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Added support for occluders occluding other occluders, which helps reduce

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the number of occluder that will be used in cull traversal to only the
ones that will be effective. Note. Holes in occluders arn't handled in
this occluder occlusion test, will implement this later.
This commit is contained in:
Robert Osfield
2002-06-18 22:35:48 +00:00
parent aa58ecae2f
commit 5e85cd59ab
6 changed files with 99 additions and 31 deletions
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41
src/osg/CollectOccludersVisitor.cpp
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@@ -5,6 +5,8 @@
#include <osg/OccluderNode>
#include <osg/Projection>
#include <algorithm>
using namespace osg;
CollectOccludersVisitor::CollectOccludersVisitor()
@@ -137,7 +139,7 @@ void CollectOccludersVisitor::apply(osg::OccluderNode& node)
{
// need to test occluder against view frustum.
//std::cout << " adding in Occluder"<<std::endl;
_occluderList.push_back(svo);
_occluderSet.insert(svo);
}
else
{
@@ -155,4 +157,41 @@ void CollectOccludersVisitor::apply(osg::OccluderNode& node)
popOccludersCurrentMask(_nodePath);
}
void CollectOccludersVisitor::removeOccludedOccluders()
{
if (_occluderSet.empty()) return;
ShadowVolumeOccluderSet::iterator occludeeItr=_occluderSet.begin();
// skip the first element as this can't be occluded by anything else.
occludeeItr++;
// step through the rest of the occluders, remove occluders which are themselves occluded.
for(;
occludeeItr!=_occluderSet.end();
++occludeeItr)
{
// search for any occluders that occlude the current occluder,
// we only need to test any occluder near the front of the set since
// you can't be occluder by something smaller than you.
const ShadowVolumeOccluder& occludee = *occludeeItr;
for(ShadowVolumeOccluderSet::iterator occluderItr=_occluderSet.begin();
occluderItr!=occludeeItr;
++occluderItr)
{
// cast away constness of the std::set element since ShadowVolumeOccluder::contains() is non const,
// and the std::set is a const, just for the invariance of the operator <!! Ahhhhh. oh well the below
// should be robust since contains won't change the getVolume which is used by the operator <. Honest, :-)
ShadowVolumeOccluder* occluder = const_cast<ShadowVolumeOccluder*>(&(*occluderItr));
if (occluder->contains(occludee._occluderVolume.getReferenceVertexList()))
{
// erase occluder from set.
// take a copy of the iterator then rewind it one element so to prevent invalidating the occludeeItr.
ShadowVolumeOccluderSet::iterator eraseItr = occludeeItr--;
_occluderSet.erase(eraseItr);
break;
}
}
}
}