Re: Poor Alpha Blending

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From: Brian Furtaw (brian++at++sgi.com)
Date: 05/30/2001 04:06:30

You could try different versions of the pfTranparency. Try the
PFTR_HIGH_QUALITY token. In your pfGeoState you would set this token
like this,

gstate->setMode(PFSTATE_TRANSPARENCY, PFTR_HIGH_QUALITY);

You can also set the pfAlphaFunc() ref value so that you fade to
completely transparent after a certain value. Usually used to eliminate
ghosting around transparent objects. Like this,

gstate->setMode(PFSTATE_TRANSPARENCY, PFTR_BLEND_ALPHA);
gstate->setMode (PFSTATE_ALPHAFUNC, PFAF_NOTEQUAL);
gstate->setVal (PFSTATE_ALPHAREF, 0.0f);

Brian

Hui Li wrote:
>
> Hi,
>
> I have Onyx2 Reality workstation, when rendering a face with alpha-texture to
> simulate a shade, I find that at the place where alpha number gradually transfer
> from 255 to 0, I got a stair like result, not smooth at all. it seems that
> the alpha value have very limited choice, are there any configuration in performer
> to correct this?
>
> Hui
> .+-·!S÷¬Løm¶YÿÃ,,'(?û(~Ü­ïéz·è®g«üê^?7¯zZ)?éí>º#yËa¶Úþ?,²?¢oé®^ÞrÛ?¥êߢ¹?¯ô®nh¬²*'²)ߢ-«~Sæz» ?Ê&Ù¢?·ª¹ë-²)ߢ-«~SæzºÞªç¬¶È"com= 

-- 
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Brian Furtaw  (brian++at++sgi.com)	
Graphics Guru		       Office:(301)572-3293   Fax: (603)250-0370
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