RE: [GD-Windows] From OGL To D3D

[Paul B. <pa...@mi...>]

OpenGL uses -1 < w < 1 for the clip space, while D3D=20
uses 0 < w < 1 which for practical purposes means you
have to scale (or divide) by two in some places to get
exact visual similarity.  I don't remember the details
either, but I think that was the biggest problem.

Paul


> -----Original Message-----
> From: Brian Hook [mailto:bri...@py...]=20
> Sent: Friday, February 08, 2002 11:00 AM
> To: gam...@li...
> Subject: Re: [GD-Windows] From OGL To D3D
>=20
>=20
> At 11:49 AM 2/8/2002 -0500, Dave Smith wrote:
> >Before I embark on this great quest of porting some of my=20
> code from OGL=20
> >to D3D, I would like to know if there are any good sites=20
> that discuss=20
> >this issue.
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> No sites, unfortunately, at least that I'm aware of.
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> If you're targeting DX8, then the transition should be fairly smooth=20
> (depending on how much OGL you were using).  Most of the=20
> state stuff has=20
> direct analogs.  Probably the biggest area of confusion for=20
> me was making=20
> sure my matrices were matching correctly.  I don't remember the exact=20
> details, but it took some trial and error before I figured=20
> out how to map=20
> an OpenGL projection matrix to the D3D one.
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> Brian
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>=20
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