Hi Frank,
So, I'm sure it's probably not possible to create a render context without
having a window of some kind. My guess is that (in Windows, at least), creating
a render context requires a Win32 device context, and that getting a device
context requires an HWND. So, I suppose my only option would be to create an
invisible window. If possible, I think it would be acceptable to create an
invisible window, and then just glReadPixels from the back buffer or something.
No, on Windows as well as on Linux and MacOS X it is possible to create
a context without a window. The trick is to create a pbuffer instead of
a graphics context, i.e. set pbuffer = true in the traits structure you
pass to osg::GraphicsContext::create().
Perhaps currently you don't even call this, and the graphics context (by
default a GraphicsWindow, i.e. a window containing a context) is created
for you by the viewer, but if after creating your viewer you create a
graphics context with pbuffer = true and assign it to the viewer's (or
view's) camera, then it won't create the default one.
See the code in osgconv (applications/osgconv/osgconv.cpp) for an
example of this.
Once you have that, you can use your viewer as before, but it will
render in the pbuffer (offscreen) and if you're so inclined, you can
read back the result of the render after the frame is done into CPU
memory and do what you want with it. You are right that it will be
slow... AFAIK, WPF has no inherent support for an OpenGL widget like Qt
does, but if performance is not a concern then you probably don't even
need this.
Hope this helps,
J-S
--
______________________________________________________
Jean-Sebastien Guay jean-sebastien.g...@cm-labs.com
http://www.cm-labs.com/
http://whitestar02.dyndns-web.com/
_______________________________________________
osg-users mailing list
osg-users@lists.openscenegraph.org
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
