PSP: Fix bug #10239: PSP port incorrect 4:3 aspect ratio

This is based on a patch supplied by dam-soft. A new graphics mode is
added to the PSP port. The graphics mode is called '4:3 Aspect Ratio'
and fixes the incorrect AR. The older modes are also still present and
behave as before.

2 files changed, 23 insertions, 9 deletions

diff --git a/backends/platform/psp/display_manager.cpp b/backends/platform/psp/display_manager.cpp
index 2e995c809e..f8be51e4e9 100644
--- a/backends/platform/psp/display_manager.cpp
+++ b/backends/platform/psp/display_manager.cpp
@@ -55,7 +55,8 @@ uint32 __attribute__((aligned(16))) MasterGuRenderer::_displayList[2048];
 const OSystem::GraphicsMode DisplayManager::_supportedModes[] = {
 	{ "Original Resolution", "Original Resolution", ORIGINAL_RESOLUTION },
 	{ "Keep Aspect Ratio", "Keep Aspect Ratio", KEEP_ASPECT_RATIO },
-	{ "Full Screen", "Full Screen", STRETCHED_FULL_SCREEN },
+	{ "4:3 Aspect Ratio", "4:3 Aspect Ratio", ASPECT_RATIO_CORRECTION },
+	{ "Stretched Full Screen", "Stretched Full Screen", STRETCHED_FULL_SCREEN },
 	{0, 0, 0}
 };
 
@@ -358,23 +359,35 @@ void DisplayManager::calculateScaleParams() {
 	switch (_graphicsMode) {
 	case ORIGINAL_RESOLUTION:
 		// check if we can fit the original resolution inside the screen
-		if ((_displayParams.screenSource.width < PSP_SCREEN_WIDTH) &&
-			(_displayParams.screenSource.height < PSP_SCREEN_HEIGHT)) {
+		if ((_displayParams.screenSource.width <= PSP_SCREEN_WIDTH) &&
+			(_displayParams.screenSource.height <= PSP_SCREEN_HEIGHT)) {
 			_displayParams.screenOutput.width =  _displayParams.screenSource.width;
 			_displayParams.screenOutput.height =  _displayParams.screenSource.height;
-		} else { // revert to stretch to fit
-			_displayParams.screenOutput.width = PSP_SCREEN_WIDTH;
-			_displayParams.screenOutput.height = PSP_SCREEN_HEIGHT;
+			break;
 		}
-		break;
+		// else revert to keep aspect ratio
 	case KEEP_ASPECT_RATIO:	{ // maximize the height while keeping aspect ratio
 			float aspectRatio = (float)_displayParams.screenSource.width / (float)_displayParams.screenSource.height;
 
 			_displayParams.screenOutput.height = PSP_SCREEN_HEIGHT;	// always full height
 			_displayParams.screenOutput.width = (uint32)(PSP_SCREEN_HEIGHT * aspectRatio);
 
-			if (_displayParams.screenOutput.width > PSP_SCREEN_WIDTH) // we can't have wider than the screen
+			if (_displayParams.screenOutput.width > PSP_SCREEN_WIDTH) { // shrink if wider than screen
+				_displayParams.screenOutput.height = (uint32) (((float) PSP_SCREEN_HEIGHT * (float) PSP_SCREEN_WIDTH) / (float) _displayParams.screenOutput.width); 
+				_displayParams.screenOutput.width = PSP_SCREEN_WIDTH;
+			}
+		}
+		break;
+	case ASPECT_RATIO_CORRECTION: { // maximize the height while forcing 4:3 aspect ratio
+			float aspectRatio = 4.0f / 3.0f;
+			
+			_displayParams.screenOutput.height = PSP_SCREEN_HEIGHT;	// always full height
+			_displayParams.screenOutput.width = (uint32)(PSP_SCREEN_HEIGHT * aspectRatio);
+
+			if (_displayParams.screenOutput.width > PSP_SCREEN_WIDTH) { // // shrink if wider than screen
+				_displayParams.screenOutput.height = (uint32) (((float) PSP_SCREEN_HEIGHT * (float) PSP_SCREEN_WIDTH) / (float) _displayParams.screenOutput.width); 
 				_displayParams.screenOutput.width = PSP_SCREEN_WIDTH;
+			}
 		}
 		break;
 	case STRETCHED_FULL_SCREEN:	// we simply stretch to the whole screen
diff --git a/backends/platform/psp/display_manager.h b/backends/platform/psp/display_manager.h
index b1b748a68c..ba11963f8c 100644
--- a/backends/platform/psp/display_manager.h
+++ b/backends/platform/psp/display_manager.h
@@ -106,6 +106,7 @@ public:
 	enum GraphicsModeID {			///> Possible output formats onscreen
 		ORIGINAL_RESOLUTION,
 		KEEP_ASPECT_RATIO,
+		ASPECT_RATIO_CORRECTION,
 		STRETCHED_FULL_SCREEN
 	};
 	DisplayManager() : _screen(0), _cursor(0), _overlay(0), _keyboard(0),
@@ -118,7 +119,7 @@ public:
 	bool setGraphicsMode(int mode);
 	bool setGraphicsMode(const char *name);
 	int getGraphicsMode() const { return _graphicsMode; }
-	uint32 getDefaultGraphicsMode() const { return STRETCHED_FULL_SCREEN; }
+	uint32 getDefaultGraphicsMode() const { return KEEP_ASPECT_RATIO; }
 	const OSystem::GraphicsMode* getSupportedGraphicsModes() const { return _supportedModes; }
 
 	// Setters for pointers