Robert,
I figured out why my case diverges from the osgviewer application. I
override osgViewer::Viewer::checkNeedToDoFrame(), member function, and
call eventTraversal() on a code path where it would otherwise not be
called. Specifically, I don't want the default behavior where a new
frame is scheduled if the camera has an update callback, or the scene
has update callbacks associated with it.
The attached patch contains a modification to
osg/applications/osgviewer/osgviewer.cpp that exposes the problem I ran
into. Notice that the checkNeedToDoFrame() implementation is exactly the
same as it exists in osgViewer::Viewer except for the 3 lines that were
removed via the #if 0 macro.
After applying the patch, I recompiled and ran:
osgviewer --run-on-demand --SingleThreaded --screen 1 spaceship.osgt
Throwing the model with the middle or right mouse button will
occasionally cause the model to disappear. Granted, it does not
reproduce every time. Right clicking and dragging horizontally seems to
be the best way to reproduce the behavior (sometimes right clicking over
and over while dragging).
I guess I need to figure out a different way to prevent frames from
being scheduled when update callbacks are present?
Thanks again,
Judson
On 5/23/2013 3:30 AM, Robert Osfield wrote:
Hi Judson,
Great detective work. The change to the frame() was done to avoid
issues with events being given times that aren't in sequence -
previously we'd get time delta's that could be negative.
Do you have an idea of how to reproduce the problem now? Once I can
reproduce it I'll be able to work out the best west to resolve the
problem.
Robert.
On 22 May 2013 22:50, Judson Weissert <[email protected]> wrote:
Robert,
I found the revision that caused the regression. Ironically, it occurred way
before the 3.1.6 release...
See r13092 associated with
http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk/src/osgViewer/Viewer.cpp
The 3.1.2 behavior returned when I reverted that revision. A notable
behavior change that I noticed is that before I reverted r13092, the
OSG_INFO<<"Reset event time from ..." line in EventQueue::takeEvents() would
trigger extremely often (e.g., while hovering over the viewer window). It
does not trigger at all after I reverted r13092.
See also the cutOffTime variable in Viewer::eventTraversal() which explains
the link to ON_DEMAND frame scheduling.
Do you happen to know the original intention of r13092? The log message is
"Moved the frame() event into the event traversal after then events and
their state have been accumulated."
Thanks for the help,
Judson
On 5/22/2013 3:02 PM, Judson Weissert wrote:
Robert,
I have made some progress. The problem appears to be caused by an
eventTimeDelta of zero which is calculated within
StandardManipulator::performMovement(). It eventually results in a divide by
zero and the propagation of non-finite value(s) through the remainder of the
call chain. Specifically, dy in OrbitManipulator::zoomModel() and
OrbitManipulator::panModel() ends up being a non-finite value.
Thus, I have found an explanation for the symptoms, but I have not tracked
down the underlying cause of eventTimeDelta being calculated as zero.
Therefore, I have not been able to create a small example case yet.
Regards,
Judson
On 5/22/2013 2:37 PM, Robert Osfield wrote:
Hi Judson,
It's a curious set of circumstances but as yet I can't think of a
specific cause.
Is there any chance you can create a small example that illustrates
the problem so that I can try it out and see if I can spot the
problems.
Cheers,
Robert.
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Index: osgviewer.cpp
===================================================================
--- osgviewer.cpp (revision 45025)
+++ osgviewer.cpp (working copy)
@@ -52,6 +52,68 @@
#define GL_TIMEOUT_IGNORED 0xFFFFFFFFFFFFFFFFull
#endif
+namespace
+{
+
+/// Modified Viewer implementation to expose the problem I encountered.
+class osg_viewer_t : public osgViewer::Viewer
+{
+public:
+ osg_viewer_t ();
+
+ osg_viewer_t (osg::ArgumentParser &arguments);
+
+ /// Copy constructor (not implemented).
+ osg_viewer_t (
+ const osgViewer::Viewer &viewer, const osg::CopyOp ©op
+ );
+
+ /* osgViewer::ViewerBase */
+
+ virtual bool
+ checkNeedToDoFrame ();
+};
+
+} // anonymous namespace
+
+osg_viewer_t::osg_viewer_t ()
+: osgViewer::Viewer ()
+{
+}
+
+osg_viewer_t::osg_viewer_t (osg::ArgumentParser &arguments)
+: osgViewer::Viewer (arguments)
+{
+}
+
+// Copied (slightly modified) from Viewer::checkNeedToDoFrame().
+bool
+osg_viewer_t::checkNeedToDoFrame ()
+{
+ if (_requestRedraw) return true;
+ if (_requestContinousUpdate) return true;
+
+
+ // If the database pager is going to update the scene the render flag is
+ // set so that the updates show up
+ if(getDatabasePager()->requiresUpdateSceneGraph() ||
getDatabasePager()->getRequestsInProgress()) return true;
+
+#if 0
+ // if there update callbacks then we need to do frame.
+ if (_camera->getUpdateCallback()) return true;
+ if (getSceneData()!=0 &&
getSceneData()->getNumChildrenRequiringUpdateTraversal()>0) return true;
+#endif
+
+ // now do a eventTraversal to see if any events might require a new frame.
+ eventTraversal();
+
+ // now check if any of the event handles have prompted a redraw.
+ if (_requestRedraw) return true;
+ if (_requestContinousUpdate) return true;
+
+ return false;
+}
+
class MySwapBuffersCallback : public osg::GraphicsContext::SwapCallback
{
public:
@@ -151,7 +213,7 @@
arguments.getApplicationUsage()->addCommandLineOption("--login <url>
<username> <password>","Provide authentication information for http file
access.");
arguments.getApplicationUsage()->addCommandLineOption("--device
<device-name>","add named device to the viewer");
- osgViewer::Viewer viewer(arguments);
+ osg_viewer_t viewer(arguments);
unsigned int helpType = 0;
if ((helpType = arguments.readHelpType()))
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