【iOS-Cocos2d游戏开发之十一】使用Box2d物理系统以及在cocos2d框架添加Box2d物理系统lib包的方法

//   //  HelloWorldLayer.mm   //  Box2dProject   //   //  Created by 华明 李 on 11-9-14.   //  Himi   //   // Import the interfaces   #import "HelloWorldLayer.h"     #define PTM_RATIO 32    // enums that will be used as tags   enum {     kTagTileMap = 1,    kTagAnimation1 = 1,   };     // HelloWorldLayer implementation   @implementation HelloWorldLayer    +(CCScene ) scene   {    CCScene scene = [CCScene node];     HelloWorldLayer *layer = [HelloWorldLayer node];    [scene addChild: layer];    return scene;   }    // on "init" you need to initialize your instance   -(id) init   {     //初始化中，在屏幕上创建了物理世界，并且创建了在屏幕四周创建了刚体防止物理世界中的刚体超屏     //最后并且调用一个tick方法用于让物理世界不断的去模拟     if( (self=[super init])) {      self.isTouchEnabled = YES;      self.isAccelerometerEnabled = YES;      CGSize screenSize = [CCDirector sharedDirector].winSize;       CCLOG(@"Screen width %0.2f screen height %0.2f",screenSize.width,screenSize.height);      // Define the gravity vector.       b2Vec2 gravity;       gravity.Set(0.0f, -10.0f);       bool doSleep = true;       world = new b2World(gravity, doSleep);      world->SetContinuousPhysics(true);      // Debug Draw functions       m_debugDraw = new GLESDebugDraw( PTM_RATIO );       world->SetDebugDraw(m_debugDraw);      uint32 flags = 0;       flags += b2DebugDraw::e_shapeBit;      m_debugDraw->SetFlags(flags);        b2BodyDef groundBodyDef;       groundBodyDef.position.Set(0, 0); // bottom-left corner      b2Body groundBody = world->CreateBody(&groundBodyDef);      b2PolygonShape groundBox;              // bottom       groundBox.SetAsEdge(b2Vec2(0,0), b2Vec2(screenSize.width/PTM_RATIO,0));       groundBody->CreateFixture(&groundBox,0);            // top       groundBox.SetAsEdge(b2Vec2(0,screenSize.height/PTM_RATIO), b2Vec2(screenSize.width/PTM_RATIO,screenSize.height/PTM_RATIO));       groundBody->CreateFixture(&groundBox,0);            // left       groundBox.SetAsEdge(b2Vec2(0,screenSize.height/PTM_RATIO), b2Vec2(0,0));       groundBody->CreateFixture(&groundBox,0);            // right       groundBox.SetAsEdge(b2Vec2(screenSize.width/PTM_RATIO,screenSize.height/PTM_RATIO), b2Vec2(screenSize.width/PTM_RATIO,0));       groundBody->CreateFixture(&groundBox,0);                   CCLabelTTF label = [CCLabelTTF labelWithString:@"Himi" fontName:@"Marker Felt" fontSize:32];       [self addChild:label z:0];       label.position = ccp( screenSize.width/2, screenSize.height-50);      [self schedule: @selector(tick:)];     }     return self;   }    //Box2d调试模式，因为物理世界是看不到摸不到的，那么物理世界中的刚体其实也一样无法看到，   //但是为了便于开发调试，Box2d提供了调试类，主要作用是能将物理世界的所有刚体、关节等都利用线条框出来，   //这样便于设置你的Body与Sprite之间的位置关系 ----   -(void) draw   {     glDisable(GL_TEXTURE_2D);     glDisableClientState(GL_COLOR_ARRAY);     glDisableClientState(GL_TEXTURE_COORD_ARRAY);    world->DrawDebugData();    // restore default GL states     glEnable(GL_TEXTURE_2D);     glEnableClientState(GL_COLOR_ARRAY);     glEnableClientState(GL_TEXTURE_COORD_ARRAY);    }   //---添加一个刚体，首先需要创建刚体的皮肤，可以理解这个皮肤是刚体的属性，然后利用皮肤包装出一个刚体   -(void) addNewSpriteWithCoords:(CGPoint)p sp:(CCSprite*)sprite   {     CCLOG(@"Add sprite %0.2f x %02.f",p.x,p.y);    sprite.position = ccp( p.x, p.y);     b2BodyDef bodyDef;     bodyDef.type = b2_dynamicBody;     bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO);     //将精灵信息赋值给刚体皮肤，这样就能让精灵的运动轨迹与这个即将创建出的刚体在物理世界中的运动轨迹同步     bodyDef.userData = sprite;     b2Body body = world->CreateBody(&bodyDef);     b2PolygonShape dynamicBox;     dynamicBox.SetAsBox(.9f, .9f);    b2FixtureDef fixtureDef;     fixtureDef.shape = &dynamicBox;    fixtureDef.density = 1.0f;     fixtureDef.friction = 0.3f;     body->CreateFixture(&fixtureDef);     //给body施加一个力     b2Vec2 force = body->GetWorldVector(b2Vec2(1000.0f, 600.0f));     b2Vec2 point = body->GetWorldPoint(b2Vec2(0.4f, 0.4f));     body->ApplyForce(force, point);//----------备注1  Himi   }     //此方法中，首先是让物理世界进行物理模拟，然后不断的遍历物理世界中的刚体运动轨迹复制给对应的精灵   -(void) tick: (ccTime) dt   {        int32 velocityIterations = 8;     int32 positionIterations = 1;    world->Step(dt, velocityIterations, positionIterations);     for (b2Body b = world->GetBodyList(); b; bb = b->GetNext())     {       if (b->GetUserData() != NULL) {         //Synchronize the AtlasSprites position and rotation with the corresponding body         CCSprite *myActor = (CCSprite)b->GetUserData();         myActor.position = CGPointMake( b->GetPosition().x  PTM_RATIO, b->GetPosition().y * PTM_RATIO);         myActor.rotation = -1  CC_RADIANS_TO_DEGREES(b->GetAngle());       }      }   }   //---触屏将添加一个body和精灵，位置为玩家触屏的坐标   - (void)ccTouchesEnded:(NSSet )touches withEvent:(UIEvent *)event   {     for( UITouch touch in touches ) {       CGPoint location = [touch locationInView: [touch view]];      location = [[CCDirector sharedDirector] convertToGL: location];       CCSprite sprite =[CCSprite spriteWithFile:@"icon.png"];       [self addChild:sprite];       [self addNewSpriteWithCoords: location sp:sprite];     }   }    - (void)accelerometer:(UIAccelerometer*)accelerometer didAccelerate:(UIAcceleration)acceleration   {      static float prevX=0, prevY=0;        //#define kFilterFactor 0.05f     #define kFilterFactor 1.0f  // don't use filter. the code is here just as an example        float accelX = (float) acceleration.x  kFilterFactor + (1- kFilterFactor)*prevX;     float accelY = (float) acceleration.y  kFilterFactor + (1- kFilterFactor)prevY;     prevX = accelX;     prevY = accelY;     b2Vec2 gravity( -accelY * 10, accelX * 10);     world->SetGravity( gravity );   }     - (void) dealloc   {    delete world;     world = NULL;    delete m_debugDraw;    [super dealloc];   }   @end