Hi Dat, The screen distance and fusion distance are relevant to monitor or projection based stereo systems, not for HMD's. The OSG doesn't use a convergence angle as this is not appropriate for proper stereo effect in monitor or projection based stereo system, instead the OSG uses the mathematically correct system of shearing the projection matrix.
Things a bit different for HMD, as the projection matrix is identical for both eyes, and only the view matrix is offset (and perhaps rotated). One method to accurate control this is to use a SceneView::ComputeStereoMatricesCallback, but now with have the osgViewer it's probably easier just to manually create two slave Camera's with the appropriate view matrix translation to account for the inter-ocular distance. FYI, osgViewer hasn't yet taken over management of all stereo modes from the lower level SceneView, but this is my plan - to migrate all stereo support into the high level class, and then provide configuration file support for it. This will be done well after 2.8. Robert. On Sat, Dec 20, 2008 at 3:37 AM, tien dat <[email protected]> wrote: > Hi all, > > I have a question about controlling stereo with HMD in OpenSceneGraph. > > Basically to setup stereo display you need the distance of two eyes > and the convergence angle. When I take a look at OpenSceneGraph code > for setting up stereo with HMD, I see two other variables which are > screen distance and fusion distance. There is also a matrix to > multiple with each view for each eye that uses these variables. So > could any of you tell me what they mean and what happens if I change > these variables. > > Thank you very much, > > Dat > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org

