Cocos2D-Android-1之源碼詳解：5.Box2dTest

package org.cocos2d.tests;

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.

 * <br/>

 * <br/>

 * 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 {//物理盒子系統

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

static {

        System.loadLibrary("gdx");//加載一個gdx庫

}

    private CCGLSurfaceView mGLSurfaceView;//創建一個view

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        requestWindowFeature(Window.FEATURE_NO_TITLE);//無標題

        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，并關聯上下文到導演

CCDirector director = CCDirector.sharedDirector();//生成得到導演（唯一）

director.attachInView(mGLSurfaceView);//把view交給導演的list

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

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

        // show FPS

        CCDirector.sharedDirector().setDisplayFPS(true);//顯示幀頻率

        // frames per second

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

        CCScene scene = CCScene.node();//得到一個場景

        scene.addChild(new Box2DTestLayer());//把一個box的圖層添加到場景里

        // Make the Scene active

        CCDirector.sharedDirector().runWithScene(scene);//讓導演運行這個場景，運行到剛才的view中

    }

    @Override

    public void onStart() {//開始方法

        super.onStart();

    }

    @Override

    public void onPause() {//暫停方法

        super.onPause();

        CCDirector.sharedDirector().onPause();

    }

    @Override

    public void onResume() {

        super.onResume();

        CCDirector.sharedDirector().onResume();

    }

    @Override

    public void onDestroy() {//銷毀方法

        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 {//以下是這個方法生成的方法

        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();//得到整個動畫的幀頻率

        private static float rdelta = 0;

        protected final World bxWorld;//生成一個世界的引用..

        public Box2DTestLayer() {//構造方法

        super();

            this.setIsTouchEnabled(true);//可以點擊

        this.setIsAccelerometerEnabled(true);//啟用設置加速，加速控制器可以啟動

        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);//定義一個二維向量

        float scaledWidth = s.width/PTM_RATIO;//縮放寬

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

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

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

        bxWorld = new World(gravity, true);//新建并設置這個世界的重力向量

        bxWorld.setContinuousPhysics(true);//連續物理可用

    // Define the ground body.

            BodyDef bxGroundBodyDef = new BodyDef();//定義地面身體

            bxGroundBodyDef.position.set(0.0f, 0.0f);//身體的位置

    // 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);//將身體添加到世界

         // Define the ground box shape.

            EdgeShape groundBox = new EdgeShape();//定義一個形狀

            Vector2 bottomLeft = new Vector2(0f,0f);//定義4個2維向量

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

            Vector2 topRight = new Vector2(scaledWidth,scaledHeight);

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

    // bottom

    groundBox.set( bottomLeft, bottomRight );//設置一條線

    groundBody.createFixture(groundBox,0);//把這條線作為物理盒子的邊界

    // 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);

//建立一個圖像表單，用來拆分出小塊

            addChild(mgr, 0, kTagSpriteManager);//表單添加進去，順序0，把標簽號定為1

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

            //上面是一個方法下面解釋

            CCLabel label = CCLabel.makeLabel("Tap screen", "DroidSans", 32);//創建一個標記

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

            label.setColor(new ccColor3B(0, 0, 255));//設置顏色

            addChild(label);

        }

        private UpdateCallback tickCallback = new UpdateCallback() {//創建一個時間返回

@Override

public void update(float d) {//時間更新

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);//得到一個表格

    //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);//定義一個隨機數。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));//生成一個精靈。用那個圖片，截取公式位置的圖像

//     this.addChild(sprite);//添加精靈

    CCSprite sprite = CCSprite.sprite(sheet, CGRect.make(32 * idx,32 * idy,32,32));//生成精靈，用剛才的那個圖集，截取某塊

    sheet.addChild(sprite);//添加子類

    sprite.setPosition(pos);  //設置點  

    // Define the dynamic body.

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

    BodyDef bodyDef = new BodyDef();//新建一個剛體

    bodyDef.type = BodyType.DynamicBody;//設置為類型3動態剛體

    bodyDef.position.set(pos.x/PTM_RATIO, pos.y/PTM_RATIO);//設置身體位置

    // Define another box shape for our dynamic body.

    PolygonShape dynamicBox = new PolygonShape();//新建多邊形

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

//作為一個盒子時的頂點0.5,0.5

//     dynamicBox.density = 1.0f;

//            dynamicBox.friction = 0.3f;

        synchronized (bxWorld) {//線程鎖

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

        Body body = bxWorld.createBody(bodyDef);//在世界內創建這個剛體

        body.setUserData(sprite);//使用這個數據精靈

        FixtureDef fixtureDef = new FixtureDef();//固定的東西

        fixtureDef.shape = dynamicBox;

        fixtureDef.density = 1.0f;//密度

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

        body.createFixture(fixtureDef);//把這些固定參數給這個物體

        }        

        }

        public synchronized void tick(float delta) {//時間類

        if ((rdelta += delta) < FPS) return;//計算得不用快過幀..

        // 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);//計算的速度

        }

        rdelta = 0;//累計時間

        // Iterate over the bodies in the physics world

        Iterator<Body> it = bxWorld.getBodies();//新建迭代器得到世界的剛體集合

        while(it.hasNext()) {

        Body b = it.next();//得到剛體

        Object userData = b.getUserData();//剛體的數據

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

//如果數據不為空，且是個精靈的實例而

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

        final CCSprite sprite = (CCSprite)userData;//得到這個圖像

        final Vector2 pos = b.getPosition();//得到這個剛體的點

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

//設置點

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

        }

        }

        }

        @Override

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

            CGPoint location = CCDirector.sharedDirector()

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

            addNewSpriteWithCoords(location);//添加一個物品在那個點

            return CCTouchDispatcher.kEventHandled;//返回數據

        }

        static float prevX=0, prevY=0;

        Vector2 gravity = new Vector2();//定義2維數組

@Override

   public void ccAccelerometerChanged(float accelX, float accelY, float accelZ) {//當加速傳感器有感覺了

//#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 ); //給世界設置重力向量

}

    }

}