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HTML5 canvas绘图制作打击视频玻璃破碎动画效果

2015-06-06 12:56 856 查看
HTML5 canvas绘图制作打击视频玻璃破碎动画效果

<!DOCTYPE >

<html >

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<title></title>

<script type="text/javascript">
var video;

var copy;

var copycanvas;

var draw;
var TILE_WIDTH = 32;

var TILE_HEIGHT = 24;

var TILE_CENTER_WIDTH = 16;

var TILE_CENTER_HEIGHT = 12;

var SOURCERECT = {x:0, y:0, width:0, height:0};

var PAINTRECT = {x:0, y:0, width:1000, height:600};
function init(){

video = document.getElementById('sourcevid');

copycanvas = document.getElementById('sourcecopy');

copy = copycanvas.getContext('2d');

var outputcanvas = document.getElementById('output');

draw = outputcanvas.getContext('2d');

setInterval("processFrame()", 33);

}

function createTiles(){

var offsetX = TILE_CENTER_WIDTH+(PAINTRECT.width-SOURCERECT.width)/2;

var offsetY = TILE_CENTER_HEIGHT+(PAINTRECT.height-SOURCERECT.height)/2;

var y=0;

while(y < SOURCERECT.height){

var x=0;

while(x < SOURCERECT.width){

var tile = new Tile();

tile.videoX = x;

tile.videoY = y;

tile.originX = offsetX+x;

tile.originY = offsetY+y;

tile.currentX = tile.originX;

tile.currentY = tile.originY;

tiles.push(tile);

x+=TILE_WIDTH;

}

y+=TILE_HEIGHT;

}

}
var RAD = Math.PI/180;

var randomJump = false;

var tiles = [];

var debug = false;

function processFrame(){

if(!isNaN(video.duration)){

if(SOURCERECT.width == 0){

SOURCERECT = {x:0,y:0,width:video.videoWidth,height:video.videoHeight};

createTiles();

}

if(randomJump){

randomJump = false;

video.currentTime = Math.random()*video.duration;

}

if(video.currentTime == video.duration){

video.currentTime = 0;

}

}

var debugStr = "";

copy.drawImage(video, 0, 0);

draw.clearRect(PAINTRECT.x, PAINTRECT.y,PAINTRECT.width,PAINTRECT.height);

for(var i=0; i<tiles.length; i++){

var tile = tiles[i];

if(tile.force > 0.0001){

tile.moveX *= tile.force;

tile.moveY *= tile.force;

tile.moveRotation *= tile.force;

tile.currentX += tile.moveX;

tile.currentY += tile.moveY;

tile.rotation += tile.moveRotation;

tile.rotation %= 360;

tile.force *= 0.9;

if(tile.currentX <= 0 || tile.currentX >= PAINTRECT.width){

tile.moveX *= -1;

}

if(tile.currentY <= 0 || tile.currentY >= PAINTRECT.height){

tile.moveY *= -1;

}

}else if(tile.rotation != 0 || tile.currentX != tile.originX || tile.currentY != tile.originY){

var diffx = (tile.originX-tile.currentX)*0.2;

var diffy = (tile.originY-tile.currentY)*0.2;

var diffRot = (0-tile.rotation)*0.2;

if(Math.abs(diffx) < 0.5){

tile.currentX = tile.originX;

}else{

tile.currentX += diffx;

}

if(Math.abs(diffy) < 0.5){

tile.currentY = tile.originY;

}else{

tile.currentY += diffy;

}

if(Math.abs(diffRot) < 0.5){

tile.rotation = 0;

}else{

tile.rotation += diffRot;

}

}else{

tile.force = 0;

}

draw.save();

draw.translate(tile.currentX, tile.currentY);

draw.rotate(tile.rotation*RAD);

draw.drawImage(copycanvas, tile.videoX, tile.videoY, TILE_WIDTH, TILE_HEIGHT, -TILE_CENTER_WIDTH, -TILE_CENTER_HEIGHT, TILE_WIDTH, TILE_HEIGHT);

draw.restore();

}

if(debug){

debug = false;

document.getElementById('trace').innerHTML = debugStr;

}

}
function explode(x, y){

for(var i=0; i<tiles.length; i++){

var tile = tiles[i];

var xdiff = tile.currentX-x;

var ydiff = tile.currentY-y;

var dist = Math.sqrt(xdiff*xdiff + ydiff*ydiff);

var randRange = 220+(Math.random()*30);

var range = randRange-dist;

var force = 3*(range/randRange);

if(force > tile.force){

tile.force = force;

var radians = Math.atan2(ydiff, xdiff);

tile.moveX = Math.cos(radians);

tile.moveY = Math.sin(radians);

tile.moveRotation = 0.5-Math.random();

}

}

tiles.sort(zindexSort);

processFrame();

}

function zindexSort(a, b){

return (a.force-b.force);

}
function dropBomb(evt, obj){

var posx = 0;

var posy = 0;

var e = evt || window.event;

if (e.pageX || e.pageY){

posx = e.pageX;

posy = e.pageY;

}else if (e.clientX || e.clientY) {

posx = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;

posy = e.clientY + document.body.scrollTop + document.documentElement.scrollTop;

}

var canvasX = posx-obj.offsetLeft;

var canvasY = posy-obj.offsetTop;

explode(canvasX, canvasY);

}
function Tile(){

this.originX = 0;

this.originY = 0;

this.currentX = 0;

this.currentY = 0;

this.rotation = 0;

this.force = 0;

this.z = 0;

this.moveX= 0;

this.moveY= 0;

this.moveRotation = 0;

this.videoX = 0;

this.videoY = 0;

}

function getPixel(imageData, x, y){

var data = imageData.data;

var pos = (x + y * imageData.width) * 4;

return {r:data[pos], g:data[pos+1], b:data[pos+2], a:data[pos+3]}

}
function setPixel(imageData, x, y, pixel){

var data = imageData.data;

var pos = (x + y * imageData.width) * 4;

data[pos] = pixel.r;

data[pos+1] = pixel.g;

data[pos+2] = pixel.b;

data[pos+3] = pixel.a;

}
function copyPixel(sImageData, sx, sy, dImageData, dx, dy){

var spos = (sx + sy * sImageData.width) * 4;

var dpos = (dx + dy * dImageData.width) * 4;

dImageData.data[dpos] = sImageData.data[spos]; //R

dImageData.data[dpos+1] = sImageData.data[spos+1]; //G

dImageData.data[dpos+2] = sImageData.data[spos+2]; //B

dImageData.data[dpos+3] = sImageData.data[spos+3]; //A

}

</script>

</head>
<body onload="init()" style="margin:0px;">

<div style="display:none">

<video id="sourcevid" autoplay="true" loop="true">

<source src="BigBuckBunny_640x360.mp4" type="video/mp4"/>

</video>

<canvas id="sourcecopy" width="640" height="360"></canvas>

</div>

<div>

<center>

<div style="z-index:1;position:relative;text-align:center;font-size:16px;font-weight:bold;width:1000px;top:60px;"></div>

<canvas id="output" width="1000" height="600" onmousedown="dropBomb(event, this)" style="border: 0 none"></canvas>

</center>

</div>

</body>

</html>









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