I have also made changes to the RotateCylinderDragger to provide a cylinder ring with a thickness. It is totally optional, but IMHO makes the default behavior work better than a solid cylinder (which typically obscures the geometry you are trying to drag). Gives it a bit more to grab, especially in the case where eyepoint and cylinder axis are near parallel.
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* If the eyepoint and cylinder axis are close to parallel (given some tolerance), then it uses a plane perpendicular to the cylinder axis.
* Otherwise it uses a plane parallel to the cylinder axis oriented towards the eyepoint (previous behavior). This gives decent behavior and is the only path that was taken in the previous code. I kept with previous behavior and that allowed a good bit of code to be removed, simplifying things. There is now no need for the _onCylinder flag, but since there is a public accessor, I wasn't sure how to handle it for backwards compatibility, so I left it in. NOTE - there is no default initialized value, so if it is kept in, it should be set to 'false' to keep same behavior as before. I am not quite sure how the _onCylinder case was supposed to behave as even forcing that path gave undesirable behavior, even with carefully controlled dragging.
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The major modification concern the LineProjector class in Projector.cpp. The intersection was previously done in window space, I've modified it to compute it in object space."
class to encapsulate the pixel coords, SceneView and picking operations in prep for
making the code more general purpose, and less reliant on classes like osgUtil::SceneView and osgUtil::IntersectVisitor.
Vivek's email to osg-submissions:
"I'm happy to release the osgdragger nodekit to the OSG community. I
implemented the nodekit for my company, Fugro-Jason Inc., and they
have kindly agreed to open source it.
The nodekit contains a few draggers but it should be easy to build new
draggers on top of it. The design of the nodekit is based on a
SIGGRAPH 2002 course - "Design and Implementation of Direct
Manipulation in 3D". You can find the course notes at
http://www.pauliface.com/Sigg02/index.html. Reading pages 20 - 29 of
the course notes should give you a fair understanding of how the
nodekit works.
The source code also contains an example of how to use the draggers."
