Re: (no subject)

[Roger H. <rog...@mi...>]

> Assuming this is all correct, the reader will be wondering: Why do 
> Dispose a Q3Object, but I can only GetReference to a Q3SharedObject? 
> It doesn't seem very parallel.  And, is it safe to call Q3SharedObject 
> on something that is not, in fact, a Q3SharedObject (and what's an 
> example of a Q3Object like that)?
>
> I don't have good answers to these questions, so I'm hoping you do!

An object knows how to dispose of itself, just like it knows how to 
submit itself or
how to make a copy of itself. We do not need separate routines to 
dispose of a box,
an ellipsoid, a polygon etc so we do not need a separate routine for 
shared and
unshared objects. Using C++ terminology you just say "delete fred" and 
the system
uses the object's virtual destructor (and any base classes virtual 
destructors in turn).

The only thing that Q3Shared_GetReference does is to increment the 
reference count.
Why It was not called something more appropriate I don't know. As an 
unshared object
does not have a reference count it is both pointless and invalid to 
call GetReference on
one. To get a reference to an unshared object you just assign its 
pointer to another
pointer, but you have to keep track (in the programmer's head) of when 
the object is
no longer needed. Actually you can do the same thing with shared 
objects, and I do,
but only in simple pieces of code where it is easy to track the 
pointers. For more
complex cases this is impossible and the small overhead of calling
Q3Shared_GetReference and Q3Object_Dispose is worth every nanosecond.

Roger.