Do not duplicate relative mouse mode state

The relative mouse mode is tracked by SDL, and accessible via
SDL_GetRelativeMouseMode().

This is more robust in case SDL changes the relative mouse mode on its
own.

app/src/screen.c

@@ -163,14 +163,21 @@ sc_screen_is_relative_mode(struct sc_screen *screen) {
 }
 
 static void
-sc_screen_capture_mouse(struct sc_screen *screen, bool capture) {
+sc_screen_set_mouse_capture(bool capture) {
     if (SDL_SetRelativeMouseMode(capture)) {
         LOGE("Could not set relative mouse mode to %s: %s",
              capture ? "true" : "false", SDL_GetError());
-        return;
     }
+}
+
+static inline bool
+sc_screen_get_mouse_capture(void) {
+    return SDL_GetRelativeMouseMode();
+}
 
-    screen->mouse_captured = capture;
+static inline void
+sc_screen_toggle_mouse_capture(void) {
+    sc_screen_set_mouse_capture(!sc_screen_get_mouse_capture());
 }
 
 static void
@@ -372,7 +379,6 @@ sc_screen_init(struct sc_screen *screen,
     screen->fullscreen = false;
     screen->maximized = false;
     screen->event_failed = false;
-    screen->mouse_captured = false;
     screen->mouse_capture_key_pressed = 0;
 
     screen->req.x = params->window_x;
@@ -710,7 +716,7 @@ sc_screen_update_frame(struct sc_screen *screen) {
 
         if (sc_screen_is_relative_mode(screen)) {
             // Capture mouse on start
-            sc_screen_capture_mouse(screen, true);
+            sc_screen_set_mouse_capture(true);
         }
     }
 
@@ -823,7 +829,7 @@ sc_screen_handle_event(struct sc_screen *screen, SDL_Event *event) {
                     break;
                 case SDL_WINDOWEVENT_FOCUS_LOST:
                     if (relative_mode) {
-                        sc_screen_capture_mouse(screen, false);
+                        sc_screen_set_mouse_capture(false);
                     }
                     break;
             }
@@ -853,8 +859,7 @@ sc_screen_handle_event(struct sc_screen *screen, SDL_Event *event) {
                     if (key == cap) {
                         // A mouse capture key has been pressed then released:
                         // toggle the capture mouse mode
-                        sc_screen_capture_mouse(screen,
-                                                !screen->mouse_captured);
+                        sc_screen_toggle_mouse_capture();
                     }
                     // Mouse capture keys are never forwarded to the device
                     return;
@@ -864,7 +869,7 @@ sc_screen_handle_event(struct sc_screen *screen, SDL_Event *event) {
         case SDL_MOUSEWHEEL:
         case SDL_MOUSEMOTION:
         case SDL_MOUSEBUTTONDOWN:
-            if (relative_mode && !screen->mouse_captured) {
+            if (relative_mode && !sc_screen_get_mouse_capture()) {
                 // Do not forward to input manager, the mouse will be captured
                 // on SDL_MOUSEBUTTONUP
                 return;
@@ -880,8 +885,8 @@ sc_screen_handle_event(struct sc_screen *screen, SDL_Event *event) {
             }
             break;
         case SDL_MOUSEBUTTONUP:
-            if (relative_mode && !screen->mouse_captured) {
-                sc_screen_capture_mouse(screen, true);
+            if (relative_mode && !sc_screen_get_mouse_capture()) {
+                sc_screen_set_mouse_capture(true);
                 return;
             }
             break;

app/src/screen.h

@@ -60,7 +60,6 @@ struct sc_screen {
 
     bool event_failed; // in case SDL_PushEvent() returned an error
 
-    bool mouse_captured; // only relevant in relative mouse mode
     // To enable/disable mouse capture, a mouse capture key (LALT, LGUI or
     // RGUI) must be pressed. This variable tracks the pressed capture key.
     SDL_Keycode mouse_capture_key_pressed;

app/src/usb/screen_otg.c

@@ -5,15 +5,21 @@
 #include "util/log.h"
 
 static void
-sc_screen_otg_capture_mouse(struct sc_screen_otg *screen, bool capture) {
-    assert(screen->mouse);
+sc_screen_otg_set_mouse_capture(bool capture) {
     if (SDL_SetRelativeMouseMode(capture)) {
         LOGE("Could not set relative mouse mode to %s: %s",
              capture ? "true" : "false", SDL_GetError());
-        return;
     }
+}
+
+static inline bool
+sc_screen_otg_get_mouse_capture(void) {
+    return SDL_GetRelativeMouseMode();
+}
 
-    screen->mouse_captured = capture;
+static inline void
+sc_screen_otg_toggle_mouse_capture(void) {
+    sc_screen_otg_set_mouse_capture(!sc_screen_otg_get_mouse_capture());
 }
 
 static void
@@ -31,7 +37,6 @@ sc_screen_otg_init(struct sc_screen_otg *screen,
     screen->keyboard = params->keyboard;
     screen->mouse = params->mouse;
 
-    screen->mouse_captured = false;
     screen->mouse_capture_key_pressed = 0;
 
     const char *title = params->window_title;
@@ -81,7 +86,7 @@ sc_screen_otg_init(struct sc_screen_otg *screen,
 
     if (screen->mouse) {
         // Capture mouse on start
-        sc_screen_otg_capture_mouse(screen, true);
+        sc_screen_otg_set_mouse_capture(true);
     }
 
     return true;
@@ -193,7 +198,7 @@ sc_screen_otg_handle_event(struct sc_screen_otg *screen, SDL_Event *event) {
                     break;
                 case SDL_WINDOWEVENT_FOCUS_LOST:
                     if (screen->mouse) {
-                        sc_screen_otg_capture_mouse(screen, false);
+                        sc_screen_otg_set_mouse_capture(false);
                     }
                     break;
             }
@@ -227,8 +232,7 @@ sc_screen_otg_handle_event(struct sc_screen_otg *screen, SDL_Event *event) {
                     if (key == cap) {
                         // A mouse capture key has been pressed then released:
                         // toggle the capture mouse mode
-                        sc_screen_otg_capture_mouse(screen,
-                                                    !screen->mouse_captured);
+                        sc_screen_otg_toggle_mouse_capture();
                     }
                     // Mouse capture keys are never forwarded to the device
                     return;
@@ -240,26 +244,26 @@ sc_screen_otg_handle_event(struct sc_screen_otg *screen, SDL_Event *event) {
             }
             break;
         case SDL_MOUSEMOTION:
-            if (screen->mouse && screen->mouse_captured) {
+            if (screen->mouse && sc_screen_otg_get_mouse_capture()) {
                 sc_screen_otg_process_mouse_motion(screen, &event->motion);
             }
             break;
         case SDL_MOUSEBUTTONDOWN:
-            if (screen->mouse && screen->mouse_captured) {
+            if (screen->mouse && sc_screen_otg_get_mouse_capture()) {
                 sc_screen_otg_process_mouse_button(screen, &event->button);
             }
             break;
         case SDL_MOUSEBUTTONUP:
             if (screen->mouse) {
-                if (screen->mouse_captured) {
+                if (sc_screen_otg_get_mouse_capture()) {
                     sc_screen_otg_process_mouse_button(screen, &event->button);
                 } else {
-                    sc_screen_otg_capture_mouse(screen, true);
+                    sc_screen_otg_set_mouse_capture(true);
                 }
             }
             break;
         case SDL_MOUSEWHEEL:
-            if (screen->mouse && screen->mouse_captured) {
+            if (screen->mouse && sc_screen_otg_get_mouse_capture()) {
                 sc_screen_otg_process_mouse_wheel(screen, &event->wheel);
             }
             break;

app/src/usb/screen_otg.h

@@ -18,7 +18,6 @@ struct sc_screen_otg {
     SDL_Texture *texture;
 
     // See equivalent mechanism in screen.h
-    bool mouse_captured;
     SDL_Keycode mouse_capture_key_pressed;
 };