diff --git a/src/video/sdl2_v.cpp b/src/video/sdl2_v.cpp
--- a/src/video/sdl2_v.cpp
+++ b/src/video/sdl2_v.cpp
@@ -674,6 +674,8 @@ const char *VideoDriver_SDL::Start(const
 	}
 	if (ret_code < 0) return SDL_GetError();
 
+	this->UpdateAutoResolution();
+
 	GetVideoModes();
 	if (!CreateMainSurface(_cur_resolution.width, _cur_resolution.height, false)) {
 		return SDL_GetError();
@@ -930,4 +932,12 @@ void VideoDriver_SDL::ReleaseBlitterLock
 	if (_draw_mutex != nullptr) _draw_mutex->unlock();
 }
 
+Dimension VideoDriver_SDL::GetScreenSize() const
+{
+	SDL_DisplayMode mode;
+	if (SDL_GetCurrentDisplayMode(0, &mode) != 0) return VideoDriver::GetScreenSize();
+
+	return { static_cast<uint>(mode.w), static_cast<uint>(mode.h) };
+}
+
 #endif /* WITH_SDL2 */