今天又要为大家带来一款超酷的HTML5 Canvas 3D动画特效，是一款可以旋转的HTML5 Logo标志。画面上一共有两块可旋转的区域，第一是可旋转的背景，第二则是可旋转的Logo标志。Logo标志在旋转的时候还有3D的视觉效果，这一切我们都是在canvas上实现的。具体演示和实现过程可以看下文。
你也可以在这里查看在线演示
下面我们来简单分析一下实现这款3D动画的过程及其部分核心代码，主要由HTML代码以及Javascript代码组成。
HTML代码：
<canvas id="canvas" style="background-color:#ddd"></canvas>
非常简单，仅仅是构造了一个canvas容器，接下来的3D动画，包括旋转的特效都将在这里绘制和实现。
Javascript代码：
function onloadHandler()
{
var canvas = document.getElementById('canvas');
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
var k3dmain = new K3D.Controller(canvas, true); // generate 3D objects var obj1 = new K3D.K3DObject();
with (obj1)
{
drawmode = "solid";
shademode = "lightsource";
sortmode = "unsorted";
addphi = -0.5;
abouty = -90;
perslevel = 1000;
init(
[{x:-80,y:180,z:0},{x:0,y:180,z:-80},{x:0,y:0,z:-80},{x:-80,y:20,z:0},{x:-50,y:150,z:-30},{x:0,y:150,z:-80},{x:0,y:130,z:-80},{x:-30,y:130,z:-50},{x:-28,y:110,z:-52},{x:0,y:110,z:-80},{x:0,y:90,z:-80},{x:-45,y:90,z:-35},{x:-44,y:80,z:-36},{x:-25,y:80,z:-55},{x:-22,y:66,z:-58},{x:0,y:60,z:-80},{x:0,y:40,z:-80},{x:-40,y:50,z:-40}],
[],
[{color:[227,76,38],vertices:[0,1,2,3,0]},{color:[235,235,235],vertices:[4,5,6,7,8,9,10,11,4]},{color:[235,235,235],vertices:[12,13,14,15,16,17,12]}]
);
}
k3dmain.addK3DObject(obj1); var obj2 = new K3D.K3DObject();
with (obj2)
{
drawmode = "solid";
shademode = "lightsource";
sortmode = "unsorted";
addphi = -0.5;
abouty = -90;
perslevel = 1000;
init(
[{x:0,y:180,z:-80},{x:80,y:180,z:0},{x:80,y:20,z:0},{x:0,y:0,z:-80},{x:0,y:165,z:-80},{x:68,y:165,z:-12},{x:55,y:35,z:-25},{x:0,y:20,z:-80},{x:0,y:150,z:-80},{x:50,y:150,z:-30},{x:47,y:130,z:-33},{x:0,y:130,z:-80},{x:0,y:110,z:-80},{x:45,y:110,z:-35},{x:40,y:50,z:-40},{x:0,y:40,z:-80},{x:0,y:60,z:-80},{x:20,y:66,z:-60},{x:23,y:90,z:-57},{x:0,y:90,z:-80}],
[],
[{color:[227,76,38],vertices:[0,1,2,3,0]},{color:[240,101,41],vertices:[4,5,6,7,4]},{color:[235,235,235],vertices:[8,9,10,11,8]},{color:[235,235,235],vertices:[12,13,14,15,16,17,18,19,12]}]
);
}
k3dmain.addK3DObject(obj2); var obj3 = new K3D.K3DObject();
with (obj3)
{
drawmode = "solid";
shademode = "lightsource";
sortmode = "unsorted";
addphi = -0.5;
abouty = -90;
perslevel = 1000;
init(
[{x:80,y:180,z:0},{x:0,y:180,z:80},{x:0,y:0,z:80},{x:80,y:20,z:0},{x:50,y:150,z:30},{x:0,y:150,z:80},{x:0,y:130,z:80},{x:30,y:130,z:50},{x:28,y:110,z:52},{x:0,y:110,z:80},{x:0,y:90,z:80},{x:45,y:90,z:35},{x:44,y:80,z:36},{x:25,y:80,z:55},{x:22,y:66,z:58},{x:0,y:60,z:80},{x:0,y:40,z:80},{x:40,y:50,z:40}],
[],
[{color:[227,76,38],vertices:[0,1,2,3,0]},{color:[235,235,235],vertices:[4,5,6,7,8,9,10,11,4]},{color:[235,235,235],vertices:[12,13,14,15,16,17,12]}]
);
}
k3dmain.addK3DObject(obj3); var obj4 = new K3D.K3DObject();
with (obj4)
{
drawmode = "solid";
shademode = "lightsource";
sortmode = "unsorted";
addphi = -0.5;
abouty = -90;
perslevel = 1000;
init(
[{x:0,y:180,z:80},{x:-80,y:180,z:0},{x:-80,y:20,z:0},{x:0,y:0,z:80},{x:0,y:165,z:80},{x:-68,y:165,z:12},{x:-55,y:35,z:25},{x:0,y:20,z:80},{x:0,y:150,z:80},{x:-50,y:150,z:30},{x:-47,y:130,z:33},{x:0,y:130,z:80},{x:0,y:110,z:80},{x:-45,y:110,z:35},{x:-40,y:50,z:40},{x:0,y:40,z:80},{x:0,y:60,z:80},{x:-20,y:66,z:60},{x:-23,y:90,z:57},{x:0,y:90,z:80}],
[],
[{color:[227,76,38],vertices:[0,1,2,3,0]},{color:[240,101,41],vertices:[4,5,6,7,4]},{color:[235,235,235],vertices:[8,9,10,11,8]},{color:[235,235,235],vertices:[12,13,14,15,16,17,18,19,12]}]
);
}
k3dmain.addK3DObject(obj4); var objBase = new K3D.K3DObject();
with (objBase)
{
drawmode = "solid";
shademode = "lightsource";
sortmode = "unsorted";
addphi = -0.5;
abouty = -90;
perslevel = 1000;
init(
[{x:0,y:0,z:-80},{x:-80,y:20,z:0},{x:0,y:0,z:80},{x:80,y:20,z:0}],
[],
[{color:[227,76,38],vertices:[0,2,1,0]},{color:[227,76,38],vertices:[0,3,2,0]}]
);
}
k3dmain.addK3DObject(objBase); var objHtml = new K3D.K3DObject();
with (objHtml)
{
drawmode = "solid";
shademode = "lightsource";
//sortmode = "unsorted";
color = [64,64,64];
doublesided = true;
addphi = -0.5;
abouty = 100;
scale = 0.75;
perslevel = 1000;
init(
[{x:-80,y:40,z:0},{x:-70,y:40,z:0},{x:-70,y:30,z:0},{x:-60,y:30,z:0},{x:-60,y:40,z:0},{x:-50,y:40,z:0},{x:-50,y:10,z:0},{x:-60,y:10,z:0},{x:-60,y:20,z:0},{x:-70,y:20,z:0},{x:-70,y:10,z:0},{x:-80,y:10,z:0},{x:-40,y:40,z:0},{x:-10,y:40,z:0},{x:-10,y:30,z:0},{x:-20,y:30,z:0},{x:-20,y:10,z:0},{x:-30,y:10,z:0},{x:-30,y:30,z:0},{x:-40,y:30,z:0},{x:0,y:40,z:0},{x:10,y:40,z:0},{x:20,y:30,z:0},{x:30,y:40,z:0},{x:40,y:40,z:0},{x:40,y:10,z:0},{x:30,y:10,z:0},{x:30,y:30,z:0},{x:20,y:20,z:0},{x:10,y:30,z:0},{x:10,y:10,z:0},{x:0,y:10,z:0},{x:50,y:40,z:0},{x:60,y:40,z:0},{x:60,y:20,z:0},{x:80,y:20,z:0},{x:80,y:10,z:0},{x:50,y:10,z:0}],
[],
[{vertices:[0,1,2,3,4,5,6,7,8,9,10,11,0]},{vertices:[12,13,14,15,16,17,18,19,12]},{vertices:[20,21,22,23,24,25,26,27,28,29,30,31,20]},{vertices:[32,33,34,35,36,37,32]}]
);
}
k3dmain.addK3DObject(objHtml); // add render loop callback
var ctx = canvas.getContext('2d');
var rotationOffset = 0;
var len = (canvas.height > canvas.width ? canvas.height : canvas.width) * 0.7;
k3dmain.clearBackground = false;
k3dmain.callback = function()
{
// manually clear bg - as we want to render some extra goodies
ctx.clearRect(0, 0, canvas.width, canvas.height); // draw bg effect before K3D does its 3D rendering
ctx.save();
ctx.translate(canvas.width/2, canvas.height/2);
ctx.rotate(rotationOffset); // first fill pass - outer rays
var RAYCOUNT = 24;
ctx.fillStyle = "#eee";
ctx.beginPath();
for (var i=0; i<RAYCOUNT; i++)
{
// rotate context
ctx.rotate(TWOPI / RAYCOUNT);
ctx.moveTo(0, 0);
ctx.lineTo(-20, len);
ctx.lineTo(20, len);
}
ctx.closePath();
ctx.fill();
// second fill pass - inner rays
ctx.fillStyle = "#fff";
ctx.beginPath();
for (var i=0; i<RAYCOUNT; i++)
{
// rotate context
ctx.rotate(TWOPI / RAYCOUNT);
ctx.moveTo(0, 0);
ctx.lineTo(-15, len);
ctx.lineTo(15, len);
}
ctx.closePath();
ctx.fill();
ctx.restore();
rotationOffset += 0.005; // apply user interaction to rotation
for (var i=0, objs=k3dmain.objects; i<objs.length; i++)
{
objs[i].ophi += targetRotationX;
} if (targetRotationX > -0.5) targetRotationX -= 0.05;
else if (targetRotationX < -0.55) targetRotationX += 0.05;
if (targetRotationX > -0.55 && targetRotationX < -0.5) targetRotationX = -0.5;
}; // start demo loop
k3dmain.paused = true;
setInterval(function(){k3dmain.tick()}, 1000/60);
}
这部分代码是整个动画的初始化代码，其中我们利用了k3d的脚本库，所以你需要在项目中引用它，关于k3d，你可以在最后的源代码中找到它。
<script src="k3d-min.js"></script>
下面是一些鼠标事件，你可以拖动鼠标来让其旋转，具体代码如下：
function onDocumentMouseDown( event ) {
event.preventDefault();
document.addEventListener('mousemove', onDocumentMouseMove, false);
document.addEventListener('mouseup', onDocumentMouseUp, false);
document.addEventListener('mouseout', onDocumentMouseOut, false);
mouseXOnMouseDown = event.clientX - windowHalfX;
targetRotationOnMouseDownX = targetRotationX;
mouseYOnMouseDown = event.clientY - windowHalfY;
targetRotationOnMouseDownY = targetRotationY;
}
function onDocumentMouseMove( event )
{
mouseX = event.clientX - windowHalfX;
targetRotationX = targetRotationOnMouseDownX + (mouseX - mouseXOnMouseDown) * 0.02;
mouseY = event.clientY - windowHalfY;
targetRotationY = targetRotationOnMouseDownY + (mouseY - mouseYOnMouseDown) * 0.02;
}
function onDocumentMouseUp( event )
{
document.removeEventListener('mousemove', onDocumentMouseMove, false);
document.removeEventListener('mouseup', onDocumentMouseUp, false);
document.removeEventListener('mouseout', onDocumentMouseOut, false);
}
function onDocumentMouseOut( event )
{
document.removeEventListener('mousemove', onDocumentMouseMove, false);
document.removeEventListener('mouseup', onDocumentMouseUp, false);
document.removeEventListener('mouseout', onDocumentMouseOut, false);
}
function onDocumentTouchStart( event )
{
if (event.touches.length == 1)
{
event.preventDefault();
mouseXOnMouseDown = event.touches[0].pageX - windowHalfX;
targetRotationOnMouseDownX = targetRotationX;
mouseYOnMouseDown = event.touches[0].pageY - windowHalfY;
targetRotationOnMouseDownY = targetRotationY;
}
}
好了，一个简单的3D动画实现起来还是有点复杂的，你可以下载源代码来研究学习。源码下载>>