From: Angus Dorbie (dorbie++at++sgi.com)
Date: 11/01/2000 14:02:50
This could be due to an IRISGL implementation issue. Or maybe IGLOO if
you are running OpenGL.
Try and compile & link for IRISGL to be sure.
Also, IRISGL never tied this stuff down in a spec as clearly (I can't
remember), it was mainly a bunch of man pages and internal loosely
defined knowledge, so the 'spec' may not define the fog ranges in this
way, in addition the hardware may be using w or something for linear fog
which may make things less flexible w.r.t. setting arbitrary ranges.
Cheers,ANgus.
Roy Ruddle wrote:
>
> Hi there,
>
> I'm trying to implement a simple linear fog model on our Crimson RE,
> running Irix 6.2/Performer 2.2/Open GL. The application is for
> navigating a building (i.e., Z = 0 is the plane of the floor, and a
> user's eyepoint moves in the Z=1.65 m plane). The relevant code is:
>
> pfEarthSky *esky = new pfEarthSky;
> esky->setMode(PFES_BUFFER_CLEAR, PFES_SKY_GRND);
> esky->setAttr(PFES_GRND_HT, -1.0 );
> pfFog *fog = new pfFog;
> fog->setFogType( PFFOG_VTX_LIN );
> fog->setColor( 1.0, 1.0, 1.0 );
> fog->setRange( fog_range_min, fog_range_max );
> esky->setFog( PFES_GENERAL, fog );
>
> This works fine on a MaxImpact running irix 6.5 but, on the Crimson, I can
> clearly see my scene beyond the fog_range_max distance. Any thoughts? Have
> I missed something out in my fog/earth-sky calls, meaning that it's pure
> luck the code works on the Impact?
>
> many thanks
>
> roy
>
> ------------------------------------------------------------------------
> Roy Ruddle, Senior Research Associate
> Cardiff Human Interfaces and Virtual Environments Laboratory (C-HIVE)
> School of Psychology, Cardiff University, PO Box 901, Cardiff CF10 3YG
> Tel: +44 (0)29 2087 5030 (direct), Fax: +44 (0)29 2087 4858
> Email: Ruddle++at++CARDIFF.AC.UK http://www.cf.ac.uk/psych/ruddle/
>
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