6 files changed, 58 insertions, 18 deletions

diff --git a/backends/graphics/openglsdl/openglsdl-graphics.cpp b/backends/graphics/openglsdl/openglsdl-graphics.cpp
index f664314862..efc10a0d2c 100644
--- a/backends/graphics/openglsdl/openglsdl-graphics.cpp
+++ b/backends/graphics/openglsdl/openglsdl-graphics.cpp
@@ -509,16 +509,8 @@ bool OpenGLSdlGraphicsManager::setupMode(uint width, uint height) {
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, _glContextMajor);
 	SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, _glContextMinor);
 
-	if (!_window->createOrUpdateWindow(width, height, flags)) {
-		// We treat fullscreen requests as a "hint" for now. This means in
-		// case it is not available we simply ignore it.
-		if (_wantsFullScreen) {
-			_window->createOrUpdateWindow(width, height, SDL_WINDOW_OPENGL | SDL_WINDOW_RESIZABLE);
-		}
-
-		if (!_window->getSDLWindow()) {
-			return false;
-		}
+	if (!createOrUpdateWindow(width, height, flags)) {
+		return false;
 	}
 
 	_glContext = SDL_GL_CreateContext(_window->getSDLWindow());
diff --git a/backends/graphics/sdl/sdl-graphics.cpp b/backends/graphics/sdl/sdl-graphics.cpp
index a13ca45477..aa6087beae 100644
--- a/backends/graphics/sdl/sdl-graphics.cpp
+++ b/backends/graphics/sdl/sdl-graphics.cpp
@@ -21,13 +21,16 @@
  */
 
 #include "backends/graphics/sdl/sdl-graphics.h"
-
 #include "backends/platform/sdl/sdl-sys.h"
 #include "backends/events/sdl/sdl-events.h"
 #include "common/textconsole.h"
 
 SdlGraphicsManager::SdlGraphicsManager(SdlEventSource *source, SdlWindow *window)
-	: _eventSource(source), _window(window) {
+	: _eventSource(source), _window(window)
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	, _allowWindowSizeReset(false), _lastFlags(0)
+#endif
+	  {
 }
 
 SdlGraphicsManager::~SdlGraphicsManager() {
@@ -73,3 +76,26 @@ bool SdlGraphicsManager::setState(const State &state) {
 	}
 }
 
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+bool SdlGraphicsManager::createOrUpdateWindow(const int width, const int height, const Uint32 flags) {
+	if (!_window) {
+		return false;
+	}
+
+	// We only update the actual window when flags change (which usually means
+	// fullscreen mode is entered/exited) or when updates are forced so that we
+	// do not reset the window size whenever a game makes a call to change the
+	// size or pixel format of the internal game surface (since a user may have
+	// resized the game window)
+	if (!_window->getSDLWindow() || _lastFlags != flags || _allowWindowSizeReset) {
+		if (!_window->createOrUpdateWindow(width, height, flags)) {
+			return false;
+		}
+
+		_lastFlags = flags;
+		_allowWindowSizeReset = false;
+	}
+
+	return true;
+}
+#endif
diff --git a/backends/graphics/sdl/sdl-graphics.h b/backends/graphics/sdl/sdl-graphics.h
index 7f8790a9b4..937beef9b4 100644
--- a/backends/graphics/sdl/sdl-graphics.h
+++ b/backends/graphics/sdl/sdl-graphics.h
@@ -123,6 +123,17 @@ public:
 	SdlWindow *getWindow() const { return _window; }
 
 protected:
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+public:
+	void unlockWindowSize() { _allowWindowSizeReset = true; }
+
+protected:
+	Uint32 _lastFlags;
+	bool _allowWindowSizeReset;
+
+	bool createOrUpdateWindow(const int width, const int height, const Uint32 flags);
+#endif
+
 	SdlEventSource *_eventSource;
 	SdlWindow *_window;
 };
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 983b71ab28..cd7e11b32d 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -784,9 +784,14 @@ void SurfaceSdlGraphicsManager::initSize(uint w, uint h, const Graphics::PixelFo
 	}
 #endif
 
-	// Avoid redundant res changes
+#if !SDL_VERSION_ATLEAST(2, 0, 0)
+	// Avoid redundant res changes, only in SDL1. In SDL2, redundancies may not
+	// actually be redundant if ScummVM is switching between game engines and
+	// the screen dimensions are being reinitialized, since window resizing is
+	// supposed to reset when this happens
 	if ((int)w == _videoMode.screenWidth && (int)h == _videoMode.screenHeight)
 		return;
+#endif
 
 	_videoMode.screenWidth = w;
 	_videoMode.screenHeight = h;
@@ -2797,7 +2802,7 @@ SDL_Surface *SurfaceSdlGraphicsManager::SDL_SetVideoMode(int width, int height,
 		createWindowFlags |= SDL_WINDOW_FULLSCREEN_DESKTOP;
 	}
 
-	if (!_window->createOrUpdateWindow(width, height, createWindowFlags)) {
+	if (!createOrUpdateWindow(width, height, createWindowFlags)) {
 		return nullptr;
 	}
 
diff --git a/backends/platform/sdl/sdl.cpp b/backends/platform/sdl/sdl.cpp
index bbd5c89f80..f44d87666a 100644
--- a/backends/platform/sdl/sdl.cpp
+++ b/backends/platform/sdl/sdl.cpp
@@ -297,20 +297,28 @@ void OSystem_SDL::initBackend() {
 	dynamic_cast<SdlGraphicsManager *>(_graphicsManager)->activateManager();
 }
 
-#if defined(USE_TASKBAR)
 void OSystem_SDL::engineInit() {
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	dynamic_cast<SdlGraphicsManager *>(_graphicsManager)->unlockWindowSize();
+#endif
+#ifdef USE_TASKBAR
 	// Add the started engine to the list of recent tasks
 	_taskbarManager->addRecent(ConfMan.getActiveDomainName(), ConfMan.get("description"));
 
 	// Set the overlay icon the current running engine
 	_taskbarManager->setOverlayIcon(ConfMan.getActiveDomainName(), ConfMan.get("description"));
+#endif
 }
 
 void OSystem_SDL::engineDone() {
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	dynamic_cast<SdlGraphicsManager *>(_graphicsManager)->unlockWindowSize();
+#endif
+#ifdef USE_TASKBAR
 	// Remove overlay icon
 	_taskbarManager->setOverlayIcon("", "");
-}
 #endif
+}
 
 void OSystem_SDL::initSDL() {
 	// Check if SDL has not been initialized
diff --git a/backends/platform/sdl/sdl.h b/backends/platform/sdl/sdl.h
index bc4292be0b..61513fa65f 100644
--- a/backends/platform/sdl/sdl.h
+++ b/backends/platform/sdl/sdl.h
@@ -59,10 +59,8 @@ public:
 
 	// Override functions from ModularBackend and OSystem
 	virtual void initBackend();
-#if defined(USE_TASKBAR)
 	virtual void engineInit();
 	virtual void engineDone();
-#endif
 	virtual void quit();
 	virtual void fatalError();