Physics/Graphics Components
- by Brett Powell
I have spent the last 48 hours reading up on Object Component systems, and feel I am ready enough to start implementing it. I got the base Object and Component classes created, but now that I need to start creating the actual components I am a bit confused. When I think of them in terms of HealthComponent or something that would basically just be a property, it makes perfect sense. When it is something more general as a Physics/Graphics component, I get a bit confused.
My Object class looks like this so far (If you notice any changes I should make please let me know, still new to this)...
typedef unsigned int ID;
class GameObject
{
public:
GameObject(ID id, Ogre::String name = "");
~GameObject();
ID &getID();
Ogre::String &getName();
virtual void update() = 0;
// Component Functions
void addComponent(Component *component);
void removeComponent(Ogre::String familyName);
template<typename T>
T* getComponent(Ogre::String familyName)
{
return dynamic_cast<T*>(m_components[familyName]);
}
protected:
// Properties
ID m_ID;
Ogre::String m_Name;
float m_flVelocity;
Ogre::Vector3 m_vecPosition;
// Components
std::map<std::string,Component*> m_components;
std::map<std::string,Component*>::iterator m_componentItr;
};
Now the problem I am running into is what would the general population put into Components such as Physics/Graphics? For Ogre (my rendering engine) the visible Objects will consist of multiple Ogre::SceneNode (possibly multiple) to attach it to the scene, Ogre::Entity (possibly multiple) to show the visible meshes, and so on. Would it be best to just add multiple GraphicComponent's to the Object and let each GraphicComponent handle one SceneNode/Entity or is the idea to have one of each Component needed?
For Physics I am even more confused. I suppose maybe creating a RigidBody and keeping track of mass/interia/etc. would make sense. But I am having trouble thinking of how to actually putting specifics into a Component.
Once I get a couple of these "Required" components done, I think it will make a lot more sense. As of right now though I am still a bit stumped.
