SGI Windows NT Toolbox

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320 and 540 pixel formats


System:   any Category:   graphics Last Modified:   2/22/99
OS version:   NT 4.0 Product:   OpenGL Service Pack:  
Description

What pixel formats, or "visuals", are supported on the Silicon Graphics 320 and the Silicon Graphics 540?

Problem Resolution

Both the Silicon Graphics 320 and Silicon Graphics 540 Visual Workstations support RGB and Color Indexed (CI) formats, as well as overlay windows.

However, the list of available pixel formats changes depending on display settings (see Display Properties->Settings from the Control Panel). Note also that, depending on the display mode, some OpenGL features (and acceleration) may be disabled. See the program "wglinfo.exe," included with the Graphics Software Development Kit listed below, to get a list of available pixel formats.

RGB modes
RGB double-buffered pixel formats are supported in both 16 and 32-bit depths. The 16-bit format is organized as 5551, the 32-bit format as 8888. Both modes support single and double-buffered windows. The type of pixel format allocated is consistent with, and controlled by, the global settings in the Display Properties dialog of NT. As a shortcut, use your right mouse on the background, then select "Properties".


Color Indexed Modes
On the Silicon Graphics 320 and Silicon Graphics 540, 12-bit CI modes are not supported. However, 8-bit CI modes are supported.

See the online documentation that comes with the Silicon Graphics OpenGL SDK for more details (SDK link below).


Overlay
An 8-bit, single-buffered overlay is available. It has its own colormap where entry 0 is the transparent color. The following extensions may be used to modify the palette for the overlay:

wglSetLayerPaletteEntries()
wglGetLayerPaletteEntries()
wglRealizeLayerPalette()

For more information on the above wgl functions, see the documentation that comes with wgl.

More documentation about the above pixel formats, as well as programming examples, are included in the Graphics Software Development Kit (SDK):

http://www.sgi.com/developers/nt/sdk


Send comments on this case to kbase@sgi.com.


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