The calculations which are done in order to get the correct colour for each texel. There a 3 different filters, bilinear, trilinear and anisotropic.

Bilinear or trilinear filtering. Also known as sub-texel positioning. If a pixel is in between texels, the program colours the pixel with an average of the texels' colours instead of assigning it the exact colour of one single texel. If this is not done, the texture gets very blocky up close as multiple pixels get the exact same texel colouring, while the texture shimmers at a distance because small position changes keep producing large texel changes.

Bilinear or trilinear filtering, also known as sub-texel positioning. If a pixel is in between texels, the program colors the pixel with an average of the texels' colors instead of assigning it the exact color of a single texel.