Improve handling of view loading/unloading

openVulkanoCpp/Host/iOS/OpenVulkanoViewController.mm

@@ -153,10 +153,38 @@ public:
 	manager = new GraphicsAppManager(app.get(), &window);
 	manager->StartUp();
 	
-	OpenVulkanoView* mtkView = (OpenVulkanoView*)(self.view);
+	if ([self.view isKindOfClass:[MTKView class]]) {
+		MTKView* mtkView = (MTKView*)(self.view);
 		 mtdelegate = [[MetalViewDelegate alloc] initWithGAM:manager win:&window];
 		 [mtkView setDelegate:mtdelegate];
 		 mtkView.preferredFramesPerSecond = 60;
+	} else {
+		_displayLink = [CADisplayLink displayLinkWithTarget: self selector: @selector(renderLoop)];
+		[_displayLink setPreferredFramesPerSecond: 60];
+		[_displayLink addToRunLoop: NSRunLoop.currentRunLoop forMode: NSDefaultRunLoopMode];
+	}
+}
+
+-(void) viewWillAppear:(BOOL)animated {
+	[super viewWillAppear:animated];
+	self.view.contentScaleFactor = UIScreen.mainScreen.nativeScale / 1.5f;
+
+	auto size = self.view.bounds.size;
+	auto sizeX = size.width * self.view.contentScaleFactor;
+	auto sizeY = size.height * self.view.contentScaleFactor;
+	manager->OnWindowResize(&window, sizeX, sizeY);
+}
+
+-(void) viewDidDisappear:(BOOL)animated {
+	[_displayLink release];
+	_displayLink = nil;
+	[super viewDidDisappear:animated];
+}
+
+-(void) viewDidUnload {
+	[_displayLink release];
+	_displayLink = nil;
+	[super viewDidUnload];
 }
 
 -(void) renderLoop {