OpenGL

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.