Pinball (3) 背景画像に物理構造を与える

HelloWorldScene.cpp

#include "HelloWorldScene.h"
#include "GB2ShapeCache-x.h"

USING_NS_CC;

#define PTM_RATIO 1024

CCScene* HelloWorld::scene()
{
    CCScene *scene = CCScene::create();
    HelloWorld *layer = HelloWorld::create();
    scene->addChild(layer);
    return scene;
}

bool HelloWorld::init()
{
    if ( !CCLayer::init() )
    {
        return false;
    }
    
    // シェイプデータの読込み
    gbox2d::GB2ShapeCache::sharedGB2ShapeCache()->addShapesWithFile("pinball.plist");
    
    // 物理空間の生成
    initPhysics();
    
    // 背景を追加
    createBackground();
    
    // 毎フレーム処理の開始
    scheduleUpdate();
    
    return true;
}

void HelloWorld::createBackground()
{
    CCSize winSize = CCDirector::sharedDirector()->getWinSize();
    
    CCSprite* background = CCSprite::create("background.png");
    background->setPosition(ccp(winSize.width / 2, winSize.height / 2));
    this->addChild(background);

    // 背景の物理構造
    b2BodyDef bgBodyDef;
    bgBodyDef.type = b2_staticBody;
    bgBodyDef.position.Set(background->getPositionX() / PTM_RATIO, background->getPositionY() / PTM_RATIO);
    bgBodyDef.userData = background;
    bgBody = world->CreateBody(&bgBodyDef);

    gbox2d::GB2ShapeCache* sc = gbox2d::GB2ShapeCache::sharedGB2ShapeCache();
    sc->addFixturesToBody(bgBody, "background");
    background->setAnchorPoint(sc->anchorPointForShape("background"));
}

void HelloWorld::initPhysics()
{
    b2Vec2 gravity;
    gravity.Set(0.0f, -0.8f);
    world = new b2World(gravity);
}

void HelloWorld::update(float dt)
{
    int velocityIterations = 8;
    int positionIterations = 1;

    world->Step(dt, velocityIterations, positionIterations);
}

HelloWorldScene.h

#ifndef __HELLOWORLD_SCENE_H__
#define __HELLOWORLD_SCENE_H__

#include "cocos2d.h"
#include "Box2D.h"

class HelloWorld : public cocos2d::CCLayer
{
protected:
    void createBackground();
    
    b2World* world;
    void initPhysics();
    
    b2Body* bgBody;
    
public:
    virtual bool init();
    static cocos2d::CCScene* scene();
    CREATE_FUNC(HelloWorld);
    
    void update(float dt);
};

#endif // __HELLOWORLD_SCENE_H__