HTML5 Canvas 破碎重组的视频特效

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也许你见过HTML5图片破碎动画特效，实现的原理也挺简单的。但是你应该没有见过视频也可以破碎重组，这个HTML5动画就是利用Canvas的相关特性，实现了点击鼠标让视频破碎重组的效果。在视频区域点击鼠标，即可让该区域的视频破碎，让后经过一段时间后，破碎的区域又可以重组还原，视觉效果非常棒。

在线演示源码下载

HTML代码

<div style="display:none"><video id="sourcevid" autoplay="true" loop="true"><source src="BigBuckBunny_640x360.mp4" type="video/mp4"/><source src="BigBuckBunny_640x360.ogv" type="video/ogg"/></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;">Click video to blow it up!</div><canvas id="output" width="1000" height="600" onmousedown="dropBomb(event, this)" style="border: 0 none">        </canvas></center></div>

JavaScript代码

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();}//this is to keep my sanity while developingif(randomJump){randomJump = false;video.currentTime = Math.random()*video.duration;}//loopif(video.currentTime == video.duration){video.currentTime = 0;}}var debugStr = "";//copy tilescopy.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){//expandtile.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){//contractvar 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;}/*getPixelreturn pixel object {r,g,b,a}*/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]}}/*setPixelset pixel object {r,g,b,a}*/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;}/*copyPixelfaster then using getPixel/setPixel combo*/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];     //RdImageData.data[dpos+1] = sImageData.data[spos+1]; //GdImageData.data[dpos+2] = sImageData.data[spos+2]; //BdImageData.data[dpos+3] = sImageData.data[spos+3]; //A}</script>

在线演示源码下载