tr2/shell: fix support for dual monitors

Addresses #2820.

docs/tr2/CHANGELOG.md

@@ -45,6 +45,9 @@
 - fixed pushblocks being rotated when Lara grabs them, most noticeable if asymmetric textures have been used (#2776)
 - fixed the boat briefly having an underwater hue when Lara first climbs on (#2787)
 - fixed destroyed gondolas appearing embedded in the ground after loading a save (#1612)
+- fixed a crash in custom levels with large rooms (#2749)
+- fixed the viewport not always in sync with the window (#2820)
+- fixed inability to move the window to another screen (#2820)
 - fixed flares flipped to the right when thrown (regression from 0.10)
 - fixed the camera going out of bounds in 60fps near specific invalid floor data (known as no-space) (#2764, regression from 0.10)
 - fixed sprites rendering black if no shade value is assigned in the level (#2701, regression from 0.8)
@@ -53,9 +56,7 @@
 - fixed the `/pos` console command reporting the base room number when Lara is actually in a flipped room (#2487, regression from 0.3)
 - fixed a crash if an image was missing
 - fixed a crash on level load if an animation has no frames (#2746, regression from 0.8)
-- fixed a crash in custom levels with large rooms (#2749)
-- fixed flares missing the flicker effect in 60 FPS (#2806)
-- fixed the viewport not always in sync with the window (#2820)
+- fixed flares missing the flicker effect in 60 FPS (#2806, regression from 0.10)
 - improved performance when moving the window around
 - improved pause exit dialog - it can now be canceled with escape
 - removed the need to specify in the game flow levels that have no secrets (secrets will be automatically counted) (#1582)

src/libtrx/game/shell/common.c

@@ -156,9 +156,16 @@ SHELL_SIZE Shell_GetCurrentSize(void)
 
 SHELL_SIZE Shell_GetCurrentDisplaySize(void)
 {
+    int32_t display_idx = 0;
+    SDL_Window *const window = Shell_GetWindow();
+    if (window != nullptr) {
+        display_idx = SDL_GetWindowDisplayIndex(window);
+    }
     SDL_DisplayMode dm;
-    SDL_GetCurrentDisplayMode(0, &dm);
-    return (SHELL_SIZE) { .w = dm.w, .h = dm.h };
+    if (SDL_GetCurrentDisplayMode(display_idx, &dm) == 0) {
+        return (SHELL_SIZE) { .w = dm.w, .h = dm.h };
+    }
+    return (SHELL_SIZE) { .w = -1, .h = -1 };
 }
 
 void Shell_ScheduleExit(void)

src/tr2/game/shell/common.c

@@ -79,6 +79,7 @@ static SHELL_ARGS m_Args = {
 
 static SHELL_SIZE m_ViewportSize = { .w = -1, .h = -1 };
 static Uint64 m_UpdateDebounce = 0;
+static bool m_IgnoreConfigChanges = false;
 
 static void M_SyncToWindow(void);
 static void M_SyncFromWindow(bool update_viewport);
@@ -155,7 +156,7 @@ static void M_SyncFromWindow(const bool update_viewport)
     // Determine if this call should sync config, i.e., skip immediate
     // programmatic events
     const Uint32 now = SDL_GetTicks();
-    const bool skip_config = (now - m_UpdateDebounce) < 100;
+    const bool skip_config = (now - m_UpdateDebounce) < 500;
 
     // Always pull current window state for logging and viewport reset
     const Uint32 window_flags = SDL_GetWindowFlags(g_SDLWindow);
@@ -176,7 +177,9 @@ static void M_SyncFromWindow(const bool update_viewport)
             g_Config.window.height = height;
         }
         if (g_Config.loaded) {
+            m_IgnoreConfigChanges = true;
             Config_Write();
+            m_IgnoreConfigChanges = false;
         }
     }
 
@@ -351,6 +354,10 @@ static void M_LoadConfig(void)
 
 static void M_HandleConfigChange(const EVENT *const event, void *const data)
 {
+    if (m_IgnoreConfigChanges) {
+        return;
+    }
+
     const CONFIG *const old = &g_Config;
     const CONFIG *const new = &g_SavedConfig;