(svn r27775) -Fix [FS#6510]: Insufficient thread synchronisation when switching blitters. (JGR)

5 files changed, 39 insertions, 4 deletions

diff --git a/src/video/sdl_v.cpp b/src/video/sdl_v.cpp
index 4bb44c9d7..3668f8602 100644
--- a/src/video/sdl_v.cpp
+++ b/src/video/sdl_v.cpp
@@ -818,10 +818,17 @@ bool VideoDriver_SDL::ToggleFullscreen(bool fullscreen)
 
 bool VideoDriver_SDL::AfterBlitterChange()
 {
+	return CreateMainSurface(_screen.width, _screen.height);
+}
+
+void VideoDriver_SDL::AcquireBlitterLock()
+{
 	if (_draw_mutex != NULL) _draw_mutex->BeginCritical(true);
-	bool ret = CreateMainSurface(_screen.width, _screen.height);
+}
+
+void VideoDriver_SDL::ReleaseBlitterLock()
+{
 	if (_draw_mutex != NULL) _draw_mutex->EndCritical(true);
-	return ret;
 }
 
 #endif /* WITH_SDL */
diff --git a/src/video/sdl_v.h b/src/video/sdl_v.h
index 730f82b93..8855c3566 100644
--- a/src/video/sdl_v.h
+++ b/src/video/sdl_v.h
@@ -31,6 +31,10 @@ public:
 
 	/* virtual */ bool AfterBlitterChange();
 
+	/* virtual */ void AcquireBlitterLock();
+
+	/* virtual */ void ReleaseBlitterLock();
+
 	/* virtual */ bool ClaimMousePointer();
 
 	/* virtual */ const char *GetName() const { return "sdl"; }
diff --git a/src/video/video_driver.hpp b/src/video/video_driver.hpp
index 916044d35..5cb3c6cc3 100644
--- a/src/video/video_driver.hpp
+++ b/src/video/video_driver.hpp
@@ -49,6 +49,7 @@ public:
 
 	/**
 	 * Callback invoked after the blitter was changed.
+	 * This may only be called between AcquireBlitterLock and ReleaseBlitterLock.
 	 * @return True if no error.
 	 */
 	virtual bool AfterBlitterChange()
@@ -56,6 +57,18 @@ public:
 		return true;
 	}
 
+	/**
+	 * Acquire any lock(s) required to be held when changing blitters.
+	 * These lock(s) may not be acquired recursively.
+	 */
+	virtual void AcquireBlitterLock() { }
+
+	/**
+	 * Release any lock(s) required to be held when changing blitters.
+	 * These lock(s) may not be acquired recursively.
+	 */
+	virtual void ReleaseBlitterLock() { }
+
 	virtual bool ClaimMousePointer()
 	{
 		return true;
diff --git a/src/video/win32_v.cpp b/src/video/win32_v.cpp
index c37ebd7dd..e536ae8e5 100644
--- a/src/video/win32_v.cpp
+++ b/src/video/win32_v.cpp
@@ -1334,10 +1334,17 @@ bool VideoDriver_Win32::ToggleFullscreen(bool full_screen)
 
 bool VideoDriver_Win32::AfterBlitterChange()
 {
+	return AllocateDibSection(_screen.width, _screen.height, true) && this->MakeWindow(_fullscreen);
+}
+
+void VideoDriver_Win32::AcquireBlitterLock()
+{
 	if (_draw_mutex != NULL) _draw_mutex->BeginCritical(true);
-	bool ret = AllocateDibSection(_screen.width, _screen.height, true) && this->MakeWindow(_fullscreen);
+}
+
+void VideoDriver_Win32::ReleaseBlitterLock()
+{
 	if (_draw_mutex != NULL) _draw_mutex->EndCritical(true);
-	return ret;
 }
 
 void VideoDriver_Win32::EditBoxLostFocus()
diff --git a/src/video/win32_v.h b/src/video/win32_v.h
index 21d59185b..7609d0422 100644
--- a/src/video/win32_v.h
+++ b/src/video/win32_v.h
@@ -31,6 +31,10 @@ public:
 
 	/* virtual */ bool AfterBlitterChange();
 
+	/* virtual */ void AcquireBlitterLock();
+
+	/* virtual */ void ReleaseBlitterLock();
+
 	/* virtual */ bool ClaimMousePointer();
 
 	/* virtual */ void EditBoxLostFocus();