Canvas 3D球形文字云动画特效

body {

color:#555555;

}

h4 {

font-family:sans-serif;

color:#555555;

font-size:16px;

}

h3 {

font-family:sans-serif;

color:#555555;

}

p {

font-family:sans-serif;

color:#888888;

font-size:14px;

}

a {

font-family:sans-serif;

color:#d15423;

text-decoration:none;

}

window.addEventListener("load", windowLoadHandler, false);

var sphereRad = 280;

var radius_sp=1;

var opt_display_dots = false;

var unicodeFlakes = ['?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '我', '蒌', '火', '的', '山', '首', '页', '嫖', '是', '肺', '化', '?', '化', '?', '符', '?', '是', '原', '子', '序', '?', '是', '它', '是', '肺', '灰', '白', '色', '?', '金', '?', '有', '光', '?', '冱', '硬', '?', '於', '碳', '族', '化', '?', '性', '冱', '陪', '同', '族', '的', '遽', '陪', '矽', '相', '共', '有', '五', '肺', '同', '位', '素', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '?', '才', '菜', '参', '餐', '层', '茶', '差', '长', '常', '场', '唱', '超', '车', '成', '城', '程', '吃', '店', '定', '订', '丢', '东', '冬', '懂', '动', '都', '读', '独', '度', '短', '对', '多', '饿', '儿', '而', '发', '法', '反', '饭', '方', '房', '放', '飞', '非', '费', '分', '份', '风', '封', '夫', '服', '附', '父', '复', '该', '改', '干', '感', '刚', '高', '告', '哥', '歌', '格', '个', '给', '号', '喝', '和', '河', '贺', '黑', '很', '红', '后', '候', '湖', '护', '花', '化', '画', '话', '坏', '欢', '还', '换', '黄', '回', '会', '婚', '活', '火', '或', '机', '鸡', '级', '极', '急', '际', '济', '继', '寄', '加', '家', '假', '价', '力', '历', '丽', '联', '凉', '两', '亮', '谅', '辆', '了', '林', '零', '六', '楼', '路', '录', '旅', '妈', '马', '码', '吗', '买', '卖', '满', '慢', '忙', '猫', '毛', '贸', '么', '没', '每', '美', '妹', '米', '面', '民', '明', '末', '母', '目', '拿', '哪', '那', '奶', '男', '南', '难', '脑', '呢', '能', '你', '年', '念', '鸟', '您', '牛', '农', '努', '女', '暖', '欧', '怕', '乓', '旁', '胖', '跑', '朋', '片', '漂', '票', '乒', '平', '期', '其', '奇', '骑', '起', '气', '汽', '千', '前', '签', '轻', '清', '情', '请', '秋', '球', '区', '取', '去', '趣', '全', '然', '让', '首', '售', '书', '术', '树', '双', '谁', '水', '睡', '说', '司', '思', '死', '四', '送', '诉', '算', '虽', '岁', '孙', '所', '他', '她', '它', '台', '太', '谈', '汤', '堂', '套', '特', '踢', '提', '题', '体', '天', '填', '条', '铁', '听', '厅', '庭', '通', '同', '头', '图', '外', '玩', '完', '晚', '万', '王', '网', '往', '忘', '望', '卫', '为', '位', '文', '我', '卧', '五', '午', '务', '物', '西', '吸', '希', '息', '习', '牙', '亚', '烟', '言', '羊', '阳', '样', '药', '要', '也', '业', '夜', '一', '衣', '医', '已', '以', '易', '意', '因', '音', '印', '银', '应', '英', '影', '硬', '用', '邮', '油', '游', '友', '有', '又', '右', '鱼', '愉', '雨', '语', '元', '员', '园', '原', '远', '院', '愿', '月', '在', '早', '怎', '张', '找', '照', '者', '这', '真', '正', '证', '知', '只', '之', '直', '止', '纸', '至', '治', '中', '钟', '种', '重', '周', '洲', '主', '住', '助', '祝', '注', '专', '准' ];

//for debug messages

var Debugger = function() { };

Debugger.log = function(message) {

try {

console.log(message);

}

catch (exception) {

return;

}

}

function windowLoadHandler() {

canvasApp();

}

function canvasSupport() {

return Modernizr.canvas;

}

function canvasApp() {

if (!canvasSupport()) {

return;

}

var theCanvas = document.getElementById("canvasOne");

var context = theCanvas.getContext("2d");

var displayWidth;

var displayHeight;

var timer;

var wait;

var count;

var numToAddEachFrame;

var particleList;

var recycleBin;

var particleAlpha;

var r,g,b;

var fLen;

var m;

var projCenterX;

var projCenterY;

var zMax;

var turnAngle;

var turnSpeed;

var sphereCenterX, sphereCenterY, sphereCenterZ;

var particleRad;

var zeroAlphaDepth;

var randAccelX, randAccelY, randAccelZ;

var gravity;

var rgbString;

//we are defining a lot of variables used in the screen update functions globally so that they don't have to be redefined every frame.

var p;

var outsideTest;

var nextParticle;

var sinAngle;

var cosAngle;

var rotX, rotZ;

var depthAlphaFactor;

var i;

var theta, phi;

var x0, y0, z0;

init();

// INITIALLI

function init() {

wait = 1;

count = wait - 1;

numToAddEachFrame = 4;

//particle color

r = 70;

g = 255;

b = 140;

rgbString = "rgba("+r+","+g+","+b+","; //partial string for color which will be completed by appending alpha value.

particleAlpha = 1; //maximum alpha

displayWidth = theCanvas.width;

displayHeight = theCanvas.height;

fLen = 320; //represents the distance from the viewer to z=0 depth.

//projection center coordinates sets location of origin

projCenterX = displayWidth/2;

projCenterY = displayHeight/2;

//we will not draw coordinates if they have too large of a z-coordinate (which means they are very close to the observer).

zMax = fLen-2;

particleList = {};

recycleBin = {};

//random acceleration factors - causes some random motion

randAccelX = 0.1;

randAccelY = 0.1;

randAccelZ = 0.1;

gravity = -0; //try changing to a positive number (not too large, for example 0.3), or negative for floating upwards.

particleRad = 2.5;

sphereCenterX = 0;

sphereCenterY = 0;

sphereCenterZ = -3 - sphereRad;

//alpha values will lessen as particles move further back, causing depth-based darkening:

zeroAlphaDepth = -750;

turnSpeed = 2*Math.PI/1200; //the sphere will rotate at this speed (one complete rotation every 1600 frames).

turnAngle = 0; //initial angle

timer = setInterval(onTimer, 10/24);

}

function onTimer() {

//if enough time has elapsed, we will add new particles.

count++;

if (count >= wait) {

count = 0;

for (i = 0; i < numToAddEachFrame; i++) {

theta = Math.random()*2*Math.PI;

phi = Math.acos(Math.random()*2-1);

x0 = sphereRad*Math.sin(phi)*Math.cos(theta);

y0 = sphereRad*Math.sin(phi)*Math.sin(theta);

z0 = sphereRad*Math.cos(phi);

//We use the addParticle function to add a new particle. The parameters set the position and velocity components.

//Note that the velocity parameters will cause the particle to initially fly outwards away from the sphere center (after

//it becomes unstuck).

var p = addParticle(x0, sphereCenterY + y0, sphereCenterZ + z0, 0.002*x0, 0.002*y0, 0.002*z0);

//we set some "envelope" parameters which will control the evolving alpha of the particles.

p.attack = 50;

p.hold = 50;

p.decay = 100;

p.initValue = 0;

p.holdValue = particleAlpha;

p.lastValue = 0;

//the particle will be stuck in one place until this time has elapsed:

p.stuckTime = 90 + Math.random()*20;

p.accelX = 0;

p.accelY = gravity;

p.accelZ = 0;

}

}

//update viewing angle

turnAngle = (turnAngle + turnSpeed) % (2*Math.PI);

sinAngle = Math.sin(turnAngle);

cosAngle = Math.cos(turnAngle);

//background fill

context.fillStyle = "#000000";

context.fillRect(0,0,displayWidth,displayHeight);

//update and draw particles

p = particleList.first;

while (p != null) {

//before list is altered record next particle

nextParticle = p.next;

//update age

p.age++;

//if the particle is past its "stuck" time, it will begin to move.

if (p.age > p.stuckTime) {

p.velX += p.accelX + randAccelX*(Math.random()*2 - 1);

p.velY += p.accelY + randAccelY*(Math.random()*2 - 1);

p.velZ += p.accelZ + randAccelZ*(Math.random()*2 - 1);

p.x += p.velX;

p.y += p.velY;

p.z += p.velZ;

}

/*

We are doing two things here to calculate display coordinates.

The whole display is being rotated around a vertical axis, so we first calculate rotated coordinates for

x and z (but the y coordinate will not change).

Then, we take the new coordinates (rotX, y, rotZ), and project these onto the 2D view plane.

*/

rotX =  cosAngle*p.x + sinAngle*(p.z - sphereCenterZ);

rotZ =  -sinAngle*p.x + cosAngle*(p.z - sphereCenterZ) + sphereCenterZ;

m =radius_sp* fLen/(fLen - rotZ);

p.projX = rotX*m + projCenterX;

p.projY = p.y*m + projCenterY;

//update alpha according to envelope parameters.

if (p.age < p.attack+p.hold+p.decay) {

if (p.age < p.attack) {

p.alpha = (p.holdValue - p.initValue)/p.attack*p.age + p.initValue;

}

else if (p.age < p.attack+p.hold) {

p.alpha = p.holdValue;

}

else if (p.age < p.attack+p.hold+p.decay) {

p.alpha = (p.lastValue - p.holdValue)/p.decay*(p.age-p.attack-p.hold) + p.holdValue;

}

}

else {

p.dead = true;

}

//see if the particle is still within the viewable range.

if ((p.projX > displayWidth)||(p.projX<0)||(p.projY<0)||(p.projY>displayHeight)||(rotZ>zMax)) {

outsideTest = true;

}

else {

outsideTest = false;

}

if (outsideTest||p.dead) {

recycle(p);

}

else {

//depth-dependent darkening

depthAlphaFactor = (1-rotZ/zeroAlphaDepth);

depthAlphaFactor = (depthAlphaFactor > 1) ? 1 : ((depthAlphaFactor<0) ? 0 : depthAlphaFactor);

context.fillStyle = rgbString + depthAlphaFactor*p.alpha + ")";

/*ADD TEXT function!*/

/*ADD TEXT function!*/

/*ADD TEXT function!*/

/*ADD TEXT function!*/

context.fillText(p.flake,p.projX, p.projY);

/*ADD TEXT function!*/

/*ADD TEXT function!*/

/*ADD TEXT function!*/

/*ADD TEXT function!*/

//draw

context.beginPath();

if(opt_display_dots)

{context.arc(p.projX, p.projY, m*particleRad, 0, 2*Math.PI, false);}

context.closePath();

context.fill();

}

p = nextParticle;

}

}

function addParticle(x0,y0,z0,vx0,vy0,vz0) {

var newParticle;

var color;

//check recycle bin for available drop:

if (recycleBin.first != null) {

newParticle = recycleBin.first;

//remove from bin

if (newParticle.next != null) {

recycleBin.first = newParticle.next;

newParticle.next.prev = null;

}

else {

recycleBin.first = null;

}

}

//if the recycle bin is empty, create a new particle (a new ampty object):

else {

newParticle = {};

}

//add to beginning of particle list

if (particleList.first == null) {

particleList.first = newParticle;

newParticle.prev = null;

newParticle.next = null;

}

else {

newParticle.next = particleList.first;

particleList.first.prev = newParticle;

particleList.first = newParticle;

newParticle.prev = null;

}

//initialize

newParticle.x = x0;

newParticle.y = y0;

newParticle.z = z0;

newParticle.velX = vx0;

newParticle.velY = vy0;

newParticle.velZ = vz0;

newParticle.age = 0;

newParticle.dead = false;

newParticle.flake = unicodeFlakes[Math.floor(Math.random() * unicodeFlakes.length)];

if (Math.random() < 0.5) {

newParticle.right = true;

}

else {

newParticle.right = false;

}

return newParticle;

}

function recycle(p) {

//remove from particleList

if (particleList.first == p) {

if (p.next != null) {

p.next.prev = null;

particleList.first = p.next;

}

else {

particleList.first = null;

}

}

else {

if (p.next == null) {

p.prev.next = null;

}

else {

p.prev.next = p.next;

p.next.prev = p.prev;

}

}

//add to recycle bin

if (recycleBin.first == null) {

recycleBin.first = p;

p.prev = null;

p.next = null;

}

else {

p.next = recycleBin.first;

recycleBin.first.prev = p;

recycleBin.first = p;

p.prev = null;

}

}

}