Glossary
ELSA ERAZOR II and ELSA VICTORY Erazor LT
33
average colors for inserted pixels). Horizontal
interpolation is relatively easy to perform, since
the pixels are drawn to the screen in lines.
Vertical interpolation is more difficult and
requires a complete pixel line to be buffered.
쮿MIP mapping – In MIP mapping a number of
textures are assigned to an object depending
on distance. The representation of the object
becomes more detailed as the observer
approaches the object.
쮿Multifrequency/Multisync monitor – A
monitor that can be operated at various hori-
zontal scan frequencies, or that automatically
adapts itself to different video signals (resolu-
tions).
쮿OpenGL – 3D software interface (3D API).
E.g. implemented in Windows NT and avail-
able for Windows 95. Based on Iris GL from Sil-
icon Graphics and licensed from Microsoft.
쮿Page Flipping – The image generated in the
➞back buffer is displayed
쮿PCI bus – Abbreviation of Peripheral Compo-
nent Interconnect Bus. An advanced bus sys-
tem, i.e. a system of parallel data lines to
transfer information between individual system
components, especially to expansion boards.
쮿Phong shading – ➞ 'Shading'.
쮿Pixel – Picture element. Dot in the image.
쮿Pixel frequency – Pixel clock frequency
(number of pixels drawn per second in MHz).
쮿Primitive – Simple, polygonal geometrical
object, such as a triangle. 3D landscapes are
generally broken down into triangles.
쮿RAM – Abbreviation of Random Access Mem-
ory. Chip memory of a computer or expansion
board that can be read from and written to
(unlike ROM = Read Only Memory).
쮿RAMDAC – The RAMDAC converts the digital
signals to analog signals on a graphics board.
VGA monitors are only capable of processing
analog signals.
쮿RealColor – RealColor normally designates a
15-bpp or 16-bpp (bits per pixel) graphics mode,
i.e. 32,768 or 65,536 colors).
쮿Refresh rate – or image refresh frequency (in
Hz) indicates how many times per second an
image on the monitor is refreshed.
쮿Rendering – Process for calculating the repre-
sentation of a 3D scene, in which the position
and color of each point in space is determined.
The depth information is held in the ➞Z buffer,
the color and size information is held in the
➞frame buffer.
쮿Resolution – The number of pixels in horizon-
tal and vertical direction on the screen, for
example 640 horizontal by 480 vertical pixels
(640 x 480).
쮿RGB – Color information is saved in the Red/
Green/Blue color format.
쮿ROM – Abbreviation of Read Only Memory.
Semiconductor memory that can only be read
and not written to.
쮿Shading – Shading or rendering is a way to
define the colors on curved surfaces in order to
give an object a natural appearance. To
achieve this, the surfaces are subdivided into
many small triangles. The three most impor-
tant 3D shading methods differ in the algorithm
used to apply colors to these triangles:
Flat shading: the triangles are uniformly col-
ored.
Gouraud shading: The color shades on a trian-
gle are calculated by interpolating the vertex
colors, resulting in a smooth appearance of the
surface.
Phong shading: the color shades on a triangle