Added new method OSystem::getScreenChangeID(), which can be used by code to track screen changes even without getting all EVENT_SCREEN_CHANGED events

svn-id: r23661

4 files changed, 6 insertions, 1 deletions

diff --git a/backends/platform/sdl/events.cpp b/backends/platform/sdl/events.cpp
index 72afad36df..22bf8f9564 100644
--- a/backends/platform/sdl/events.cpp
+++ b/backends/platform/sdl/events.cpp
@@ -180,6 +180,7 @@ bool OSystem_SDL::pollEvent(Event &event) {
 	if (_modeChanged) {
 		_modeChanged = false;
 		event.type = EVENT_SCREEN_CHANGED;
+		_screenChangeCount++;
 		return true;
 	}
 
diff --git a/backends/platform/sdl/sdl-common.h b/backends/platform/sdl/sdl-common.h
index f4c9383c63..093e7950f9 100644
--- a/backends/platform/sdl/sdl-common.h
+++ b/backends/platform/sdl/sdl-common.h
@@ -69,6 +69,8 @@ public:
 	// Typically, 320x200
 	virtual void initSize(uint w, uint h); // overloaded by CE backend
 
+	virtual int getScreenChangeID() const { return _screenChangeCount; }
+
 	// Set colors of the palette
 	void setPalette(const byte *colors, uint start, uint num);
 
@@ -265,6 +267,7 @@ protected:
 	/** Current video mode flags (see DF_* constants) */
 	uint32 _modeFlags;
 	bool _modeChanged;
+	int _screenChangeCount;
 
 	/** True if aspect ratio correction is enabled. */
 	bool _adjustAspectRatio;
diff --git a/backends/platform/sdl/sdl.cpp b/backends/platform/sdl/sdl.cpp
index b6d2d675df..ca00349020 100644
--- a/backends/platform/sdl/sdl.cpp
+++ b/backends/platform/sdl/sdl.cpp
@@ -178,7 +178,7 @@ OSystem_SDL::OSystem_SDL()
 	_overlayVisible(false),
 	_overlayscreen(0), _tmpscreen2(0),
 	_samplesPerSec(0),
-	_cdrom(0), _scalerProc(0), _modeChanged(false), _dirtyChecksums(0),
+	_cdrom(0), _scalerProc(0), _modeChanged(false), _screenChangeCount(0), _dirtyChecksums(0),
 	_mouseVisible(false), _mouseDrawn(false), _mouseData(0), _mouseSurface(0),
 	_mouseOrigSurface(0), _cursorTargetScale(1), _cursorPaletteDisabled(true),
 	_joystick(0),
diff --git a/backends/platform/wince/wince-sdl.cpp b/backends/platform/wince/wince-sdl.cpp
index 6ba02e3949..f29c3dde96 100644
--- a/backends/platform/wince/wince-sdl.cpp
+++ b/backends/platform/wince/wince-sdl.cpp
@@ -2082,6 +2082,7 @@ bool OSystem_WINCE3::pollEvent(Event &event) {
 	if (_modeChanged) {
 		_modeChanged = false;
 		event.type = EVENT_SCREEN_CHANGED;
+		screenChangeCount++;
 		return true;
 	}