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Rendition OpenGL ICD - Advanced Configuration

This driver supports a full OpenGL 1.1 ICD for the V2x00 generation of chips. As this is a beta release, you should expect to find bugs (potentially serious) and a few remaining missing features. Use this ICD at your own risk.

CONFIGURATION INSTRUCTIONS

The latest ICD uses registry entries and/or environment variables to modify behavior. Three features that can be adjusted are:
  1. Triple buffering (when you are a full screen app, and ask for double buffering you actually have 3 buffers allocated - 6 if stereo - in a transparent fashion to the user). Triple buffering drastically reduces the time the graphics chip spends waiting for the vertical sync between frames. An offshoot of this is that it is no longer necessary to have the highest refresh rate to see maximum performance. On the other hand we can run at the lowest comfortable refresh rate, having the CRT controller access the framebuffer much less frequently and thereby freeing up memory bandwidth for rendering. So setting the lowest refresh rate gives best results when triple buffering is enabled. When it is not, then highest refresh rate gives you the fastest results.
  2. Line doubled stereo. When viewing stereo, if the vertical resolution is halved the eye gets fooled into believing that there is almost as much resolution as in a non-stereo buffer with twice the vertical resolution. Halving the vertical resolution, halves the memory/rendering bandwidths required. So we are able to run almost as fast as the non-stereo case (not quite true if the geometry is the bottleneck).
  3. Mipmapping. This release of the ICD supports per-polygon mipmapping.
Triple buffering is on by default. Stereo line doubling is off by default. Mipmapping defaults to "none". There is no need to edit your registry if you do not wish to change this default behavior.

REGISTRY ENTRIES

To change these settings, use regedit to add the following to the local machine registry under "Software\Rendition\OpenGL":

Name Type Values Default Description
TripleBuffering DWORD 0 or 1 1 enable/disable triple buffering
MipMapMode STRING None or PerPolygon None changes mipmapping mode
StereoLineDouble DWORD 0 or 1 0 enable/disable line doubling in stereo
TexLockedMemSize DWORD 1000000 to 8000000 8000000 bytes of memory to lock for texture swapping
GL_EXT_vertex_array DWORD 0 or 1 1 enable/disable GL_EXT_vertex_array
WGL_EXT_swap_control DWORD 0 or 1 1 enable/disable WGL_EXT_swap_control
WGL_EXT_gamma_control DWORD 0 or 1 1 enable/disable WGL_EXT_gamma_control
GL_EXT_point_parameters DWORD 0 or 1 1 enable/disable GL_EXT_point_parameters
GL_EXT_bgra DWORD 0 or 1 1 enable/disable GL_EXT_bgra
GL_EXT_compile_vertex_array DWORD 0 or 1 1 enable/disable GL_EXT_compile_vertex_array
GL_EXT_clip_volume_hint DWORD 0 or 1 1 enable/disable GL_EXT_clip_volume_hint
GL_WIN_swap_hint DWORD 0 or 1 1 enable/disable GL_WIN_swap_hint
GL_DFI_eight_bit_source_EXT DWORD 0 or 1 1 enable/disable GL_DFI_eight_bit_source_EXT
GL_REND_screen_coordinates DWORD 0 or 1 1 enable/disable GL_REND_screen_coordinates
Disable3DNow DWORD 0 or 1 0 enable/disable 3DNow support

ENVIRONMENT VARIABLES

The registry settings can be overridden with environment variables. Set the following variables within your DOS session to override the defaults or under Windows NT under MyComputer/Properties/Environment or under Window 9x in your autoexec.bat

Note:
False = F = No = N = 0 :: these all mean False
True = T = Yes = Y = 1 :: these all mean True
This is handy for writing scripts or creating icons to start apps with your desired settings.

3DNow Support

This release contains preliminary support for AMD's 3DNow technology. OpenGL 3DNow support works best with 3DNow enabled applications, and it may actually slow down with non-3DNow applications. For more information on 3DNow enabled products, please contact AMD at 'www.amd.com'. Also, 'www.3dnow.net' is another web site with useful 3DNow related information.

3DNow support can be disabled with the 'Disable3DNow' registry or environment setting. It is enabled by default.

APP NOTES

Triple buffering uses 50% more frame buffer memory than double buffering. On a 4MB card, memory may be scarce in some applications. If you notice any performance problems with triple buffering enabled, you may wish to disable it or run at a lower resolution.

Quake 1 assumes a double-buffered screen, and when run with triple buffering may exhibit flashing. At the console "set gl_triplebuffer 1" to fix this.

To turn on stereo in Quake 2, type "set cl_stereo 1", "set gl_ztrick 0", followed by a "vidrestart".

With line-doubling enabled, the default console font in Quake 2 is very difficult to read. You may wish to experiment with different fonts, or to turn off stereo mode temporarily while working with the console.

If you experience crashes and think you may be running out of memory, try decreasing the amount of memory locked for texture swapping. A system with 24MB may not have enough memory left over to run many applications after the default 8MB has been locked.

Make sure that the Window's provided `OpenGL32.dll' is present in your `windows/system' directory, and that no other OpenGL32.dll files are present in your app's directory or anywhere they might override the default. Many badly behaved application and driver installations can mess this up and overwrite the default, so be sure and keep a spare copy of the Microsoft OpenGL32.dll around. This file is included in Windows98, and Windows95 OSR2.

RELEASE NOTES

This is a beta version of Rendition's OpenGL ICD. The following should be kept in mind at all times:
  1. Performance is still being improved upon
  2. A few known bugs still exist

Read Me First - License - Release Notes - Read Me GL