GUI: Add clearOSD() method

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

2 files changed, 18 insertions, 0 deletions

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);