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Bump mapping〔http://www.ics.uci.edu/~majumder/VC/classes/BEmap.pdf〕 is a technique in computer graphics for simulating bumps and wrinkles on the surface of an object. This is achieved by perturbing the surface normals of the object and using the perturbed normal during lighting calculations. The result is an apparently bumpy surface rather than a smooth surface although the surface of the underlying object is not actually changed. Bump mapping was introduced by James Blinn in 1978.〔Blinn, James F. ("Simulation of Wrinkled Surfaces" ), Computer Graphics, Vol. 12 (3), pp. 286-292 SIGGRAPH-ACM (August 1978)〕 Normal mapping is the most common variation of bump mapping used.〔Mikkelsen, Morten. (Simulation of Wrinkled Surfaces Revisited ), 2008 (PDF)〕 ==Bump mapping basics== Bump mapping is a technique in computer graphics to make a rendered surface look more realistic by simulating small displacements of the surface. However, unlike displacement mapping, the surface geometry is not modified. Instead only the surface normal is modified ''as if'' the surface had been displaced. The modified surface normal is then used for lighting calculations (using, for example, the Phong reflection model) giving the appearance of detail instead of a smooth surface. Bump mapping is much faster and consumes less resources for the same level of detail compared to displacement mapping because the geometry remains unchanged. There are also extensions which modify other surface features in addition to increasing the sense of depth. Parallax mapping is one such extension. The primary limitation with bump mapping is that it perturbs only the surface normals without changing the underlying surface itself.〔(Real-Time Bump Map Synthesis ), Jan Kautz1, Wolfgang Heidrichy2 and Hans-Peter Seidel1, (1Max-Planck-Institut für Informatik, 2University of British Columbia)〕 Silhouettes and shadows therefore remain unaffected, which is especially noticeable for larger simulated displacements. This limitation can be overcome by techniques including the displacement mapping where bumps are actually applied to the surface or using an isosurface. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bump mapping」の詳細全文を読む スポンサード リンク
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