Posted in Javascript onDecember 19, 2019
本文实例为大家分享了js通过循环多张图片实现动画展示的具体代码,供大家参考,具体内容如下
以小鱼摇尾巴和眨眼睛为例
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>
document.body.onload = game; var can1, ctx1, canWidth, canHeight, lastTime = Date.now(), deltaTime = 0, body = new Image(); function game() { init(); gameloop(); } function init() { can1 = document.getElementById("canvas1"); //fonr--fishes, UI, circles, dust ctx1 = can1.getContext("2d"); canWidth = can1.width; canHeight = can1.height; body.src = './src/baby.png'; } function bodyDraw(){ ctx1.drawImage( body, -body.width * 0.5, -body.height * 0.5); } function gameloop() { requestAnimFrame(gameloop); //时间帧间隔 var now = Date.now(); deltaTime = now - lastTime; lastTime = now; ctx1.clearRect(0, 0, canWidth, canHeight); bodyDraw(); } window.requestAnimFrame = (function() { return window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function( /* function FrameRequestCallback */ callback, /* DOMElement Element */ element) { return window.setTimeout(callback, 1000 / 60); }; })();
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
var bTailTimer, //计时器 bTailCount, //计数器 babyTail = []; //图片数组 function init() { //尾巴初始化 bTailTimer = 0; 8 bTailCount = 0; 9 for (var i = 0; i < 8; i++) { babyTail[i] = new Image(); babyTail[i].src = './src/tail' + i +'.png'; } } function tailDraw(){ bTailTimer += deltaTime; if(bTailTimer > 50){ bTailCount = (bTailCount + 1)% 8; bTailTimer %= 50; //初始化计数器 } ctx1.drawImage( babyTail[bTailCount], -babyTail[bTailCount].width * 0.5, -babyTail[bTailCount].height * 0.5); } function gameloop() { ctx1.clearRect(0, 0, canWidth, canHeight); bodyDraw(); tailDraw(); }
第三步: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
var bEyeTimer, bEyeCount, bEyeInterval, //时间间隔变量 babyEye = []; function init() { //眼睛初始化 bEyeTimer = 0; bEyeCount = 0; bEyeInterval = 1000; //间隔时间 for (var i = 0; i < 2; i++) { babyEye[i] = new Image(); babyEye[i].src = './src/Eye' + i + '.png'; } } function eyeDraw() { bEyeTimer += deltaTime; if (bEyeTimer > bEyeInterval) { bEyeCount = (bEyeCount + 1)% 2; bEyeTimer %= bEyeInterval; if (bEyeCount == 0) { //眼睛睁开保持的时间随机 bEyeInterval = Math.random() * 1500 + 2000; //[2000,3500) } else { //眼睛闭上保持时间固定为100ms bEyeInterval = 100; } } } function gameloop() { eyeDraw(); }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持三水点靠木。
js通过循环多张图片实现动画效果
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