BACKENDS: Fix shake position getting stuck

If a game is doing a screen shake (for example, DOTT when the
stereo is on), and the user does an RTL, the screen shake offset
may get stuck if the engine does not reset it on shutdown. To
avoid this in all cases, just always reset the screen shake
whenever the graphics manager is told to switch to a new graphics
mode.

2 files changed, 3 insertions, 0 deletions

diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index 7bac4c85cb..7d29a81f12 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -342,6 +342,7 @@ void OpenGLGraphicsManager::initSize(uint width, uint height, const Graphics::Pi
 
 	_currentState.gameWidth = width;
 	_currentState.gameHeight = height;
+	_gameScreenShakeOffset = 0;
 }
 
 int16 OpenGLGraphicsManager::getWidth() const {
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index c2e0fd20e4..6e8561321b 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -748,6 +748,8 @@ bool SurfaceSdlGraphicsManager::setShader(int id) {
 void SurfaceSdlGraphicsManager::initSize(uint w, uint h, const Graphics::PixelFormat *format) {
 	assert(_transactionMode == kTransactionActive);
 
+	_newShakePos = 0;
+
 #ifdef USE_RGB_COLOR
 	//avoid redundant format changes
 	Graphics::PixelFormat newFormat;