From e885438363a8a947b3066266eee62dd9e084f4ce Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 6 Apr 2016 19:34:34 -0400
Subject: [PATCH] The penny has finally dropped that I can drive the CPU stuff
 in a manner completely decoupled from the GPU stuff. For much improved
 parallelisation.

---
 .../Documents/MachineDocument.swift           |  6 ++----
 .../Mac/Clock Signal/Views/CSOpenGLView.m     | 19 ++++---------------
 2 files changed, 6 insertions(+), 19 deletions(-)

diff --git a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift
index 062a69158..cc72a643f 100644
--- a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
+++ b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
@@ -41,12 +41,10 @@ class MachineDocument: NSDocument, CSOpenGLViewDelegate, CSOpenGLViewResponderDe
 		let cycleCount = cycleCountLow + cycleCountHigh
 		if let lastCycleCount = lastCycleCount {
 			let elapsedTime = cycleCount - lastCycleCount
-			// if the emulation has fallen too far behind then silently swallow the request;
+			// if the emulation has fallen too far behind then silently limit the request;
 			// some actions — e.g. the host computer waking after sleep — may give us a
 			// prohibitive backlog
-			if elapsedTime < intendedCyclesPerSecond / 25 {
-				runForNumberOfCycles(Int32(elapsedTime))
-			}
+			runForNumberOfCycles(max(Int32(elapsedTime), Int32(intendedCyclesPerSecond / 25)))
 		}
 		lastCycleCount = cycleCount
 	}
diff --git a/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m b/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m
index 3514e9001..5f50e1ec8 100644
--- a/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m	
+++ b/OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m	
@@ -13,7 +13,6 @@
 @implementation CSOpenGLView {
 	CVDisplayLinkRef _displayLink;
 	uint32_t _updateIsOngoing;
-	int _missedFrames;
 }
 
 - (void)prepareOpenGL
@@ -53,28 +52,18 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 
 - (void)drawAtTime:(const CVTimeStamp *)now
 {
+	// Always post a -didUpdateToTime:. This is the hook upon which the substantial processing occurs.
+	[self.delegate openGLView:self didUpdateToTime:*now];
+
+	// Draw the display only if a previous draw is not still ongoing.
 	const uint32_t activityMask = 0x01;
 	if(!OSAtomicTestAndSet(activityMask, &_updateIsOngoing))
 	{
-		_missedFrames = 0;
-		CVTimeStamp time = *now;
 		dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
-			[self.delegate openGLView:self didUpdateToTime:time];
 			[self drawViewOnlyIfDirty:YES];
 			OSAtomicTestAndClear(activityMask, &_updateIsOngoing);
 		});
 	}
-	else
-	{
-		_missedFrames++;
-		if(_missedFrames == 10)
-		{
-			_missedFrames = 0;
-			dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
-				[self drawViewOnlyIfDirty:YES];
-			});
-		}
-	}
 }
 
 - (void)invalidate