Hi Chris,
These PagedLOD holes were the main reason I have given up on writing a
simple Metaflight loader (I emailed the list about that this morning).
You're right; subclassing PagedLOD was very difficult.  I was trying
to use a NodeVisitor to seek out PagedLODs with unloaded data, and
it's just too much of a headache.

For now it looks like I'll have to give up on a simple MetaFlight
loader and complicate the code by adding my own paging utility (maybe
based on NodeVisitor::DatabaseRequestHandler, or maybe not.  I haven't
decided yet).  If you have any other thoughts on the subject I'd be
glad to hear them.
--
Terry Welsh - mogumbo 'at' gmail.com
www.reallyslick.com  |  www.mogumbo.com


Message: 46
Date: Mon, 08 Jan 2007 11:25:13 -0700
From: Chris Hanson <[EMAIL PROTECTED]>
Subject: Re: [osg-users] PageLOD holes
To: osg users <[email protected]>
Message-ID: <[EMAIL PROTECTED]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Terry Welsh wrote:
> The only thing I can think of now is to subclass PagedLOD and try to
> give them knowledge of when their parents and/or children have loaded
> their tiles.  I can't think of a very elegant way to do this, though,
> and it would probably have problems with DatabasePager.

   Subclassing PagedLOD will be very difficult, I expect. I think most of 
DatabasePager is
only aware of the parent PagedLOD class. I think the only way to do this would 
be to
extend the base PagedLOD class to have additional virtual-method hooks that can 
be
overridden in a derived class or as callbacks on particular instance.

   It sounds like your design would have all your PagedLOD instances behaving
consistently, so configuring things to support this behaviour in a derived 
class is
probably the way to do it.

   I can advise a little on this, but I'm in a non-OSG development phase right 
now, and my
OSG tree is not at all current to CVS and I'm not checking the list very often.

--
      Chris 'Xenon' Hanson | Xenon @ 3D Nature | http://www.3DNature.com/
                Highway Design: http://highway-design.net/
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