On 14/12/10 10:23 , Bart Jan Schuit wrote: > I want to build an app which should have one camera (or two identical, > meaning that > they are at the same position, facing the same direction, if that is more > convenient) and > multiple screens. The screens will be aligned in a 90 degree angle towards > each other. So > they are perpendicular top view:> > > | <- 1 > | 2 > | | > | v > |________ > > > O
> In the PcubeE paper > (http://hct.ece.ubc.ca/publications/pdf/stavness-lam-fels-CHI2010.pdf) they > say: > To generate perspective-corrected images on each screen of pCubee, we use a > standard > off-axis projection scheme as described by Deering [9]. This is done in OSG > by creating > three View objects that correspond to the three visible screens on pCubee. > The camera for > each View is located at the user’s eye-position (which I will set manually at > like right > in the middle of the two screens, so at 45 degrees), oriented perpendicular > to its > corresponding virtual screen, and given a view frustum that passes through > the corners of > its virtual screen. >... As I understand it, they're setting up two cameras, located in the eye point '0'. Camera 1 is projecting onto the vertical screen, and camera two is projecting onto the horizontal screen (as per your drawing). Camera 1 would look due right (down the X axis in your drawing), and camera 2 would look up/north (down the Y axis in your drawing). The frustum for camera 1 would then be *sheared* (not rotated) in the positive Y direction to coincide with the bounds or the projection rectangle. (This is one of those cases where a drawing says more than 1000 words, but I suck at drawing, as I've just rediscovered.) Hope this still makes some sense, Cheers, /ulrich _______________________________________________ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
