public bool ReserveForHostAccess()
{
if (Base != null)
{
return(Base.ReserveForHostAccess());
}
else
{
bool result = true;
// A very light lock, as this case is uncommon.
ThreadedHelpers.SpinUntilExchange(ref _createLock, 1, 0);
if (Base != null)
{
result = Base.ReserveForHostAccess();
}
else
{
_reserved = true;
}
Volatile.Write(ref _createLock, 0);
return(result);
}
}
public bool TryHostConditionalRendering(ICounterEvent value, ulong compare, bool isEqual)
{
// Compare an event and a constant value.
if (value is CounterQueueEvent evt)
{
// Easy host conditional rendering when the check matches what GL can do:
// - Event is of type samples passed.
// - Result is not a combination of multiple queries.
// - Comparing against 0.
// - Event has not already been flushed.
if (compare == 0 && evt.Type == CounterType.SamplesPassed && evt.ClearCounter)
{
if (!value.ReserveForHostAccess())
{
// If the event has been flushed, then just use the values on the CPU.
// The query object may already be repurposed for another draw (eg. begin + end).
return(false);
}
if (Gd.Capabilities.SupportsConditionalRendering)
{
var buffer = evt.GetBuffer().Get(Cbs, 0, sizeof(long)).Value;
var flags = isEqual ? ConditionalRenderingFlagsEXT.ConditionalRenderingInvertedBitExt : 0;
var conditionalRenderingBeginInfo = new ConditionalRenderingBeginInfoEXT()
{
SType = StructureType.ConditionalRenderingBeginInfoExt,
Buffer = buffer,
Flags = flags
};
// Gd.ConditionalRenderingApi.CmdBeginConditionalRendering(CommandBuffer, conditionalRenderingBeginInfo);
}
_activeConditionalRender = evt;
return(true);
}
}
// The GPU will flush the queries to CPU and evaluate the condition there instead.
FlushPendingQuery(); // The thread will be stalled manually flushing the counter, so flush commands now.
return(false);
}