overview of OpenGL
environment variables
environment variables
Here is a list of environment variables used by HP’s implementation of OpenGL.
HPOGL_ALLOW_LOCAL_INDIRECT_CONTEXTS
This variable may be set if a need arises to really create a local indirect context. By default, if an indirect context is requested for a local HP display connection, a direct context will be created instead because the performance will be much better.
HPOGL_ENABLE_MIT_SHMEM
When rendering locally using the VM Driver, this variable allows the server and client to look at the rendering buffer at the same time. This variable has no effect through DHA. It merely eliminates the data transfer for XPutImage() that is done by VMD. This only offers a performance improvement on simple wireframes. Under most circumstances, it does not provide any performance improvements.
HPOGL_FORCE_VGL
This variable can be set to force HP’s Virtual GL (VGL) rendering mode using VMD. This differs from HPOGL_FORCE_VMD in that the GLX Visual list and other GLX extension information is not retrieved from the GLX Server extension, but is rather synthesized from standard X Visual information and the capabilities known to exist in VMD.
HPOGL_FORCE_VMD
This variable forces clients to render through the VMD. This variable can be used as a temporary fix and/or a diagnostic. You should set this variable when a rendering defect in the hardware device driver is suspected. When this variable is set, rendering speed will slow down. If rendering is identical in both hardware and software, then this may indicate a problem in the application code.
HPOGL_LIB_PATH
This variable can be used to load OpenGL driver libraries from a directory outside the standard LIB_PATH. This variable should be set to the actual directory the libraries are in, with or without a trailing’/’.
HPOGL_LIGHTING_SPACE (HP Visualize fx family only)
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