码迷,mamicode.com
首页 > Web开发 > 详细

js通过循环多张图片实现动画效果

时间:2017-01-03 20:19:32      阅读:395      评论:0      收藏:0      [点我收藏+]

标签:log   i++   web   out   c51   框架   llb   com   anim   

以小鱼摇尾巴和眨眼睛为例

技术分享

动画思路:

1.将图片资源放在数组里面

2.通过计时器来设定间隔时间

3.通过计数器来取相应的图片

 

第一步:基本框架,鱼身体

<body>
    <canvas id="canvas1" width="800" height="600"></canvas>
</body>
技术分享
 1 document.body.onload = game;
 2 
 3 var can1,
 4     ctx1,
 5     canWidth,
 6     canHeight,
 7     lastTime = Date.now(),
 8     deltaTime = 0,
 9     body = new Image();
10 
11 
12 
13 function game() {
14     init();
15     gameloop();
16 }
17 
18 function init() { 
19     can1 = document.getElementById("canvas1"); //fonr--fishes, UI, circles, dust
20     ctx1 = can1.getContext("2d"); 
21     canWidth = can1.width;
22     canHeight = can1.height;
23 
24     body.src = ‘./src/baby.png‘;
25 }
26 
27 function bodyDraw(){
28     ctx1.drawImage( body, -body.width * 0.5, -body.height * 0.5);
29 }
30 
31 function gameloop() {
32     requestAnimFrame(gameloop);
33 
34     //时间帧间隔
35     var now = Date.now();
36     deltaTime = now - lastTime; 
37     lastTime = now;
38 
39     ctx1.clearRect(0, 0, canWidth, canHeight); 
40     
41     bodyDraw();
42  }
43 
44 
45 
46  window.requestAnimFrame = (function() {
47     return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame ||
48         function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element) {
49             return window.setTimeout(callback, 1000 / 60);
50         };
51 })();
View Code

 

第二步:摇动尾巴

1.图片资源有8张,从tail0.png ~ tail7.png

2.尾巴是匀速的运动,间隔时间为固定值

 1 var bTailTimer, //计时器
 2     bTailCount, //计数器
 3     babyTail = []; //图片数组
 4 
 5 function init() { 
 6 //尾巴初始化
 7     bTailTimer = 0; 8     bTailCount = 0; 9     for (var i = 0; i < 8; i++) {
10         babyTail[i] = new Image();
11         babyTail[i].src = ‘./src/tail‘ + i +‘.png‘;
12     }
13 }
14 
15 function tailDraw(){
16     bTailTimer += deltaTime;
17     if(bTailTimer > 50){
18         bTailCount = (bTailCount + 1)% 8;
19         bTailTimer %= 50; //初始化计数器
20     }
21     ctx1.drawImage( babyTail[bTailCount], -babyTail[bTailCount].width * 0.5, -babyTail[bTailCount].height * 0.5);
22 }
23 
24 function gameloop() {
25  ctx1.clearRect(0, 0, canWidth, canHeight); 
26 
27     bodyDraw();
28     tailDraw();
29  }

 

 第二步:眨眼睛

1.图片资源有2张,从eye0.png ~ eye7.png

2.眼睛睁开时间不定时,闭上时间固定值

 1 var bEyeTimer,
 2     bEyeCount,
 3     bEyeInterval, //时间间隔变量
 4     babyEye = [];
 5 
 6 function init() { 
 7 //眼睛初始化
 8     bEyeTimer = 0;
 9     bEyeCount = 0;
10     bEyeInterval = 1000; //间隔时间
11     for (var i = 0; i < 2; i++) {
12         babyEye[i] = new Image();
13         babyEye[i].src = ‘./src/Eye‘ + i + ‘.png‘;
14     }
15 }
16 
17 function eyeDraw() {
18     bEyeTimer += deltaTime;
19     if (bEyeTimer > bEyeInterval) 
20     {
21         bEyeCount = (bEyeCount + 1)% 2;
22         bEyeTimer %= bEyeInterval;
23 
24         if (bEyeCount == 0) 
25         {
26             //眼睛睁开保持的时间随机
27             bEyeInterval = Math.random() * 1500 + 2000; //[2000,3500)
28         } else 
29         {
30             //眼睛闭上保持时间固定为100ms
31             bEyeInterval = 100;
32         }
33     }
34 }
35 
36 function gameloop() {
37 eyeDraw();
38  }

 

js通过循环多张图片实现动画效果

标签:log   i++   web   out   c51   框架   llb   com   anim   

原文地址:http://www.cnblogs.com/regina1123/p/6245741.html

(0)
(0)
   
举报
评论 一句话评论(0
登录后才能评论!
© 2014 mamicode.com 版权所有  联系我们:gaon5@hotmail.com
迷上了代码!