
This is the "gold" release of OpenGL 1.1 for OS2.  Please forwared any
problems to IBM support or mail a description of the problem and a 
testcase to - os2-opengl@utsi.com.


   Important Troubleshooting Tips
   ------------------------------

   OpenGL makes a lot of demands on the setup of your system, and when
   the setup reported by the graphics device driver does not exactly
   match the actual one, problems can arise. If OpenGL does not render,
   or if the image looks incorrect, one of the following items may help.
   These settings will override whatever OpenGL queries from your graphics
   device, so do not use them unless you are having trouble.

   - A "squished" OpenGL image is most likely the result of an incorrect
     bits-per-pixel report from your OS/2 graphics device driver when
     running in 24 bit. In this case, setting  OGL_BIT_COUNT=32 in your
     environment by adding "SET OGL_BIT_COUNT=32" to the config.sys should
     correct the image. Please be aware that this statement should not be used
     when in 8 or 16 bit.

   - An OpenGL rendering that has a repeated image that goes beyond the bounds
     of the window is probably the result of an incorrect scanline size report.
     Scanline sizes are usually the product of the horizontal screen resolution
     and the screen depth in bytes-per-pixel (a 1024x768x64k setting may use a
     scanline size of 2048, since 64K is 2**16 which means every pixel is
     comprised of 2 bytes). In this case, adding "SET OGL_SCANLINE_SIZE=2048"
     to the config.sys should correct the problem. Please be aware that a
     OGL_SCANLINE_SIZE setting that works in one screen resolution and depth
     setting will not work in another.

   - When running with a color depth of 8 bit, OpenGL will attempt to preserve
     the PM colors used on the desktop, but as a result, OpenGL may not receive
     all of the colors in its palette. The results obtained are very graphic
     card dependent. If OpenGL is not receiving all of the colors it needs
     for an image, OpenGL can force PM to use the OpenGL colors by setting
     "OGL_OVERRIDE_COLORS=1" in your environment. Be aware that the PM desktop
     will flash and the PM colors may not be preserved when the OpenGL window
     has focus, but the OpenGL window will obtain all of its colors.  Setting
     "OGL_OVERRIDE_COLORS=" will reset the overriding of PM colors. But in all
     cases the best visual results will be obtained when 
     "System Setup->System->256 Colors->Workplace shell palette aware" is
     checked (see Helpful Information).


   Helpful Information
   -------------------

   When running in 256 color mode, the following check box should be selected
   for optimal visual results:
       "System Setup->System->256 Colors->Workplace shell palette aware"

   The best OpenGL performance will be attained with a PCI graphics card that
   is not bank-switched at the desired screen resolution and depth. When
   running in 24 bit, a non packed pixel (32 bot) device driver and graphics
   card combination will yield better performance then a packed pixel (24 bit)
   one.

   Running OpenGL on a Matrox Millennium in 24 bit requires that DIVE support
   is enabled. See the documentation that came your Matrox for information on
   how to enable DIVE support in 24 bit.

   Summary of Settable Environment Variables
   -----------------------------------------

   The following strings are scanned for in the current environment by OpenGL,
   these can be set by using the "SET" command in OS/2 (issue "help set" in an
   OS/2 Window for information on the "SET" command). may help. These settings
   will override whatever OpenGL queries from your graphics device, so do not
   use them unless you are having trouble.


   OGL_BIT_COUNT - used by OpenGL to replace the bits-per-pixel report from the
   graphics device driver. Primary use is for when 32 bpp(non-packed)
   setup actually reports 24 bpp (packed). See "Important Troubleshooting Tips"
   section.

   OGL_SCANLINE_SIZE - used by OpenGL to replace the scanline size report from
   the graphics device driver. See "Important Troubleshooting Tips" section.

   OGL_OVERRIDE_COLORS - used by OpenGL to override the PM colors in the color
   palette. Only applicable when running in 8 bit. See "Important
   Troubleshooting Tips" section.
