调用 playSound。
var canvas = document.getElementById("canvasID"); // get the canvas
canvas.addEventListener("click",playSound); // call playSound when clicked
// See below for the function playSound
您还可以为 mousedown 和 mouseup 添加事件侦听器，因为只有在释放鼠标按钮时才会调用 click，这可能不是所需的效果。
加载声音
由于需要加载声音，这可能需要一些时间，因此您需要有一种方法来指示声音已加载并准备好播放。对于这个简单的答案，信号量就可以解决问题。只需设置一个属性来指示已加载。
var sound = new Audio(); // create the audio
sound.src = "SoundFileURL.mp3"; // set the resource location
sound.oncanplaythrough = function(){ // When the sound has completely loaded
sound.readyToRock = true; // flag sound is ready to play
// I just made it up and can be anything
};
sound.onerror = function(){ // not required but if there are problems this will help debug the problem
console.log("Sound file SoundFileURL.mp3 failed to load.")
};
重复播放声音
功能playSound。音频资源只能以一种声音的形式播放。你不能超越它本身。重复单击时，您需要重置声音播放位置，以便重新开始。为此，只需将 设为currentTime0（声音的开始）并调用方法play。这样每次点击都会启动声音或倒带并重新开始，无需检查是否正在播放。如果您希望声音重叠，则需要加载它的多个副本，并在每次单击时循环播放哪个副本。
// assuming sound is in scope from above code
function playSound(){
if(sound && sound.readyToRock){ // check for the sound and if it has loaded
sound.currentTime = 0; // seek to the start
sound.play(); // play it till it ends
}
}
声音重叠
从阵列中播放相同的声音，使其重叠。将相同的声音多次加载到数组中。保留一个变量，该变量将指向数组中要在用户调用该函数（通过单击事件）时播放的下一个声音，然后寻找开始并播放声音。增加下一个声音指针，为下一次单击做好准备。
这将使声音自行播放。加载声音的次数取决于用户点击的频率以及声音的时长。不要太过分，因为有一个点你无法判断新的声音是否已经开始，或者正在播放的声音是否已经重新开始。
多次加载相同的声音
var sounds = []; // array to hold the sound
for(var i = 0; i < 4; i++){
var sound = new Audio(); // create the audio
sound.src = "SoundFileURL.mp3"; // set the resource location
sounds.push(sound); // put the sound on the array
}
播放声音数组
// assuming that the array sounds has the sounds you want to overlap
// and that they have been loaded so there is no need to check their status
var soundToPlay = 0; // the next sound to play
// the click event function.
function playSound(){
var sound = sounds[soundToPlay % sounds.length]; // get the next sound
// making sure that it
// does not go past the
// of the array
sound.currentTime = 0; // seek to start
sound.play(); // play it
soundToPlay += 1; // point to the next sound to play
}