Displacement mapping: Difference between revisions

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'''Displacement mapping''' is an alternative computer graphics technique in contrast to [[bump mapping|bump]], [[normal mapping|normal]], and [[Parallax mapping|parallax]] [[Texture mapping|mapping]], using a [[textureImage mappingtexture|texture]] or [[heightmap|height map]] to cause an effect where the actual geometric position of points over the textured surface are ''displaced'', often along the [[Locally|local]] [[surface normal]], according to the value the texture function evaluates to at each point on the surface.<ref>{{Cite web |title=Chapter 8. Per-Pixel Displacement Mapping with Distance Functions |url=https://developer.nvidia.com/gpugems/gpugems2/part-i-geometric-complexity/chapter-8-pixel-displacement-mapping-distance-functions |access-date=2023-05-10 |website=NVIDIA Developer |language=en}}</ref> It gives surfaces a great sense of depth and detail, permitting in particular self-occlusion, [[self-shadowing]] and silhouettes; on the other hand, it is the most costly of this class of techniques owing to the large amount of additional geometry.

For years, displacement mapping was a peculiarity of high-end rendering systems like [[PhotoRealistic RenderMan]], while realtime [[Application programming interface|APIs]], like [[OpenGL]] and [[DirectX]], were only starting to use this feature. One of the reasons for this is that the original implementation of displacement mapping required an adaptive [[Tessellation (computer graphics)|tessellation]] of the surface in order to obtain enough [[micropolygon]]s whose size matched the size of a pixel on the screen.{{citation needed|date=March 2020}}