Best way to organize entities in a game?

Question

Let\'s say I\'m creating an OpenGL game in C++ that will have many objects created (enemies, player characters, items, etc.). I\'m wondering the best way to organize these since

Answer 1

I'm not sure I fully understand the question but I think you are wanting to create a collection of polymorphic objects. When accessing a polymorphic object, you must always refer to it by a pointer or a reference.

Here is an example. First you need to set up a base class to derive your objects from:

class BaseObject
{
public:
    virtual void Render() = 0;
};

Then create the array of pointers. I use an STL set because that makes it easy to add and remove members at random:

#include 

typedef std::set GAMEOBJECTS;
GAMEOBJECTS g_gameObjects;

To add an object, create a derived class and instantiate it:

class Enemy : public BaseObject
{
public:
    Enemy() { }
    virtual void Render()
    {
      // Rendering code goes here...
    }
};

g_gameObjects.insert(new Enemy());

Then to access objects, just iterate through them:

for(GAMEOBJECTS::iterator it = g_gameObjects.begin();
    it != g_gameObjects.end();
    it++)
{
    (*it)->Render();
}

To create different types of object, just derive more classes from class BaseObject. Don't forget to delete the objects when you remove them from the collection.