Cocos2D-Android-1之源码详解：5.Box2dTest

package org.cocos2d.tests;

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import java.util.Iterator;

import org.cocos2d.actions.UpdateCallback;

import org.cocos2d.config.ccMacros;

import org.cocos2d.events.CCTouchDispatcher;

import org.cocos2d.layers.CCLayer;

import org.cocos2d.layers.CCScene;

import org.cocos2d.nodes.CCDirector;

import org.cocos2d.nodes.CCLabel;

import org.cocos2d.nodes.CCSprite;

import org.cocos2d.nodes.CCSpriteSheet;

import org.cocos2d.opengl.CCGLSurfaceView;

import org.cocos2d.types.CGPoint;

import org.cocos2d.types.CGRect;

import org.cocos2d.types.CGSize;

import org.cocos2d.types.ccColor3B;

import android.app.Activity;

import android.os.Bundle;

import android.view.MotionEvent;

import android.view.Window;

import android.view.WindowManager;

import com.badlogic.gdx.math.Vector2;

import com.badlogic.gdx.physics.box2d.Body;

import com.badlogic.gdx.physics.box2d.BodyDef;

import com.badlogic.gdx.physics.box2d.BodyDef.BodyType;

import com.badlogic.gdx.physics.box2d.EdgeShape;

import com.badlogic.gdx.physics.box2d.FixtureDef;

import com.badlogic.gdx.physics.box2d.PolygonShape;

import com.badlogic.gdx.physics.box2d.World;

/** 

 * A test that demonstrates basic JBox2D integration by using AtlasSprites connected to physics bodies.

 *

 *

 * This implementation is based on the original Box2DTest (from cocos2d-iphone) but using the JBox2D

 * library and adjusting for differences with the new API as well as some differences in sensitivity

 * (and such) that were observed when testing on the Android platform.

 * 

 * @author Ray Cardillo

 */

// Box2dTest, there is a downloadable demo here:

//   http://code.google.com/p/cocos2d-android-1/downloads/detail?name=cocos2d%20%20and%20jbox2d.3gp&can=2&q=#makechanges

//

public class Box2dTest extends Activity {//物理盒子系统

    // private static final String LOG_TAG = JBox2DTest.class.getSimpleName();

static {

        System.loadLibrary("gdx");//加载一个gdx库

}

    private CCGLSurfaceView mGLSurfaceView;//创建一个view

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);//无标题

        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

                WindowManager.LayoutParams.FLAG_FULLSCREEN);//全屏

getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON, 

WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);//不黑屏

mGLSurfaceView = new CCGLSurfaceView(this);//生成view，并关联上下文到导演

CCDirector director = CCDirector.sharedDirector();//生成得到导演（唯一）

director.attachInView(mGLSurfaceView);//把view交给导演的list

director.setDeviceOrientation(CCDirector.kCCDeviceOrientationLandscapeLeft);//横屏

setContentView(mGLSurfaceView);//把view映射刀屏幕

        // show FPS

        CCDirector.sharedDirector().setDisplayFPS(true);//显示帧频率

        // frames per second

        CCDirector.sharedDirector().setAnimationInterval(1.0f / 60.0f);//帧速

        CCScene scene = CCScene.node();//得到一个场景

        scene.addChild(new Box2DTestLayer());//把一个box的图层添加到场景里

        // Make the Scene active

        CCDirector.sharedDirector().runWithScene(scene);//让导演运行这个场景，运行到刚才的view中

    }

    @Override

    public void onStart() {//开始方法

        super.onStart();

    }

    @Override

    public void onPause() {//暂停方法

        super.onPause();

        CCDirector.sharedDirector().onPause();

    }

    @Override

    public void onResume() {

        super.onResume();

        CCDirector.sharedDirector().onResume();

    }

    @Override

    public void onDestroy() {//销毁方法

        super.onDestroy();

        CCDirector.sharedDirector().end();

        //CCTextureCache.sharedTextureCache().removeAllTextures();

    }

    //

    // Demo of calling integrating Box2D physics engine with cocos2d sprites

    // a cocos2d example

    // http://code.google.com/p/cocos2d-iphone

    //

    // by Steve Oldmeadow

    //

    static class Box2DTestLayer extends CCLayer {//以下是这个方法生成的方法

        public static final int kTagTileMap = 1;

        public static final int kTagSpriteManager = 1;

        public static final int kTagAnimation1 = 1;

// Pixel to meters ratio. Box2D uses meters as the unit for measurement.

// This ratio defines how many pixels correspond to 1 Box2D "meter"

// Box2D is optimized for objects of 1x1 meter therefore it makes sense

// to define the ratio so that your most common object type is 1x1 meter.

        protected static final float PTM_RATIO = 32.0f;

        // Simulation space should be larger than window per Box2D recommendation.

        protected static final float BUFFER = 1.0f;

        //FPS for the PhysicsWorld to sync to

        protected static final float FPS = (float)CCDirector.sharedDirector().getAnimationInterval();//得到整个动画的帧频率

        private static float rdelta = 0;

        protected final World bxWorld;//生成一个世界的引用..

        public Box2DTestLayer() {//构造方法

        super();

            this.setIsTouchEnabled(true);//可以点击

        this.setIsAccelerometerEnabled(true);//启用设置加速，加速控制器可以启动

        CGSize s = CCDirector.sharedDirector().winSize();//得到屏幕的大小引用

      // Define the gravity vector.

        Vector2 gravity = new Vector2(9.8f, -9.8f);//定义一个二维向量

        float scaledWidth = s.width/PTM_RATIO;//缩放宽

            float scaledHeight = s.height/PTM_RATIO;//缩放高

//        Vector2 lower = new Vector2(-BUFFER, -BUFFER);//更小

//        Vector2 upper = new Vector2(scaledWidth+BUFFER, scaledHeight+BUFFER);//更大

        bxWorld = new World(gravity, true);//新建并设置这个世界的重力向量

        bxWorld.setContinuousPhysics(true);//连续物理可用

    // Define the ground body.

            BodyDef bxGroundBodyDef = new BodyDef();//定义地面身体

            bxGroundBodyDef.position.set(0.0f, 0.0f);//身体的位置

    // Call the body factory which allocates memory for the ground body

    // from a pool and creates the ground box shape (also from a pool).

    // The body is also added to the world.

            Body groundBody = bxWorld.createBody(bxGroundBodyDef);//将身体添加到世界

         // Define the ground box shape.

            EdgeShape groundBox = new EdgeShape();//定义一个形状

            Vector2 bottomLeft = new Vector2(0f,0f);//定义4个2维向量

            Vector2 topLeft = new Vector2(0f,scaledHeight);

            Vector2 topRight = new Vector2(scaledWidth,scaledHeight);

            Vector2 bottomRight = new Vector2(scaledWidth,0f);

    // bottom

    groundBox.set( bottomLeft, bottomRight );//设置一条线

    groundBody.createFixture(groundBox,0);//把这条线作为物理盒子的边界

    // top

    groundBox.set( topLeft, topRight );//同理

    groundBody.createFixture(groundBox,0);

    // left

    groundBox.set( topLeft, bottomLeft );

    groundBody.createFixture(groundBox,0);

    // right

    groundBox.set( topRight, bottomRight );

    groundBody.createFixture(groundBox,0);

            //Set up sprite

             CCSpriteSheet mgr = CCSpriteSheet.spriteSheet("blocks.png", 150);

//建立一个图像表单，用来拆分出小块

            addChild(mgr, 0, kTagSpriteManager);//表单添加进去，顺序0，把标签号定为1

            addNewSpriteWithCoords(CGPoint.ccp(s.width / 2.0f, s.height / 2.0f));

            //上面是一个方法下面解释

            CCLabel label = CCLabel.makeLabel("Tap screen", "DroidSans", 32);//创建一个标记

            label.setPosition(CGPoint.make(s.width / 2f, s.height - 50f));//设置坐标

            label.setColor(new ccColor3B(0, 0, 255));//设置颜色

            addChild(label);

        }

        private UpdateCallback tickCallback = new UpdateCallback() {//创建一个时间返回

@Override

public void update(float d) {//时间更新

tick(d);

}

};

@Override

public void onEnter() {

super.onEnter();

// start ticking (for physics simulation)

schedule(tickCallback);

}

@Override

public void onExit() {

super.onExit();

// stop ticking (for physics simulation)

unschedule(tickCallback);

}

private void addNewSpriteWithCoords(CGPoint pos) {

      CCSpriteSheet sheet = (CCSpriteSheet) getChildByTag(kTagSpriteManager);//得到一个表格

    //We have a 64x64 sprite sheet with 4 different 32x32 p_w_picpaths.  The following code is

    //just randomly picking one of the p_w_picpaths

    int idx = (ccMacros.CCRANDOM_0_1() > .5 ? 0:1);//定义一个随机数。得到1/0

    int idy = (ccMacros.CCRANDOM_0_1() > .5 ? 0:1);

//     CCSprite sprite = CCSprite.sprite("blocks.png", CGRect.make(32 * idx,32 * idy,32,32));//生成一个精灵。用那个图片，截取公式位置的图像

//     this.addChild(sprite);//添加精灵

    CCSprite sprite = CCSprite.sprite(sheet, CGRect.make(32 * idx,32 * idy,32,32));//生成精灵，用刚才的那个图集，截取某块

    sheet.addChild(sprite);//添加子类

    sprite.setPosition(pos);  //设置点  

    // Define the dynamic body.

    //Set up a 1m squared box in the physics world

    BodyDef bodyDef = new BodyDef();//新建一个刚体

    bodyDef.type = BodyType.DynamicBody;//设置为类型3动态刚体

    bodyDef.position.set(pos.x/PTM_RATIO, pos.y/PTM_RATIO);//设置身体位置

    // Define another box shape for our dynamic body.

    PolygonShape dynamicBox = new PolygonShape();//新建多边形

    dynamicBox.setAsBox(.5f, .5f);//These are mid points for our 1m box

//作为一个盒子时的顶点0.5,0.5

//     dynamicBox.density = 1.0f;

//            dynamicBox.friction = 0.3f;

        synchronized (bxWorld) {//线程锁

        // Define the dynamic body fixture and set mass so it's dynamic.

        Body body = bxWorld.createBody(bodyDef);//在世界内创建这个刚体

        body.setUserData(sprite);//使用这个数据精灵

        FixtureDef fixtureDef = new FixtureDef();//固定的东西

        fixtureDef.shape = dynamicBox;

        fixtureDef.density = 1.0f;//密度

        fixtureDef.friction = 0.3f;//摩擦系数

        body.createFixture(fixtureDef);//把这些固定参数给这个物体

        }        

        }

        public synchronized void tick(float delta) {//时间类

        if ((rdelta += delta) < FPS) return;//计算得不用快过帧..

        // It is recommended that a fixed time step is used with Box2D for stability

        // of the simulation, however, we are using a variable time step here.

        // You need to make an informed choice, the following URL is useful

        // http://gafferongames.com/game-physics/fix-your-timestep/

        // Instruct the world to perform a simulation step. It is

        // generally best to keep the time step and iterations fixed.

        synchronized (bxWorld) {

        bxWorld.step(FPS, 8, 1);//计算的速度

        }

        rdelta = 0;//累计时间

        // Iterate over the bodies in the physics world

        Iterator it = bxWorld.getBodies();//新建迭代器得到世界的刚体集合

        while(it.hasNext()) {

        Body b = it.next();//得到刚体

        Object userData = b.getUserData();//刚体的数据

        if (userData != null && userData instanceof CCSprite) {

//如果数据不为空，且是个精灵的实例而

        //Synchronize the Sprites position and rotation with the corresponding body

        final CCSprite sprite = (CCSprite)userData;//得到这个图像

        final Vector2 pos = b.getPosition();//得到这个刚体的点

        sprite.setPosition(pos.x * PTM_RATIO, pos.y * PTM_RATIO);

//设置点

        sprite.setRotation(-1.0f * ccMacros.CC_RADIANS_TO_DEGREES(b.getAngle()));//设置弧度

        }

        }

        }

        @Override

        public boolean ccTouchesBegan(MotionEvent event) {//触屏事件

            CGPoint location = CCDirector.sharedDirector()

            .convertToGL(CGPoint.make(event.getX(), event.getY()));//得到点

            addNewSpriteWithCoords(location);//添加一个物品在那个点

            return CCTouchDispatcher.kEventHandled;//返回数据

        }

        static float prevX=0, prevY=0;

        Vector2 gravity = new Vector2();//定义2维数组

@Override

   public void ccAccelerometerChanged(float accelX, float accelY, float accelZ) {//当加速传感器有感觉了

//#define kFilterFactor 0.05f

float kFilterFactor  = 1.0f;// don't use filter. the code is here just as an example

float accX = (float) accelX * kFilterFactor + (1- kFilterFactor)* prevX;//x方向

float accY = (float) accelY * kFilterFactor + (1- kFilterFactor)* prevY;//y方向

prevX = accX;

prevY = accY;

// no filtering being done in this demo (just magnify the gravity a bit)

gravity.set( accY * 9.8f, accX * -9.8f );//得到重力的向量

bxWorld.setGravity( gravity ); //给世界设置重力向量

}

    }

}