Limitations
Bilinear filtering is rather accurate until the scaling of the texture gets below half or above double the original size of the texture - that is, if the texture was 256 pixels in each direction, scaling it to below 128 or above 512 pixels can make the texture look bad, because of missing pixels or too much smoothness. Often, mipmapping is used to provide a scaled-down version of the texture for better performance; however, the transition between two differently-sized mipmaps on a texture in perspective using bilinear filtering can be very abrupt. Trilinear filtering, though somewhat more complex, can make this transition smooth throughout.
For a quick demonstration of how a texel can be missing from a filtered texture, here's a list of numbers representing the centers of boxes from an 8-texel-wide texture (in red and black), intermingled with the numbers from the centers of boxes from a 3-texel-wide down-sampled texture (in blue). The red numbers represent texels that would not be used in calculating the 3-texel texture at all.
0.0625, 0.1667, 0.1875, 0.3125, 0.4375, 0.5000, 0.5625, 0.6875, 0.8125, 0.8333, 0.9375
Read more about this topic: Bilinear Filtering
Famous quotes containing the word limitations:
“That all may be so, but when I begin to exercise that power I am not conscious of the power, but only of the limitations imposed on me.”
—William Howard Taft (1857–1930)
“Growing up means letting go of the dearest megalomaniacal dreams of our childhood. Growing up means knowing they can’t be fulfilled. Growing up means gaining the wisdom and skills to get what we want within the limitations imposed by reality—a reality which consists of diminished powers, restricted freedoms and, with the people we love, imperfect connections.”
—Judith Viorst (20th century)
“No man could bring himself to reveal his true character, and, above all, his true limitations as a citizen and a Christian, his true meannesses, his true imbecilities, to his friends, or even to his wife. Honest autobiography is therefore a contradiction in terms: the moment a man considers himself, even in petto, he tries to gild and fresco himself.”
—H.L. (Henry Lewis)