Texture Filtering : Antialiasing

No 1 to 1 mapping between texel (pixels in the texture map) and pixels on the screen.

Forward mapping or inverse mapping.

Since there will almost never be a 1 to 1 mapping between pixels in the texture map (texels) and pixels on the screen, we must filter the texture map when mapping it to the screen. The way in which we accomplish the filtering depends on whether we are forward mapping or inverse mapping.

Relative size of the textels on the screen