Re: [Plib-users] Pre/Post draw callbacks on ssgBranches.

[Jon A. <jan...@on...>]

>
> > It's split into two parts, a terrain class, and a patch class. Each
> > patch is just a subset of the terrain, to facilitate frustum culling. Each
> > frame, the terrain class initializes, and then tessellates each of its
> > patches.
>
>So a 'terrain' object *contains* the 'patch' objects?
>
>Is that why you need it to be an ssgBranch-derived class?

Yes.


> >  It seems like they only get called on leafs.  So I have to activate 
> the tessellating
> > outside of the normal ssgCullAndDraw().
>
>That's kindof ugly - I agree.  But if you have derived your own class, why do
>you need to mess with callbacks?  You can draw the scene whenever you like.


Well, when I first started, I attached all the Terrain and the Patches as 
user data on a ssgBranch and ssgVtxTable, respectively.  That  was okay to 
get it up an running, but made it clunky to use.

> >  This isn't so bad, except it means no culling is done prior to 
> tessellation.
>
>Yes - I think I understand.
>
>Can I see the code?  It would be easier to discuss.

I'll post it somewhere tonight.

>Not that I know of...but those are pretty simple by comparison to your
>efforts - all you need is alternative 'cull/hot/isect' member functions
>derived from an ssgBranch node.

Okay, that's what I thought.  I probably need to study the code a bit 
more.  I wasn't sure if these were implemented as member functions, or if 
it was an external iterator running over the tree that performed these 
functions.


Thanks for the suggestions,
Jon