Added support for the UIScene life cycle on Apple platforms

Fixes https://github.com/libsdl-org/SDL/issues/12680

include/SDL3/SDL_video.h

@@ -97,6 +97,8 @@ typedef Uint32 SDL_WindowID;
  * uninitialized will either return the user provided value, if one was set
  * prior to initialization, or NULL. See docs/README-wayland.md for more
  * information.
+ *
+ * \since This macro is available since SDL 3.2.0.
  */
 #define SDL_PROP_GLOBAL_VIDEO_WAYLAND_WL_DISPLAY_POINTER "SDL.video.wayland.wl_display"
 

src/video/uikit/SDL_uikitappdelegate.h

@@ -29,6 +29,15 @@
 
 @end
 
+API_AVAILABLE(ios(13.0))
+@interface SDLUIKitSceneDelegate : NSObject <UIApplicationDelegate, UIWindowSceneDelegate>
+
++ (NSString *)getSceneDelegateClassName;
+
+- (void)hideLaunchScreen;
+
+@end
+
 @interface SDLUIKitDelegate : NSObject <UIApplicationDelegate>
 
 + (id)sharedAppDelegate;

src/video/uikit/SDL_uikitappdelegate.m

@@ -59,7 +59,15 @@ int SDL_RunApp(int argc, char *argv[], SDL_main_func mainFunction, void *reserve
 
     // Give over control to run loop, SDLUIKitDelegate will handle most things from here
     @autoreleasepool {
-        UIApplicationMain(argc, argv, nil, [SDLUIKitDelegate getAppDelegateClassName]);
+        NSString *name = nil;
+
+        if (@available(iOS 13.0, tvOS 13.0, *)) {
+            name = [SDLUIKitSceneDelegate getSceneDelegateClassName];
+        }
+        if (!name) {
+            name = [SDLUIKitDelegate getAppDelegateClassName];
+        }
+        UIApplicationMain(argc, argv, nil, name);
     }
 
     // free the memory we used to hold copies of argc and argv
@@ -162,6 +170,7 @@ static UIImage *SDL_LoadLaunchImageNamed(NSString *name, int screenh)
 @end
 #endif // !SDL_PLATFORM_TVOS
 
+
 @interface SDLLaunchScreenController ()
 
 #ifndef SDL_PLATFORM_TVOS
@@ -343,7 +352,170 @@ static UIImage *SDL_LoadLaunchImageNamed(NSString *name, int screenh)
 }
 #endif // !SDL_PLATFORM_TVOS
 
-@end
+@end // SDLLaunchScreenController
+
+
+API_AVAILABLE(ios(13.0))
+@implementation SDLUIKitSceneDelegate
+{
+    UIWindow *launchWindow;
+}
+
++ (NSString *)getSceneDelegateClassName
+{
+    return @"SDLUIKitSceneDelegate";
+}
+
+- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions
+{
+    if (![scene isKindOfClass:[UIWindowScene class]]) {
+        return;
+    }
+
+    UIWindowScene *windowScene = (UIWindowScene *)scene;
+    windowScene.delegate = self;
+
+    NSBundle *bundle = [NSBundle mainBundle];
+
+#ifdef SDL_IPHONE_LAUNCHSCREEN
+    UIViewController *vc = nil;
+    NSString *screenname = nil;
+
+#if !defined(SDL_PLATFORM_TVOS) && !defined(SDL_PLATFORM_VISIONOS)
+    screenname = [bundle objectForInfoDictionaryKey:@"UILaunchStoryboardName"];
+
+    if (screenname) {
+        @try {
+            UIStoryboard *storyboard = [UIStoryboard storyboardWithName:screenname bundle:bundle];
+            __auto_type storyboardVc = [storyboard instantiateInitialViewController];
+            vc = [[SDLLaunchStoryboardViewController alloc] initWithStoryboardViewController:storyboardVc];
+        }
+        @catch (NSException *exception) {
+            // Do nothing (there's more code to execute below).
+        }
+    }
+#endif
+
+    if (vc == nil) {
+        vc = [[SDLLaunchScreenController alloc] initWithNibName:screenname bundle:bundle];
+    }
+
+    if (vc.view) {
+#ifdef SDL_PLATFORM_VISIONOS
+        CGRect viewFrame = CGRectMake(0, 0, SDL_XR_SCREENWIDTH, SDL_XR_SCREENHEIGHT);
+#else
+        CGRect viewFrame = windowScene.coordinateSpace.bounds;
+#endif
+        launchWindow = [[UIWindow alloc] initWithWindowScene:windowScene];
+        launchWindow.frame = viewFrame;
+
+        launchWindow.windowLevel = UIWindowLevelNormal + 1.0;
+        launchWindow.hidden = NO;
+        launchWindow.rootViewController = vc;
+    }
+#endif
+
+    // Set working directory to resource path
+    [[NSFileManager defaultManager] changeCurrentDirectoryPath:[bundle resourcePath]];
+
+    // Handle any connection options (like opening URLs)
+    for (NSUserActivity *activity in connectionOptions.userActivities) {
+        if (activity.webpageURL) {
+            [self handleURL:activity.webpageURL];
+        }
+    }
+
+    for (UIOpenURLContext *urlContext in connectionOptions.URLContexts) {
+        [self handleURL:urlContext.URL];
+    }
+
+    SDL_SetMainReady();
+    [self performSelector:@selector(postFinishLaunch) withObject:nil afterDelay:0.0];
+}
+
+- (void)scene:(UIScene *)scene openURLContexts:(NSSet<UIOpenURLContext *> *)URLContexts
+{
+    for (UIOpenURLContext *context in URLContexts) {
+        [self handleURL:context.URL];
+    }
+}
+
+- (void)sceneDidBecomeActive:(UIScene *)scene
+{
+    SDL_OnApplicationDidEnterForeground();
+}
+
+- (void)sceneWillResignActive:(UIScene *)scene
+{
+    SDL_OnApplicationWillEnterBackground();
+}
+
+- (void)sceneWillEnterForeground:(UIScene *)scene
+{
+    SDL_OnApplicationWillEnterForeground();
+}
+
+- (void)sceneDidEnterBackground:(UIScene *)scene
+{
+    SDL_OnApplicationDidEnterBackground();
+}
+
+- (void)handleURL:(NSURL *)url
+{
+    const char *sourceApplicationCString = NULL;
+    NSURL *fileURL = url.filePathURL;
+    if (fileURL != nil) {
+        SDL_SendDropFile(NULL, sourceApplicationCString, fileURL.path.UTF8String);
+    } else {
+        SDL_SendDropFile(NULL, sourceApplicationCString, url.absoluteString.UTF8String);
+    }
+    SDL_SendDropComplete(NULL);
+}
+
+- (void)hideLaunchScreen
+{
+    UIWindow *window = launchWindow;
+
+    if (!window || window.hidden) {
+        return;
+    }
+
+    launchWindow = nil;
+
+    [UIView animateWithDuration:0.2
+        animations:^{
+          window.alpha = 0.0;
+        }
+        completion:^(BOOL finished) {
+          window.hidden = YES;
+          UIKit_ForceUpdateHomeIndicator();
+        }];
+}
+
+- (void)postFinishLaunch
+{
+    [self performSelector:@selector(hideLaunchScreen) withObject:nil afterDelay:0.0];
+
+    SDL_SetiOSEventPump(true);
+    exit_status = forward_main(forward_argc, forward_argv);
+    SDL_SetiOSEventPump(false);
+
+    if (launchWindow) {
+        launchWindow.hidden = YES;
+        launchWindow = nil;
+    }
+}
+
+- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options API_AVAILABLE(ios(13.0))
+{
+    // This doesn't appear to be called, but it needs to be implemented to signal that we support the UIScene life cycle
+    UISceneConfiguration *config = [[UISceneConfiguration alloc] initWithName:@"SDLSceneConfiguration" sessionRole:connectingSceneSession.role];
+    config.delegateClass = [SDLUIKitSceneDelegate class];
+    return config;
+}
+
+@end // SDLUIKitSceneDelegate
+
 
 @implementation SDLUIKitDelegate
 {
@@ -514,6 +686,6 @@ static UIImage *SDL_LoadLaunchImageNamed(NSString *name, int screenh)
     return YES;
 }
 
-@end
+@end // SDLUIKitDelegate
 
 #endif // SDL_VIDEO_DRIVER_UIKIT

src/video/uikit/SDL_uikitwindow.m

@@ -152,6 +152,43 @@ static bool SetupWindowData(SDL_VideoDevice *_this, SDL_Window *window, UIWindow
     return true;
 }
 
+API_AVAILABLE(ios(13.0))
+static UIWindowScene *GetActiveWindowScene(void)
+{
+    if (@available(iOS 13.0, tvOS 13.0, *)) {
+        NSSet<UIScene *> *connectedScenes = [UIApplication sharedApplication].connectedScenes;
+
+        // First, try to find an active foreground scene
+        for (UIScene *scene in connectedScenes) {
+            if ([scene isKindOfClass:[UIWindowScene class]]) {
+                UIWindowScene *windowScene = (UIWindowScene *)scene;
+                if (windowScene.activationState == UISceneActivationStateForegroundActive) {
+                    return windowScene;
+                }
+            }
+        }
+
+        // If no active scene, return any foreground scene
+        for (UIScene *scene in connectedScenes) {
+            if ([scene isKindOfClass:[UIWindowScene class]]) {
+                UIWindowScene *windowScene = (UIWindowScene *)scene;
+                if (windowScene.activationState == UISceneActivationStateForegroundInactive) {
+                    return windowScene;
+                }
+            }
+        }
+
+        // Last resort: return first window scene
+        for (UIScene *scene in connectedScenes) {
+            if ([scene isKindOfClass:[UIWindowScene class]]) {
+                return (UIWindowScene *)scene;
+            }
+        }
+    }
+
+    return nil;
+}
+
 bool UIKit_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_PropertiesID create_props)
 {
     @autoreleasepool {
@@ -197,13 +234,21 @@ bool UIKit_CreateWindow(SDL_VideoDevice *_this, SDL_Window *window, SDL_Properti
         }
 #endif // !SDL_PLATFORM_TVOS
 
-        // ignore the size user requested, and make a fullscreen window
-        // !!! FIXME: can we have a smaller view?
+        UIWindow *uiwindow = nil;
+        if (@available(iOS 13.0, tvOS 13.0, *)) {
+            UIWindowScene *scene = GetActiveWindowScene();
+            if (scene) {
+                uiwindow = [[SDL_uikitwindow alloc] initWithWindowScene:scene];
+            }
+        }
+        if (!uiwindow) {
+            // ignore the size user requested, and make a fullscreen window
 #ifdef SDL_PLATFORM_VISIONOS
-        UIWindow *uiwindow = [[SDL_uikitwindow alloc] initWithFrame:CGRectMake(window->x, window->y, window->w, window->h)];
+            uiwindow = [[SDL_uikitwindow alloc] initWithFrame:CGRectMake(0, 0, SDL_XR_SCREENWIDTH, SDL_XR_SCREENHEIGHT)];
 #else
-        UIWindow *uiwindow = [[SDL_uikitwindow alloc] initWithFrame:data.uiscreen.bounds];
+            uiwindow = [[SDL_uikitwindow alloc] initWithFrame:data.uiscreen.bounds];
 #endif
+        }
 
         // put the window on an external display if appropriate.
 #ifndef SDL_PLATFORM_VISIONOS