jdg/requestAnimationFrame
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Cleaning up

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José David Guillén 2021-11-11 22:06:54 +01:00
parent 56c478d614
commit a025dae28d
2 changed files with 58 additions and 40 deletions
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1
index.html
View File

@ -3,6 +3,5 @@
<script src="index.js"></script>
</head>
<body>
<canvas id="canvas"></canvas>
</body>
</html>

81
index.js
View File

@ -1,26 +1,37 @@
"use strict";
document.addEventListener('DOMContentLoaded', init);
document.addEventListener('DOMContentLoaded', () => init());
let ctx, canvas = document.createElement("canvas");
function init() {
var canvas = document.getElementById("canvas");
function start() {
canvas.width = window.innerWidth
canvas.height = window.innerHeight
ctx = canvas.getContext('2d');
document.body.insertBefore(canvas, document.body.childNodes[0]);
document.addEventListener('keydown', controls);
run();
const ctx = canvas.getContext('2d');
var balls = [];
add();
document.addEventListener('keydown', control);
for (let i = 0; i < 15; i++) add();
}
anim();
function run() {
ctx.clearRect(0, 0, canvas.width, canvas.height);
update();
requestAnimationFrame(run);
}
function control(e) {
switch(e.key) {
function controls(e) {
switch (e.key) {
case 'ArrowUp': add(); break;
case 'ArrowDown': remove(); break;
}
}
// -------------------------------------------------------------------
let balls = [];
function remove() {
balls.pop();
}
@ -31,39 +42,47 @@ function init() {
let speed = 1 + Math.floor(Math.random() * 10);
let angle = Math.floor(Math.random() * 360);
// angle must be in radians (now it's wrong)
balls.push({ x: x, y: y, size: 20, speed: speed, angle: angle, color:'black' });
balls.push(new ball(x, y, speed, angle));
}
function anim() {
ctx.fillStyle = 'white';
ctx.fillRect(0, 0, canvas.width, canvas.height);
balls.forEach(b => {
update(b);
draw(b);
}
);
requestAnimationFrame(anim);
function update() {
balls.forEach(b => b.update());
}
start();
}
function update(b) {
b.x += b.speed * Math.cos(b.angle);
b.y += b.speed * Math.sin(b.angle);
if ( b.x<0 || b.x>canvas.width || b.y<0 || b.y>canvas.height ) bounce(b);
class ball {
constructor(x, y, speed, angle) {
this.x = x;
this.y = y;
this.speed = speed;
this.angle = angle;
this.color = 'black';
this.size = 20;
}
function bounce(b) {
b.angle += 180;
update() {
this.move();
this.draw();
}
function draw(b) {
ctx.fillStyle = b.color;
ctx.fillRect(b.x, b.y, b.size, b.size);
draw() {
ctx.fillStyle = this.color;
ctx.fillRect(this.x, this.y, this.size, this.size);
}
move() {
this.x += this.speed * Math.cos(this.angle);
this.y += this.speed * Math.sin(this.angle);
if (this.x < 0 || this.x > canvas.width || this.y < 0 || this.y > canvas.height)
this.bounce();
}
bounce() {
this.angle += 180;
}
}