Clock updates

tests/RenderCadenceCompositorClockTests.cpp

@@ -60,6 +60,27 @@ void TestLatePollRecordsSkippedFrames()
 	Expect(cadence.SkippedFrameCount() == 3, "late poll accumulates skipped frames");
 }
 
+void TestLatePollSkipsMissedIntervalsInsteadOfCatchingUp()
+{
+	using Clock = RenderCadenceClock::Clock;
+	RenderCadenceClock cadence(10.0);
+	const auto start = Clock::now();
+	cadence.Reset(start);
+
+	const auto late = start + std::chrono::milliseconds(35);
+	const auto tick = cadence.Poll(late);
+	Expect(tick.due, "late skipped-interval poll is due");
+	Expect(tick.skippedFrames == 3, "late skipped-interval poll counts missed frames");
+
+	cadence.MarkRendered(late);
+	Expect(cadence.NextRenderTime() > late, "late render schedules the next tick in the future");
+	Expect(cadence.NextRenderTime() - late <= std::chrono::milliseconds(6), "late render does not leave catch-up frames due immediately");
+
+	const auto immediateFollowup = cadence.Poll(late);
+	Expect(!immediateFollowup.due, "cadence does not allow an immediate catch-up render after a late frame");
+	Expect(immediateFollowup.sleepFor > RenderCadenceClock::Duration::zero(), "cadence reports wait time after skipping missed intervals");
+}
+
 void TestMarkRenderedRebasesAfterLargeStall()
 {
 	using Clock = RenderCadenceClock::Clock;
@@ -81,6 +102,7 @@ int main()
 	TestEarlyPollWaitsWithoutAdvancing();
 	TestDuePollRendersWithoutSkipping();
 	TestLatePollRecordsSkippedFrames();
+	TestLatePollSkipsMissedIntervalsInsteadOfCatchingUp();
 	TestMarkRenderedRebasesAfterLargeStall();
 
 	if (gFailures != 0)