Fix mouse relative calculation to ensure pointer goes from minX to maxX (and Y) included.

Signed-off-by: Andrea Odetti <mariofutire@gmail.com>

source/frontends/sdl/imgui/sdlimguiframe.cpp

@@ -152,8 +152,11 @@ namespace sa2
     int width, height;
     SDL_GetWindowSize(myWindow.get(), &width, &height);
 
-    x = double(motion.x) / double(width);
+    const int posY = std::max(motion.y - myDeadTopZone, 0);
-    y = double(std::max(motion.y, myDeadTopZone) - myDeadTopZone) / double(std::max(height - myDeadTopZone, 1));
+    height = std::max(height - myDeadTopZone, 1);  // a real window has a minimum size of 1
+
+    x = GetRelativePosition(motion.x, width);
+    y = GetRelativePosition(posY, height);
   }
 
   void SDLImGuiFrame::RenderPresent()

source/frontends/sdl/imgui/sdlimguiframe.h

@@ -39,7 +39,7 @@ namespace sa2
     size_t myBorderlessWidth;
     size_t myBorderlessHeight;
 
-    Sint32 myDeadTopZone; // for mouse position
+    int myDeadTopZone; // for mouse position
 
     SDL_GLContext myGLContext;
     ImTextureID myTexture;

source/frontends/sdl/renderer/sdlrendererframe.cpp

@@ -65,8 +65,8 @@ namespace sa2
     int width, height;
     SDL_GetWindowSize(myWindow.get(), &width, &height);
 
-    x = double(motion.x) / double(width);
+    x = GetRelativePosition(motion.x, width);
-    y = double(motion.y) / double(height);
+    y = GetRelativePosition(motion.y, height);
   }
 
 

source/frontends/sdl/sdlframe.cpp

@@ -296,6 +296,13 @@ namespace sa2
     }
   }
 
+  double SDLFrame::GetRelativePosition(const int value, const int size)
+  {
+    // the minimum size of a window is 1
+    const double result = double(value) / double(std::max(1, size - 1));
+    return result;
+  }
+
   void SDLFrame::ProcessMouseMotion(const SDL_MouseMotionEvent & motion)
   {
     CardManager & cardManager = GetCardMgr();
@@ -339,14 +346,16 @@ namespace sa2
       }
       else
       {
-        const int sizeX = iMaxX - iMinX + 1;
+        const int sizeX = iMaxX - iMinX;
-        const int sizeY = iMaxY - iMinY + 1;
+        const int sizeY = iMaxY - iMinY;
+
 
         double x, y;
         GetRelativeMousePosition(motion, x, y);
 
-        const int newX = lround(x * sizeX + iMinX);
+        const int newX = lround(x * sizeX) + iMinX;
-        const int newY = lround(y * sizeY + iMinY);
+        const int newY = lround(y * sizeY) + iMinY;
+
         dx = newX - iX;
         dy = newY - iY;
       }

source/frontends/sdl/sdlframe.h

@@ -56,6 +56,8 @@ namespace sa2
     void ExecuteInRunningMode(const size_t msNextFrame);
     void ExecuteInDebugMode(const size_t msNextFrame);
 
+    static double GetRelativePosition(const int value, const int width);
+
     std::shared_ptr<SDL_Window> myWindow;
 
     bool myForceCapsLock;