Philip,
What I meant to say is that my understanding is that DirectX has many
features (perhaps 100 to 200 video functions - at one time I'd heard a
figure of 63) and that each video card manufacturer may or may not
provide support for each of those features (or may supply a slightly
different implementation). So while a video card supports DirectX, at
least in the past, the "full" support has been inconsistent.
As a crude example let's say video card manufacturer XYZ decides to take
a shortcut and doesn't implement "fog". So their card works "fine"
(DirectX is supported) but when a software application calls for "fog"
the elcheapo driver ignores it and thus the visual result is not
consistent with another card (or driver).
Philip, could you comment on how consistent the implementation of
DirectX is between vendors such as ATI, Matrox, NVidia (or others)?
Just how much visual disparity should we expect from one card to the
next? As far as I know these issues apply to OpenGL as well as DirectX.
- John Wright
Starfire Research
PS - This and all my comments are in no way an endorsement of one API vs
another. I'm just simply trying to illuminate the differences between
using the two different implementations of Java 3D. Ultimately we'd
hope that Java 3D would completely isolate us from this issue (thus
Windows users could benefit from a kick ass implementation via DirectX
and Linux users could benefit from an equally powerful implementation
via OpenGL).
Philip Taylor wrote:
>
> Kelvin produced a pretty accurate rendition of the deltas in the APIs.
>
> in terms of driver support, we are not aware of where IHVs are not
> providing DX drivers. not sure I can do anything about it other than
> contact the IHV in question, but please send me private mail so I can
> understand the issues.
>
> -----Original Message-----
> From: Kelvin Chung [mailto:[EMAIL PROTECTED]]
> Sent: Thursday, August 16, 2001 10:20 AM
> To: [EMAIL PROTECTED]
> Subject: Re: [JAVA3D] Diferences between DirectX e OpenGL ?
>
> >Delivered-To: [EMAIL PROTECTED]
> >MIME-Version: 1.0
> >Date: Thu, 16 Aug 2001 17:24:56 +0200
> >From: Joachim Diepstraten <[EMAIL PROTECTED]>
> >Subject: Re: [JAVA3D] Diferences between DirectX e OpenGL ?
> >To: [EMAIL PROTECTED]
> >
> >Hi John
> >
> >> differences. Perhaps Microsoft could comment on if video card
> >> manufacturers are being more consistent in fully supporting DirectX
> now?
> >Definitly as it seems new leading technology seems to be first
> integrated
> >into DX (see Vertex/Texture/Pixel shader stuff) before any weired sort
> of
> >vendor specific OGL extension. And it's also common known that ATI
> drivers
> >are not the best OGL wise but DX is mostly fine. [IMHO a pitty]
> >
>
> Except for those function not support by D3D
> as mention in README such as
> line width/point size/line pattern/texture
> border color (most driver don't support
> the last two in hardware accelerated mode)
>
> Other differences are:
>
> (i) The SpotLight falloff model is different between
> OGL & D3D.
> (ii) Specular highlight in Texture mapping. In v1.3
> OGL will use GL_EXT_separate_specular_color to
> make the highlight same as D3D if driver support.
>
> Since vendors support of OGL & D3D may varies,
> try both to see which one works better in your
> machine.
>
> - Kelvin
> ---------------
> Java 3D Team
> Sun Microsystems Inc.
>
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