先看效果，如下图：
具体代码如下：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><embed src="D:\音乐\G.E.M.邓紫棋 - 龙卷风.mp3 " width="0" height="0" type="audio/mpeg loop="ture" autostart="ture" volume="0" .></EMBED><HTML><HEAD><TITLE> New Document </TITLE><META NAME="Generator" CONTENT="EditPlus"><META NAME="Author" CONTENT=""><META NAME="Keywords" CONTENT=""><META NAME="Description" CONTENT=""><style>html, body {margin: 0px;width: 100%;height: 100%;overflow: hidden;background: #000;}#canvas {position: absolute;width: 100%;height: 100%;}</style></HEAD><BODY><canvas id="canvas"></canvas><script>function project3D(x, y, z, vars) {var p, d;x -= vars.camX;y -= vars.camY - 8;z -= vars.camZ;p = Math.atan2(x, z);d = Math.sqrt(x * x + z * z);x = Math.sin(p - vars.yaw) * d;z = Math.cos(p - vars.yaw) * d;p = Math.atan2(y, z);d = Math.sqrt(y * y + z * z);y = Math.sin(p - vars.pitch) * d;z = Math.cos(p - vars.pitch) * d;var rx1 = -1000;var ry1 = 1;var rx2 = 1000;var ry2 = 1;var rx3 = 0;var ry3 = 0;var rx4 = x;var ry4 = z;var uc = (ry4 - ry3) * (rx2 - rx1) - (rx4 - rx3) * (ry2 - ry1);var ua = ((rx4 - rx3) * (ry1 - ry3) - (ry4 - ry3) * (rx1 - rx3)) / uc;var ub = ((rx2 - rx1) * (ry1 - ry3) - (ry2 - ry1) * (rx1 - rx3)) / uc;if (!z) z = 0.000000001;if (ua > 0 && ua < 1 && ub > 0 && ub < 1) {return {x: vars.cx + (rx1 + ua * (rx2 - rx1)) * vars.scale,y: vars.cy + y / z * vars.scale,d: (x * x + y * y + z * z)};} else {return { d: -1 };}}function elevation(x, y, z) {var dist = Math.sqrt(x * x + y * y + z * z);if (dist && z / dist >= -1 && z / dist <= 1) return Math.acos(z / dist);return 0.00000001;}function rgb(col) {col += 0.000001;var r = parseInt((0.5 + Math.sin(col) * 0.5) * 16);var g = parseInt((0.5 + Math.cos(col) * 0.5) * 16);var b = parseInt((0.5 - Math.sin(col) * 0.5) * 16);return "#" + r.toString(16) + g.toString(16) + b.toString(16);}function interpolateColors(RGB1, RGB2, degree) {var w2 = degree;var w1 = 1 - w2;return [w1 * RGB1[0] + w2 * RGB2[0], w1 * RGB1[1] + w2 * RGB2[1], w1 * RGB1[2] + w2 * RGB2[2]];}function rgbArray(col) {col += 0.000001;var r = parseInt((0.5 + Math.sin(col) * 0.5) * 256);var g = parseInt((0.5 + Math.cos(col) * 0.5) * 256);var b = parseInt((0.5 - Math.sin(col) * 0.5) * 256);return [r, g, b];}function colorString(arr) {var r = parseInt(arr[0]);var g = parseInt(arr[1]);var b = parseInt(arr[2]);return "#" + ("0" + r.toString(16)).slice(-2) + ("0" + g.toString(16)).slice(-2) + ("0" + b.toString(16)).slice(-2);}function process(vars) {if (vars.points.length < vars.initParticles) for (var i = 0; i < 5; ++i) spawnParticle(vars);var p, d, t;p = Math.atan2(vars.camX, vars.camZ);d = Math.sqrt(vars.camX * vars.camX + vars.camZ * vars.camZ);d -= Math.sin(vars.frameNo / 80) / 25;t = Math.cos(vars.frameNo / 300) / 165;vars.camX = Math.sin(p + t) * d;vars.camZ = Math.cos(p + t) * d;vars.camY = -Math.sin(vars.frameNo / 220) * 15;vars.yaw = Math.PI + p + t;vars.pitch = elevation(vars.camX, vars.camZ, vars.camY) - Math.PI / 2;var t;for (var i = 0; i < vars.points.length; ++i) {x = vars.points[i].x;y = vars.points[i].y;z = vars.points[i].z;d = Math.sqrt(x * x + z * z) / 1.0075;t = .1 / (1 + d * d / 5);p = Math.atan2(x, z) + t;vars.points[i].x = Math.sin(p) * d;vars.points[i].z = Math.cos(p) * d;vars.points[i].y += vars.points[i].vy * t * ((Math.sqrt(vars.distributionRadius) - d) * 2);if (vars.points[i].y > vars.vortexHeight / 2 || d < .25) {vars.points.splice(i, 1);spawnParticle(vars);}}}function drawFloor(vars) {var x, y, z, d, point, a;for (var i = -25; i <= 25; i += 1) {for (var j = -25; j <= 25; j += 1) {x = i * 2;z = j * 2;y = vars.floor;d = Math.sqrt(x * x + z * z);point = project3D(x, y - d * d / 85, z, vars);if (point.d != -1) {size = 1 + 15000 / (1 + point.d);a = 0.15 - Math.pow(d / 50, 4) * 0.15;if (a > 0) {vars.ctx.fillStyle = colorString(interpolateColors(rgbArray(d / 26 - vars.frameNo / 40), [0, 128, 32], .5 + Math.sin(d / 6 - vars.frameNo / 8) / 2));vars.ctx.globalAlpha = a;vars.ctx.fillRect(point.x - size / 2, point.y - size / 2, size, size);}}}}vars.ctx.fillStyle = "#82f";for (var i = -25; i <= 25; i += 1) {for (var j = -25; j <= 25; j += 1) {x = i * 2;z = j * 2;y = -vars.floor;d = Math.sqrt(x * x + z * z);point = project3D(x, y + d * d / 85, z, vars);if (point.d != -1) {size = 1 + 15000 / (1 + point.d);a = 0.15 - Math.pow(d / 50, 4) * 0.15;if (a > 0) {vars.ctx.fillStyle = colorString(interpolateColors(rgbArray(-d / 26 - vars.frameNo / 40), [32, 0, 128], .5 + Math.sin(-d / 6 - vars.frameNo / 8) / 2));vars.ctx.globalAlpha = a;vars.ctx.fillRect(point.x - size / 2, point.y - size / 2, size, size);}}}}}function sortFunction(a, b) {return b.dist - a.dist;}function draw(vars) {vars.ctx.globalAlpha = .15;vars.ctx.fillStyle = "#000";vars.ctx.fillRect(0, 0, canvas.width, canvas.height);drawFloor(vars);var point, x, y, z, a;for (var i = 0; i < vars.points.length; ++i) {x = vars.points[i].x;y = vars.points[i].y;z = vars.points[i].z;point = project3D(x, y, z, vars);if (point.d != -1) {vars.points[i].dist = point.d;size = 1 + vars.points[i].radius / (1 + point.d);d = Math.abs(vars.points[i].y);a = .8 - Math.pow(d / (vars.vortexHeight / 2), 1000) * .8;vars.ctx.globalAlpha = a >= 0 && a <= 1 ? a : 0;vars.ctx.fillStyle = rgb(vars.points[i].color);if (point.x > -1 && point.x < vars.canvas.width && point.y > -1 && point.y < vars.canvas.height) vars.ctx.fillRect(point.x - size / 2, point.y - size / 2, size, size);}}vars.points.sort(sortFunction);}function spawnParticle(vars) {var p, ls;pt = {};p = Math.PI * 2 * Math.random();ls = Math.sqrt(Math.random() * vars.distributionRadius);pt.x = Math.sin(p) * ls;pt.y = -vars.vortexHeight / 2;pt.vy = vars.initV / 20 + Math.random() * vars.initV;pt.z = Math.cos(p) * ls;pt.radius = 200 + 800 * Math.random();pt.color = pt.radius / 1000 + vars.frameNo / 250;vars.points.push(pt);}function frame(vars) {if (vars === undefined) {var vars = {};vars.canvas = document.querySelector("canvas");vars.ctx = vars.canvas.getContext("2d");vars.canvas.width = document.body.clientWidth;vars.canvas.height = document.body.clientHeight;window.addEventListener("resize", function () {vars.canvas.width = document.body.clientWidth;vars.canvas.height = document.body.clientHeight;vars.cx = vars.canvas.width / 2;vars.cy = vars.canvas.height / 2;}, true);vars.frameNo = 0;vars.camX = 0;vars.camY = 0;vars.camZ = -14;vars.pitch = elevation(vars.camX, vars.camZ, vars.camY) - Math.PI / 2;vars.yaw = 0;vars.cx = vars.canvas.width / 2;vars.cy = vars.canvas.height / 2;vars.bounding = 10;vars.scale = 500;vars.floor = 26.5;vars.points = [];vars.initParticles = 2000;vars.initV = .01;vars.distributionRadius = 800;vars.vortexHeight = 25;}vars.frameNo++;requestAnimationFrame(function () {frame(vars);});process(vars);draw(vars);}frame();</script></BODY></HTML>
