SDL: Overhaul OSystem_SDL::getSupportedFormats

* Do not use global constructor for the RGBList and BGRList
  tables anymore, by moving them inside a function.
* Update the list of supported formats if the hardware
  screen surface changes. Previously, the list of supported
  pixel formats (and its order) was computed only once and
  then never changed.

svn-id: r50832

2 files changed, 64 insertions, 43 deletions

diff --git a/backends/platform/sdl/graphics.cpp b/backends/platform/sdl/graphics.cpp
index 05870015cb..f48800f0d8 100644
--- a/backends/platform/sdl/graphics.cpp
+++ b/backends/platform/sdl/graphics.cpp
@@ -214,42 +214,54 @@ OSystem::TransactionError OSystem_SDL::endGFXTransaction() {
 }
 
 #ifdef USE_RGB_COLOR
-const Graphics::PixelFormat RGBList[] = {
+
+Common::List<Graphics::PixelFormat> OSystem_SDL::getSupportedFormats() const {
+	assert(!_supportedFormats.empty());
+	return _supportedFormats;
+}
+
+void OSystem_SDL::detectSupportedFormats() {
+
+	// Clear old list
+	_supportedFormats.clear();
+
+	// Some tables with standard formats that we always list
+	// as "supported". If frontend code tries to use one of
+	// these, we will perform the necessary format
+	// conversion in the background. Of course this incurs a
+	// performance hit, but on desktop ports this should not
+	// matter. We still push the currently active format to
+	// the front, so if frontend code just uses the first
+	// available format, it will get one that is "cheap" to
+	// use.
+	const Graphics::PixelFormat RGBList[] = {
 #ifdef ENABLE_32BIT
-	// RGBA8888, ARGB8888, RGB888
-	Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0),
-	Graphics::PixelFormat(4, 8, 8, 8, 8, 16, 8, 0, 24),
-	Graphics::PixelFormat(3, 8, 8, 8, 0, 16, 8, 0, 0),
+		// RGBA8888, ARGB8888, RGB888
+		Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0),
+		Graphics::PixelFormat(4, 8, 8, 8, 8, 16, 8, 0, 24),
+		Graphics::PixelFormat(3, 8, 8, 8, 0, 16, 8, 0, 0),
 #endif
-	// RGB565, XRGB1555, RGB555, RGBA4444, ARGB4444
-	Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0),
-	Graphics::PixelFormat(2, 5, 5, 5, 1, 10, 5, 0, 15),
-	Graphics::PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0),
-	Graphics::PixelFormat(2, 4, 4, 4, 4, 12, 8, 4, 0),
-	Graphics::PixelFormat(2, 4, 4, 4, 4, 8, 4, 0, 12)
-};
-const Graphics::PixelFormat BGRList[] = {
+		// RGB565, XRGB1555, RGB555, RGBA4444, ARGB4444
+		Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0),
+		Graphics::PixelFormat(2, 5, 5, 5, 1, 10, 5, 0, 15),
+		Graphics::PixelFormat(2, 5, 5, 5, 0, 10, 5, 0, 0),
+		Graphics::PixelFormat(2, 4, 4, 4, 4, 12, 8, 4, 0),
+		Graphics::PixelFormat(2, 4, 4, 4, 4, 8, 4, 0, 12)
+	};
+	const Graphics::PixelFormat BGRList[] = {
 #ifdef ENABLE_32BIT
-	// ABGR8888, BGRA8888, BGR888
-	Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24),
-	Graphics::PixelFormat(4, 8, 8, 8, 8, 8, 16, 24, 0),
-	Graphics::PixelFormat(3, 8, 8, 8, 0, 0, 8, 16, 0),
+		// ABGR8888, BGRA8888, BGR888
+		Graphics::PixelFormat(4, 8, 8, 8, 8, 0, 8, 16, 24),
+		Graphics::PixelFormat(4, 8, 8, 8, 8, 8, 16, 24, 0),
+		Graphics::PixelFormat(3, 8, 8, 8, 0, 0, 8, 16, 0),
 #endif
-	// BGR565, XBGR1555, BGR555, ABGR4444, BGRA4444
-	Graphics::PixelFormat(2, 5, 6, 5, 0, 0, 5, 11, 0),
-	Graphics::PixelFormat(2, 5, 5, 5, 1, 0, 5, 10, 15),
-	Graphics::PixelFormat(2, 5, 5, 5, 0, 0, 5, 10, 0),
-	Graphics::PixelFormat(2, 4, 4, 4, 4, 0, 4, 8, 12),
-	Graphics::PixelFormat(2, 4, 4, 4, 4, 4, 8, 12, 0)
-};
-
-// TODO: prioritize matching alpha masks
-Common::List<Graphics::PixelFormat> OSystem_SDL::getSupportedFormats() const {
-	static Common::List<Graphics::PixelFormat> list;
-	static bool inited = false;
-
-	if (inited)
-		return list;
+		// BGR565, XBGR1555, BGR555, ABGR4444, BGRA4444
+		Graphics::PixelFormat(2, 5, 6, 5, 0, 0, 5, 11, 0),
+		Graphics::PixelFormat(2, 5, 5, 5, 1, 0, 5, 10, 15),
+		Graphics::PixelFormat(2, 5, 5, 5, 0, 0, 5, 10, 0),
+		Graphics::PixelFormat(2, 4, 4, 4, 4, 0, 4, 8, 12),
+		Graphics::PixelFormat(2, 4, 4, 4, 4, 4, 8, 12, 0)
+	};
 
 	bool BGR = false;
 	int listLength = ARRAYSIZE(RGBList);
@@ -268,31 +280,29 @@ Common::List<Graphics::PixelFormat> OSystem_SDL::getSupportedFormats() const {
 			format.aLoss = 8;
 
 		// Push it first, as the prefered format.
-		list.push_back(format);
+		_supportedFormats.push_back(format);
 
 		if (format.bShift > format.rShift)
 			BGR = true;
-
-		// Mark that we don't need to do this any more.
-		inited = true;
 	}
 
+	// TODO: prioritize matching alpha masks
 	for (int i = 0; i < listLength; i++) {
-		if (inited && (RGBList[i].bytesPerPixel > format.bytesPerPixel))
+		if (_hwscreen && (RGBList[i].bytesPerPixel > format.bytesPerPixel))
 			continue;
 		if (BGR) {
 			if (BGRList[i] != format)
-				list.push_back(BGRList[i]);
-			list.push_back(RGBList[i]);
+				_supportedFormats.push_back(BGRList[i]);
+			_supportedFormats.push_back(RGBList[i]);
 		} else {
 			if (RGBList[i] != format)
-				list.push_back(RGBList[i]);
-			list.push_back(BGRList[i]);
+				_supportedFormats.push_back(RGBList[i]);
+			_supportedFormats.push_back(BGRList[i]);
 		}
 	}
-	list.push_back(Graphics::PixelFormat::createFormatCLUT8());
-	return list;
+	_supportedFormats.push_back(Graphics::PixelFormat::createFormatCLUT8());
 }
+
 #endif
 
 bool OSystem_SDL::setGraphicsMode(int mode) {
@@ -574,6 +584,10 @@ bool OSystem_SDL::loadGFXMode() {
 	_hwscreen = SDL_SetVideoMode(_videoMode.hardwareWidth, _videoMode.hardwareHeight, 16,
 		_videoMode.fullscreen ? (SDL_FULLSCREEN|SDL_SWSURFACE) : SDL_SWSURFACE
 	);
+#ifdef USE_RGB_COLOR
+	detectSupportedFormats();
+#endif
+
 	if (_hwscreen == NULL) {
 		// DON'T use error(), as this tries to bring up the debug
 		// console, which WON'T WORK now that _hwscreen is hosed.
diff --git a/backends/platform/sdl/sdl.h b/backends/platform/sdl/sdl.h
index 480e0af41b..5c901ba711 100644
--- a/backends/platform/sdl/sdl.h
+++ b/backends/platform/sdl/sdl.h
@@ -274,6 +274,13 @@ protected:
 #ifdef USE_RGB_COLOR
 	Graphics::PixelFormat _screenFormat;
 	Graphics::PixelFormat _cursorFormat;
+	Common::List<Graphics::PixelFormat> _supportedFormats;
+
+	/**
+	 * Update the list of supported pixel formats.
+	 * This method is invoked by loadGFXMode().
+	 */
+	void detectSupportedFormats();
 #endif
 
 	// temporary screen (for scalers)