Fix crash on background on iOS

openVulkanoCpp/Host/iOS/OpenVulkanoViewController.h

@@ -5,21 +5,19 @@
  */
 
 #import <UIKit/UIKit.h>
-
+#import <MetalKit/MTKView.h>
 
 #pragma mark -
 #pragma mark OpenVulkanoViewController
 
-/** The main view controller for the demo storyboard. */
 @interface OpenVulkanoViewController : UIViewController
 -(void*) makeGraphicsApp;
 @end
 
 
 #pragma mark -
-#pragma mark DemoView
+#pragma mark OpenVulkanoView
 
-/** The Metal-compatibile view for the demo Storyboard. */
-@interface DemoView : UIView
+@interface OpenVulkanoView : MTKView
 @end
 

openVulkanoCpp/Host/iOS/OpenVulkanoViewController.mm

@@ -83,11 +83,38 @@ public:
 	void Close() override {}
 };
 
+@interface MetalViewDelegate : NSObject<MTKViewDelegate>
+- (id)initWithGAM:(GraphicsAppManager*)gam;
+- (void) mtkView:(MTKView *) view drawableSizeWillChange:(CGSize) size;
+- (void) drawInMTKView:(MTKView *) view;
+@end
+
+@implementation MetalViewDelegate
+{
+	GraphicsAppManager* manager;
+}
+
+- (id)initWithGAM:(GraphicsAppManager*)gam
+{
+	manager = gam;
+	return self;
+}
+
+- (void) mtkView:(MTKView *) view drawableSizeWillChange:(CGSize) size
+{}
+
+- (void) drawInMTKView:(MTKView *) view
+{
+	manager->LoopTick();
+}
+@end
+
 @implementation OpenVulkanoViewController {
 	CADisplayLink* _displayLink;
 	GraphicsAppManager* manager;
 	ViewWindow window;
 	std::unique_ptr<IGraphicsApp> app;
+	MetalViewDelegate* mtdelegate;
 }
 
 -(void*) makeGraphicsApp {
@@ -117,9 +144,10 @@ public:
 	manager = new GraphicsAppManager(app.get(), &window);
 	manager->StartUp();
 	
-	_displayLink = [CADisplayLink displayLinkWithTarget: self selector: @selector(renderLoop)];
-	[_displayLink setPreferredFramesPerSecond: 60];
-	[_displayLink addToRunLoop: NSRunLoop.currentRunLoop forMode: NSDefaultRunLoopMode];
+	OpenVulkanoView* mtkView = (OpenVulkanoView*)(self.view);
+	mtdelegate = [[MetalViewDelegate alloc] initWithGAM:manager];
+	[mtkView setDelegate:mtdelegate];
+	mtkView.preferredFramesPerSecond = 60;
 }
 
 -(void) renderLoop {
@@ -139,9 +167,9 @@ public:
 
 
 #pragma mark -
-#pragma mark DemoView
+#pragma mark OpenVulkanoView
 
-@implementation DemoView
+@implementation OpenVulkanoView
 
 /** Returns a Metal-compatible layer. */
 +(Class) layerClass { return [CAMetalLayer class]; }