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Glossary
41
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ELSA GLADIAC
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EN
➞
Luminance are separated. This results
in improved image quality.
쎲
Shading –
The shading of curved areas
to make them appear as realistic as
possible. To do so, the curved areas are
divided into many small triangles. The
three most important 3D shading methods
differ by how the color gradients within
the triangles are represented: Flat
shading: The triangles are colored
uniformly. Gouraud shading: The color
gradient is determined by the interpolation
of the corner color values. Phong shading:
The color gradient is determined by the
interpolation of the normal vector plus the
calculation of the light incidence for each
pixel. These shading methods are not
supported directly in the standard OpenGL
API.
쎲
Single buffer –
Unlike the double buffer,
where there is doubled display memory,
single buffer mode does not allow access
to the next prepared image, resulting in
animation that is not smooth.
쎲
Sphere environment mapping –
➞
Cube environment mapping.
쎲
Stencil buffer –
This buffer permits the
color information of the pixels to be
supplemented with further information.
This can be used to create stencils,
volumetric shadows and reflective
surfaces, for example.
쎲
Strips and fans –
This is a process to
reduce the data volume related to complex
3D objects. Strips are used for objects
consisting of several parallel rows of
triangles. Rather than calculating each
individual triangle, the vertices are
transferred only once. A fan object is used
when several triangles converge to a
single point. In this case, the vertices are
also transferred only once. These
processes can reduce the data volume by
approximately 50%.
쎲
Tearing –
If there is no synchronization
with the monitor when switching between
images (pages) in double buffering mode,
areas of the images can become offset. To
resolve this, the switching between pages
is synchronized with the monitor
frequency (Wait on Vertical Blank).
쎲
Tesselation –
Tessellation subdivides
objects into polygons (triangles) for 3D
rendering. For each triangle, the corner
point and color values as well as the
transparency value if necessary are
determined.
쎲
Textures –
The overlaying of a surface
with a texture with correction for
perspective, such as a wood grain or the
drawing of a wall with wallpaper in a
perspective view. A video, too, can be
used as a texture.
쎲
Transformation & Lighting (T&L) –
Using T&L, the main computer processor is
freed up from the consuming task of
computing geometric calculations. This
computational process, which includes all
of the coordinates of a 3D object during
rotation, shifting, scaling and color, is
taken over by the graphics board
processor.
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