我一直在尝试重建
this Project
在画布和JavaScript中。我无法破译原始代码,所以我从头开始。不同的是,我的项目开始滞后于大约2500个粒子,而上面的项目使用30000个粒子。
我将把整个代码粘贴到下面,但这些是相关的部分:
var particleContainer = []
var distance = 10
for(let i = 0; i< square.height/distance; i++){
for(let j = 0; j< square.height/distance; j++){
particleContainer.push( new Particle(square.x + i*distance,square.y + j*distance) )
}
}
if( c < 90 ){
i.xVelocity = a/c * -20
i.yVelocity = b/c * -20
}else if(90 < c && c < 95){
i.xVelocity = a/c * -1
i.yVelocity = b/c * -1
}else if(c2 !== 0){
i.xVelocity =( a2/c2 )
i.yVelocity = (b2/c2 )
}
我正在创建一个新的粒子,每“距离”我的正方形像素,并将它们全部推到一个数组中。当我的鼠标靠近其中一个时,粒子将开始远离鼠标,直到它距离鼠标90-95px。
从这条线来看,30000像素的工作方式类似
for ( i = 0; i < NUM_PARTICLES; i++ ) {
p = Object.create( particle );
p.x = p.ox = MARGIN + SPACING * ( i % COLS );
p.y = p.oy = MARGIN + SPACING * Math.floor( i / COLS );
list[i] = p;
}
但该项目不会遇到与我相同的性能问题。
我的完整代码供参考(HTML只是一个画布):
var canvas = document.querySelector("canvas")
var c = canvas.getContext('2d')
function getMousePos(canvas, evt) {
// var rect = canvas.getBoundingClientRect();
return {
x: evt.clientX,
y: evt.clientY
};
}
document.addEventListener('mousemove', function(evt) {
var mousePos = getMousePos(canvas, evt);
mouse.x= mousePos.x;
mouse.y= mousePos.y;
}, false);
var mouse = {
x:0,
y:0
}
function Particle(x,y){
this.x = x;
this.y = y;
this.xFixed = x;
this.yFixed = y;
this.radius = 1
this.xVelocity = 0
this.yVelocity = 0
this.color = 'white'
}
Particle.prototype.draw = function(){
c.save()
c.beginPath()
c.arc(this.x, this.y, this.radius,0,Math.PI*2,false)
c.fillStyle = this.color
c.fill()
}
Particle.prototype.update = function(){
this.draw()
this.x += this.xVelocity
this.y += this.yVelocity
}
var square = {
x: 500,
y: 150,
height: 500,
width: 500,
color: 'white'
}
var particleContainer = []
var distance = 10
for(let i = 0; i< square.height/distance; i++){
for(let j = 0; j< square.height/distance; j++){
particleContainer.push( new Particle(square.x + i*distance,square.y + j*distance) )
}
}
function animate(){
requestAnimationFrame(animate);
c.clearRect(0,0,window.innerWidth,window.innerHeight)
canvas.width = window.innerWidth
canvas.height = window.innerHeight
for(i of particleContainer){
let a = mouse.x - i.x
let b = mouse.y - i.y
let c = Math.sqrt(Math.pow(b,2) + Math.pow(a,2))
let a2 = i.xFixed - i.x
let b2 = i.yFixed - i.y
let c2 = Math.sqrt(Math.pow(b2,2) + Math.pow(a2,2))
if( c < 90 ){
i.xVelocity = a/c * -20
i.yVelocity = b/c * -20
}else if(90 < c && c < 95){
i.xVelocity = a/c * -1
i.yVelocity = b/c * -1
}else if(c2 !== 0){
i.xVelocity =( a2/c2 )
i.yVelocity = (b2/c2 )
}
}
for(i of particleContainer){
i.update()
}
}
animate()
