Nvidia QUADRO G-SYNC II, User Manual

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Buffer Swap Criteria
The criteria for buffer swaps involves when a window is
ready to swap and when a group is ready to swap.
Window Buffer Swaps
Any rendering surface that is not a window—such as a non-visible
rendering buffer—is always ready, otherwise the following criteria must
be satis
fi ed before a buffer swap for a window can be performed:
 The window itself must be ready, meaning:
A buffer swap command has been issued for it.
Its swap interval has elapsed.

If the window belongs to a group, all the
windows in the group must be ready.

If the window belongs to a group and that group is bound to
a barrier, all groups bound to that barrier must be ready.
Group and Barrier Buffer Swaps

Buffer swaps for all windows in a swap group take place
concurrently and buffer swaps for all groups using a barrier take
place concurrently.For barrier swaps, the vertical retraces of the
screens of all the groups must also be synchronized, otherwise
there is no guarantee of concurrency between groups.
 An implementation may support a limited number of swap groups and
barriers and may have restrictions on where the users of a barrier can
reside.
For example, an implementation may allow the users to reside
on different display devices or even hosts. An implementation
may return zero for any of maxGroups and maxBarriers returned
by
QueryMaxSwapGroupsNV
if swap groups or barriers are
not available in that implementation or on that host.
Using the OpenGL Extensions
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