From: Corner, Steve (s.corner++at++vr-centre.com)
Date: 12/02/2002 06:01:54
render a unit sphere sky dome.
the size is irrelivant because you're not rendering the z-buffer component
anyway.
S.
-----Original Message-----
From: MLM Veraart [mailto:veraart++at++fel.tno.nl]
Sent: 02 December 2002 13:54
To: Corner Steve
Cc: info-performer++at++sgi.com
Subject: Re: [info-performer] overriding the clipping plane
"Corner, Steve" wrote:
>
> turn off z-buffering
> render sky dome
I think the clipping routines in the graphics pipe will clip the dome
if you use this method.
By disabling the Z-buffer you don't eliminate the far clipping plane.
You might try to setup a different projection matrix while drawing the dome.
But in essence this might be as much work (draw time) as using a second
channel.
Mario
> turn on z-buffering
> render the rest of the scene.
>
> you only have to clear the z-buffer each frame too....
>
> S.
>
> -----Original Message-----
> From: MLM Veraart [mailto:veraart++at++fel.tno.nl]
> Sent: 02 December 2002 12:31
> To: Brad Schwagler
> Cc: info-performer++at++sgi.com
> Subject: Re: [info-performer] overriding the clipping plane
>
> Brad Schwagler wrote:
> >
> > I have a driving simulator with many objects in the
> > scenegraph. If I make the clipping plane closer,
> > distant objects are not drawn and the program runs at
> > an acceptable drawing rate. This is what I want, but
> > how can I still draw the sky-dome? I tried setting a
> > pre-draw callback on the sky model where I would
> > temporarily move back the clipping plane. The problem
> > is that the channel and pipe are NULL in the callback
> > func. Would it be better to use hundreds of LOD nodes
> > on each indvidual object instead? Is there a
> > different way of overriding the clipping plane?
> > thanks
>
> There are two ways I know to solve this.
>
> 1) remodel the dome a bit smaller
>
> 2) Put the dome in a separate pfScene.
> Use an other channel mapped 'behind'/first to the window.
> In this channel put the dome scene and set the clipping range right.
> In the other scene disable the clearing of frame and Z-buffer in the
> draw-callback.
>
> Mario
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