From: Paul Berridge (paulb++at++equipe.ltd.uk)
Date: 05/25/2000 01:04:30
Hello Marcin.
I'm having similar problems to Devrim and I don't see which of the
PFMPASS flags fixes it.
I'm trying to simulate an aircraft landing light with a fully textured
scene that includes light points/emissive polygons and semi-transparent
textures.
When I enable a projected texture light source the emissive objects only
appear if I set PFMPASS_EMISSIVE_PASS but they are very dim. I have a
simple test program which displays the light points at full intensity
but haven't been able to find out why this works but my main application
does not.
Semi-transparent textures become opaque and I don't see that any of the
PFMPASS flags will fix this.
I'm also seeing colour banding/quantization which is particularly
evident when other light sources are set to low intensity.
Which PFMPASS should I use? Do you have any suggestions for fixing the
remaining problems?
I'm using Performer 2.2.7 with IRIX 6.5.7m on and Onyx2 IR.
-- Paul
Marcin Romaszewicz wrote:
>
> Hi Devrim,
>
> Which version of performer are you using? We did a major rewrite of the
> projective texture code in 2.2.5 to solve exactly this problem. There are
> sevral flags that you can pass to pfChannel::setTravMode which can be used
>
> to fine-tune the multipass behavior:
> #define PFMPASS_EMISSIVE_PASS 0x2
>
> This must be enabled if you have emissive geometry, which requires an
> extra pass.
>
> #define PFMPASS_NONTEX_SCENE 0x4
>
> This flag lets us skip a pass in the case of a non-textured scene.
>
> #define PFMPASS_NO_TEXTURE_ALPHA 0x8
>
> If there is no texture based transparency, we can skip another pass. For
> your trees, you want this flag off.
>
> #define PFMPASS_FORCE_MULTISAMPLE 0x10
>
> Multisampling greatly simplifies the multipass algorithm. In cases where
> there is no translucency, only full transparency or full opacity, the
> multisample version of the algorithm will work faster even on machines
> without multisampling hardware. This flag forces the multisample
> transparency mode.
>
> #define PFMPASS_BLACK_PASS 0x20
>
> If you see opaque objects in your scene appear translucent, turn on this
> flag, it will fix the problem at the cost of an extra pass.
>
> -- Marcin
>
> On Wed, 24 May 2000, devrim wrote:
>
> > Hi,
> >
> > I have been using performer projected textures within my application (
> > based on the sample in the man page ) . We also have transparent
> > textured billboards which are used for lens flare and static shadows. At
> > some point project texture is enabled and then at some point again it is
> > disabled. I have noticed that when I use projected textures transparent
> > textures look as if alpha bits are set to 1. When I don't enable
> > projected textures, it is just fine, we have nice transparency. It looks
> > like the color bit count has also decreased.
> >
> > Any ideas ?
> >
> > /*===============================================
> > M. Devrim Erdem devrim++at++infotron.com.tr
> > Simulation Software Development
> > info(+)TRON, Turkey
> > Tel: +90 216 4921002, Ext 138
> > Fax: +90 216 3432132
> > http://www.infotron-tr.com
> > http://abone.turk.net/mderdem
> > ===============================================*/
> >
> >
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-- Paul Berridge Principal Development Engineer Equipe Electronics Ltd. 13 Liverpool Gardens Worthing, W. Sussex BN11 1RY ENGLANDPhone +44 (0) 1903 216622 FAX +44 (0) 1903 216633
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