canvas实现视频播放,带炸裂特效

<!DOCTYPE html>
<html>

<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    <title>HTML5 Video Destruction</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();
	            }
	            //this is to keep my sanity while developing
	            if (randomJump) {
	                randomJump = false;
	                video.currentTime = Math.random() * video.duration;
	            }
	            //loop
	            if (video.currentTime == video.duration) {
	                video.currentTime = 0;
	            }
	        }
	        var debugStr = "";
	        //copy tiles
	        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) {
	                //expand
	                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) {
	                //contract
	                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;
	    }


	    /*
	    	getPixel
	    	return 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] }
	    }
	    /*
	    	setPixel
	    	set 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;
	    }
	    /*
	    	copyPixel
	    	faster 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]; //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="cf.mp4" type="video/mp4" />
        </video>
        <canvas id="sourcecopy" width="640" height="360"></canvas>
    </div>
    <div>
        <center>
            <canvas id="output" width="1000" height="600" onmousedown="dropBomb(event, this)" style="border: 0 none"></canvas>
        </center>
    </div>
</body>

</html>

 

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