我正在使用Java脚本和画布创建动画。我使用小提琴作为参考，当前对象正在随机生成，并且从右上角到左下角都可以。但是问题是物体产生的速度和高速下落的速度。我想让动画流变得缓慢而流畅。 我是新的canvas编程，任何帮助将非常有用。
LocaleViewController(function() {
var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame ||
function(callback) {
window.setTimeout(callback, 1000 / 60);
};
window.requestAnimationFrame = requestAnimationFrame;
})();
var particleArr = [],
canvas = document.getElementById("canvas"),
ctx = canvas.getContext("2d"),
flakeCount = 700,
mouseX = -100,
mouseY = -100,
xMultiplier = 0.015
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
function getRandomColor() {
// Random Color Generate
const colorArr = ["rgba(215,88,69, 1)", "rgba(117, 161, 199, 1)"]; // Blue & Orange Color
const randomColor = colorArr[Math.floor(Math.random() * colorArr.length)];
return randomColor;
}
function flow() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
for (var i = 0; i < flakeCount; i++) {
var flake = particleArr[i],
x = mouseX,
y = mouseY,
minDist = 150,
x2 = flake.x,
y2 = flake.y;
var dist = Math.sqrt((x2 - x) * (x2 - x) + (y2 - y) * (y2 - y)),
dx = x2 - x,
dy = y2 - y;
if (dist < minDist) {
var force = minDist / (dist * dist),
xcomp = (x - x2) / dist,
ycomp = (y - y2) / dist,
deltaV = force / 2;
flake.velX -= deltaV * xcomp;
flake.velY -= deltaV * ycomp;
} else {
flake.velX *= .98;
if (flake.velY <= flake.speed) {
flake.velY = flake.speed
}
flake.velX += Math.cos(flake.step += .05) * flake.stepSize;
}
ctx.fillStyle = getRandomColor();
flake.y += flake.velY;
flake.x += flake.velX;
if (flake.y >= canvas.height || flake.y <= 0) {
reset(flake);
}
if (flake.x >= canvas.width || flake.x <= 0) {
reset(flake);
}
ctx.beginPath();
ctx.arc(flake.x, flake.y, flake.size, 0, Math.PI * 2);
ctx.fill();
}
requestAnimationFrame(flow);
};
function reset(flake) {
let temp = (Math.random() * 1) + 0.5;
flake.x = canvas.width;
flake.y = 50;
flake.size = (Math.random() * 3) + 5;
flake.speed = (Math.random() * 7) + 0.5;
flake.velY = flake.speed;
flake.velX = -xMultiplier * canvas.width * temp;
// flake.opacity = (Math.random() * 0.5) + 0.3;
}
function init() {
for (var i = 0; i < flakeCount; i++) {
var x = canvas.width,
y = 50,
size = (Math.random() * 3) + 5,
// speed = (Math.random() * 1) + 0.5;
speed = 0;
// opacity = (Math.random() * 0.5) + 0.3;
particleArr.push({
speed: speed,
velY: speed,
velX: -xMultiplier * canvas.width * speed,
x: x,
y: y,
size: size,
stepSize: (Math.random()) / 30,
step: 0,
angle: 360
// opacity: opacity
});
}
flow();
};
canvas.addEventListener("mousemove", function(e) {
mouseX = e.clientX,
mouseY = e.clientY
});
window.addEventListener('resize', onWindowResize, false);
function onWindowResize() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
}
init();canvas {
background-color: #000000 !important;
}
body {
margin: 0;
overflow: hidden;
}
答案 0 :(得分：0)
答案 1 :(得分：0)
每帧调用flow（）的requestAnimationFrame（）函数旨在使其运行的计算机尽可能快地运行。我不会弄乱您的实际渲染循环。
尝试弄乱flake.speed或xMultiplier。这些是影响粒子速度的两个主要变量。您可以看到每次通过flow（）循环如何根据每个粒子的速度属性和位置来调整它们的位置。然后最后用ctx.arc(flake.x, flake.y, flake.size, 0, Math.PI * 2);
因此，任何传递给ctx.arc（）的变量都会影响粒子的位置。每次循环中都会重新计算许多这些变量。
我不是这里的专家，但也许尝试摆弄您的变量。
答案 2 :(得分：0)
由于代码中存在许多FX和交互作用，因此无法确定您要放慢的速度。
由于您的代码有点老旧，我从头开始重写。
OI并没有使用常量，而是使用全局变量rate（位于源代码的顶部）来控制动画的播放速率，包括用户交互。
我添加了两个按钮来减慢或加快动画播放速度。
希望这会有所帮助：）
var rate = 1;
slower.addEventListener("click", () => rate *= 1 / 1.2);
faster.addEventListener("click", () => rate *= 1.2);
const flakes = [], flakeCount = 700, xMultiplier = 0.015;
const minDist = 150, minDistSqr = minDist * minDist;
const colors = ["#F99","#F83","#AF9","#ED9","#AC8","#FA9" ];
const ctx = canvas.getContext("2d");
const mouse = {x: -100, y: -100};
const randPick = (arr, len = arr.length) => arr[Math.random() * len | 0];
Math.rand = (min, range) => Math.random() * range + min;
function Flake() {
this.reset();
this.stepSize = Math.random() / 30;
this.step = 0;
}
Flake.prototype = {
reset() {
this.x = canvas.width;
this.y = 50;
this.size = Math.rand(5, 3);
this.speed = Math.rand(0.5, 7);
this.velY = this.speed;
this.velX = -xMultiplier * canvas.width * Math.rand(0.5, 1);
this.col = randPick(colors);
},
draw() {
ctx.fillStyle = this.col;
const s = this.size, sh = -s / 2;
ctx.fillRect(this.x + sh, this.y + sh, s, s);
},
update(w, h) {
const f = this;
const dx = f.x - mouse.x;
const dy = f.y - mouse.y;
const distSqr = dx * dx + dy * dy;
if (distSqr < minDistSqr) {
const deltaV = 2 * minDist * rate / distSqr ** 1.5;
f.velX -= deltaV * dx;
f.velY -= deltaV * dy;
} else {
f.velX -= 0.1 * rate * f.velX;
if (f.velY <= f.speed ) { f.velY = f.speed }
f.velX += Math.cos(f.step += 0.05 * rate) * f.stepSize * rate;
}
f.y += f.velY * rate;
f.x += f.velX * rate;
if (f.y >= h || f.y <= 0 || f.x >= w || f.x <= 0) { this.reset() }
else { this.draw() }
}
};
init();
mainLoop();
function mainLoop() {
if (innerWidth !== canvas.width || innerHeight !== canvas.height) { resize() }
else { ctx.clearRect(0, 0, canvas.width, canvas.height) }
for (const f of flakes) { f.update(canvas.width, canvas.height) }
requestAnimationFrame(mainLoop);
}
function init() {
var i = flakeCount;
while (i--) { flakes.push(new Flake()) }
}
canvas.addEventListener("mousemove", e => { mouse.x = e.clientX; mouse.y = e.clientY });
function resize() { canvas.width = innerWidth; canvas.height = innerHeight }canvas {
background-color: #000;
}
body {
margin: 0;
}
.buttons {
position: absolute;
top: 12px;
left: 12px;
color: #000;
background-color: #AAA;
}
.buttons > div {
margin: 3px;
padding: 3px;
background-color: #EEE;
cursor: pointer;
}
.buttons > div:hover {
background-color: #DEF;
}<canvas id="canvas"></canvas>
<div class = "buttons">
<div id="slower">Slower</div>
<div id="faster">Faster</div>
</div>