物理引擎

bool HelloWorld::init()
{
    //////////////////////////////
    // 1. super init first
    if ( !Layer::init() )
    {
        return false;
    }
    
    Size visibleSize = Director::getInstance()->getVisibleSize();
    Vec2 origin = Director::getInstance()->getVisibleOrigin();
	//定义世界的边界
	auto body = PhysicsBody::createEdgeBox(visibleSize,PHYSICSBODY_MATERIAL_DEFAULT,5.0f);
	auto edgeNode = Node::create();
	edgeNode->setPosition(Vec2(visibleSize.width/2,visibleSize.height/2));
	edgeNode->setPhysicsBody(body);
	this->addChild(edgeNode);

	setTouchEnabled(true);
	//设置为单点触摸
	setTouchMode(Touch::DispatchMode::ONE_BY_ONE);

    return true;
}

bool HelloWorld::onTouchBegan(Touch* touch, Event* event)
{
	Vec2 location = touch->getLocation();
	addNewSpriteAtPosition(location);
	return false;
}	

void HelloWorld::addNewSpriteAtPosition(Vec2 p)
{    
    auto sp = Sprite::create("Ball.png");
	sp->setTag(1);
	
	auto body = PhysicsBody::createCircle(sp->getContentSize().width / 2);
    sp->setPhysicsBody(body);	
    sp->setPosition(p);
	this->addChild(sp);
}

效果如下：