Improved AirPlay mirroring

AppleCommon/GBViewBase.h

@@ -32,5 +32,5 @@ typedef enum {
 - (void) createInternalView;
 - (uint32_t *)currentBuffer;
 - (uint32_t *)previousBuffer;
-
+- (instancetype)mirroredView;
 @end

AppleCommon/GBViewBase.m

@@ -6,10 +6,13 @@
     unsigned _currentBuffer;
     GB_frame_blending_mode_t _frameBlendingMode;
     bool _oddFrame;
+    GBViewBase *_parent;
+    __weak GBViewBase *_child;
 }
 
 - (void)screenSizeChanged
 {
+    if (_parent) return;
     if (_imageBuffers[0]) free(_imageBuffers[0]);
     if (_imageBuffers[1]) free(_imageBuffers[1]);
     if (_imageBuffers[2]) free(_imageBuffers[2]);
@@ -23,12 +26,15 @@
 
 - (void)flip
 {
+    if (_parent) return;
     _currentBuffer = (_currentBuffer + 1) % self.numberOfBuffers;
     _oddFrame = GB_is_odd_frame(_gb);
+    [_child flip];
 }
 
 - (unsigned) numberOfBuffers
 {
+    assert(!_parent);
     return _frameBlendingMode? 3 : 2;
 }
 
@@ -39,16 +45,23 @@
 
 - (uint32_t *)currentBuffer
 {
+    if (unlikely(_parent)) {
+        return [_parent currentBuffer];
+    }
     return _imageBuffers[_currentBuffer];
 }
 
 - (uint32_t *)previousBuffer
 {
+    if (unlikely(_parent)) {
+        return [_parent previousBuffer];
+    }
     return _imageBuffers[(_currentBuffer + 2) % self.numberOfBuffers];
 }
 
 - (uint32_t *) pixels
 {
+    assert(!_parent);
     return _imageBuffers[(_currentBuffer + 1) % self.numberOfBuffers];
 }
 
@@ -56,10 +69,14 @@
 {
     _frameBlendingMode = frameBlendingMode;
     [self setNeedsDisplay];
+    [_child setNeedsDisplay];
 }
 
 - (GB_frame_blending_mode_t)frameBlendingMode
 {
+    if (unlikely(_parent)) {
+        return [_parent frameBlendingMode];
+    }
     if (_frameBlendingMode == GB_FRAME_BLENDING_MODE_ACCURATE) {
         if (!_gb || GB_is_sgb(_gb)) {
             return GB_FRAME_BLENDING_MODE_SIMPLE;
@@ -71,6 +88,7 @@
 
 - (void)dealloc
 {
+    if (_parent) return;
     free(_imageBuffers[0]);
     free(_imageBuffers[1]);
     free(_imageBuffers[2]);
@@ -82,4 +100,22 @@
     [self setNeedsDisplay:true];
 }
 #endif
+
+- (void)setGb:(GB_gameboy_t *)gb
+{
+    assert(!_parent);
+    _gb = gb;
+    if (_child) {
+        _child->_gb = gb;
+    }
+}
+
+- (instancetype)mirroredView
+{
+    if (_child) return _child;
+    GBViewBase *ret = [[self.class alloc] initWithFrame:self.bounds];
+    ret->_parent = self;
+    ret->_gb = _gb;
+    return _child = ret;
+}
 @end

AppleCommon/GBViewMetal.m

@@ -25,6 +25,7 @@ static const vector_float2 rect[] =
     vector_float2 _outputResolution;
     id<MTLCommandBuffer> _commandBuffer;
     bool _waitedForFrame;
+    _Atomic unsigned _pendingFrames;
 }
 
 + (bool)isSupported
@@ -236,8 +237,11 @@ static const vector_float2 rect[] =
 - (void)flip
 {
     [super flip];
+    if (_pendingFrames == 2) return;
+    _pendingFrames++;
     dispatch_async(dispatch_get_main_queue(), ^{
         [(MTKView *)self.internalView draw];
+        _pendingFrames--;
     });
 }
 

iOS/GBViewController.m

@@ -64,6 +64,9 @@
     dispatch_queue_t _cameraQueue;
     
     bool _runModeFromController;
+    
+    UIWindow *_mirrorWindow;
+    GBView *_mirrorView;
 }
 
 static void loadBootROM(GB_gameboy_t *gb, GB_boot_rom_t type)
@@ -333,9 +336,51 @@ static void rumbleCallback(GB_gameboy_t *gb, double amp)
                                                  name:GCControllerDidConnectNotification
                                                object:nil];
     
+    for (NSString *name in @[UIScreenDidConnectNotification,
+                             UIScreenDidDisconnectNotification,
+                             UIScreenModeDidChangeNotification]) {
+        [[NSNotificationCenter defaultCenter] addObserver:self
+                                                 selector:@selector(updateMirrorWindow)
+                                                     name:name
+                                                   object:nil];
+    }
+    
+    
+    
+    [self updateMirrorWindow];
+    
     return true;
 }
 
+- (void)updateMirrorWindow
+{
+    if ([UIScreen screens].count == 1) {
+        _mirrorWindow = nil;
+        _mirrorView = nil;
+        return;
+    }
+    if (_mirrorWindow && ![[UIScreen screens] containsObject:_mirrorWindow.screen]) {
+        _mirrorWindow = nil;
+        _mirrorView = nil;
+    }
+    for (UIScreen *screen in [UIScreen screens]) {
+        if (screen == UIScreen.mainScreen) continue;
+        CGRect rect = screen.bounds;
+        rect.size.height = floor(rect.size.height / 144) * 144;
+        rect.size.width = rect.size.height / 144 * 160;
+        rect.origin.x = (screen.bounds.size.width - rect.size.width) / 2;
+        rect.origin.y = (screen.bounds.size.height - rect.size.height) / 2;
+        _mirrorWindow = [[UIWindow alloc] initWithFrame:screen.bounds];
+        _mirrorWindow.screen = screen;
+        _mirrorView = [_gbView mirroredView];
+        _mirrorView.frame = rect;
+        _mirrorWindow.backgroundColor = [UIColor blackColor];
+        [_mirrorWindow addSubview:_mirrorView];
+        [_mirrorWindow setHidden:false];
+        break;
+    }
+}
+
 
 - (void)setControllerHandlers
 {