Last Updated February 28, 2013

Texture Mapping

Introduction

Mapping is a technique used to add surface detail to otherwise flat and featureless faces without increasing the polygon count. Mapping information is stored in two dimensions and applied to a polygon using various interpolations.

Texture Mapping

Colour Mapping would be a more accurate term to describe this technique, but the name Texture Mapping is in more common usage. The technique allows the user to apply an image or a pattern to a flat face or a series contiguous polygons. E.g. apply a 'brick' pattern to a wall or a company logo to a racing car. Textures can be created in any convenient drawing package and usually stored as an array of colour triplets (BitMap).

A texture is accessed as a 2D array of color information, i.e. the RGB components of diffuse reflection. Textures can be of arbitrary size. Each component of the array is known as a texture element or texel. A pair of values $(s\& t)$ are used to index the texture, $s\&t$ are know as texture coordinates and are scaled to lie the range . Usually textures are associated with faces in the modeling phase the artist associates each vertex of a polygon with a texture coordinate, however there are techniques to automatically map textures to polygons. Mapping parametric surfaces is a trivial operation as there can be a direct correspondence between surface parameters and texture coordinates.