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Theory of bumpmapping help

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I finally decided to implement bumpmapping in my game, a computationally light version of bumpmapping. I understand the basics behind bump mapping and have already implemented per-pixel lightning using shaders in my game. Is it possible to create a normal map in which every pixel rappresents a normal vector of the object in world space? So on render time the light is calculated using the normal provided by the normal map without any trasformations on the normal. This approach would lead to increased performance, however the model would have to be texture mapped without any texture overlapping. Is it possible? If so is there any program that given a model and a height map creates a normal map of this type? (not the standard blueish normal map). I think that the NormalMapper of ATI has the option to create such a normal map (however is works with 2 models one high poly and the other low poly, and not a height map and a model). Every input is appreciated! :) EDIT: Here is a picture of the normal map i'm trying to achieve (this one was done using NormalMapper): http://static.highend3d.com/tutorialimages/229/nm_tm.jpg However I want to achieve this using a heightmap and a model. [Edited by - arc4nis on February 16, 2008 8:46:20 AM]

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I think you mean that you want object space normal maps, not world space. I don't really know anything about the technique, but from the sounds of it you'll have to be careful in how you implement it. Depending on your models and how much the base normal map is repeated among your models, you could end up using significantly more memory. And trading memory for computation is never a guaranteed win, especially on modern GPU's.

Anyway like I said it's not like I really know what I'm talking about here, I just think that once you get it to work you may want to do some profiling and compare it to the traditional normal-mapping technique (preferably on various classes of hardware). Sorry I can't be of much help with actually getting it working!

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After googling to death I finally found that ZBrush can create object space (right, not world space) normal maps.

I understand the memory problem, however my game is a 3d space simulation where most of the objects are just spaceships and asteroids, so I'm willing to try this approach.

Thanks anyway, going back to learn Zbrush.

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