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dansteph

using D3DFMT_D24S8 depht buffer ?

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dansteph    122
While testing all the depht buffer format on my Tnt2 I''m allowed to the D3DFMT_D24S8 but not D3DFMT_D24X8 As quoted from the doc: D3DFMT_D24S8 ------------ 32-bit z-buffer bit depth where 24 bits are reserved for the depth channel and 8 bits are reserved for the stencil channel. D3DFMT_D24X8 ------------ 32-bit z-buffer bit depth where 24 bits are reserved for the depth channel. I don''t understand while I''m allowed to the D24S8 I''m not allowed to the D24X8 that seem less demanding (8 bits less). Also may I use this D24S8 even I don''t need the stencil channel ? I mean while I have any benefit over a simple D16. Thats unclear to me... Thanks to point me at. Dan

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S1CA    1418
*ALL* nVidia chips since the TNT1 have a restriction that the total depth+stencil bit depth MUST be the same as the bit depth of the frame buffer.

The drivers for your TNT simply doesn''t expose D24X8.

The CheckDeviceFormat() and CheckDepthStencilMatch() functions are used to check whether a) the format can be used at all on a device and b) whether it can be used with the specified frame buffer format. Do be aware though that there is an "issue" between the D3D runtime and nVidias drivers which will return success for one of the combinations which won''t actually work (I think its 32bit frame and 16bit depth).

--
Simon O''''Connor
Creative Asylum Ltd
www.creative-asylum.com

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dansteph    122
Hello Simon,

Since now even I regulary test all my screen res I didn''t encounter any trouble, I will check http://DISCUSS.MICROSOFT.COM/archives/DIRECTXDEV.html
for the issue you tell me about.

Many thanks

Dan

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S1CA    1418
Take a look on the nVidia site too where these issues are well documented. (CheckDepthStencilMatch issues in 8.0 aren''t documented)

Also try contacting nVidia directly (Richard Huddy, Dave Horne etc if you''re in Europe, probably Sim Deitrich etc if you''re in the US/Canada).

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