SDL: Fix Windows SDL1 keycodes to use the active keyboard layout

2 files changed, 62 insertions, 16 deletions

diff --git a/backends/events/sdl/sdl-events.cpp b/backends/events/sdl/sdl-events.cpp
index 00e2f25cbc..c7c717e300 100644
--- a/backends/events/sdl/sdl-events.cpp
+++ b/backends/events/sdl/sdl-events.cpp
@@ -517,15 +517,17 @@ bool SdlEventSource::handleKeyDown(SDL_Event &ev, Common::Event &event) {
 
 	SDLModToOSystemKeyFlags(SDL_GetModState(), event);
 
+	SDLKey sdlKeycode = obtainKeycode(ev.key.keysym);
+
 	// Handle scroll lock as a key modifier
-	if (ev.key.keysym.sym == SDLK_SCROLLOCK)
+	if (sdlKeycode == SDLK_SCROLLOCK)
 		_scrollLock = !_scrollLock;
 
 	if (_scrollLock)
 		event.kbd.flags |= Common::KBD_SCRL;
 
 	// Ctrl-m toggles mouse capture
-	if (event.kbd.hasFlags(Common::KBD_CTRL) && ev.key.keysym.sym == 'm') {
+	if (event.kbd.hasFlags(Common::KBD_CTRL) && sdlKeycode == 'm') {
 		if (_graphicsManager) {
 			_graphicsManager->getWindow()->toggleMouseGrab();
 		}
@@ -534,26 +536,26 @@ bool SdlEventSource::handleKeyDown(SDL_Event &ev, Common::Event &event) {
 
 #if defined(MACOSX)
 	// On Macintosh, Cmd-Q quits
-	if ((ev.key.keysym.mod & KMOD_META) && ev.key.keysym.sym == 'q') {
+	if ((ev.key.keysym.mod & KMOD_META) && sdlKeycode == 'q') {
 		event.type = Common::EVENT_QUIT;
 		return true;
 	}
 #elif defined(POSIX)
 	// On other *nix systems, Control-Q quits
-	if ((ev.key.keysym.mod & KMOD_CTRL) && ev.key.keysym.sym == 'q') {
+	if ((ev.key.keysym.mod & KMOD_CTRL) && sdlKeycode == 'q') {
 		event.type = Common::EVENT_QUIT;
 		return true;
 	}
 #else
 	// Ctrl-z quits
-	if ((event.kbd.hasFlags(Common::KBD_CTRL) && ev.key.keysym.sym == 'z')) {
+	if ((event.kbd.hasFlags(Common::KBD_CTRL) && sdlKeycode == 'z')) {
 		event.type = Common::EVENT_QUIT;
 		return true;
 	}
 
 	#ifdef WIN32
 	// On Windows, also use the default Alt-F4 quit combination
-	if ((ev.key.keysym.mod & KMOD_ALT) && ev.key.keysym.sym == SDLK_F4) {
+	if ((ev.key.keysym.mod & KMOD_ALT) && sdlKeycode == SDLK_F4) {
 		event.type = Common::EVENT_QUIT;
 		return true;
 	}
@@ -561,7 +563,7 @@ bool SdlEventSource::handleKeyDown(SDL_Event &ev, Common::Event &event) {
 #endif
 
 	// Ctrl-u toggles mute
-	if ((ev.key.keysym.mod & KMOD_CTRL) && ev.key.keysym.sym == 'u') {
+	if ((ev.key.keysym.mod & KMOD_CTRL) && sdlKeycode == 'u') {
 		event.type = Common::EVENT_MUTE;
 		return true;
 	}
@@ -570,8 +572,8 @@ bool SdlEventSource::handleKeyDown(SDL_Event &ev, Common::Event &event) {
 		return true;
 
 	event.type = Common::EVENT_KEYDOWN;
-	event.kbd.keycode = SDLToOSystemKeycode(ev.key.keysym.sym);
-	event.kbd.ascii = mapKey(ev.key.keysym.sym, (SDLMod)ev.key.keysym.mod, obtainUnicode(ev.key.keysym));
+	event.kbd.keycode = SDLToOSystemKeycode(sdlKeycode);
+	event.kbd.ascii = mapKey(sdlKeycode, (SDLMod)ev.key.keysym.mod, obtainUnicode(ev.key.keysym));
 
 	return true;
 }
@@ -580,6 +582,7 @@ bool SdlEventSource::handleKeyUp(SDL_Event &ev, Common::Event &event) {
 	if (remapKey(ev, event))
 		return true;
 
+	SDLKey sdlKeycode = obtainKeycode(ev.key.keysym);
 	SDLMod mod = SDL_GetModState();
 
 	// Check if this is an event handled by handleKeyDown(), and stop if it is
@@ -587,21 +590,21 @@ bool SdlEventSource::handleKeyUp(SDL_Event &ev, Common::Event &event) {
 	// Check if the Ctrl key is down, so that we can trap cases where the
 	// user has the Ctrl key down, and has just released a special key
 	if (mod & KMOD_CTRL) {
-		if (ev.key.keysym.sym == 'm' ||	// Ctrl-m toggles mouse capture
+		if (sdlKeycode == 'm' ||	// Ctrl-m toggles mouse capture
 #if defined(MACOSX)
 			// Meta - Q, handled below
 #elif defined(POSIX)
-			ev.key.keysym.sym == 'q' ||	// On other *nix systems, Control-Q quits
+			sdlKeycode == 'q' ||	// On other *nix systems, Control-Q quits
 #else
-			ev.key.keysym.sym == 'z' ||	// Ctrl-z quit
+			sdlKeycode == 'z' ||	// Ctrl-z quit
 #endif
-			ev.key.keysym.sym == 'u')	// Ctrl-u toggles mute
+			sdlKeycode == 'u')	// Ctrl-u toggles mute
 			return false;
 	}
 
 	// Same for other keys (Meta and Alt)
 #if defined(MACOSX)
-	if ((mod & KMOD_META) && ev.key.keysym.sym == 'q')
+	if ((mod & KMOD_META) && sdlKeycode == 'q')
 		return false;	// On Macintosh, Cmd-Q quits
 #endif
 
@@ -609,8 +612,8 @@ bool SdlEventSource::handleKeyUp(SDL_Event &ev, Common::Event &event) {
 	// continue normally
 
 	event.type = Common::EVENT_KEYUP;
-	event.kbd.keycode = SDLToOSystemKeycode(ev.key.keysym.sym);
-	event.kbd.ascii = mapKey(ev.key.keysym.sym, (SDLMod)ev.key.keysym.mod, 0);
+	event.kbd.keycode = SDLToOSystemKeycode(sdlKeycode);
+	event.kbd.ascii = mapKey(sdlKeycode, (SDLMod)ev.key.keysym.mod, 0);
 
 	// Ctrl-Alt-<key> will change the GFX mode
 	SDLModToOSystemKeyFlags(mod, event);
@@ -868,6 +871,44 @@ bool SdlEventSource::handleResizeEvent(Common::Event &event, int w, int h) {
 	return false;
 }
 
+SDLKey SdlEventSource::obtainKeycode(const SDL_keysym keySym) {
+#if !SDL_VERSION_ATLEAST(2, 0, 0) && defined(WIN32)
+	// WORKAROUND: SDL 1.2 on Windows does not use the user configured keyboard layout,
+	// resulting in "keySym.sym" values to always be those expected for an US keyboard.
+	// For example, SDL returns SDLK_Q when pressing the 'A' key on an AZERTY keyboard.
+	// This defeats the purpose of keycodes which is to be able to refer to a key without
+	// knowing where it is physically located.
+	// We work around this issue by querying the currently active Windows keyboard layout
+	// using the scancode provided by SDL.
+
+	if (keySym.sym >= SDLK_0 && keySym.sym <= SDLK_9) {
+		// The keycode returned by SDL is kept for the number keys.
+		// Querying the keyboard layout for those would return the base key values
+		// for AZERTY keyboards, which are not numbers. For example, SDLK_1 would
+		// map to SDLK_AMPERSAND. This is theoratically correct but practically unhelpful,
+		// because it makes it impossible to handle key combinations such as "ctrl-1".
+		return keySym.sym;
+	}
+
+	int vk = MapVirtualKey(keySym.scancode, MAPVK_VSC_TO_VK);
+	if (vk) {
+		int ch = (MapVirtualKey(vk, MAPVK_VK_TO_CHAR) & 0x7FFF);
+		// The top bit of the result of MapVirtualKey with MAPVK_VSC_TO_VK signals
+		// a dead key was pressed. In that case we keep the value of the accent alone.
+		if (ch) {
+			if (ch >= 'A' && ch <= 'Z') {
+				// Windows returns uppercase ASCII whereas SDL expects lowercase
+				return (SDLKey)(SDLK_a + (ch - 'A'));
+			} else {
+				return (SDLKey)ch;
+			}
+		}
+	}
+#endif
+
+	return keySym.sym;
+}
+
 uint32 SdlEventSource::obtainUnicode(const SDL_keysym keySym) {
 #if SDL_VERSION_ATLEAST(2, 0, 0)
 	SDL_Event events[2];
diff --git a/backends/events/sdl/sdl-events.h b/backends/events/sdl/sdl-events.h
index caa60c1354..7e590aed3c 100644
--- a/backends/events/sdl/sdl-events.h
+++ b/backends/events/sdl/sdl-events.h
@@ -148,6 +148,11 @@ protected:
 	 */
 	uint32 obtainUnicode(const SDL_keysym keySym);
 
+	/**
+	 * Extracts the keycode for the specified key sym.
+	 */
+	SDLKey obtainKeycode(const SDL_keysym keySym);
+
 #if SDL_VERSION_ATLEAST(2, 0, 0)
 	/**
 	 * Whether _fakeKeyUp contains an event we need to send.