Hi,
I am using osg::PagedLOD nodes in my project for large models visualization.
The model is splitted into several parts (like octree) and multiresolution tree
is made - same as VPB uses:
Code:
Group
PagedLOD
child 0 -> local tile geometry at low resolution
child 1 -> external file reference
PagedLOD
child 0 -> local tile geometry at low resolution
child 1 -> external file reference
I understand the system of unloading nodes by DatabasePager, when PagedLOD
nodes count is bigger than OSG_MAX_PAGEDLOD (I hope that unloaded pagedlod
nodes unload also corresponding data on GPU - when using VBO)
The system works fine, but the problem is in good PagedLOD::setRangeMode and
PagedLOD::setRange (between lower res. geode and external reference) data
setting. Since my model is not terrain, definition of setRange value is
crucial. I use PIXEL_SIZE_ON_SCREEN metrics and by low setRange number the high
resolution files are requested, high number of Geometries is loaded and openGL
out-of-memory occurs and no new nodes are loaded. The setRange number depends
on graphical window size, GPU memory, so it should be calculated somehow - to
get the best performance from hardware.
Does anyone have tip how to dynamically adjust setRange values? Or is any
better technique with different metrics?
I have an idea to adjust setRange (or change LODScale) when an out-of-memory
openGL error occurs. Then I would change the setRange value (it is same for all
pagedLOD nodes), free the GPU memory and load again.
What do you think about this idea?
How do I free occupied GPU memory? Is is enough to reconnect the subtree from
scene?
How do I catch openGL error?
Could culling settings help here to have smaller scene? Culling in my app is
set to OSG default.
Many thanks in advance,
Tomas
------------------
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http://forum.openscenegraph.org/viewtopic.php?p=33000#33000
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