glXWaitVideoSyncSGI(3G) OpenGL Reference - GLX glXWaitVideoSyncSGI(3G)NAME
glXWaitVideoSyncSGI - wait for vertical retrace
C SPECIFICATION
int glXWaitVideoSyncSGI( int divisor,
int remainder,
unsigned int *count )
PARAMETERS
divisor
remainder glXWaitVideoSyncSGI puts the calling process to sleep until
the value of the vertical retrace counter modulo divisor
equals remainder.
count Pointer to variable which receives the value of the vertical
retrace counter when the calling process wakes up.
DESCRIPTION
glXWaitVideoSyncSGI is part of the SGI_video_sync extension. This
extension provides a way to synchronize with the video frame rate of a
monitor (in the case of an interlaced display, the synchronization is
actually with the field rate).
A vertical retrace precedes the display of each video frame. The kernel
maintains a 32-bit unsigned integer counter for each graphics pipe in the
system. This counter is initialized via the /usr/gfx/gfxinit command,
and incremented upon each vertical retrace. Since all the video output
channels of a graphics pipe must be genlocked, one counter suffices for
all the monitors driven by a pipe.
A process can query or sleep on the counter of the graphics pipe
associated with its current OpenGL rendering context, provided that the
rendering context is direct. (See glXCreateContext.)
glXWaitVideoSyncSGI puts the calling process to sleep until the vertical
retrace counter modulo divisor equals remainder. When this condition is
met it places the value of the vertical retrace counter in the location
referenced by count and returns zero.
If the current context is not direct, glXWaitVideoSyncSGI returns
GLX_BAD_CONTEXT_SGI. If divisor is less than or equal to zero,
glXWaitVideoSyncSGI returns GLX_BAD_VALUE_SGI. If remainder is less than
zero, or greater than or equal to divisor, glXWaitVideoSyncSGI returns
GLX_BAD_VALUE_SGI.
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glXWaitVideoSyncSGI(3G) OpenGL Reference - GLX glXWaitVideoSyncSGI(3G)MACHINE DEPENDENCIES
glXWaitVideoSyncSGI is not supported on Personal Iris or VGX and VGXT
systems.
SEE ALSO
glXGetVideoSyncSGI, glXCreateContext, glXQueryVersion, glGetString
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