1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
| var testBox = function(){
var canvas = document.getElementById("cas"),
ctx = canvas.getContext('2d'),
borderWidth = 2,
Balls = [];
var ball = function(x , y , vx , vy , useCache){
this.x = x;
this.y = y;
this.vx = vx;
this.vy = vy;
this.r = getZ(getRandom(20,40));
this.color = [];
this.cacheCanvas = document.createElement("canvas");
this.cacheCtx = this.cacheCanvas.getContext("2d");
this.cacheCanvas.width = 2*this.r;
this.cacheCanvas.height = 2*this.r;
var num = getZ(this.r/borderWidth);
for(var j=0;j<num;j++){
this.color.push(
"rgba("+getZ(getRandom(0,255))+",
"+getZ(getRandom(0,255))+",
"+getZ(getRandom(0,255))+",1)");
}
this.useCache = useCache;
if(useCache){
this.cache();
}
}
function getZ(num){
var rounded;
rounded = (0.5 + num) | 0;
// A double bitwise not.
rounded = ~~ (0.5 + num);
// Finally, a left bitwise shift.
rounded = (0.5 + num) << 0;
return rounded;
}
ball.prototype = {
paint:function(ctx){
if(!this.useCache){
ctx.save();
var j=0;
ctx.lineWidth = borderWidth;
for(var i=1;i<this.r;i+=borderWidth){
ctx.beginPath();
ctx.strokeStyle = this.color[j];
ctx.arc(this.x , this.y , i , 0 , 2*Math.PI);
ctx.stroke();
j++;
}
ctx.restore();
} else{
ctx.drawImage(this.cacheCanvas , this.x-this.r , this.y-this.r);
}
},
cache:function(){
this.cacheCtx.save();
var j=0;
this.cacheCtx.lineWidth = borderWidth;
for(var i=1;i this.cacheCtx.beginPath();
this.cacheCtx.strokeStyle = this.color[j];
this.cacheCtx.arc(this.r , this.r , i , 0 , 2*Math.PI);
this.cacheCtx.stroke();
j++;
}
this.cacheCtx.restore();
},
move:function(){
this.x += this.vx;
this.y += this.vy;
if(this.x>(canvas.width-this.r)||this.x<this.r){
this.x=this.x this.vx = -this.vx;
}
if(this.y>(canvas.height-this.r)||this.y<this.r){
this.y=this.y this.vy = -this.vy;
}
this.paint(ctx);
}
}
var Game = {
init:function(){
for(var i=0;i<1000;i++){
var b = new ball(
getRandom(0,canvas.width) ,
getRandom(0,canvas.height) ,
getRandom(-10 , 10) ,
getRandom(-10 , 10) ,
true)
Balls.push(b);
}
},
update:function(){
ctx.clearRect(0,0,canvas.width,canvas.height);
for(var i=0;i Balls[i].move();
}
},
loop:function(){
var _this = this;
this.update();
RAF(function(){
_this.loop();
})
},
start:function(){
this.init();
this.loop();
}
}
window.RAF = (function(){
return window.requestAnimationFrame
|| window.webkitRequestAnimationFrame
|| window.mozRequestAnimationFrame
|| window.oRequestAnimationFrame
|| window.msRequestAnimationFrame
|| function (callback) {window.setTimeout(callback, 1000 / 60); };
})();
return Game;
}();
function getRandom(a , b){
return Math.random()*(b-a)+a;
}
window.onload = function(){
testBox.start();
}
|
