Transformation, Clipping And Lighting Support; Threads Restriction; No Backing Store/Save Under For 3D Windows; Multiple Graphics Cards Support - HP 7500 PCI Installation Manual

HP OpenVMS I64 – Graphics Software Installation & Customization
ATI RADEON 7500 PCI Graphics Controller Installation Guide
the libraries provide support for the ATI RADEON 7500 TCL hardware, hardware alpha and stencil
planes, 3D multi-texturing, and 3D cube map textures.
The RADEON 7500 Mesa3D software will, by default, force a direct-rendered 3D context whenever the
3D client requests connection to the X11 server using the LOCAL transport. Direct rendering is a
highly desirable performance feature for 3D applications.
You can override this default behavior and force the default to always be indirect rendering (indirect
rendering means that all 3D operations are executed by the X11 OpenGL server extension) by defining
the following logical name before running the 3D application:
$ DEFINE LIBGL_ALWAYS_INDIRECT 1
This can also be achieved by using the DECNET or TCPIP transports.
Hardware acceleration can be disabled entirely by defining the system logical:
$ DEFINE/SYSTEM/NOLOG DECW$SERVER_NOACCEL TRUE
HP recommends that the direct rendering interface be used for 3D operation.

Transformation, Clipping and Lighting Support

The Mesa3D driver for the RADEON 7500 contains support for the on-board transformation, clipping,
and lighting (TCL) hardware of the RADEON 7500 for increased primitive rendering performance.
The embedded graphics typically found on HP Integrity systems is based on the ATI RADEON 7000,
and also provides 3D capability, but does not have TCL hardware capability.

Threads Restriction

The RADEON 7500 Mesa3D library for OpenVMS is not thread safe. However, Mesa3D can be used in
a multithreaded program if the use of Mesa3D is restricted to a single thread within the program.

No Backing Store/Save Under for 3D Windows

Backing store and save under features are not supported when 3D is in use.

Multiple Graphics Cards Support

The ATI RADEON 7500 software has been tested for up to 4 cards per system. All operations, including
hardware accelerated 3D graphics, are supported on every card in the system. Consult your Integrity
system options documentation for detailed information on number of cards supported and configuration
limitations.
The embedded graphics available on most HP Integrity systems based on the ATI RADEON 7000 is
compatible with multi-head operation with the ATI RADEON 7500 option card, and can be combined
when using multi-head operation.

Multi-Screen Versus XINERAMA

By default, multiple screens are handled as traditional X11 multiple screens. However, the screens can
be handled as a single "virtual" screen using the XINERAMA extension. This is documented both in the
DECW$PRIVATE_SERVER_SETUP.COM procedure, and in the Motif documentation.
NOTE: Only 2D operation is possible when using XINERAMA. 3D operation will not function
correctly, or will use software only (no acceleration).
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