FGFS-4.1/OpenSceneGraph
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From Jannik Heller, "This submission fixes a stuttering issue that may occur when occlusion query nodes are in view. The problem is that OSG retrieves the occlusion query result without first checking if it's available (GL_QUERY_RESULT_AVAILABLE). Thus, the driver has to sync with the GPU i.e. wait for all queued draw calls to complete. This is particularly bad in V-Synced situations where the driver may be using multi frame queueing techniques - coupled with the fact that OSG only runs an occlusion query every 5th frame, results in very unpleasant stuttering in some situations.

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The change I made is to check GL_QUERY_RESULT_AVAILABLE before retrieving the query, to ensure that there won't be a stall. If the query result is not available yet, we'll leave it alone and try again in the next frame.

Had to make a few more changes than I'd liked, mostly because the TestResult mechanism wasn't designed for holding on to query objects for more than one frame. As well, I'm thinking that RetrieveQueriesCallback and ClearQueriesCallback could be merged together, if we wanted to go for more refactoring. For though now my strategy is to make as little changes as possible. Let me know what you think of the patch."
This commit is contained in:
Robert Osfield
2016-03-01 10:37:41 +00:00
parent be98c884bd
commit 5d03bb9a2b
2 changed files with 59 additions and 52 deletions
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107
src/osg/OcclusionQueryNode.cpp
View File

@@ -98,7 +98,7 @@ StateSet* initOQDebugState()
struct RetrieveQueriesCallback : public osg::Camera::DrawCallback
{
typedef std::vector<osg::TestResult*> ResultsVector;
typedef std::vector<osg::ref_ptr<osg::TestResult> > ResultsVector;
ResultsVector _results;
RetrieveQueriesCallback( osg::GLExtensions* ext=NULL )
@@ -144,7 +144,7 @@ struct RetrieveQueriesCallback : public osg::Camera::DrawCallback
ResultsVector::const_iterator it = _results.begin();
while (it != _results.end())
{
osg::TestResult* tr = const_cast<osg::TestResult*>( *it );
osg::TestResult* tr = const_cast<osg::TestResult*>( (*it).get() );
if (!tr->_active || !tr->_init)
{
@@ -160,31 +160,20 @@ struct RetrieveQueriesCallback : public osg::Camera::DrawCallback
OSG_DEBUG <<
"osgOQ: RQCB: Retrieving..." << std::endl;
#ifdef FORCE_QUERY_RESULT_AVAILABLE_BEFORE_RETRIEVAL
// Should not need to do this, but is required on some platforms to
// work aroung issues in the device driver. For example, without this
// code, we've seen crashes on 64-bit Mac/Linux NVIDIA systems doing
// multithreaded, multipipe rendering (as in a CAVE).
// Tried with ATI and verified this workaround is not needed; the
// problem is specific to NVIDIA.
GLint ready( 0 );
while( !ready )
GLint ready = 0;
ext->glGetQueryObjectiv( tr->_id, GL_QUERY_RESULT_AVAILABLE, &ready );
if (ready)
{
// Apparently, must actually sleep here to avoid issues w/ NVIDIA Quadro.
OpenThreads::Thread::microSleep( 5 );
ext->glGetQueryObjectiv( tr->_id, GL_QUERY_RESULT_AVAILABLE, &ready );
};
#endif
ext->glGetQueryObjectiv( tr->_id, GL_QUERY_RESULT, &(tr->_numPixels) );
if (tr->_numPixels < 0)
OSG_WARN << "osgOQ: RQCB: " <<
"glGetQueryObjectiv returned negative value (" << tr->_numPixels << ")." << std::endl;
ext->glGetQueryObjectiv( tr->_id, GL_QUERY_RESULT, &(tr->_numPixels) );
if (tr->_numPixels < 0)
OSG_WARN << "osgOQ: RQCB: " <<
"glGetQueryObjectiv returned negative value (" << tr->_numPixels << ")." << std::endl;
// Either retrieve last frame's results, or ignore it because the
// camera is inside the view. In either case, _active is now false.
tr->_active = false;
// Either retrieve last frame's results, or ignore it because the
// camera is inside the view. In either case, _active is now false.
tr->_active = false;
}
// else: query result not available yet, try again next frame
it++;
count++;
@@ -197,7 +186,13 @@ struct RetrieveQueriesCallback : public osg::Camera::DrawCallback
void reset()
{
_results.clear();
for (ResultsVector::iterator it = _results.begin(); it != _results.end();)
{
if (!(*it)->_active || !(*it)->_init) // remove results that have already been retrieved or their query objects deleted.
it = _results.erase(it);
else
++it;
}
}
void add( osg::TestResult* tr )
@@ -269,9 +264,9 @@ QueryGeometry::reset()
ResultMap::iterator it = _results.begin();
while (it != _results.end())
{
TestResult& tr = it->second;
if (tr._init)
QueryGeometry::deleteQueryObject( tr._contextID, tr._id );
osg::ref_ptr<TestResult> tr = it->second;
if (tr->_init)
QueryGeometry::deleteQueryObject( tr->_contextID, tr->_id );
it++;
}
_results.clear();
@@ -303,10 +298,30 @@ QueryGeometry::drawImplementation( osg::RenderInfo& renderInfo ) const
}
// Get TestResult from Camera map
TestResult* tr;
osg::ref_ptr<osg::TestResult> tr;
{
OpenThreads::ScopedLock<OpenThreads::Mutex> lock( _mapMutex );
tr = &( _results[ cam ] );
tr = ( _results[ cam ] );
if (!tr.valid())
{
tr = new osg::TestResult;
_results[ cam ] = tr;
}
}
// Issue query
if (!tr->_init)
{
ext->glGenQueries( 1, &(tr->_id) );
tr->_contextID = contextID;
tr->_init = true;
}
if (tr->_active)
{
// last query hasn't been retrieved yet
return;
}
// Add TestResult to RQCB.
@@ -319,15 +334,6 @@ QueryGeometry::drawImplementation( osg::RenderInfo& renderInfo ) const
}
rqcb->add( tr );
// Issue query
if (!tr->_init)
{
ext->glGenQueries( 1, &(tr->_id) );
tr->_contextID = contextID;
tr->_init = true;
}
OSG_DEBUG <<
"osgOQ: QG: Querying for: " << _oqnName << std::endl;
@@ -358,12 +364,17 @@ QueryGeometry::drawImplementation( osg::RenderInfo& renderInfo ) const
unsigned int
QueryGeometry::getNumPixels( const osg::Camera* cam )
{
TestResult tr;
osg::ref_ptr<osg::TestResult> tr;
{
OpenThreads::ScopedLock<OpenThreads::Mutex> lock( _mapMutex );
tr = _results[ cam ];
if (!tr.valid())
{
tr = new osg::TestResult;
_results[ cam ] = tr;
}
}
return tr._numPixels;
return tr->_numPixels;
}
@@ -384,15 +395,11 @@ QueryGeometry::releaseGLObjects( osg::State* state ) const
ResultMap::iterator it = _results.begin();
while (it != _results.end())
{
TestResult& tr = it->second;
if (tr._contextID == contextID)
osg::ref_ptr<osg::TestResult> tr = it->second;
if (tr->_contextID == contextID)
{
#if 1
osg::get<QueryObjectManager>(contextID)->scheduleGLObjectForDeletion(tr._id );
#else
QueryGeometry::deleteQueryObject( contextID, tr._id );
#endif
tr._init = false;
osg::get<QueryObjectManager>(contextID)->scheduleGLObjectForDeletion(tr->_id );
tr->_init = false;
}
it++;
}