<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
body {
background: #111;
padding:0;
margin:0;
overflow:hidden;
}
</style>
</head>
<body>
<div id="wrapper"></div>
</body>
<script>
(function(){
'use strict';
let wrapper, canvas, ctx, width, height,
Tau=Math.PI*2, PI180=Math.PI/180,
systems=[];
/* PlanetarySystem */
let PlanetarySystem = function(id='pSys'){
Object.defineProperty(this, 'id', { value:id, writable:true} );
Object.defineProperty(this, 'x', { value:0, writable:true });
Object.defineProperty(this, 'y', { value:0, writable:true });
Object.defineProperty(this, 'allBodies', { value:[], writable:true });
Object.defineProperty(this, 'allBodiesLookup', { value:{}, writable:true }); // fast id lookup for children
Object.defineProperty(this, 'numBodies', { value:0, writable:true });
}
PlanetarySystem.prototype.addBody = function(vo) {
vo.parentSystem = this;
vo.parentBody = vo.parentBody === null ? this : this.allBodiesLookup[vo.parentBody];
let body = new PlanetaryBody(vo);
body.update();
this.allBodies.push(body);
this.allBodiesLookup[vo.id] = body;
this.numBodies += 1;
}
PlanetarySystem.prototype.setSpeedFactor = function(value){
let body;
for(let i=0; i<this.numBodies; i++){
body = this.allBodies[i];
body.setSpeedFactor(value);
}
}
PlanetarySystem.prototype.update = function(){
let body;
for(let i=0; i<this.numBodies; i++){
body = this.allBodies[i];
body.update();
}
}
/* PlanetaryBody */
let PlanetaryBody = function(vo){
Object.defineProperty(this, 'id', { value:vo.id, writable:true} );
Object.defineProperty(this, 'diameter', { value:vo.diameter, writable:true });
Object.defineProperty(this, 'colour', { value:vo.colour, writable:true });
Object.defineProperty(this, 'x', { value:0, writable:true });
Object.defineProperty(this, 'y', { value:0, writable:true });
Object.defineProperty(this, 'vx', { value:0, writable:true });
Object.defineProperty(this, 'vy', { value:0, writable:true });
Object.defineProperty(this, 'degrees', { value:vo.degrees, writable:true });
Object.defineProperty(this, 'speedBase', { value:vo.speed, writable:true });
Object.defineProperty(this, 'speed', { value:vo.speed , writable:true });
Object.defineProperty(this, 'orbitalRadius', { value:vo.orbitalRadius, writable:true });
Object.defineProperty(this, 'parentSystem', { value:vo.parentSystem, writable:true });
Object.defineProperty(this, 'parentBody', { value:vo.parentBody, writable:true });
return this;
}
PlanetaryBody.prototype.update = function(){
let angle = this.degrees * PI180;
this.degrees += this.speed;
this.vx = this.orbitalRadius * Math.cos(angle);
this.vy = this.orbitalRadius * Math.sin(angle);
// update position
if(this.parentBody != null){
this.x = this.vx + this.parentBody.x;
this.y = this.vy + this.parentBody.y;
}
}
/* init() */
function init(){
wrapper = document.querySelector('#wrapper');
canvas = createCanvas('canvas', width, height);
wrapper.appendChild(canvas);
ctx = canvas.getContext('2d');
setupEvents();
resizeCanvas();
/* Define new PlanetarySystem and set values */
let system1 = new PlanetarySystem('pSys1');
systems.push(system1);
system1.x = width * .5;
system1.y = height * .5;
system1.addBody({id:'sun', diameter:5, degrees:0, speed:0, colour:'#FDFE1D', orbitalRadius:0, parentBody:null});
for(let loop=30, i=0; i<loop; i+=1){
system1.addBody({ id: 'ball'+i,
diameter: 5,
degrees: 0,
speed: 2 + (loop * 0.15) - (i* 0.2),
colour: '#FDFE1D',
orbitalRadius: 7*(i+1),
parentBody: 'sun'});
}
}
/* Methods */
function createCanvas(id, w, h){
let tCanvas = document.createElement('canvas');
tCanvas.width = w;
tCanvas.height = h;
tCanvas.id = id;
return tCanvas;
}
function setupEvents(){
window.onresize = resizeCanvas;
}
function resizeCanvas(){
let rect = wrapper.getBoundingClientRect();
width = window.innerWidth;
height = window.innerHeight - rect.top -2;
canvas.width = width;
canvas.height = height;
for(let i=0; i<systems.length; i++){
systems[i].x = width * .5;
systems[i].y = height * .5;
}
}
function update(){
for(let loop=systems.length, i=0; i<loop; i++){
systems[i].update();
}
}
function draw(){
let system;
let prev = null;
for(let i=0; i<systems.length; i++){
system = systems[i];
let planetaryBody;
for(let loop=system.numBodies, j=1; j<loop; j+=1) {
planetaryBody = system.allBodies[j];
ctx.beginPath();
ctx.arc(planetaryBody.x, planetaryBody.y, planetaryBody.diameter, 0, Tau, false);
ctx.fillStyle = planetaryBody.colour;
ctx.fill();
if(j>1){
ctx.strokeStyle = planetaryBody.colour;
ctx.lineWidth = 2;
ctx.beginPath();
ctx.moveTo(planetaryBody.x, planetaryBody.y);
ctx.lineTo(prev.x, prev.y);
ctx.stroke();
}
prev = {x:planetaryBody.x, y:planetaryBody.y};
}
}
}
function animate(){
ctx.fillStyle = 'rgba(0,0,0, .05)';
ctx.fillRect(0, 0, width, height);
update();
draw();
requestAnimationFrame(animate);
}
init();
animate();
}());
</script>
</html>
到此這篇關于Canvas波浪花環的示例代碼的文章就介紹到這了,更多相關Canvas 波浪花環內容請搜索腳本之家以前的文章或繼續瀏覽下面的相關文章，希望大家以后多多支持腳本之家！
