Adjust mouse sensivity based on SCALE_2X option

src/mouse.cc

@@ -1,6 +1,7 @@
 #include "mouse.h"
 
 #include "color.h"
+#include "debug.h"
 #include "dinput.h"
 #include "input.h"
 #include "kb.h"
@@ -53,6 +54,10 @@ static unsigned char* _mouse_fptr = nullptr;
 // 0x51E2A0
 static double gMouseSensitivity = 1.0;
 
+static double gMouseSensitivityDpiHorizontal = 1.0;
+static double gMouseSensitivityDpiVertical = 1.0;
+double gMouseSensitivityScale2Xoption = 1.0;
+
 // 0x51E2AC
 static int last_buttons = 0;
 
@@ -454,8 +459,8 @@ void _mouse_info()
     }
 
     // Adjust for mouse senstivity.
-    x = (int)(x * gMouseSensitivity);
-    y = (int)(y * gMouseSensitivity);
+    x = (int)(x * gMouseSensitivity * gMouseSensitivityDpiHorizontal * gMouseSensitivityScale2Xoption);
+    y = (int)(y * gMouseSensitivity * gMouseSensitivityDpiVertical * gMouseSensitivityScale2Xoption);
 
     _mouse_simulate_input(x, y, buttons);
 
@@ -676,6 +681,25 @@ void mouseSetSensitivity(double value)
     if (value >= 1.0 && value <= 2.5) {
         gMouseSensitivity = value;
     }
+
+    gMouseSensitivityDpiHorizontal = 1.0;
+    gMouseSensitivityDpiVertical = 1.0;
+    if (gSdlWindow) {
+        int displayIndex = SDL_GetWindowDisplayIndex(gSdlWindow);
+        float ddpi, hdpi, vdpi;
+        if (SDL_GetDisplayDPI(displayIndex, &ddpi, &hdpi, &vdpi) == 0) {
+            hdpi /= 96.0f; // 96 is standard DPI
+            vdpi /= 96.0f; // 96 is standard DPI
+            gMouseSensitivityDpiHorizontal = 1 / hdpi;
+            gMouseSensitivityDpiVertical = 1 / vdpi;
+            debugPrint("Mouse DPI scaling: horizontal = %.2f, vertical = %.2f", hdpi, vdpi);
+            debugPrint("Mouse DPI sensitivity: horizontal = %.2f, vertical = %.2f", gMouseSensitivityDpiHorizontal, gMouseSensitivityDpiVertical);
+        } else {
+            debugPrint("Mouse DPI sensitivity is not available, SDL_GetDisplayDPI failed");
+        }
+    } else {
+        debugPrint("Mouse DPI sensitivity is not available, SDL window is null");
+    }
 }
 
 void mouseGetPositionInWindow(int win, int* x, int* y)

src/mouse.h

@@ -54,6 +54,7 @@ void mouseGetWheel(int* x, int* y);
 void convertMouseWheelToArrowKey(int* keyCodePtr);
 int mouse_get_last_buttons();
 
+extern double gMouseSensitivityScale2Xoption;
 } // namespace fallout
 
 #endif /* FALLOUT_MOUSE_H_ */

src/svga.cc

@@ -6,6 +6,7 @@
 #include <SDL.h>
 
 #include "config.h"
+#include "debug.h"
 #include "draw.h"
 #include "interface.h"
 #include "memory.h"
@@ -186,6 +187,14 @@ int _GNW95_init_mode_ex(int width, int height, int bpp)
     _zero_mem = _GNW95_zero_vid_mem;
     _mouse_blit = _GNW95_ShowRect;
 
+    if (scale != 1) {
+        gMouseSensitivityScale2Xoption = 1.0 / scale;
+        debugPrint("Mouse sensitivity adjusted according to scale into %f\n", gMouseSensitivityScale2Xoption);
+    } else {
+        gMouseSensitivityScale2Xoption = 1.0;
+        debugPrint("Mouse sensitivity not adjusted for 2X scale\n");
+    }
+
     return 0;
 }