[osg-users] camera/cameraview questions

[Robert Osfield]

Hi Carsten,

The CameraView node is meant to be placed within the scene graph as a
leaf node, the accumulated transform matrix down to the CameraView
provides its final position in space just like any other node.
CameraView is a passive object, effectively a marker that you put into
the scene graph it doesn't do any rendering itself.   One would use it
for marking various view points in the scene, or for creating a camera
view that tracks a node in the scene i.e. a car.

To render the view one must get the the accumulated view matrix (the
world to local transform) and pass it onto the viewers Camera setting
it's view matrix.   Right now there isn't a convenience method built
into osgViewer for doing this, so you'll need to manage this in your
own application.  You could use the NodeTrackerManipulator for to
attach to the CameraView, but this manipulator is general purpose and
doesn't know about some of the specific features of CameraView.

CameraView isn't widely used, which is why it hasn't been wired up in
osgViewer, perhaps further down the line we'll revisit this, feel free
to contribute to this effort.


Robert.


On 8/28/07, Carsten Scharfe <dragonblk at versanet.de> wrote:
> hi there,
>
> do i understand the functionality of the cameraview node correct?
>
> i assume, that cameraview is used to position the camera (and animate, of course)
> within the scene, without having to manipulate view matrices directly.
>
> but then how do i retrieve the actual viewing matrix, if the camera is positioned
> by a cameraview?
>
> what happens if geometry is attached as a child of a camera node?
>
> maybe someone can help me out?
>
> cheers,
> carsten scharfe
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