Hi Jason ;-) On Wed, May 6, 2009 at 12:03 PM, Jason Fisher <[email protected]> wrote: > > robertosfield wrote: >> Hi What ever you real name is because you too much of ?? to use a reasonable >> human readable name > I think there is no reason to get offensive -- as you might understand I > formed a habit of not using my name on public forums.
You come up with a name that was taking the piss and I respond to it. > robertosfield wrote: >> please fix it if > Done. > > Thanks for your additional comments, I think (hope) it's clear to me now. Camera's and scene graphs aren't all clear cut, the concept and implementation is often used and abused all over the place. In the case of scene graphs like the OSG Camera's are something that is used in lots of different ways, but still in not some ways that some users expect. The one place that can sometimes confuse users is that you can't put a Camera as a leaf of the scene graph and expect to get the view of the scene graph from where that camera has been placed. Rather you'd get a picture of nothing in the OSG's case. In the OSG's case a Camera only renders what is below it in the scene graph, the Camera effectively "owns" the scene graph it's rendering, and the view matrix positions the world below it into it's own local eye coordinates. This fits with the concept of an OpenGL camera, but is obviously quite different from a physical camera. To achieve the positioning of the camera's view relative to scene graph elements you have to track nodes in the scene graph (such as a CameraView node) and accumulate the local to world transforms above the CameraView (or any node) on each frame to apply the inverse of this local to world matrix as the camera's view matrix. This arrangement while being a bit different from a physical camera turns out to be extremely flexible and best for integrating with other scene graph concepts and class implementations. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
