Material capture ("MatCap") shaders are popular effects used in most 3D modeling tools: A material is captured by rendering a sphere into a texture. Models can be shaded by making a simple lookup into the reference texture.

This type of shading is very efficient – no complicated computations, only a single texture lookup per pixel. The effect works great for previewing objects in a 3D modeling tool. However, it is less suited for games: The reference texture only stores one side of a sphere. The effect breaks down, when the camera moves around the object.

DigitalRune Graphics contains Predefined Effects and Samples with MatCap shaders.