Cocos2d-x Polymorphism - c++

Question

I am currently working on subdividing my cocos2dx-cpp game into a more modular system. I want to have one layer to receive all Touches and direct those touches to the affected CCSprite-derived objects.
The derived objects are stored in a CCArray in an EntityManager (which helps me create and manage the entities).
The problem I am facing is that I can't seem to access the correct virtual method for my derived CCSprites.
Here is the code from my Touch layer (called TouchManager):
void TouchManager::ccTouchesBegan( cocos2d::CCSet* pTouches , cocos2d::CCEvent* pEvents )
{
cocos2d::CCSetIterator i;
cocos2d::CCTouch* touch;
cocos2d::CCPoint tap;
auto entities = EntityManager::sharedManager()->getVisibleEntities();
for ( i = pTouches->begin() ; i != pTouches->end() ; ++i )
{
touch = ( cocos2d::CCTouch* ) ( *i );
if ( touch )
{
tap = touch->getLocation();
for ( unsigned int entityIndex = 0 ; entityIndex < entities->size() ; ++entityIndex )
{
auto entity = entities->at( entityIndex );
// OLD: auto entity = ( TouchableSprite* )entities->objectAtIndex( entityIndex );
if ( entity->boundingBox().containsPoint( tap ) )
{
entity->setTouch( touch );
entity->onTouch( tap );
}
}
}
}
}
I want to have the TouchManager detect the entity that has been touched, and send the Touch to it. But there is my problem: it detects the touch but doesn't send it further. Either I have a crash or nothing at all.
I have created a Touchable interface class:
#include "cocos2d.h"
class Touchable : public cocos2d::CCSprite
{
cocos2d::CCTouch* m_pTouch;
public:
virtual cocos2d::CCTouch* getTouch();
virtual void setTouch( cocos2d::CCTouch* touch );
virtual void onTouch( cocos2d::CCPoint location ) = 0 ;
virtual void onMoved( cocos2d::CCPoint location ) = 0 ;
virtual void onEnded( cocos2d::CCPoint location ) = 0 ;
};
as well as a TouchableSprite base class:
#include "cocos2d.h"
#include "Touchable.h"
class TouchableSprite : public Touchable
{
//cocos2d::CCTouch* m_pTouch;
public:
//virtual cocos2d::CCTouch* getTouch();
//virtual void setTouch( cocos2d::CCTouch* touch );
static TouchableSprite* createSpriteWithFile( const char* fileName );
void resetPosition( float positionX = 0.0f , float positionY = 0.0f );
virtual void onTouch( cocos2d::CCPoint location ) ;
virtual void onMoved( cocos2d::CCPoint location ) ;
virtual void onEnded( cocos2d::CCPoint location ) ;
TouchableSprite(void);
~TouchableSprite(void);
};
with simple implementation (TouchableSprite.cpp):
#include "TouchableSprite.h"
TouchableSprite::TouchableSprite(void)
{
}
TouchableSprite::~TouchableSprite(void)
{
}
TouchableSprite* TouchableSprite::createSpriteWithFile( const char* fileName )
{
auto sprite = new TouchableSprite();
if ( sprite && sprite->initWithFile( fileName ) )
{
sprite->autorelease();
return ( TouchableSprite* )sprite;
}
CC_SAFE_DELETE( sprite );
// should not reach this point
return NULL;
}
void TouchableSprite::resetPosition( float positionX , float positionY )
{
this->setPosition( ccp( positionX , positionY ) );
}
void TouchableSprite::onTouch( cocos2d::CCPoint location )
{
}
void TouchableSprite::onMoved( cocos2d::CCPoint location )
{
}
void TouchableSprite::onEnded( cocos2d::CCPoint location )
{
}
And finally, here's my derived class (in this case, ControlStickSprite):
#include "cocos2d.h"
#include "RenderSystem.h"
#include "EntityManager.h"
#include "TouchableSprite.h"
class ControlStickSprite : public TouchableSprite
{
ControlStickSprite* m_sprite;
public:
cocos2d::CCNode* create( cocos2d::CCNode* parent );
void onTouch( cocos2d::CCPoint location ) ;
void onMoved( cocos2d::CCPoint location ) ;
void onEnded( cocos2d::CCPoint location ) ;
ControlStickSprite(void);
~ControlStickSprite(void);
};
with simple implementation for testing (skipping the Create part because it works):
void ControlStickSprite::onTouch( cocos2d::CCPoint location )
{
this->setScale( 0.5f );
}
void ControlStickSprite::onMoved( cocos2d::CCPoint location )
{
this->setPosition( location );
}
void ControlStickSprite::onEnded( cocos2d::CCPoint location )
{
}
Please help me get this working! I'm not too familiar with the usage of virtual methods so maybe I missed something there. I'm also relatively new to C++ and cocos2dx programming.
Thanks in advance!
EDIT: Thanks to #musikov for fixing the first part! I updated the above code to reflect the changes. I replaced the CCArray with std::vector< TouchableSprite* > to eliminate the need for casting the from CCObject*.
Now, I am facing the problem that when touched, ControlStickSprite::onTouch() is never chosen; it's always TouchableSprite::onTouch().
Added ControlStickSprite::create and EntityManager::createEntity methods:
My ControlStickSprite::create() method is like this:
ControlStickSprite* ControlStickSprite::create( cocos2d::CCNode* parent )
{
// auto parent = this->getParent();
auto entityType = "control-stick";
auto scale = 6.0f;
auto rotation = 0.0f;
auto positionX = RenderSystem::sharedRenderSystem()->getScreenWidth() * 0.9f ;
auto positionY = RenderSystem::sharedRenderSystem()->getScreenHeight() * 0.25f ;
auto sprite = EntityManager::sharedManager()->createEntity(
parent ,
entityType ,
scale ,
rotation ,
positionX ,
positionY
);
m_sprite = ( ControlStickSprite* )sprite;
return m_sprite;
}
which makes use of my EntityManager:
cocos2d::CCNode* EntityManager::createEntity( cocos2d::CCNode* parent , const char* entityType , float scale , float rotation , float positionX , float positionY )
{
std::string extension = ".png";
std::string fileName = entityType + extension;
auto entity = TouchableSprite::createSpriteWithFile( fileName.c_str() );
entity->setRotation( rotation );
entity->setScale( scale );
entity->resetPosition( positionX , positionY );
parent->addChild( entity );
// add to VisibleEntities vector
this->addEntity( entity , true );
return entity;
}
The only thing I can think of is that the createEntity() method creates a TouchableSprite* but returns a CCNode*, which I then cast to a ControlStickSprite*. Am I doing this wrong again? :)
Thanks for all your help!

Answer 1

You have wrong create method implementation in TouchableSprite and maybe in ControlStickSprite too.
Your create method creates Sprite instance and casts it to TouchableSprite class. It's completely wrong :)
That's why your program crashed on setTouch method call - because your calling this method in Sprite instance.
You need to change your create method:
TouchableSprite* TouchableSprite::createSpriteWithFile( const char* fileName )
{
auto sprite = new TouchableSprite();
if ( sprite && sprite->initWithFile( fileName ) )
{
sprite->autorelease();
return sprite;
}
CC_SAFE_DELETE( sprite );
// should not reach this point
return NULL;
}
Added controlstick implementation
ControlStickSprite.h
#include "cocos2d.h"
#include "RenderSystem.h"
#include "EntityManager.h"
#include "TouchableSprite.h"
class ControlStickSprite : public TouchableSprite
{
public:
static ControlStickSprite* create();
bool init();
void onTouch( cocos2d::CCPoint location ) ;
void onMoved( cocos2d::CCPoint location ) ;
void onEnded( cocos2d::CCPoint location ) ;
ControlStickSprite(void);
~ControlStickSprite(void);
};
ControlStickSprite.cpp
bool ControlStickSprite::init()
{
auto entityType = "control-stick";
std::string extension = ".png";
std::string fileName = entityType + extension;
if (initWithFile( fileName.c_str() )) {
// auto parent = this->getParent();
auto scale = 6.0f;
auto rotation = 0.0f;
auto positionX = RenderSystem::sharedRenderSystem()->getScreenWidth() * 0.9f ;
auto positionY = RenderSystem::sharedRenderSystem()->getScreenHeight() * 0.25f ;
sprite->setRotation( rotation );
sprite->setScale( scale );
sprite->resetPosition( positionX , positionY );
return true;
}
return false;
}
ControlStickSprite* ControlStickSprite::create()
{
auto sprite = new ControlStickSprite();
if ( sprite && sprite->init() )
{
sprite->autorelease();
return sprite;
}
CC_SAFE_DELETE( sprite );
// should not reach this point
return NULL;
}
EntityManager:
void EntityManager::addEntity( cocos2d::CCNode* parent , TouchableSprite* entity )
{
parent->addChild( entity );
// add to VisibleEntities vector
this->addEntity( entity , true );
}
Remember to call EntityManager::addEntity(parent, entity) after ControlStickSprite::create(), if you decide to use this solution