Re: Fixed-Geometry HUD
Angus Dorbie (dorbie++at++sgi.com)
Thu, 19 Mar 1998 16:41:32 -0800
Mason D. Menninger wrote:
>
> Hello all.
>
> I'm still new to the Performer world, so please forgive
> (but feel free to point out) any glaring errors.
>
> I've been looking through the archives at various HUD
> implementations and noticed that they seem to be based on
> creating the HUD though OpenGL calls at some point in the
> draw process (But I could be mistaken). I was wondering
> how you would go about building a HUD based on fixed-geometry
> parts brought in by a loader and attached somewhere in the
> scene. Some of the immediate thoughts that came to mind were:
>
> 1) Draw the entire scene except for the HUD (possibly using
> pfNodeTravMask), set-up the appropriate stencil mask, draw
> the HUD portion of the scene graph. But I am uncertain
> how to successfully stencil just a subgraph (especially
> without clobbering the scene underneath the HUD region from
> the previous draw).
>
> 2) A similar idea would be to draw the entire scene except for
> the HUD, set-up four additional clip planes around the HUD
> region, draw the HUD portion of the scene graph. This would
> have the added benefit of being able to view the HUD from
> multiple positions in the scene. But I am uncertain how to
> successfully clip just a subgraph (without clobbering everything
> underneath).
>
> 3) Create an overlay channel just for the HUD. But I'm not
> convinced that it would be able to handle something as
> complex as what I have in mind. Also, I don't know how to
> implement overlays in pfPipeWindows.
>
> Any ideas or corrections to these thoughts would be greatly
> appreciated.
http://www.dorbie.com/ has a description of just what you need.
Cheers,Angus.
--
"Only the mediocre are always at their best." -- Jean Giraudoux
For advanced 3D graphics Performer + OpenGL based examples and tutors:
http://www.dorbie.com/
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on Mon Aug 10 1998 - 17:57:03 PDT