Hello,
Q: Can I force the database pager to load a scene? ie. when I switch a
sub-graph "on" I need the data to be ready. It takes about 100 ms to completely
load and I have ~333 ms between switch nodes so I have time but need to avoid
seeing the transitions from low->mid->high resolution.
Problem Description:
I have a sequence of large images I want to play back as a movie 3 FPS movie.
It takes about 30 seconds to load a single frame directly using osgViewer
--image and there is too much data to load it all as LOD nodes. So I need some
kind of load on demand / divide and conquer approach.
I used osgDem to convert the frame into a PagedLOD model.
I created a root node that is a switch with a node for each of frames I want to
play back as a PagedLOD. ie.
Code:
for (i=0; FileName[i]; i++) {
pNode = osgDB::readNodeFile(FileName);
if (pNode) pScene->addChild(pNode,0);
}
Now in the main loop I set which node I want to see.
This loads fairly fast. ~100 ms from low->mid->high resolution data and lets me
pan/zoom into the area of interest very smoothly.
When I advance a frame the model you see the transition from low->mid->high
resolution which 'pops' badly.
I'm only going to swap nodes every 333 ms so I have plenty of time to get the
PagedLOD loaded but I need to avoid viewing them as the load up.
I'm thinking I might be able to do something like use a node traversal or
render to texture to force a load but I've never had to use either and the
examples are a little overwhelming at first glance. So before I try going down
either path I'd like to see if anyone has a suggestions.
Thank you!
Eric Heft
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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=42846#42846
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