You probably ended up with some ignorant management type who didn't know
that Internet Explorer was free. Funny how companies get so big they become
paralyzed by their own mass.
-----Original Message-----
From: John Wright [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 18, 2001 7:51 AM
To: [EMAIL PROTECTED]
Subject: Re: [JAVA3D] Fog (Linear) Differing Results
Philip, you don't mind if I rant for a second do you?
As you said "report all driver bugs" or more generically "report all
bugs". But there is a flip side of this too. The companies need to
listen to the bugs that are reported. Many companies deal with
customers so poorly that we lose our motivation to take the time to
report anything.
I recently had such an encounter with Microsoft. I wanted to download
the latest version of Internet Explorer (last known to be a FREE
product). Contacting Microsoft I tried to point out that there isn't a
link on their website to obtain IE. After several e-mail exchanges
(give Microsoft credit for actually responding), Microsoft decided to
launch an "investigation" of ME! Apparently they decided that I was
trying to "steal" a copy of IE. HUH??? Microsoft then later
apologized, but to this date hasn't provided the information of how to
actually download a full copy of IE. Customer service? Appreciation of
a customer pointing out a bug?
- John Wright
Starfire Research
Philip Taylor wrote:
>
> there are two important bits here:
> 1) report all driver bugs
> 2) D3D fog
>
> 1) report all driver bugs.
>
> this is SO important. if all ISVs dont report driver bugs they find, the
> quality of the drivers never gets better. please take the time to report
> these.
>
> Most IHVs do have helpful dev-rel folk and want to hear this sort of
> thing to make their products better.
>
> they cant if we arent vigilant, we are all in this together.
>
> please.
>
> 2) D3D fog.
>
> D3D implements two types of fog: vertex fog and pixel fog.
>
> pixel fog ( sometimes called table fog ) should be preferred over vertex
> fog since it appears better, as long as the driver correctly implements
> it. note the key statement "as long as the driver correctly implements
> it"****. it appears better since its calculated per-pixel instead of
> calculated per-vertex and then iterated.
>
> pixel fog comes in two flavors:
>
> 1) Eye-relative pixel fog ( or w-fog indicated by the
> D3DPRASTERCAPS_WFOG caps bit ) is preferred since it avoids certain
> fogging artifacts due to non-linear distribution of z values in the
> z-buffer.
>
> 1) z-based pixel fog. If w-fog isnt supported you get z-based pixel fog.
>
> if the driver doesnt implement pixel fog, fall back to vertex fox.
>
> vertex fog comes in two flavors:
>
> 1) range based fog ( indicated by the D3DPRASTERCAPS_FOGRANGE caps bit )
> uses the actual distance from the viewpoint to the vertex rather than
> the depth of the vertex; avoiding some rotational artifacts. If
> range-based fog isnt supported, you again get z-based fog.
>
> 2) application fog. the application must use its own fog calculations
> when not using the D3D TnL pipeline. the fog factor is calculated and
> placed in the alpha component of the specular color, making specular
> really RGBF in that case.
>
> Regardless of which type of fog, pixel or vertex, you use - your
> application must provide a compliant projection matrix ( what the docs
> call a W-Friendly Projection Matrix ) to ensure that fog effects are
> properly applied. This restriction applies even to applications that do
> not use the Direct3D transformation and lighting engine. If the
> projection matrix isn't compliant with this requirement, fog effects are
> not applied properly. This is covered in more detail in the D3D doc.
>
> so, to avoid really bad artifacts the order an application should prefer
> fog features is:
> pixel w-fog
> vertex range-fog
> pixel z-fog
> vertex z-fog
> application fog.
>
> if the application isnt using the D3D TnL pipeline ( which is quite good
> and has per-processor specific optimizations ) then its highly likely
> that application fog will produce the most uniform results since you
> control your own destiny by informing the iterator what values to
> iterate at each vertex.
>
> and, as always, one must be aware of the bad drivers out there which
> would modify that order of feature preference.
>
> ****GetDeviceIdentifier allows a mechanism to identify card/drivers that
> do not comply with the spec, and provide a last-chance method to
> fallback. Applications that depend on certain functionality should
> consider maintaining an internal list of offending card/drivers and
> performing a fall-back mechanism to ensure correct visual appearance.
>
> > -----Original Message-----
> > From: Kelvin Chung [mailto:[EMAIL PROTECTED]]
> > Sent: Thursday, May 17, 2001 2:57 PM
> > To: [EMAIL PROTECTED]
> > Subject: Re: [JAVA3D] Fog (Linear) Differing Results
> >
> >
> > >X-Sender: [EMAIL PROTECTED]
> > >Date: Thu, 17 May 2001 17:49:32 -0400
> > >To: Kelvin Chung <[EMAIL PROTECTED]>
> > >From: Mark Ferneau <[EMAIL PROTECTED]>
> > >Subject: Re: [JAVA3D] Fog (Linear) Differing Results
> > >Cc: [EMAIL PROTECTED]
> > >Mime-Version: 1.0
> > >
> > >Kelvin,
> > >
> > >In the body of the email I indicated J3D (Java3D) 1.2.1_01
> > for both OGL and
> > >D3D. I think, therefore, that this is a driver
> > issue--although I see it
> > >across different machines, boards, and operating systems.
> > So essentially I
> > >should probably not rely on fog looking reasonably consistent across
> > >different platforms or graphics boards.
> > >
> > >Therefore another method will have to be used to achieve the same
> > >effect. Would you agree with that statement?
> > >
> > Not sure. If it is a driver bug we should notify the graphics
> > vendor to fix it. I suppose driver should implement it
> > according to the fog formula.
> >
> > At least under Sparc Solaris the fog effect are consistent.
> >
> > - Kelvin
> > -----------------
> > Java 3D Team
> > Sun Microsystems Inc.
> >
> > ==============================================================
> > =============
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> > include in the body
> > of the message "signoff JAVA3D-INTEREST". For general help,
> > send email to
> > [EMAIL PROTECTED] and include in the body of the message "help".
> >
>
>
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