flash物理引擎应用：创建粒子

   刚刚接触这个引擎的时候，感觉很强大，在一些演示方面已经有不错的表现。只是这些都是外国一些类库，相对来讲，英语说明还是让人看得很头疼。的确很多时候，不了解整个架构的时候，只可以一点点摸索，一点点记录下来吧。

看看这个类包：com.fileitup.fisixengine.particles

在文档api里面有四种大概的粒子，按字面意思圆形粒子，导航粒子（应该不太准备），方形粒子，还有一个还是转动粒子

圆形粒子：有坐标轴，中心线的动态圆

导航粒子：用于连接刚体物体

方形粒子; 处理多边形

转动粒子：跟圆形粒子差不多，但它能转动，

尝试一下创建一个简单的粒子：当我们打开这些包的时候，正是要去试试有什么效果，大概会知道这些是什么意思。毕竟外语很难把握就得去试试。

按习惯，我们先看看第一种粒子：CircleParticle

1.它的构造函数

CircleParticle(x:Number, y:Number, rad:Number)

Creates an instance of a CircleParticle

创建一个独立的圆形粒子

 

它有很多的方法，我们尝试一些简单的看看试试能不能发生事情。

 首先导入我们想要的包

 import com.fileitup.fisixengine.core.FisixEngine;
 import com.fileitup.fisixengine.particles.CircleParticle;
 

使用flex来创建一个as 工程。名为Example

package { import com.fileitup.fisixengine.core.FisixEngine; import com.fileitup.fisixengine.particles.CircleParticle; import flash.display.MovieClip; /**In this example, a jello-type object is created and manipulated by the mouse */ [SWF(width='700',height='500',backgroundColor='0x50464b',frameRate='30')] public class Example extends MovieClip{ private var myEngine:FisixEngine public function Example (){ myEngine = new FisixEngine() myEngine.setGravity(0,1) var circle:CircleParticle=myEngine.newCircleParticle(300,30,30); //circle.bounce=0.7; myEngine.setRender(true); //tell the engine where to render to myEngine.setRenderGraphics(graphics) myEngine.startEngine(30); } } }

程序入口：

    myEngine = new FisixEngine()//创建一个物理引擎，
    myEngine.setGravity(0,1)//指定他的重力

2.创建一个圆：

var circle:CircleParticle=myEngine.newCircleParticle(300,30,30); //这一句，我猜想是为这个物理引擎创建一个单独的圆，半径为30，坐标（300，30）。

接下来，启动引擎，渲染物体，设置引擎的帧速度

myEngine.setRender(true);
       myEngine.setRenderGraphics(graphics)
            myEngine.startEngine(30);

一个简单的圆似乎已经完成了。看看效果如何:为了显示方便，我将半径放大

在我看来，能弄出这个圆是一件很让人值得高兴的事情，因为我探索之路正在开始了。后面还会更加精彩：

还可以设置碰撞墙，弹力等效果。

package { import com.fileitup.fisixengine.core.FisixEngine; import com.fileitup.fisixengine.particles.CircleParticle; import com.fileitup.fisixengine.utils.BoundingBox; import flash.display.MovieClip; /**In this example, a jello-type object is created and manipulated by the mouse */ [SWF(width='700',height='500',backgroundColor='0x50464b',frameRate='30')] public class Example2 extends MovieClip{ private var myEngine:FisixEngine public function Example2 (){ myEngine = new FisixEngine() myEngine.setGravity(0,1) myEngine.setBounds(new BoundingBox(0,0,700,500)); myEngine.boundsCollisions=true; var circle:CircleParticle=myEngine.newCircleParticle(300,30,30); circle.bounce=0.7; myEngine.setRender(true); //tell the engine where to render to myEngine.setRenderGraphics(graphics) myEngine.startEngine(30); } } }

再进化一下：可以弄出下面的效果

package { import com.fileitup.fisixengine.constraints.SpringConstraint; import com.fileitup.fisixengine.core.FisixEngine; import com.fileitup.fisixengine.core.FisixObject; import com.fileitup.fisixengine.utils.BoundingBox; import flash.display.Bitmap; import flash.display.MovieClip; import flash.events.Event; import flash.text.TextField; /**In this example, a jello-type object is created and manipulated by the mouse */ [SWF(width='700',height='500',backgroundColor='0x50464b',frameRate='30')] [Embed (source="1.jpg")] public class Example2 extends MovieClip{ private var myEngine:FisixEngine private var txtFPS:TextField public function Example2 (){ //first, create an instance of the fisixengine object myEngine = new FisixEngine() //bound all of the objects in the simulation within a box myEngine.setBounds(new BoundingBox(0,0,700,500)) //enable collisions with the bounding box myEngine.boundsCollisions=true //set the gravity to pull down at a rate of 1 pixel per second myEngine.setGravity(0,1) //create a jello cube var jello:FisixObject = myEngine.newFisixObject(); for(var i:uint=0;i<12;i++) jello.newCircleParticle(250+100*Math.cos(i*30),200+100*Math.sin(i*30),20); SpringConstraint.constraintAll(jello,jello.particles,.9); //attach the corner of the jello to the mouse myEngine.newMouseAttacher(jello.particles[0],root,3) //turn on primitive rendering myEngine.setRender(true); //tell the engine where to render to myEngine.setRenderGraphics(graphics) addEventListener(Event.ENTER_FRAME,onEnterFrame) txtFPS = new TextField() addChild(txtFPS) } private function onEnterFrame(e:Event):void{ myEngine.mainLoop(1) txtFPS.text = int(myEngine.getRealFPS()).toString() } } }

演示效果：http://files.cnblogs.com/hero82748274/Example.swf

二、类关系：

Package	com.fileitup.fisixengine.particles
Class	public class CircleParticle
Inheritance	CircleParticle --> Particle --> CollisionObject
Subclasses	CircleParticleConveyor, Projectile, WheelParticle

 可以看出CircleParticle的类，继承了Particle，而Partilce 继承了 CollisionObject

CollisionObject 就是相当于它们的基类，从而实现了解这种层级关系。为我们实现打下一些基础