View source for Micropolygon

{{3D computer graphics}}
In [[3D computer graphics|3D computer graphics]], a '''micropolygon''' (or μ-polygon) is a [[Polygon (computer graphics)|polygon]] that is very small relative to the image being [[Rendering (computer graphics)|rendered]]. Commonly, the size of a micropolygon is close to or even less than the area of a [[Pixel|pixel]]. Micropolygons allow a renderer to create a highly detailed image.{{cn|date=March 2020}}

The concept of micropolygons was developed within the [[Reyes rendering|Reyes algorithm]], in which [[Geometric primitive|geometric primitive]]s are [[Tessellation (computer graphics)|tessellated]] at render time into a rectangular grid of tiny, four-sided polygons. A [[Shader|shader]] might fill each micropolygon with a single [[Color|color]] or assign colors on a per-[[Vertex (geometry)|vertex]] basis. Shaders that operate on micropolygons can process an entire grid of them at once in [[SIMD]] fashion. This often leads to faster shader execution, and allows shaders to compute spatial [[Derivative|derivative]]s (e.g. for texture [[Reconstruction filter|filtering]]) by comparing values at neighboring micropolygon vertices.{{cn|date=March 2020}}

Furthermore, a renderer using micropolygons can support [[Displacement mapping|displacement mapping]] simply by perturbing micropolygon vertices during shading. This displacement is usually not limited to the local [[Normal (geometry)|surface normal]] but can be given an arbitrary direction.{{cn|date=March 2020}}

==Further reading==
* Robert L. Cook., Loren Carpenter, and [[Biography:Edwin Catmull|Edwin Catmull]]. "The Reyes image rendering architecture." ''Computer Graphics (SIGGRAPH '87 Proceedings)'', pp.&nbsp;95&ndash;102.
*Anthony A. Apodaca, Larry Gritz: ''Advanced RenderMan: Creating CGI for Motion Pictures'', Morgan Kaufmann Publishers, {{ISBN|1-55860-618-1}}

[[Category:3D computer graphics]]



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{{Sourceattribution|Micropolygon}}