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Bump-mapping question...

Started by simon_brown75 4 replies 1k views
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simon_brown75
simon_brown75
I just wondered if anyone out there can help me with some info on bump-mapping in Direct3D. I have a GeForce 2 GTS, and the driver (6.18 Detonator 3) is reporting No to BUMPENVMAP and BUMPENVMAPLUMINANCE, but Yes to DOTPRODUCT3. Does this mean the card can do bump-mapping in D3D or not?, I''m kinda confused. In the SDK, while DOTPRODUCT3 is listed in the bump-mapping caps section, it isn''t described as bump-mapping at all, whereas the other two are described quite clearly as per-pixel bump-mapping. Also bump-mapping is never mentioned in the SDK apart from as ''environmental bump-mapping'', which is texture->bump-map->environmental-map with multi-texturing. Is there no way to do bump-mapping *without* blending the output into an environmental map? Out of the six demos that come with the card, the ones which use bump-mapping are all OpenGL. But Tomb Raider 4, the only game i''ve got which uses bump-mapping, is definitely using it and is Direct3D. Also, last question , is bump-mapping suppose to react to the cameras view point, because the bump-mapping in Tomb Raider 4 doesn''t change at all when the view angle is changed, whereas the bump-mapping in the OpenGL demos that ship with the card definitely does. Is this the difference between bump-mapping and environmental bump-mapping? Many thanks in advanced, Simon.
simon_brown75
simon_brown75
Also, it clearly says in the DX SDK that to check if a device supports bump-mapping, check for BUMPENVMAP and BUMPENVMAPLUMINANCE, it doesn''t include DOTPRODUCT3.

This would seem to suggest the card doesn''t do bump-mapping in D3D. Can anyone help clear this up for me?
MatsG
MatsG
Check out nvidas home page they explain the dotproduct3 there

http://www.nvidia.com/Developer.nsf
simon_brown75
simon_brown75
Ok, I''ll have a look, and thanks for replying btw

The only reason I ask is that it says in the DX7 SDK to check for BUMPENVMAP and BUMPENVMAPLUMINANCE, and if the driver reports No to both, then the card doesn''t do bump-mapping.

Also the two bump-mapping sample programs from the SDK do not run with the GeForce 2. Plus when I try to enumerate valid bump-mapping pixel formats, the drivers report back none.
Sentinel
Sentinel
GeForce can do DotProduct 3 Bump Mapping. What are you trying to do is Enviroment Bump Mapping...
Sentinel
Sentinel
You just create another RGB texture (it should be 32bpp), and fill it with per pixel normals (RGB -> XYZ). Than you can make SetTextureStageState(x,D3DTSS_COLOROP,D3DOP_DOTPRODUCT3)

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