Re: [osg-users] Issues with RotateCylinderDragger
I tracked down the problem. It seems that the original code tried to come up with a plane parallel to the cylinder axis oriented towards the eye/pick point. This calculation breaks down when the eye and cylinder axis are close to being parallel. I have fixed the problem and will be submitting a patch within the next day. I am trying to go through the code to do more cleanup as the original has a number of code paths that are never reached. Regards, Chuck On Feb 20, 2012, at 4:50 AM, Marius Kintel wrote: On 17 February 2012 17:47, Chuck Seberino seber...@energid.org wrote: The behavior I am seeing is that a small change in mouse drag will cause a large rotation and in certain cases will also cause a rotation in the opposite direction. I'm seeing the same thing and it's annoying, but it hasn't yet annoyed me enough to look into that code in detail. It would be cool if you post your findings here :) Cheers, -Marius ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Issues with RotateCylinderDragger
Hi Chuck, I tracked down the problem. It seems that the original code tried to come up with a plane parallel to the cylinder axis oriented towards the eye/pick point. This calculation breaks down when the eye and cylinder axis are close to being parallel. I have fixed the problem and will be submitting a patch within the next day. I am trying to go through the code to do more cleanup as the original has a number of code paths that are never reached. I think there was a submission fixing this not too long ago. Which version of OSG are you using? It may be worth looking at the most recent code for RotateCylinderDragger in svn, and perhaps testing a build of OSG svn just to make sure you're not doing work that has already been done. J-S -- __ Jean-Sebastien Guay jean_...@videotron.ca http://whitestar02.dyndns-web.com/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Issues with RotateCylinderDragger
Hi Chuck, I'm afraid as I'm not the original author of this bit of code I can't provide insight above what you can by reading the code. Robert. On 17 February 2012 17:47, Chuck Seberino seber...@energid.org wrote: Robert et al, I have been looking at an problem I have been having with the osgManipulator::RotateCylinderDragger. I have been trying to follow the code and there are a few things that stand out as questionable. Here are two issues I found with osgManipulator/src/Projector.cpp: 1. line 202,203 - Here it is trying to find a plane perpendicular to the eyeVector by taking the cross product of the cylinder axis. It doesn't correctly handle the case where the local eyeDir is parallel with axisDir. 2. line 601-606 - The computed plane intersection being calculated in 592 is being done at the edge of cylinder and the distance will always be = the radius and therefore this code will never be hit. Likewise there is an additional check against hitCylinder here that will never be taken due to the 'if' clause on line 589. The behavior I am seeing is that a small change in mouse drag will cause a large rotation and in certain cases will also cause a rotation in the opposite direction. I haven't yet been able to determine the exact cause, but there were just some things that stuck out as odd. I am almost at the point where I am going to try replacing all of the line-cylinder intersection code with my own since it is difficult to understand/verify the algorithm. My tests have been performed on trunk using the osgmanipulator example. I have been testing both with just a RotateCylinderDragger as well as a TrackballDragger. In the case of the TrackballDragger I removed the RotateSphereDragger (_xyzDragger) to isolate the picking to just the RotateCylinderDragger(s). The specific case is trying to pick when the eyeVector is close to parallel with the major axis of the cylinder (cylinder looks like a circle). I think issue #1 is somewhat of a red herring, in that it *should* properly calculate the plane when not exactly parallel, but even in this case there is still the abnormal behavior. My findings for #2 make me question the roots of this intersection code and I wanted to get some feedback on it. Thanks in advance. Chuck Seberino ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Issues with RotateCylinderDragger
On 17 February 2012 17:47, Chuck Seberino seber...@energid.org wrote: The behavior I am seeing is that a small change in mouse drag will cause a large rotation and in certain cases will also cause a rotation in the opposite direction. I'm seeing the same thing and it's annoying, but it hasn't yet annoyed me enough to look into that code in detail. It would be cool if you post your findings here :) Cheers, -Marius ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
[osg-users] Issues with RotateCylinderDragger
Robert et al, I have been looking at an problem I have been having with the osgManipulator::RotateCylinderDragger. I have been trying to follow the code and there are a few things that stand out as questionable. Here are two issues I found with osgManipulator/src/Projector.cpp: 1. line 202,203 - Here it is trying to find a plane perpendicular to the eyeVector by taking the cross product of the cylinder axis. It doesn't correctly handle the case where the local eyeDir is parallel with axisDir. 2. line 601-606 - The computed plane intersection being calculated in 592 is being done at the edge of cylinder and the distance will always be = the radius and therefore this code will never be hit. Likewise there is an additional check against hitCylinder here that will never be taken due to the 'if' clause on line 589. The behavior I am seeing is that a small change in mouse drag will cause a large rotation and in certain cases will also cause a rotation in the opposite direction. I haven't yet been able to determine the exact cause, but there were just some things that stuck out as odd. I am almost at the point where I am going to try replacing all of the line-cylinder intersection code with my own since it is difficult to understand/verify the algorithm. My tests have been performed on trunk using the osgmanipulator example. I have been testing both with just a RotateCylinderDragger as well as a TrackballDragger. In the case of the TrackballDragger I removed the RotateSphereDragger (_xyzDragger) to isolate the picking to just the RotateCylinderDragger(s). The specific case is trying to pick when the eyeVector is close to parallel with the major axis of the cylinder (cylinder looks like a circle). I think issue #1 is somewhat of a red herring, in that it *should* properly calculate the plane when not exactly parallel, but even in this case there is still the abnormal behavior. My findings for #2 make me question the roots of this intersection code and I wanted to get some feedback on it. Thanks in advance. Chuck Seberino ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
