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Separate normal and bump map

PostPosted: Sat Oct 30, 2010 3:18 pm
by cc.zero
Hi,

I'm currently evaluating the pro version of L3DT. (which is quite impressive so far)
I noticed during the terrain normal creation that it is possible to create a regular normal map or a normal map with applied bump mapping and a tangent bump map.
However, when the bump mapping is already incorporated in the normal map what would I need an extra bump map for?
So what I'd actually want is a normal map without bump mapping and the tangent bump map. Unfortunately the dialog only allows me to create the bump map when it is applied at the same time.
Is there a way to separate these two processes or do I have to do it manually?

Thanks in advance and greetings

PostPosted: Mon Nov 01, 2010 12:52 am
by lmaceleighton
Well this is a bit of an educated guess on my part, as I don't know ALL the game engines or terrain engines out there that you might display what you made here but here is what I think:
The bump map may be incorporated into the Normal map to provide a more Bumpy surface that wouldn't otherwise be there if you engine does support a bump map as well as normal maps, ambient occ map ect. Basically it is there to make sure you have all the tools necessary to make good terrain and have it be compatible across a large variety of engines and such which is what L3DT does. So the extra setting may seem redundant but that largely depends on what you are outputting it too. Does this help?
Bobby

Re: Separate normal and bump map

PostPosted: Wed Nov 03, 2010 10:24 am
by Aaron
Hi cc.zero,

cc.zero wrote:However, when the bump mapping is already incorporated in the normal map what would I need an extra bump map for?


You may need it if your render only accepts tangent-space bump maps, rather than the combined normals + bump maps. This was the case with the user that requested that feature. They had no regard for the combined normals + bump map, so I did not change that part of the output.

You are right however that the production of the combined normals + bump map is probably superfluous when the tangent space normals are produced (for most imaginable use cases), and instead the normal map should be produced without bump maps. I'll consider this for the next release.

cc.zero wrote:So what I'd actually want is a normal map without bump mapping and the tangent bump map. Unfortunately the dialog only allows me to create the bump map when it is applied at the same time.
Is there a way to separate these two processes or do I have to do it manually?


Until I make the above change you will unfortunately have to perform the calculation twice, with and without tthe bump-mapping and tangent-space normals flags enabled.

Best regards,
Aaron.