HTML5 - Canvas动画样例（谷歌弹跳球）
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HTML5 - Canvas动画样例（谷歌弹跳球）
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1，樣例說明
（1）在沒有鼠標介入的情況下，這些球就像有磁性一樣拼成“Google”字樣。 （2）在鼠標移動到其中后，小球像是受到了排斥，向畫布的四周擴散，然后不規則地反彈回來。
原文出自：www.hangge.com??轉載請保留原文鏈接：http://www.hangge.com/blog/cache/detail_1059.html
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2.源碼：
<!DOCTYPE HTML>
<html> ??<head> ????<style> ??????body { ????????margin: 0px; ????????padding: 0px; ??????} ??????canvas { ????????cursor: pointer; ????????border: 1px solid black; ????????margin:20px 20px 20px 20px; ????} ????</style> ??</head> ??<body> ????<canvas id="myCanvas"?width="578"?height="200"></canvas> ????<script> ??????window.requestAnimFrame = (function(callback) { ????????return?window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || ????????function(callback) { ??????????window.setTimeout(callback, 1000 / 60); ????????}; ??????})(); ??????function?initBalls() { ????????balls = []; ????????var?blue =?'#3A5BCD'; ????????var?red =?'#EF2B36'; ????????var?yellow =?'#FFC636'; ????????var?green =?'#02A817'; ????????// G ????????balls.push(new?Ball(173, 63, 0, 0, blue)); ????????balls.push(new?Ball(158, 53, 0, 0, blue)); ????????balls.push(new?Ball(143, 52, 0, 0, blue)); ????????balls.push(new?Ball(130, 53, 0, 0, blue)); ????????balls.push(new?Ball(117, 58, 0, 0, blue)); ????????balls.push(new?Ball(110, 70, 0, 0, blue)); ????????balls.push(new?Ball(102, 82, 0, 0, blue)); ????????balls.push(new?Ball(104, 96, 0, 0, blue)); ????????balls.push(new?Ball(105, 107, 0, 0, blue)); ????????balls.push(new?Ball(110, 120, 0, 0, blue)); ????????balls.push(new?Ball(124, 130, 0, 0, blue)); ????????balls.push(new?Ball(139, 136, 0, 0, blue)); ????????balls.push(new?Ball(152, 136, 0, 0, blue)); ????????balls.push(new?Ball(166, 136, 0, 0, blue)); ????????balls.push(new?Ball(174, 127, 0, 0, blue)); ????????balls.push(new?Ball(179, 110, 0, 0, blue)); ????????balls.push(new?Ball(166, 109, 0, 0, blue)); ????????balls.push(new?Ball(156, 110, 0, 0, blue)); ????????// O ????????balls.push(new?Ball(210, 81, 0, 0, red)); ????????balls.push(new?Ball(197, 91, 0, 0, red)); ????????balls.push(new?Ball(196, 103, 0, 0, red)); ????????balls.push(new?Ball(200, 116, 0, 0, red)); ????????balls.push(new?Ball(209, 127, 0, 0, red)); ????????balls.push(new?Ball(223, 130, 0, 0, red)); ????????balls.push(new?Ball(237, 127, 0, 0, red)); ????????balls.push(new?Ball(244, 114, 0, 0, red)); ????????balls.push(new?Ball(242, 98, 0, 0, red)); ????????balls.push(new?Ball(237, 86, 0, 0, red)); ????????balls.push(new?Ball(225, 81, 0, 0, red)); ????????// O ????????var?oOffset = 67; ????????balls.push(new?Ball(oOffset + 210, 81, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 197, 91, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 196, 103, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 200, 116, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 209, 127, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 223, 130, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 237, 127, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 244, 114, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 242, 98, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 237, 86, 0, 0, yellow)); ????????balls.push(new?Ball(oOffset + 225, 81, 0, 0, yellow)); ????????// G ????????balls.push(new?Ball(370, 80, 0, 0, blue)); ????????balls.push(new?Ball(358, 79, 0, 0, blue)); ????????balls.push(new?Ball(346, 79, 0, 0, blue)); ????????balls.push(new?Ball(335, 84, 0, 0, blue)); ????????balls.push(new?Ball(330, 98, 0, 0, blue)); ????????balls.push(new?Ball(334, 111, 0, 0, blue)); ????????balls.push(new?Ball(348, 116, 0, 0, blue)); ????????balls.push(new?Ball(362, 109, 0, 0, blue)); ????????balls.push(new?Ball(362, 94, 0, 0, blue)); ????????balls.push(new?Ball(355, 128, 0, 0, blue)); ????????balls.push(new?Ball(340, 135, 0, 0, blue)); ????????balls.push(new?Ball(327, 142, 0, 0, blue)); ????????balls.push(new?Ball(325, 155, 0, 0, blue)); ????????balls.push(new?Ball(339, 165, 0, 0, blue)); ????????balls.push(new?Ball(352, 166, 0, 0, blue)); ????????balls.push(new?Ball(367, 161, 0, 0, blue)); ????????balls.push(new?Ball(371, 149, 0, 0, blue)); ????????balls.push(new?Ball(366, 137, 0, 0, blue)); ????????// L ????????balls.push(new?Ball(394, 49, 0, 0, green)); ????????balls.push(new?Ball(381, 50, 0, 0, green)); ????????balls.push(new?Ball(391, 61, 0, 0, green)); ????????balls.push(new?Ball(390, 73, 0, 0, green)); ????????balls.push(new?Ball(392, 89, 0, 0, green)); ????????balls.push(new?Ball(390, 105, 0, 0, green)); ????????balls.push(new?Ball(390, 118, 0, 0, green)); ????????balls.push(new?Ball(388, 128, 0, 0, green)); ????????balls.push(new?Ball(400, 128, 0, 0, green)); ????????// E ????????balls.push(new?Ball(426, 101, 0, 0, red)); ????????balls.push(new?Ball(436, 98, 0, 0, red)); ????????balls.push(new?Ball(451, 95, 0, 0, red)); ????????balls.push(new?Ball(449, 83, 0, 0, red)); ????????balls.push(new?Ball(443, 78, 0, 0, red)); ????????balls.push(new?Ball(430, 77, 0, 0, red)); ????????balls.push(new?Ball(418, 82, 0, 0, red)); ????????balls.push(new?Ball(414, 93, 0, 0, red)); ????????balls.push(new?Ball(412, 108, 0, 0, red)); ????????balls.push(new?Ball(420, 120, 0, 0, red)); ????????balls.push(new?Ball(430, 127, 0, 0, red)); ????????balls.push(new?Ball(442, 130, 0, 0, red)); ????????balls.push(new?Ball(450, 125, 0, 0, red)); ????????return?balls; ??????} ??????function?getMousePos(canvas, evt) { ????????// get canvas position ????????var?obj = canvas; ????????var?top = 0; ????????var?left = 0; ????????while(obj.tagName !=?'BODY') { ??????????top += obj.offsetTop; ??????????left += obj.offsetLeft; ??????????obj = obj.offsetParent; ????????} ????????// return relative mouse position ????????var?mouseX = evt.clientX - left + window.pageXOffset; ????????var?mouseY = evt.clientY - top + window.pageYOffset; ????????return?{ ??????????x: mouseX, ??????????y: mouseY ????????}; ??????} ??????function?updateBalls(canvas, balls, timeDiff, mousePos) { ????????var?context = canvas.getContext('2d'); ????????var?collisionDamper = 0.3; ????????var?floorFriction = 0.0005 * timeDiff; ????????var?mouseForceMultiplier = 1 * timeDiff; ????????var?restoreForce = 0.002 * timeDiff; ????????for(var?n = 0; n < balls.length; n++) { ??????????var?ball = balls[n]; ??????????// set ball position based on velocity ??????????ball.y += ball.vy; ??????????ball.x += ball.vx; ??????????// restore forces ??????????if(ball.x > ball.origX) { ????????????ball.vx -= restoreForce; ??????????} ??????????else?{ ????????????ball.vx += restoreForce; ??????????} ??????????if(ball.y > ball.origY) { ????????????ball.vy -= restoreForce; ??????????} ??????????else?{ ????????????ball.vy += restoreForce; ??????????} ??????????// mouse forces ??????????var?mouseX = mousePos.x; ??????????var?mouseY = mousePos.y; ??????????var?distX = ball.x - mouseX; ??????????var?distY = ball.y - mouseY; ??????????var?radius = Math.sqrt(Math.pow(distX, 2) + Math.pow(distY, 2)); ??????????var?totalDist = Math.abs(distX) + Math.abs(distY); ??????????var?forceX = (Math.abs(distX) / totalDist) * (1 / radius) * mouseForceMultiplier; ??????????var?forceY = (Math.abs(distY) / totalDist) * (1 / radius) * mouseForceMultiplier; ??????????if(distX > 0) {// mouse is left of ball ????????????ball.vx += forceX; ??????????} ??????????else?{ ????????????ball.vx -= forceX; ??????????} ??????????if(distY > 0) {// mouse is on top of ball ????????????ball.vy += forceY; ??????????} ??????????else?{ ????????????ball.vy -= forceY; ??????????} ??????????// floor friction ??????????if(ball.vx > 0) { ????????????ball.vx -= floorFriction; ??????????} ??????????else?if(ball.vx < 0) { ????????????ball.vx += floorFriction; ??????????} ??????????if(ball.vy > 0) { ????????????ball.vy -= floorFriction; ??????????} ??????????else?if(ball.vy < 0) { ????????????ball.vy += floorFriction; ??????????} ??????????// floor condition ??????????if(ball.y > (canvas.height - ball.radius)) { ????????????ball.y = canvas.height - ball.radius - 2; ????????????ball.vy *= -1; ????????????ball.vy *= (1 - collisionDamper); ??????????} ??????????// ceiling condition ??????????if(ball.y < (ball.radius)) { ????????????ball.y = ball.radius + 2; ????????????ball.vy *= -1; ????????????ball.vy *= (1 - collisionDamper); ??????????} ??????????// right wall condition ??????????if(ball.x > (canvas.width - ball.radius)) { ????????????ball.x = canvas.width - ball.radius - 2; ????????????ball.vx *= -1; ????????????ball.vx *= (1 - collisionDamper); ??????????} ??????????// left wall condition ??????????if(ball.x < (ball.radius)) { ????????????ball.x = ball.radius + 2; ????????????ball.vx *= -1; ????????????ball.vx *= (1 - collisionDamper); ??????????} ????????} ??????} ??????function?Ball(x, y, vx, vy, color) { ????????this.x = x; ????????this.y = y; ????????this.vx = vx; ????????this.vy = vy; ????????this.color = color; ????????this.origX = x; ????????this.origY = y; ????????this.radius = 10; ??????} ??????function?animate(canvas, balls, lastTime, mousePos) { ????????var?context = canvas.getContext('2d'); ????????// update ????????var?date =?new?Date(); ????????var?time = date.getTime(); ????????var?timeDiff = time - lastTime; ????????updateBalls(canvas, balls, timeDiff, mousePos); ????????lastTime = time; ????????// clear ????????context.clearRect(0, 0, canvas.width, canvas.height); ????????// render ????????for(var?n = 0; n < balls.length; n++) { ??????????var?ball = balls[n]; ??????????context.beginPath(); ??????????context.arc(ball.x, ball.y, ball.radius, 0, 2 * Math.PI,?false); ??????????context.fillStyle = ball.color; ??????????context.fill(); ????????} ????????// request new frame ????????requestAnimFrame(function() { ??????????animate(canvas, balls, lastTime, mousePos); ????????}); ??????} ??????var?canvas = document.getElementById('myCanvas'); ??????var?balls = initBalls(); ??????var?date =?new?Date(); ??????var?time = date.getTime(); ??????/* ???????* set mouse position really far away ???????* so the mouse forces are nearly obsolete ???????*/ ??????var?mousePos = { ????????x: 9999, ????????y: 9999 ??????}; ??????canvas.addEventListener('mousemove',?function(evt) { ????????var?pos = getMousePos(canvas, evt); ????????mousePos.x = pos.x; ????????mousePos.y = pos.y; ??????}); ??????canvas.addEventListener('mouseout',?function(evt) { ????????mousePos.x = 9999; ????????mousePos.y = 9999; ??????}); ??????animate(canvas, balls, time, mousePos); ????</script> ??</body> </html>轉載于:https://www.cnblogs.com/LiuJL/p/6078212.html
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