A full communication pathway now leads to Atari2600.mm (for now) being in possession of a frame and receiving a command to draw, with a suitable OpenGL context being active and whatever is drawn subsequently appearing.

OSBindings/Mac/Clock Signal/Atari2600.h

@@ -8,9 +8,18 @@
 
 #import <Foundation/Foundation.h>
 
+@class CSAtari2600;
+@protocol CSAtari2600Delegate
+- (void)atari2600NeedsRedraw:(CSAtari2600 *)atari2600;
+@end
+
 @interface CSAtari2600 : NSObject
 
+@property (nonatomic, weak) id <CSAtari2600Delegate> delegate;
+
 - (void)runForNumberOfCycles:(int)cycles;
 - (void)setROM:(NSData *)rom;
 
+- (void)draw;
+
 @end

OSBindings/Mac/Clock Signal/Atari2600.mm

@@ -8,6 +8,7 @@
 
 #import "Atari2600.h"
 #import "Atari2600.hpp"
+#import <OpenGL/gl.h>
 
 @interface CSAtari2600 (Callbacks)
 - (void)crtDidEndFrame:(Outputs::CRTFrame *)frame;
@@ -23,18 +24,35 @@ struct Atari2600CRTDelegate: public Outputs::CRT::CRTDelegate {
 	Atari2600CRTDelegate _crtDelegate;
 
 	dispatch_queue_t _serialDispatchQueue;
+	Outputs::CRTFrame *_queuedFrame;
 }
 
 - (void)crtDidEndFrame:(Outputs::CRTFrame *)frame {
 
 	dispatch_async(dispatch_get_main_queue(), ^{
+		if(_queuedFrame) {
+			dispatch_async(_serialDispatchQueue, ^{
+				_atari2600.get_crt()->return_frame();
+			});
+		}
+		_queuedFrame = frame;
 
-		printf("\n\n===\n\n");
+		[self.delegate atari2600NeedsRedraw:self];
+	});
+}
+
+- (void)draw {
+
+	if(_queuedFrame)
+	{
+		glClearColor(1.0, 0.0, 0.0, 1.0);
+		glClear(GL_COLOR_BUFFER_BIT);
+/*		printf("\n\n===\n\n");
 		int c = 0;
-		for(int run = 0; run < frame->number_of_runs; run++)
+		for(int run = 0; run < _queuedFrame->number_of_runs; run++)
 		{
 			char character = ' ';
-			switch(frame->runs[run].type)
+			switch(_queuedFrame->runs[run].type)
 			{
 				case Outputs::CRTRun::Type::Sync:	character = '<'; break;
 				case Outputs::CRTRun::Type::Level:	character = '_'; break;
@@ -42,14 +60,14 @@ struct Atari2600CRTDelegate: public Outputs::CRT::CRTDelegate {
 				case Outputs::CRTRun::Type::Blank:	character = ' '; break;
 			}
 
-			if(frame->runs[run].start_point.dst_x < 1.0 / 224.0)
+			if(_queuedFrame->runs[run].start_point.dst_x < 1.0 / 224.0)
 			{
-				printf("\n[%0.2f]: ", frame->runs[run].start_point.dst_y);
+				printf("\n[%0.2f]: ", _queuedFrame->runs[run].start_point.dst_y);
 				c++;
 			}
 
-			printf("(%0.2f): ", frame->runs[run].start_point.dst_x);
-			float length = fabsf(frame->runs[run].end_point.dst_x - frame->runs[run].start_point.dst_x);
+			printf("(%0.2f): ", _queuedFrame->runs[run].start_point.dst_x);
+			float length = fabsf(_queuedFrame->runs[run].end_point.dst_x - _queuedFrame->runs[run].start_point.dst_x);
 			int iLength = (int)(length * 64.0);
 			for(int c = 0; c < iLength; c++)
 			{
@@ -57,12 +75,8 @@ struct Atari2600CRTDelegate: public Outputs::CRT::CRTDelegate {
 			}
 		}
 
-		printf("\n\n[%d]\n\n", c);
-
-		dispatch_async(_serialDispatchQueue, ^{
-			_atari2600.get_crt()->return_frame();
-		});
-	});
+		printf("\n\n[%d]\n\n", c);*/
+	}
 }
 
 - (void)runForNumberOfCycles:(int)cycles {

OSBindings/Mac/Clock Signal/Atari2600Document.swift

@@ -8,7 +8,7 @@
 
 import Cocoa
 
-class Atari2600Document: NSDocument, CSOpenGLViewDelegate {
+class Atari2600Document: NSDocument, CSOpenGLViewDelegate, CSAtari2600Delegate {
 
 	override init() {
 	    super.init()
@@ -44,9 +44,12 @@ class Atari2600Document: NSDocument, CSOpenGLViewDelegate {
 		// You can also choose to override readFromFileWrapper:ofType:error: or readFromURL:ofType:error: instead.
 		// If you override either of these, you should also override -isEntireFileLoaded to return false if the contents are lazily loaded.
 		atari2600 = CSAtari2600()
-		atari2600?.setROM(data)
+		atari2600!.setROM(data)
+		atari2600!.delegate = self
 	}
 
+	// MARK: CSOpenGLViewDelegate
+
 	private var lastCycleCount: Int64?
 	func openGLView(view: CSOpenGLView!, didUpdateToTime time: CVTimeStamp) {
 
@@ -66,4 +69,14 @@ class Atari2600Document: NSDocument, CSOpenGLViewDelegate {
 		}
 		lastCycleCount = cycleCount
 	}
+
+	func openGLViewDrawView(view: CSOpenGLView!) {
+		atari2600!.draw()
+	}
+
+	// MARK: CSAtari2600Delegate
+
+	func atari2600NeedsRedraw(atari2600: CSAtari2600!) {
+		openGLView?.needsDisplay = true
+	}
 }

OSBindings/Mac/Clock Signal/OpenGLView.h

@@ -13,6 +13,7 @@
 
 @protocol CSOpenGLViewDelegate
 - (void)openGLView:(CSOpenGLView *)view didUpdateToTime:(CVTimeStamp)time;
+- (void)openGLViewDrawView:(CSOpenGLView *)view;
 @end
 
 @interface CSOpenGLView : NSOpenGLView

OSBindings/Mac/Clock Signal/OpenGLView.m

@@ -8,6 +8,7 @@
 
 #import "OpenGLView.h"
 @import CoreVideo;
+#import <OpenGL/gl.h>
 
 @implementation CSOpenGLView {
 	CVDisplayLinkRef displayLink;
@@ -23,7 +24,7 @@
 	CVDisplayLinkCreateWithActiveCGDisplays(&displayLink);
  
 	// Set the renderer output callback function
-	CVDisplayLinkSetOutputCallback(displayLink, &MyDisplayLinkCallback, (__bridge void * __nullable)(self));
+	CVDisplayLinkSetOutputCallback(displayLink, DisplayLinkCallback, (__bridge void * __nullable)(self));
  
 	// Set the display link for the current renderer
 	CGLContextObj cglContext = [[self openGLContext] CGLContextObj];
@@ -34,7 +35,7 @@
 	CVDisplayLinkStart(displayLink);
 }
 
-static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp* now, const CVTimeStamp* outputTime, CVOptionFlags flagsIn, CVOptionFlags* flagsOut, void* displayLinkContext)
+static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp* now, const CVTimeStamp* outputTime, CVOptionFlags flagsIn, CVOptionFlags* flagsOut, void* displayLinkContext)
 {
 	CSOpenGLView *view = (__bridge CSOpenGLView *)displayLinkContext;
 	[view.delegate openGLView:view didUpdateToTime:*now];
@@ -47,4 +48,15 @@ static CVReturn MyDisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTime
 	CVDisplayLinkRelease(displayLink);
 }
 
+- (void)drawRect:(NSRect)dirtyRect
+{
+	[self.openGLContext makeCurrentContext];
+
+	CGSize viewSize = [self convertSize:self.bounds.size toView:self];
+	glViewport((GLint)0, (GLint)0, (GLsizei)viewSize.width, (GLsizei)viewSize.height);
+	[self.delegate openGLViewDrawView:self];
+
+	glSwapAPPLE();
+}
+
 @end