Hi Nico, On 21 February 2017 at 08:19, Nico Kruithof <[email protected]> wrote: > There are two ways to add a camera to a view. First, there is the addSlave > (osgcamera example) and second, you can add the camera to a group node in > the scene (osgprerendercubemap example). What is the difference between the > two and when would you use one or the other?
You can implement the same effects with both approaches so it's mainly down to conceptual and practical considerations. Conceptually a Camera assigned to a View(er) as a master Camera or slave Camera provides guidance on how the viewer views the scene. So if you had a HMD you would naturally use two slave Camera, one for each eye. Also if you want to do distortion correction again this would likely be conceptually something associated with how you view the scene so again would naturally fit as a slave Camera. Practically in both these cases configuring the viewer with different combinations of slave Camera enables you to vary how the scene is viewed on different physical devices, completely decoupled from the scene graph. With effects like shadows or reflections conceptually these are related to the scene that you are viewing rather than how you are viewing it, so naturally you would put such a Camrea into the scene graph itself. Again practically this is a good fit as you can serialize out the scene graph and then load into a application that has a completely different viewer setup and it'll work, i.e. you can move from a desktop to HMD or a powerwall and have the scene still look as intended without having to hardware the application to it. The design of osg::Camera and osgViewer is based on these concepts/practical consideration, the class relationships and naming all fall naturally from this desire to be able to conceptually and practically decouple the needs of the viewer from the needs of the scene. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
