Time for action – adding GameSprite.cpp

From here on, we'll create any new classes inside Xcode, but you could do it just as easily in Eclipse if you remember to update the Make file. I'll show you how to do that later in this chapter.

  1. In Xcode, select the Classes folder and then go to File | New | File and navigate to iOS | Source select C++ File.
  2. Call it GameSprite and make sure the Also create a header file option is selected.
  3. Select the new GameSprite.h interface file and replace the code there with this: 
    #ifndef __GAMESPRITE_H__
#define __GAMESPRITE_H__
#include "cocos2d.h"
using namespace cocos2d;
class GameSprite : public Sprite {
public:
   CC_SYNTHESIZE(Vec2, _nextPosition, NextPosition);
   CC_SYNTHESIZE(Vec2, _vector, Vector);
   CC_SYNTHESIZE(Touch*, _touch, Touch);
   GameSprite();
   virtual ~GameSprite();
   static GameSprite* gameSpriteWithFile(const char*  pszFileName);
   virtual void setPosition(const Vec2& pos) override;
   float radius();
};
#endif // __GAMESPRITE_H__

What just happened?

In the interface, we declare the class to be a subclass of the public Sprite class.

Then we add three synthesized properties. In Cocos2d-x, these are macros to create getters and setters. You declare the type, the protected variable name, and the words that will be appended to the get and set methods. So in the first CC_SYNTHESIZE method, the getNextPosition and setNextPosition method will be created to deal with the Point value inside the _nextPosition protected variable.

We also add the constructor and destructor for our class, and the ubiquitous static method for instantiation. This receives as a parameter, the image filename used by the sprite. We finish off by overriding setPosition from Sprite and adding the declaration for our helper method radius.

The next step then is to implement our new class.

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