102 Video Game Design Foundations
or fi nishing. Therefore, the defi nition of interpolation is a refi ning of the
spaces between the points or pixels of an object.
When a computer makes an object larger, it needs to fi ll in the spaces
between each pixel. This effect is called dithering. If it does not fi ll in that
space, the object would look really funny as it would separate into little dots.
The computer uses interpolation to dither an image when it is resized.
When dithering an image, the computer
chooses a blended color to fi ll in between
the pixels that moved. This process repeats
every time the object is enlarged by more than
one pixel spacing. As more blended pixels are
inserted, the object develops a blurry look as
the color between the two native poles or
pixels continues to distort.
In Figure 4-12, green pixels touch red
pixels in certain locations. If this picture is
enlarged, the computer must interpolate a new pixel between these two
native pixels. The fi gure shows what an interpolated pixel might look like.
The computer adds a pixel and colors it based on information from the
surrounding pixels. The red-green-blue (RGB) color of the red pixel is
222,0,0 (222 density of red, 0 green, and 0 blue). The RGB color of the
green pixel is 0,128,0 (0 density of red, 128 green, and 0 blue). The inter-
polated pixel has an RGB color of 222,128,0. As you can see, that color is
nothing like either of the original colors. This causes the picture to get fuzzy,
distorted, and discolored as the size increases.
Designers of digital scenes need to make the images clear enough to
look like the item being shown. However, making images too fi ne will take
more computer memory to generate items due to the greater number of
pixels. The designer will also have to know on what type of computer system
the game will be played. That determines the total background frame size
CHEAT CODE: NATIVE POLES
Native poles or native pixels are the original
pixels of an object before it was modifi ed.
The computer creates an interpolated
pixel between two native pixels when
an object is resized.
Adjacent pixels
Interpolated pixel
Figure 4-12. When an image is resized, the computer must decide what color the new pixels should be. This can cause
an image to become blurry or muddy.