GUI: Add clearOSD() method

So one can erase everything from OSD and then blit something on it.

5 files changed, 52 insertions, 0 deletions

diff --git a/backends/graphics/graphics.h b/backends/graphics/graphics.h
index 8b0ac19d9e..1063a10a9c 100644
--- a/backends/graphics/graphics.h
+++ b/backends/graphics/graphics.h
@@ -85,6 +85,7 @@ public:
 
 	virtual void displayMessageOnOSD(const char *msg) {}
 	virtual void copyRectToOSD(const void *buf, int pitch, int x, int y, int w, int h) {}
+	virtual void clearOSD() {}
 
 	// Graphics::PaletteManager interface
 	//virtual void setPalette(const byte *colors, uint start, uint num) = 0;
diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index e9f26bc7bc..97788be3ad 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -757,6 +757,23 @@ void OpenGLGraphicsManager::copyRectToOSD(const void *buf, int pitch, int x, int
 #endif
 }
 
+void OpenGLGraphicsManager::clearOSD() {
+#ifdef USE_OSD
+	// HACK: Actually no client code should use graphics functions from
+	// another thread. But the MT-32 emulator still does, thus we need to
+	// make sure this doesn't happen while a updateScreen call is done.
+	Common::StackLock lock(_osdMutex);
+
+	Graphics::Surface *dst = _osd->getSurface();
+	_osd->fill(0);
+	_osd->flagDirty();
+
+	// Init the OSD display parameters.
+	_osdAlpha = kOSDInitialAlpha;
+	_osdFadeStartTime = g_system->getMillis() + kOSDFadeOutDelay;
+#endif
+}
+
 void OpenGLGraphicsManager::setPalette(const byte *colors, uint start, uint num) {
 	assert(_gameScreen->hasPalette());
 
diff --git a/backends/graphics/opengl/opengl-graphics.h b/backends/graphics/opengl/opengl-graphics.h
index e0d1664e76..f36d5d17f2 100644
--- a/backends/graphics/opengl/opengl-graphics.h
+++ b/backends/graphics/opengl/opengl-graphics.h
@@ -116,6 +116,7 @@ public:
 
 	virtual void displayMessageOnOSD(const char *msg);
 	virtual void copyRectToOSD(const void *buf, int pitch, int x, int y, int w, int h);
+	virtual void clearOSD();
 
 	// PaletteManager interface
 	virtual void setPalette(const byte *colors, uint start, uint num);
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 88fdc09f0a..4a33890f42 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -2245,6 +2245,38 @@ void SurfaceSdlGraphicsManager::copyRectToOSD(const void *buf, int pitch, int x,
 	// Ensure a full redraw takes place next time the screen is updated
 	_forceFull = true;
 }
+
+void SurfaceSdlGraphicsManager::clearOSD() {
+	assert(_transactionMode == kTransactionNone);	
+
+	Common::StackLock lock(_graphicsMutex);	// Lock the mutex until this function ends
+
+	// Lock the OSD surface for drawing
+	if (SDL_LockSurface(_osdSurface))
+		error("displayMessageOnOSD: SDL_LockSurface failed: %s", SDL_GetError());
+
+	Graphics::Surface dst;
+	dst.init(_osdSurface->w, _osdSurface->h, _osdSurface->pitch, _osdSurface->pixels,
+		Graphics::PixelFormat(_osdSurface->format->BytesPerPixel,
+			8 - _osdSurface->format->Rloss, 8 - _osdSurface->format->Gloss,
+			8 - _osdSurface->format->Bloss, 8 - _osdSurface->format->Aloss,
+			_osdSurface->format->Rshift, _osdSurface->format->Gshift,
+			_osdSurface->format->Bshift, _osdSurface->format->Ashift));
+
+	// Clear everything with the "transparent" color, i.e. the colorkey
+	SDL_FillRect(_osdSurface, 0, kOSDColorKey);
+
+	// Finished drawing, so unlock the OSD surface again
+	SDL_UnlockSurface(_osdSurface);
+
+	// Init the OSD display parameters, and the fade out
+	_osdAlpha = SDL_ALPHA_TRANSPARENT + kOSDInitialAlpha * (SDL_ALPHA_OPAQUE - SDL_ALPHA_TRANSPARENT) / 100;
+	_osdFadeStartTime = SDL_GetTicks() + kOSDFadeOutDelay;
+	SDL_SetAlpha(_osdSurface, SDL_RLEACCEL | SDL_SRCCOLORKEY | SDL_SRCALPHA, _osdAlpha);
+
+	// Ensure a full redraw takes place next time the screen is updated
+	_forceFull = true;
+}
 #endif
 
 bool SurfaceSdlGraphicsManager::handleScalerHotkeys(Common::KeyCode key) {
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.h b/backends/graphics/surfacesdl/surfacesdl-graphics.h
index a8bafd0a84..01974cf6ab 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.h
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.h
@@ -146,6 +146,7 @@ public:
 #ifdef USE_OSD
 	virtual void displayMessageOnOSD(const char *msg);
 	virtual void copyRectToOSD(const void *buf, int pitch, int x, int y, int w, int h);
+	virtual void clearOSD();
 #endif
 
 	// Override from Common::EventObserver