parent
c62cb6c9da
commit
1bf8cf79d5
3 changed files with 116 additions and 0 deletions
@ -0,0 +1,102 @@ |
||||
//宇宙特效
|
||||
var canvas = document.querySelector('#canvas'), |
||||
ctx = canvas.getContext('2d'), |
||||
w = canvas.width = window.innerWidth, |
||||
h = canvas.height = window.innerHeight, |
||||
|
||||
hue = 217, |
||||
stars = [], |
||||
count = 0, |
||||
maxStars = 1300;//星星数量
|
||||
|
||||
var canvas2 = document.createElement('canvas'), |
||||
ctx2 = canvas2.getContext('2d'); |
||||
canvas2.width = 100; |
||||
canvas2.height = 100; |
||||
var half = canvas2.width / 2, |
||||
gradient2 = ctx2.createRadialGradient(half, half, 0, half, half, half); |
||||
gradient2.addColorStop(0.025, '#CCC'); |
||||
gradient2.addColorStop(0.1, 'hsl(' + hue + ', 61%, 33%)'); |
||||
gradient2.addColorStop(0.25, 'hsl(' + hue + ', 64%, 6%)'); |
||||
gradient2.addColorStop(1, 'transparent'); |
||||
|
||||
ctx2.fillStyle = gradient2; |
||||
ctx2.beginPath(); |
||||
ctx2.arc(half, half, half, 0, Math.PI * 2); |
||||
ctx2.fill(); |
||||
|
||||
// End cache
|
||||
|
||||
function random(min, max) { |
||||
if (arguments.length < 2) { |
||||
max = min; |
||||
min = 0; |
||||
} |
||||
|
||||
if (min > max) { |
||||
var hold = max; |
||||
max = min; |
||||
min = hold; |
||||
} |
||||
|
||||
return Math.floor(Math.random() * (max - min + 1)) + min; |
||||
} |
||||
|
||||
function maxOrbit(x, y) { |
||||
var max = Math.max(x, y), |
||||
diameter = Math.round(Math.sqrt(max * max + max * max)); |
||||
return diameter / 2; |
||||
//星星移动范围,值越大范围越小,
|
||||
} |
||||
|
||||
var Star = function() { |
||||
|
||||
this.orbitRadius = random(maxOrbit(w, h)); |
||||
this.radius = random(60, this.orbitRadius) / 8;
|
||||
//星星大小
|
||||
this.orbitX = w / 2; |
||||
this.orbitY = h / 2; |
||||
this.timePassed = random(0, maxStars); |
||||
this.speed = random(this.orbitRadius) / 1000000;
|
||||
//星星移动速度
|
||||
this.alpha = random(2, 10)/1000; |
||||
|
||||
count++; |
||||
stars[count] = this; |
||||
} |
||||
|
||||
Star.prototype.draw = function() { |
||||
var x = Math.sin(this.timePassed) * this.orbitRadius + this.orbitX, |
||||
y = Math.cos(this.timePassed) * this.orbitRadius + this.orbitY, |
||||
twinkle = random(10); |
||||
|
||||
if (twinkle === 1 && this.alpha > 0) { |
||||
this.alpha -= 0.05; |
||||
} else if (twinkle === 2 && this.alpha < 1) { |
||||
this.alpha += 0.05; |
||||
} |
||||
|
||||
ctx.globalAlpha = this.alpha; |
||||
ctx.drawImage(canvas2, x - this.radius / 2, y - this.radius / 2, this.radius, this.radius); |
||||
this.timePassed += this.speed; |
||||
} |
||||
|
||||
for (var i = 0; i < maxStars; i++) { |
||||
new Star(); |
||||
} |
||||
|
||||
function animation() { |
||||
ctx.globalCompositeOperation = 'source-over'; |
||||
ctx.globalAlpha = 0.5; //尾巴
|
||||
ctx.fillStyle = 'hsla(' + hue + ', 64%, 6%, 2)'; |
||||
ctx.fillRect(0, 0, w, h) |
||||
|
||||
ctx.globalCompositeOperation = 'lighter'; |
||||
for (var i = 1, l = stars.length; i < l; i++) { |
||||
stars[i].draw(); |
||||
}; |
||||
|
||||
window.requestAnimationFrame(animation); |
||||
} |
||||
|
||||
animation(); |
Loading…
Reference in new issue