[PD] (GEM) Getting the z-buffer value of a pixel in a rendered image

Jack jack at rybn.org
Thu Jun 16 14:21:26 CEST 2011

It is possible to use shader to define the z-buffer.
gl_ModelViewMatrix * gl_Vertex gives the eye coordinate position of each
vertex (it is what we need here to define the depth of each vertex).
See example attached.
You can change this example to apply the depth to alpha channel.


Le mercredi 15 juin 2011 à 17:09 -0400, Mathieu Bouchard a écrit :
> On Fri, 10 Jun 2011, Matteo Sisti Sette wrote:
> > Is there a way in GEM to take a snapshot of a rendered scene (such as 
> > with pix_snap) and save the z-buffer information, for example saving it 
> > as an extra channel? (e.g. have the z value saved as the alpha channel)? 
> > I'm interested in getting an image of the scene as it would appear if it 
> > was captured by a depth sensor like a Kinect...
> How many bits do you expect the z-buffer to be, and how can that possibly 
> fit in any GEM pix structure ?
> AFAIK, only GridFlow, PDP and iemmatrix are equipped to handle that data.
>   _______________________________________________________________________
> | Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray, Montréal, QC
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