HTML5 - Canvas动画样例（谷歌弹跳球）

<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>

秒客网

HTML5 - Canvas动画样例（谷歌弹跳球）

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