Anisotropic filtering is not part of the core OpenGL specification, but is a widely available extension.

It dramatically improves the quality of texture filtering operations.

The standard texture filtering modes use texture coordinates to average texel colours.

• This works fine when the surface being textured is viewed orthogonal to the camera direction vector
• At oblique views, the texture may look blurry.

A more realistic sampling would consider the viewing angle when sampling – anistropic filtering provides this.


Source: OpenGL Superbible

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