HP c8000 manual Miscellaneous topics, Double buffer extensions

configuring X Windows on HP-UX (HP Visualize graphics cards)

X Server configuration

Screen /dev/crt0 SingleLogicalScreen 1 2 /dev/crt1 /dev/crt2

Figure 2-7 Three physical displays, screen plus single logical screen(1x2)

<host>:0.0

/dev/crt0

<host>:0.0

/dev/crt1 /dev/crt2

miscellaneous topics

double buffer extensions

DBE is an extension to the X Server that provides a double-buffering Application Programming Interface (API). For more information about DBE and the API, consult the DBE man pages:

DBE

XdbeQueryExtension

XdbeGetVisualInfo

XdbeFreeVisualInfo

XdbeAllocateBackBufferName

XdbeDeallocateBackBufferName

XdbeSwapBuffers

XdbeBeginIdiom

XdbeEndIdiom

XdbeGetBackBufferAttributes

performing buffer swaps on vertical blank

For performance reasons, the default DBE behavior is to not synchronize buffer swaps with the monitor’s vertical retrace period. In some instances, therefore, image tearing (seeing part of the old image and part of the new image on the display at the same time) could be visible while swapping large DBE windows. For those instances where tearing would occur and is undesirable, an optional X Server mode is available to allow for synchronization of buffer swaps with vertical retrace. To activate this optional X Server mode, set the following screen option in the X*screens File before the X Server is started:

SwapBuffersOnVBlank

20 Chapter 2