Specifies the quality of texture filtering. Texture filtering is how a texture is displayed when it is made smaller (TGLMinFilter) or bigger (TGLMagFilter) than the original texture. Anisotropic filtering looks better than isotropic filtering but only newer 3D cards have this filtering so is ignored by older cards. TGLTextureFilteringQuality is the enumerated type:

    TGLTextureFilteringQuality = (tfIsotropic, tfAnisotropic);

tfIsotropic: This means that the amount of filtering done along the s and t axes of the texture is the same, and is the maximum of the filtering needed along each of the two axes individually. This can lead to excessive blurring when a texture is viewed at any angle other than straight on.
tfAnisotropic: Anisotropic filtering blends a texture three dimensionally. Instead of just averaging a central pixel's color and those pixels around it (forming a square), anisotrophy averages a pixel and the pixels around it (forming the original shape), which is ideal for most polygons.

Unit: GLTexture