Re: Dreams Eternal Entity System (was Re: [CsMain] Some progress with Dreams Eternal and some help requests)

[Thomas H. <th...@gm...>]

From: "Jorrit Tyberghein" <Jor...@uz...>
> Ed Page wrote:
>
> > The system I developed is where entities are classes that sit almost
right on CS and maybe simplify some things while objects are collections of
entities or objects.  I have objects like Camera, Body (combination
physics/model w/CD), Weapon, the weapon's proechtile for now, hopefully will
be expanded soon, vehicle, person, CameraPerson (a person with the camera,
aka a player, but maybe will change soon so that it is easier to attach a
camera to anything), and a almost dummy Ai Person (randomly walks and
shoots).
> > The only thing that would need to be done, I think, is to add SCF
interfaces, which is planned since story and Ai are planned to be plugins.
> >
>
> The Dreams Eternal entity system is fundamentally different. It does not
> relate at all to the CS entities. Entities in DE are more general. They
don't
> always describe visual objects like sprites.

That sounds very good.

> I make a dynamic entity system that doesn't use inheritance on the C++
side
> but uses inheritance on the Python side instead. On the C++ side entities
> are defined by attaching property classes. For example, to make an object
> movable you just attach the 'movable' property class. To make it have a
> sprite you attach the 'visual' property class for a sprite. If you want an
object
> that can hold other objects (like a box) then you attach the 'inventory'
property
> class.

Will it be possible to implement entity classes without using C++ at all?

> This system is very dynamic. You can add/delete property classes at
runtime.
> This is something that is much harder to do with a inheritance system.
>
> Check out the Dreams Eternal design document for more information about
> this if you are interested (http://dreams.sourceforge.net).

I have read this, and I really like some ideas that are described there. On
the other hand, I am missing some aspects that are in the csgame plugins (by
concept, because most of the stuff is not yet implemented).
The most important thing I am missing is inheritance (or I didn't fully
understand your concept). How can I reuse an existing class and just modify
selected parts of its implementation. Something like virtual functions in
C++.

In general, I think it would be reasonable to have a little more discussion
on that DE entity system on the CS mailing list, as there are alread two
other entity systems: Crystal Clear and csgame, and maybe there are some
ideas that could be shared. (Though I understand that there will probably be
no common code in the near future.)

Thomas