Add ability to create a separate render thread locked to the display refresh rate

MACHView.m

@@ -1,5 +1,6 @@
 #import <AppKit/AppKit.h>
 #import <Foundation/Foundation.h>
+#import <CoreVideo/CVDisplayLink.h>
 
 @interface MACHView : NSView
 @end
@@ -14,7 +15,11 @@ @implementation MACHView {
   void (^_scrollWheel_block)(NSEvent *);
   void (^_magnify_block)(NSEvent *);
   void (^_insertText_block)(NSEvent *, uint32_t);
+  void (^_render_block)(void);
   NSTrackingArea *trackingArea;
+  dispatch_source_t m_displaySource;
+  CVDisplayLinkRef m_displayLink;
+  BOOL _hasRenderLoop;
 }
 
 - (BOOL)canBecomeKeyView {
@@ -25,6 +30,78 @@ - (BOOL)acceptsFirstResponder {
   return YES;
 }
 
+- (void)dealloc
+{   
+  if (self->_hasRenderLoop) {
+    [self stopRenderLoop];
+  }
+}
+
+- (void)viewDidMoveToWindow
+{
+    [super viewDidMoveToWindow];
+
+    if (self->_hasRenderLoop) {
+
+      [self stopRenderLoop];
+
+      if (self.window)
+      {
+          m_displaySource = dispatch_source_create(DISPATCH_SOURCE_TYPE_DATA_ADD, 0,
+              0, dispatch_get_main_queue());
+          dispatch_source_set_event_handler(m_displaySource, ^() { [self render]; });
+          dispatch_resume(m_displaySource);
+
+          CVDisplayLinkCreateWithActiveCGDisplays(&m_displayLink);
+          CVDisplayLinkSetOutputCallback(m_displayLink, &displayLinkCallback, (__bridge void*)m_displaySource);
+          CVDisplayLinkStart(m_displayLink);
+      }
+    }
+}
+
+static CVReturn displayLinkCallback(
+    CVDisplayLinkRef displayLink,
+    const CVTimeStamp* now,
+    const CVTimeStamp* outputTime,
+    CVOptionFlags flagsIn,
+    CVOptionFlags* flagsOut,
+    void* displayLinkContext)
+{
+    @autoreleasepool
+    {
+        dispatch_source_t source = (__bridge dispatch_source_t)displayLinkContext;
+        dispatch_source_merge_data(source, 1);
+        return kCVReturnSuccess;
+    }
+}
+
+- (void)render
+{
+  if (_render_block)
+    _render_block();
+}
+
+- (void)stopRenderLoop
+{
+    if (m_displaySource)
+    {
+        dispatch_source_cancel(m_displaySource);
+        m_displaySource = nil;
+    }
+
+    if (m_displayLink)
+    {
+        CVDisplayLinkStop(m_displayLink);
+        CVDisplayLinkRelease(m_displayLink);
+        m_displayLink = nil;
+    }
+}
+
+- (void)setBlock_render:(void (^)(void))render_block
+    __attribute__((objc_direct)) {
+  _render_block = render_block;
+}
+
 - (void)setBlock_keyDown:(void (^)(NSEvent *))keyDown_block
     __attribute__((objc_direct)) {
   _keyDown_block = keyDown_block;
@@ -182,6 +259,13 @@ - (void)doCommandBySelector:(SEL)selector
 {
 }
 
+
+-(id)initWithFrame:(NSRect)frame withRenderLoop:(BOOL)loop {
+  self = [self initWithFrame:frame];
+  self->_hasRenderLoop = loop;
+  return self;
+}
+
 // This overrides the default initializer and creates a tracking area over the
 // views visible rect
 - (id)initWithFrame:(NSRect)frame {
@@ -197,24 +281,14 @@ - (id)initWithFrame:(NSRect)frame {
                                                   owner:self
                                                userInfo:nil];
     [self addTrackingArea:trackingArea];
+
   }
   return self;
 }
 
-// This is automatically called each time the view size changes
-- (void)updateTrackingAreas {
-  // Remove any existing tracking area
-  [self removeTrackingArea:trackingArea];
-  // Create a new tracking area to monitor mouse movement
-  NSTrackingAreaOptions options = NSTrackingMouseEnteredAndExited |
-                                  NSTrackingMouseMoved |
-                                  NSTrackingActiveInActiveApp;
-  NSRect rect = self.visibleRect;
-  trackingArea = [[NSTrackingArea alloc] initWithRect:rect
-                                              options:options
-                                                owner:self
-                                             userInfo:nil];
-  [self addTrackingArea:trackingArea];
-}
+
+
+
+
 
 @end