All about graphics
ELSA ERAZOR X and ERAZOR X²
21
OpenGL
Following its success in gaining a good reputation amongst professionals using CAD/
CAM programs, OpenGL is now increasingly penetrating the PC market. OpenGL is plat-
form-independent and makes a distinction between immediate and display list modes. A
display list stores specific sequences that can be recalled again later. The object descrip-
tions can then be taken directly from the list, resulting in very high performance. How-
ever, if objects need to be manipulated frequently, the display list will have to be
generated again from new. In this case, the speed advantage is lost. OpenGL provides
a wide range of graphics features, from rendering a simple geometric point, line, or filled
polygon, to the most sophisticated representations of curved surfaces with lighting and
texture mapping. The some 330 routines of OpenGL provide software developers access
to these graphics capabilities:
For further information see the Internet WWW site http://www.sgi.com
Color palettes, TrueColor and gray scales
Common graphics modes are listed in the following table. Not all graphics modes are
available on the
ELSA ERAZOR X and ERAZOR X²
boards.
VGA
In VGA graphics adapters, the digital color information stored in the video memory (4 bits
for 16 colors or 8 bits for 256 colors) is converted into a digital 18-bit value in the graphics
adapter in a CLUT (ColorLookUpTable). The 3 x 6 bits are converted separately for R/G/
B (red/green/blue) in the RAMDAC (D/A converter) and transferred to the monitor as ana-
log signals on just three lines (plus sync lines). The original color values are converted
into completely different values by means of a translation table. The value stored in the
video memory is thus not a color value, but only a pointer to a table in which the actual
color value is found. The advantage of this method: Only 8 bits need to be stored for each
Graphics mode
bpp
bpg
Colors
(from palette)
Max. gray levels
VGA 0x12
VGA 0x13
4
8
6+6+6
6+6+6
16 of 262,144
256 of 262,144
16
64
Standard
8
8
6+6+6
6+6+6
256 of 262,144
256 of 16.7 million
64
256
HighColor
15
16
16
5+5+5
6+6+4
5+6+5
32,768
65,536
65,536
32
16
32
TrueColor
24
32
8+8+8
8+8+8+8
16.7 million
16.7 million
256
256
(bpp = bits per pixel; bpg = bits per gun)
Summary of Contents for ERAZOR X
Page 1: ...ELSA ERAZORTM X ELSA ERAZORTM X Manual ...
Page 10: ...Introduction ELSA ERAZOR X and ERAZOR X 4 ...
Page 16: ...After installing the drivers ELSA ERAZOR X and ERAZOR X 10 ...
Page 22: ...Useful stuff and more ELSA ERAZOR X and ERAZOR X 16 ...
Page 30: ...All about graphics ELSA ERAZOR X and ERAZOR X 24 ...
