Relief mapping (computer graphics): Difference between revisions

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{{Short description|Texture mapping technique}}

{{Cleanup-jargon|date=June 2007}}

In [[computer graphics]], '''relief mapping''' is a [[texture mapping]] technique first introduced in 2000<ref>{{cite book|author=Oliveira, Manuel M. and Bishop, Gary and McAllister, David|title=Proceedings of the 27th annual conference on Computer graphics and interactive techniques - SIGGRAPH '00 |chapter=Relief texture mapping |year=2000|pages=359–368|doi=10.1145/344779.344947 |isbn=1581132085 |s2cid=598957 |chapter-url=https://doi.org/10.1145/344779.344947}}</ref> used to render the surface details of three-dimensional objects accurately and efficiently.<ref>{{cite book|author=Policarpo, F., Oliveira, M. M., Comba, J. L. D.|title=Proceedings of the 2005 symposium on Interactive 3D graphics and games |chapter=Real-time relief mapping on arbitrary polygonal surfaces |year=2005|pages=155–162|doi=10.1145/1053427.1053453 |isbn=1595930132 |s2cid=3445302 |chapter-url=http://www.inf.ufrgs.br/~comba/papers/2005/rtrm-i3d05.pdf}}</ref> It can produce accurate depictions of [[Hidden surface determination|self-occlusion]], [[self-shadowing]], and parallax.<ref>{{cite book|author=Policarpo, F., Oliveira, M. M.|title=Proceedings of the 2006 symposium on Interactive 3D graphics and games - SI3D '06 |chapter=Relief mapping of non-height-field surface details |year=2006|page=55 |doi=10.1145/1111411.1111422 |isbn=159593295X |s2cid=11331719 |chapter-url=http://www.inf.ufrgs.br/~oliveira/pubs_files/Policarpo_Oliveira_RTM_multilayer_I3D2006.pdf|accessdate=18 February 2011}}</ref> It is a form of short-distance [[Ray tracing (graphics)|ray tracing]] done in a [[pixel shader]].{{citation needed|date=February 2011}} Relief mapping is highly comparable in both function and approach to another displacement texture mapping technique, [[Parallax occlusion mapping]], considering that they both rely on ray tracing, though the two are not to be confused with each other, as parallax occlusion mapping uses reverse heightmap tracing.

In [[computer graphics]], '''relief mapping''' is an alternative [[texture mapping]] technique to [[parallax mapping]] that is much more accurate, and can support [[self-shadowing]] and [[normal mapping]]. It can be quite simply described as a short-distance [[raytrace]] done on a [[pixel shader]]; various techniques can be implemented to speed up the raytrace by taking variable step sizes.

Relief texture mapping supports the representation of [[3D computer graphics|3D]] surface detail, producing self-[[occlusion]], [[self-shadowing]], view-motion parallax, and [[silhouette]]s. This technique produces correct views of 3D surfaces and scenes by augmenting textures with per [[Texel (graphics)|texel]] depth.

It is not yet common in [[video games]], as it is a rather slow technique due to the need for a large amount of per-pixel processing. ''[[Crysis]]'', ''[[ The_Elder_Scrolls_IV:_Oblivion | Oblivion]]'', and ''[[ Unreal_3 | Unreal Tournament 3 ]]'' have a similar feature called [[Parallax_mapping | Parallax mapping]].

Recently Pamplona et al.<ref>Pamplona, Vitor; Oliveira, Manuel M.; Nedel, Luciana P.. ''Animating Relief Impostors Using Radial Basis Functions Textures.'' In: Scott Jacobs (ed.) Game Programming Gems 7. Charles River Media, Inc., Hingham, Massachusetts, 2008, (ISBN-13: 978-1-58450-527-3). pp. 401-412. (See the video: http://www.vimeo.com/1776230)</ref> published a new technique which animates relief impostors, billboards with normal mapping, displacement maps, or any other texture-based resolution-independent representation. The animation is encoded using an RBF representation, which is saved into a texture. At runtime, the RBF texture is used to warp the relief texture on the GPU producing the desired animation. The proposed technique preserves the relief-impostor properties, allowing the viewer to observe changes in occlusion and parallax during the animation. It can be used produce real-time realistic animations of live and moving objects undergoing repetitive motions.

==See also==

{{portalpar|Computer graphics|5-cell.gif}}

* [[Shaded relief]]

* [[Shaded relief]], a cartographic technique that portrays terrain by using simulated shadows

* [[Bump mapping]]

* [[Normal mapping]]

* [[Parallax mapping]]

==References==

{{reflist}}

<references />

==External links==

* [http://ascensionwww.sairyxinf.orgufrgs.br/Programming~oliveira/Relief_mappingRTM.html Manuel's Relief mappingtexture explanation, with codemapping]

*[http://www.inf.ufrgs.br/~oliveira/RTM.html Manuel's Relief texture mapping]

{{Texture mapping techniques}}

**[http://www.inf.ufrgs.br/~oliveira/pubs_files/Policarpo_Oliveira_Comba_RTRM_I3D_2005.pdf ''Real-Time Relief Mapping on Arbitrary Polygonal Surfaces'']

**[http://www.inf.ufrgs.br/~oliveira/pubs_files/Policarpo_Oliveira_RTM_multilayer_I3D2006.pdf ''Relief Mapping of Non-Height-Field Surface Details'']

[[Category:3D computer graphics]]

[[Category:Texture mapping]]

{{Compu-graphics-stub}}