I'm no shader expert, so I cannot answer that. I do know that osgEarth plays well with OverlayNode though -- it has some built-in vector overlay support that uses OverlayNode in perspective mode (see the osgearth_feature_overlay driver).
Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : +1.703.652.4791 On Thu, Nov 19, 2009 at 10:24 AM, Vaibhav Bansal <[email protected]>wrote: > Hello Glenn, > > > > The view dependent-with-perspective-overlay uses a shader, I am already > using a shader for my terrain(base geometry, osgearth). > > Secondly for VIEW_DEPENDENT_WITH_ORTHOGRAPHIC mode the projected texture > resolution does not decrease(/projected area does not increase) even when > the viewing direction is near parallel to terrain, it stretches ‘only’ at > certain specific angles. > > > > Is there a way to use overlay if I am already using a shader on my base > terrain? > > > > Thanks and Regards > > Vaibhav Bansal > > > > *From:* [email protected] [mailto: > [email protected]] *On Behalf Of *Glenn Waldron > *Sent:* Thursday, November 19, 2009 6:52 PM > > *To:* OpenSceneGraph Users > *Subject:* Re: [osg-users] Using OsgSim Overlay > > > > Vaibhav, > > The area covered by the projected texture changes based on your view angle. > As your angle of view gets less steep, the texture resolution appears to > descrease since it has to cover a larger area. Try > view-dependend-with-perspective-overlay, which helps with this issue. Also, > increase the texture size hint in the OverlayNode api. > > > Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : > +1.703.652.4791 > > On Thu, Nov 19, 2009 at 7:29 AM, Vaibhav Bansal <[email protected]> > wrote: > > Yes, this is what the overlay node does for me. > But I am unable to understand, why the stretching occurs only 'at' some > specific angles. > > > Regards > Vaibhav Bansal > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of J.P. > Delport > > Sent: Thursday, November 19, 2009 3:47 PM > To: OpenSceneGraph Users > Subject: Re: [osg-users] Using OsgSim Overlay > > Hi, > > Vaibhav Bansal wrote: > > Hello jp, > > > > Thanks for the quick reply. > > How do I check if the 'resolution' of ovelay geometry is changing. > > imagine the following: > You want to overlay a 1024x1024 checkerboard onto the earth and you have > a 512x512 overlay texture. If you view the whole earth it obviously > would not look good - too much detail to fit into the texture. What the > view dependent modes try to do is this: When you zoom in, you only see a > piece of the checkerboard, so now the 512x512 texture can contain only a > piece of the checkerboard and so you see "more detail" of the overlayed > geometry. > > I think this is the effect you are seeing when you are moving the view > around. > > jp > > > > > Regards > > Vaibhav Bansal > > > > -----Original Message----- > > From: [email protected] > > [mailto:[email protected]] On Behalf Of J.P. > > Delport > > Sent: Thursday, November 19, 2009 2:41 PM > > To: OpenSceneGraph Users > > Subject: Re: [osg-users] Using OsgSim Overlay > > > > Hi Vaibhav, > > > > Vaibhav Bansal wrote: > >> Hello, > >> > >> I have added a geometry as an overlay over another geometry. > >> The overlay texture seems to distort(stretch) under certain viewing > > angles. > >> It seems the projected texture is generating incorrect texture > > coordinates. > > > > The texture coordinates might be OK, but the resolution of your > > overlayed geometry might change in the generated overlayed texture. What > > happens in OBJECT_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY? Does the > > resolution/stretch stay the same? > > > > jp > > > >> The white area is the overlaySubgraph geometry, and the colored area is > > the > >> Overlay Node (base) geometry. > >> The overlay mode is VIEW_DEPENDENT_WITH_ORTHOGRAPHIC_PROJECTION. > >> > >> Can anyone suggest where should I start troubleshooting. > >> > >> Thanks > >> Vaibhav Bansal > >> > >> > >> ------------------------------------------------------------------------ > >> > >> > >> ------------------------------------------------------------------------ > >> > >> > >> ------------------------------------------------------------------------ > >> > >> _______________________________________________ > >> osg-users mailing list > >> [email protected] > >> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > > > > -- > This message is subject to the CSIR's copyright terms and conditions, > e-mail > legal notice, and implemented Open Document Format (ODF) standard. > The full disclaimer details can be found at > http://www.csir.co.za/disclaimer.html. > > This message has been scanned for viruses and dangerous content by > MailScanner, > and is believed to be clean. 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