BACKENDS: Fix window sizing of games that switch between multiple resolutions

2 files changed, 33 insertions, 14 deletions

diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index de54145d5f..897cdcb352 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -598,19 +598,11 @@ void SurfaceSdlGraphicsManager::detectSupportedFormats() {
 }
 #endif
 
-bool SurfaceSdlGraphicsManager::setGraphicsMode(int mode) {
-	Common::StackLock lock(_graphicsMutex);
-
-	assert(_transactionMode == kTransactionActive);
-
-	if (_oldVideoMode.setup && _oldVideoMode.mode == mode)
-		return true;
-
-	int newScaleFactor = 1;
-
+int SurfaceSdlGraphicsManager::getGraphicsModeScale(int mode) const {
+	int scale;
 	switch (mode) {
 	case GFX_NORMAL:
-		newScaleFactor = 1;
+		scale = 1;
 		break;
 #ifdef USE_SCALERS
 	case GFX_DOUBLESIZE:
@@ -623,18 +615,34 @@ bool SurfaceSdlGraphicsManager::setGraphicsMode(int mode) {
 #ifdef USE_HQ_SCALERS
 	case GFX_HQ2X:
 #endif
-		newScaleFactor = 2;
+		scale = 2;
 		break;
 	case GFX_TRIPLESIZE:
 	case GFX_ADVMAME3X:
 #ifdef USE_HQ_SCALERS
 	case GFX_HQ3X:
 #endif
-		newScaleFactor = 3;
+		scale = 3;
 		break;
 #endif
-
 	default:
+		scale = -1;
+	}
+
+	return scale;
+}
+
+bool SurfaceSdlGraphicsManager::setGraphicsMode(int mode) {
+	Common::StackLock lock(_graphicsMutex);
+
+	assert(_transactionMode == kTransactionActive);
+
+	if (_oldVideoMode.setup && _oldVideoMode.mode == mode)
+		return true;
+
+	int newScaleFactor = getGraphicsModeScale(mode);
+
+	if (newScaleFactor == -1) {
 		warning("unknown gfx mode %d", mode);
 		return false;
 	}
@@ -774,6 +782,15 @@ void SurfaceSdlGraphicsManager::initSize(uint w, uint h, const Graphics::PixelFo
 		return;
 #endif
 
+	if ((int)w != _videoMode.screenWidth || (int)h != _videoMode.screenHeight) {
+		const bool useDefault = defaultGraphicsModeConfig();
+		if (useDefault && w > 320) {
+			resetGraphicsScale();
+		} else {
+			setGraphicsMode(getGraphicsModeIdByName(ConfMan.get("gfx_mode")));
+		}
+	}
+
 	_videoMode.screenWidth = w;
 	_videoMode.screenHeight = h;
 
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.h b/backends/graphics/surfacesdl/surfacesdl-graphics.h
index e93cf410ea..62a4a38d3e 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.h
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.h
@@ -190,6 +190,8 @@ protected:
 	/** Hardware screen */
 	SDL_Surface *_hwscreen;
 
+	virtual int getGraphicsModeScale(int mode) const override;
+
 #if SDL_VERSION_ATLEAST(2, 0, 0)
 	/* SDL2 features a different API for 2D graphics. We create a wrapper
 	 * around this API to keep the code paths as close as possible. */