Track mouse button state by real mouse ID

We'll switch to the global mouse ID just once we are ready to deliver events.

This makes sure that any button events that come in for a specific mouse ID maintain that state if we switch to relative mode and start using that mouse ID for events.

Fixes https://github.com/libsdl-org/sdl2-compat/issues/263

src/events/SDL_mouse.c

@@ -687,11 +687,6 @@ static void SDL_PrivateSendMouseMotion(Uint64 timestamp, SDL_Window *window, SDL
     float yrel = 0.0f;
     bool window_is_relative = mouse->focus && (mouse->focus->flags & SDL_WINDOW_MOUSE_RELATIVE_MODE);
 
-    if ((!mouse->relative_mode || mouse->warp_emulation_active) && mouseID != SDL_TOUCH_MOUSEID) {
-        // We're not in relative mode, so all mouse events are global mouse events
-        mouseID = SDL_GLOBAL_MOUSE_ID;
-    }
-
     // SDL_HINT_MOUSE_TOUCH_EVENTS: controlling whether mouse events should generate synthetic touch events
     if (mouse->mouse_touch_events) {
         if (mouseID != SDL_TOUCH_MOUSEID && !relative && track_mouse_down) {
@@ -784,6 +779,11 @@ static void SDL_PrivateSendMouseMotion(Uint64 timestamp, SDL_Window *window, SDL
 
     // Post the event, if desired
     if (SDL_EventEnabled(SDL_EVENT_MOUSE_MOTION)) {
+        if ((!mouse->relative_mode || mouse->warp_emulation_active) && mouseID != SDL_TOUCH_MOUSEID) {
+            // We're not in relative mode, so all mouse events are global mouse events
+            mouseID = SDL_GLOBAL_MOUSE_ID;
+        }
+
         if (!relative && window_is_relative) {
             if (!mouse->relative_mode_warp_motion) {
                 return;
@@ -791,6 +791,7 @@ static void SDL_PrivateSendMouseMotion(Uint64 timestamp, SDL_Window *window, SDL
             xrel = 0.0f;
             yrel = 0.0f;
         }
+
         SDL_Event event;
         event.type = SDL_EVENT_MOUSE_MOTION;
         event.common.timestamp = timestamp;
@@ -873,11 +874,6 @@ static void SDL_PrivateSendMouseButton(Uint64 timestamp, SDL_Window *window, SDL
     Uint32 buttonstate;
     SDL_MouseInputSource *source;
 
-    if (!mouse->relative_mode && mouseID != SDL_TOUCH_MOUSEID) {
-        // We're not in relative mode, so all mouse events are global mouse events
-        mouseID = SDL_GLOBAL_MOUSE_ID;
-    }
-
     source = GetMouseInputSource(mouse, mouseID, down, button);
     if (!source) {
         return;
@@ -954,11 +950,18 @@ static void SDL_PrivateSendMouseButton(Uint64 timestamp, SDL_Window *window, SDL
 
     // Post the event, if desired
     if (SDL_EventEnabled(type)) {
+        if ((!mouse->relative_mode || mouse->warp_emulation_active) && mouseID != SDL_TOUCH_MOUSEID) {
+            // We're not in relative mode, so all mouse events are global mouse events
+            mouseID = SDL_GLOBAL_MOUSE_ID;
+        } else {
+            mouseID = source->mouseID;
+        }
+
         SDL_Event event;
         event.type = type;
         event.common.timestamp = timestamp;
         event.button.windowID = mouse->focus ? mouse->focus->id : 0;
-        event.button.which = source->mouseID;
+        event.button.which = mouseID;
         event.button.down = down;
         event.button.button = button;
         event.button.clicks = (Uint8)SDL_min(clicks, 255);
@@ -1001,13 +1004,13 @@ void SDL_SendMouseWheel(Uint64 timestamp, SDL_Window *window, SDL_MouseID mouseI
         return;
     }
 
-    if (!mouse->relative_mode || mouse->warp_emulation_active) {
-        // We're not in relative mode, so all mouse events are global mouse events
-        mouseID = SDL_GLOBAL_MOUSE_ID;
-    }
-
     // Post the event, if desired
     if (SDL_EventEnabled(SDL_EVENT_MOUSE_WHEEL)) {
+        if (!mouse->relative_mode || mouse->warp_emulation_active) {
+            // We're not in relative mode, so all mouse events are global mouse events
+            mouseID = SDL_GLOBAL_MOUSE_ID;
+        }
+
         SDL_Event event;
         event.type = SDL_EVENT_MOUSE_WHEEL;
         event.common.timestamp = timestamp;