Hi Sonya, you convert the intersection of the two lines (from World Space) into screen space. Then you just position the mouse there. Below is a code snippet (from a lensflare implementation) but it is the same - might give you some hints
osg::Matrixd wm = mCamera->getViewport()->computeWindowMatrix(); osg::Matrixd mx = modelView * mCamera->getViewMatrix() * mCamera->getProjectionMatrix() * wm; osg::Matrixd mxc = osg::Matrix::translate(-mCamera->getViewport()->x(),-mCamera->getViewport()->y(),0); osg::Vec3 sun = lightPos * (mx*mxc); lightPos will be your intersection world coordinate, the resulting sun position is your screen space where to snap your mouse Cheers, Nick On Sat, Jul 26, 2014 at 11:23 PM, Sonya Blade <sonyablade2...@hotmail.com> wrote: > Hi Sergey, > > >then create custom intersector to suite your needs see custom > intersectors > Thanks for giving entry point, the chapter in Cookbook also suggest to do > so, I came to know that recently. > > One more little question, I created a XY grid (Z=0) which is composed of > PrimitiveSet with GL_Lines, how can > one implement the snaping to the lines intersection points(intersection > between line segments), IMHO there > is no need to create custom intersector to detect that and picking lines > is unnecessary. As a result mouse may hoover > anywhere in vast spatial space and may not detect the intersection point. > How am I supposed to proceed with that ? > > Entry point will be appreciated. > > Regards, > > > ------------------------------ > Date: Sun, 27 Jul 2014 00:59:01 +0400 > > From: sergey.fo...@gmail.com > To: osg-users@lists.openscenegraph.org > Subject: Re: [osg-users] Mouse World Position in Perspective View > > Hi Sonya > > >but what happens if mouse is close enough and supposed > >to be snapped to vertex but mouse is not on object.? > > I can think of two things - set bounding sphere to be larger so that you > intersect object when you click near object ( see > http://vtp.googlecode.com/svn-history/r7601/trunk/TerrainSDK/vtlib/vtosg/NodeOSG.cpp > as an example), then create custom intersector to suite your needs see > custom intersectors here > http://www.packtpub.com/sites/default/files/downloads/6884_Chapter10.pdf > > Regards > Sergey > > > > On Sat, Jul 26, 2014 at 11:11 PM, Sonya Blade <sonyablade2...@hotmail.com> > wrote: > > Hi Sergey, > > Thanks for the tutorial, but I believe that the problem is: Casted ray > with world_mouse = screen_mouse*inverse(MVPW) > matrix manipulation is unware of whether it crossed an object or not, it > simply returns near/far points of frustum. > On the other hand using, the" LineSegmentIntersector >> > getWorldIntersectionPoint() " and example in *OSG cookbook* > *Ch3 Selecting a point on the model** solves* the issue of what is behind > the mouse but I believe that it has drawbacks. > Because this tecnique requires the mouse to be hoovered on object, but > what happens if mouse is close enough and supposed > to be snapped to vertex but mouse is not on object.? > > The above is my intuitive reasoning , I tried to put it in succinct manner > and hope that I well versed it. If it is not clear I'll try to > ealaborate it with images. > > Regards, > ------------------------------ > Date: Sat, 26 Jul 2014 14:11:38 +0400 > From: sergey.fo...@gmail.com > To: osg-users@lists.openscenegraph.org > Subject: Re: [osg-users] Mouse World Position in Perspective View > > > Hi Sonya, > > I think you could solve your problem if you understand theory what goes > during the whole process and test if anything works from simplest examples, > then after tests you'll uncover a problem > > for theory I think following to links are useful, but see not only first > link, but also second > > http://www.mvps.org/directx/articles/rayproj.htm > http://www.mvps.org/directx/articles/improved_ray_picking.htm > > > Regards > Sergey > > > On Sat, Jul 26, 2014 at 1:53 AM, Sonya Blade <sonyablade2...@hotmail.com> > wrote: > > Dear All, > > I'm having a hard time getting the correct results for the mouse position > in world coordinates. > The problem is: retrived world mouse position is not even close to those > when I hoover over an > object so I couldn't find any correlation between to which vertex of > object is mouse close to. > > To obtain the world mouse position I use world_mouse = > screen_mouse*inverse(MVPW), for obtaining > the vertex position I use LineSegmentIntersector >> > getWorldIntersectionPoint() and there is absolutey > not any coherent value that I can find any relation. My aim was to snap > the mouse to the closest vertex > in object, but produced results are as follow. > > world coords vertex(6.97538 20.55 18.7482" > local coords vertex(0.876922 -3.74963 4" > Mouse Position -101.794 44.6545 -130.128" > > Your help will be appreciated, > > _______________________________________________ > 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 > > _______________________________________________ > 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 > > _______________________________________________ > osg-users mailing list > osg-users@lists.openscenegraph.org > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > -- trajce nikolov nick
_______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
