Alpha blending
Combining two images with
different transparency levels so that one image appears
visible through the other. An object's transparency is
defined as its Alpha value or Alpha level.
Anti-aliasing
The removal of artifacts from
an image.
Bi-linear sampling/filtering
A combination of four colors
in a single 3D image used +to improve that image's
resolution.
Clipping
Removal of any image displayed
outside of a predefined shape.
Compressed Textures Depth cueing
Changing the color and
brightness of a 3D image as it moves, relevant to the viewer.
Color becomes less bright as the image moves away, brighter
as it moves closer.
Dithering
Substituting combinations of
colors you do have for colors that you don't. For example, if
your computer is only capable of displaying 256 colors and
you load an image that use 65,000 colors, your computer will
create substitutes for the colors you don't have by combining
the colors that you do. The color quality of a dithered image
is inferior to a non-dithered image.
Double buffering
A way for your computer to
work on an image two different ways at once. Before
displaying an image, your video card calculates what a
finished image will look like and displays that image while
it is calculating the next image in a video stream.
Double-buffering affords smoother playback for video or any
other multiple-frame file format.
Frames Per Second (FPS)
A measurement of how often
information in a video or animation file is updated on your
screen or how many frames of motion you see in a given
second. Movies and television shows are shown at 24fps.
Photo mapping
Overlaying a photo image on a
3D object, so that the photo takes the shape of that object.
Rasterization
Transformation of a 2D object
into a 3D object.
Ray tracing
One way of rendering a
picture. The computer computes the path of a light ray from
the light source to the objects (from which the ray
reflects), and further to the observer. It does this for
every pixel on the monitor. This is a very intensive
calculation, but the results are worth it.
Refraction
Bending of light when it
passes through another substance.
Rendering
Converting a graphics image
into an array of pixel colors for the display.
Shading (gouraud/phong)
Both shading methods make the
surface and color of an object appear smoother. Phong shading
takes more CPU time but gives better results. Gouraud shading
is faster.
Texture mapping
Overlaying a graphics image on
a 3D object, so that the photo takes the shape of that
object.
Transparent/Translucent
An image that can partially be
seen through.
Tri-linear mip-mapping
The texture map is stored at
several levels of detail in a structure called mip-map. You
compute the texture coordinates and the exact level of
detail. This gives you the two closest levels of detail
available in the mip-map. In each one you perform a bilinear
interpolation, and then a linear interpolation between the
two levels (that's why it's called tri-linear). High-end
graphics workstation (like SGI Reality Engine) use tri-linear
mip-mapping.
Tri-Strip processing Vertex
A point which marks the
intersection of two or more edges of a polygon or other
graphics object.
Video mapping
The same as texture mapping.
In the case of video mapping, the texture is applied to an
animation or a video clip.
Z-buffer
A two dimensional array made
up of a grid of points on a sea-level plane, each containing
the value of the depth (z) at that point. This way every
pixel on the monitor has a "depth value" so that
the program knows which polygons are in the foreground and
which are in the background.