Alan Ott wrote on Tuesday, April 28, 2009 10:34 AM:
Thanks for the info. From this, it seems like I can get a handle to
the newly
loaded node before it gets added to the main tree. The only thing now
is that
once I've got a handle to this node, I don't really know _what_ the
node is
supposed to be (is it a terrain tile, a moving model? etc.).
ReadFileCallback::readNode() gives me the ReaderWriterOptions, and it
seems
like I could make a new option string telling me how to post-process
this
model load, but I can't see how in PagedLOD to set
ReaderWriterOptions.
Unfortunately, at the moment PagedLOD doesn't have a way to specify
ReaderWriterOptions (and adding that ability is a little complicated,
because we don't want a circular dependency between osg and osgDB).
One thing you can do is subclass PagedLOD in your app to add the ability
to specify a ReaderWriterOptions when it calls readNode().
PagedLOD has the setDatabaseRequest() function, which based on another
mailing list post, looks like it is to be used as a "user data"
pointer. The
problem here is that I don't know how to get this object from inside
the
ReadFileCallback.
This makes me think you're using an older version of OSG? The latest OSG
in svn only has getDatabaseRequest() (which you can use to set the
DatabaseRequest). In any case, the database request isn't really for
"user data"; it is specifically for osgDB::DatabasePager use.
Robert Osfield wrote:
As Bryan wrote, what you need is to write a custom
osgDB::Registry::ReadFileCallback that will intercept all DB
calls,
you then leave it up to Registry itself to the do the reading
from the
plugin, but then you process the loaded data before passing the
end
result back from the callback. Have a look at the
ReadFileCallback
implementation and study the default implementations, this
should give
you a clue how to put it together.
On Mon, Apr 27, 2009 at 10:40 PM, Alan Ott <a...@signal11.us>
<mailto:a...@signal11.us> wrote:
I'm using PagedLOD to load terrain tiles off disk. The
problem I have is
that before I want the tile to actually render, I want
to do a setup of the
tile (to look up certain control nodes and set switches
according to the
current state of the system (eg: day/night mode, etc)).
So on my own update(), I check to see if each PagedLOD
has just loaded, and
if it has, I run the initialization on it. The problem
is, when a tile gets
loaded, it is rendered for one frame _before_ I can do
my initialization on
it. So for one frame, it is drawn wrong, then the next
frame, it is drawn
right.
I thought I might be able to get around this by setting
the Node Mask to 0
until it was initialized, but that seems to just keep
the tiles from getting
loaded entirely (because the update traverser isn't
getting into the
PagedLOD either).
Do any of you have any ideas of what I could try to do
to get around this?
Is there some value of the NodeMask that I could use to
enable update but
not draw? Such a value did not seem to be documented in
the API.
