HTML5游戏开发-Box2dWeb应用(一)-创建各种各样的刚体

本篇开始，会介绍lufylegend-1.4.0的新功能，怎样结合box2dweb创建一个物理世界以及这个物理世界里的各种刚体

准备工作

首先你需要下载html5开源库件lufylegend-1.4.0

http://blog.csdn.net/lufy_legend/article/details/7644932

box2dweb你可以到这里下载

http://code.google.com/p/box2dweb/downloads/list

准备三张图片，

分别用来创建圆形，矩形和三角刚体。

准备结束，现在开始制作。
下面是利用lufylegend.js中的LLoadManage类来读取图片

init(10,"mylegend",800,400,main); var backLayer,cLayer,wallLayer,bitmap,loadingLayer; var imglist = {}; var imgData = new Array( {name:"bird1",path:"./images/bird1.png"}, {name:"bird2",path:"./images/bird2.png"}, {name:"stage01",path:"./images/stage01.png"} ); function main(){ LGlobal.setDebug(true); backLayer = new LSprite(); addChild(backLayer); loadingLayer = new LoadingSample3(); backLayer.addChild(loadingLayer); LLoadManage.load( imgData, function(progress){ loadingLayer.setProgress(progress); }, function(result){ imglist = result; backLayer.removeChild(loadingLayer); loadingLayer = null; gameInit(); } ); }

LGlobal.setDebug(true);是开启debug模式，这样在创建刚体的时候，会将box2dweb所创建的debug刚体也一起显示出来，发布成品的时候，应该关闭debug模式。

LLoadManage类有三个参数，$list,$onupdate,$oncomplete，

$list是要读取的图片数组，$onupdate是读取中需要调用的函数，$oncomplete是读取完成时调用的函数

LoadingSample3类是lufylegend.js库件中的进度条显示功能，除了LoadingSample3类之外，还有LoadingSample1类和LoadingSample2类

在创建刚体之前，先创建上下左右四堵墙，来控制之后将要创建的刚体的移动范围。

wallLayer = new LSprite(); wallLayer.x = 400; wallLayer.y = 0; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(800,10,0); wallLayer = new LSprite(); wallLayer.x = 0; wallLayer.y = 200; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(10,400,0); wallLayer = new LSprite(); wallLayer.x = 400; wallLayer.y = 400; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(800,10,0); wallLayer = new LSprite(); wallLayer.x = 800; wallLayer.y = 200; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(10,400,0);不知道LSprite的用法的童鞋请翻看一下我之前的文章，这里不罗嗦了。

addBodyPolygon（w,h,type,density,friction,restitution）是给LSprite加上一个矩形body,参数分别是，（宽，高，静态或动态，密度，摩擦，弹力）

如果第3个参数设定body为静态，则后面的参数可以省略，这里是将四堵墙设为静态。

然后，给backLayer加上鼠标点击事件，准备在鼠标点击的时候，加入一个刚体

backLayer.addEventListener(LMouseEvent.MOUSE_UP,add);

在add方法中添加刚体，先来个最简单的，加入一个圆形刚体，加入圆形刚体代码如下

cLayer = new LSprite(); cLayer.x = 50 + Math.random()*700; cLayer.y = 50; backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["bird1"])); cLayer.addChild(bitmap); cLayer.addBodyCircle(bitmap.getWidth()*0.5,bitmap.getHeight()*0.5,bitmap.getWidth()*0.5,1,.5,.4,.5);addBodyCircle(radius,cx,cy,type,density,friction,restitution)是给LSprite加上一个圆形body，参数分别是，（半径，圆心坐标x，y，静态或动态，密度，摩擦，弹力）

好了，运行代码后，不断点击鼠标得到下面结果

测试URL

http://lufy.netne.net/lufylegend-js/lufylegend-1.4/box2d/sample01/index.html

接下来，修改add方法，除了加入圆形刚体的同时，有一定几率加入矩形刚体，如下

var rand = Math.random(); if(rand < 0.5){ cLayer = new LSprite(); cLayer.x = 50 + Math.random()*700; cLayer.y = 50; backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["bird1"])); cLayer.addChild(bitmap); cLayer.addBodyCircle(bitmap.getWidth()*0.5,bitmap.getHeight()*0.5,bitmap.getWidth()*0.5,1,.5,.4,.5); }else{ cLayer = new LSprite(); cLayer.x = 50 + Math.random()*700; cLayer.y = 50; backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["stage01"])); cLayer.addChild(bitmap); cLayer.addBodyPolygon(bitmap.getWidth(),bitmap.getHeight(),1,5,.4,.2); }

addBodyPolygon方法上面已经介绍过了，是给LSprite加入矩形刚体。

运行代码后，不断点击鼠标得到下面结果

测试URL

http://lufy.netne.net/lufylegend-js/lufylegend-1.4/box2d/sample01/index2.html

最后，是加入三角刚体，起始可以是任意多边形刚体，用到的是LSprite的addBodyVertices方法，

addBodyVertices(vertices,cx,cy,type,density,friction,restitution)是根据顶点数组来添加任意多边形刚体，参数分别为（顶点数组，中心坐标，静态或动态，密度，摩擦，弹力）

需要提的是这个方法有个小bug，就是令LSprite的坐标变为（0,0），所以需要用SetPosition方法重新给LSprite设定一下坐标，这个bug在lufylegend.js下次更新的时候会解决，本次添加三角刚体代码如下

cLayer = new LSprite(); backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["bird2"])); cLayer.addChild(bitmap); var shapeArray = [ [[0,54],[27,0],[54,54]] ]; cLayer.addBodyVertices(shapeArray,27,27,1,.5,.4,.5); cLayer.box2dBody.SetPosition(new LGlobal.box2d.b2Vec2((50 + Math.random()*700)/LGlobal.box2d.drawScale,50/LGlobal.box2d.drawScale));运行代码后，不断点击鼠标得到下面结果

测试URL

http://lufy.netne.net/lufylegend-js/lufylegend-1.4/box2d/sample01/index3.html

本篇结束，奉上最终代码，请期待下一篇教程

<!DOCTYPE html> <html> <head> <metacharset="UTF-8"> <title>test</title> <script type="text/javascript" src="../../Box2dWeb-2.1.a.3.min.js"></script> <script type="text/javascript" src="../../lufylegend-1.4.0.js"></script> </head> <body> <div id="mylegend">loading……</div> <script type="text/javascript"> init(10,"mylegend",800,400,main); var backLayer,cLayer,wallLayer,bitmap,loadingLayer; var imglist = {}; var imgData = new Array( {name:"bird1",path:"./images/bird1.png"}, {name:"bird2",path:"./images/bird2.png"}, {name:"stage01",path:"./images/stage01.png"} ); function main(){ LGlobal.setDebug(true); backLayer = new LSprite(); addChild(backLayer); loadingLayer = new LoadingSample3(); backLayer.addChild(loadingLayer); LLoadManage.load( imgData, function(progress){ loadingLayer.setProgress(progress); }, function(result){ imglist = result; backLayer.removeChild(loadingLayer); loadingLayer = null; gameInit(); } ); } function gameInit(event){ LGlobal.box2d = new LBox2d(); wallLayer = new LSprite(); wallLayer.graphics.drawRect(10,"#000000",[0, 0, 800, 400],true,"#cccc80"); wallLayer.alpha = 0.3; backLayer.addChild(wallLayer); wallLayer = new LSprite(); wallLayer.x = 400; wallLayer.y = 0; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(800,10,0); wallLayer = new LSprite(); wallLayer.x = 0; wallLayer.y = 200; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(10,400,0); wallLayer = new LSprite(); wallLayer.x = 400; wallLayer.y = 400; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(800,10,0); wallLayer = new LSprite(); wallLayer.x = 800; wallLayer.y = 200; backLayer.addChild(wallLayer); wallLayer.addBodyPolygon(10,400,0); backLayer.addEventListener(LMouseEvent.MOUSE_UP,add); } function add(){ var rand = Math.random(); if(rand < 0.33){ cLayer = new LSprite(); cLayer.x = 50 + Math.random()*700; cLayer.y = 50; backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["bird1"])); cLayer.addChild(bitmap); cLayer.addBodyCircle(bitmap.getWidth()*0.5,bitmap.getHeight()*0.5,bitmap.getWidth()*0.5,1,.5,.4,.5); }else if(rand < 0.66){ cLayer = new LSprite(); backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["bird2"])); cLayer.addChild(bitmap); var shapeArray = [ [[0,54],[27,0],[54,54]] ]; cLayer.addBodyVertices(shapeArray,27,27,1,.5,.4,.5); cLayer.box2dBody.SetPosition(new LGlobal.box2d.b2Vec2((50 + Math.random()*700)/LGlobal.box2d.drawScale,50/LGlobal.box2d.drawScale)); }else{ cLayer = new LSprite(); cLayer.x = 50 + Math.random()*700; cLayer.y = 50; backLayer.addChild(cLayer); bitmap = new LBitmap(new LBitmapData(imglist["stage01"])); cLayer.addChild(bitmap); cLayer.addBodyPolygon(bitmap.getWidth(),bitmap.getHeight(),1,5,.4,.2); } } </script> </body> </html>