bilinear texture filtering 
Bilinear texture filtering enhances a computer's ability to scale 3D graphics in a smoother, more realistic way. With 3D graphics, especially with games, you don't want a graphics card to grab texture maps from memory and simply write them on your computer screen: as the polygons drawn onscreen grew bigger, they would take on a blocky look. To improve the ability to scale 3D graphics, you need to filter them. Bilinear texture filtering does this by averaging the four adjacent texels (the basic elements of a texture map), thus creating a new texel that renders a more subtle, realistic texture.