Fix mouse relative mode activation triggering mouse move events on Mac

Source/Engine/Platform/Mac/MacPlatform.cpp

@@ -273,6 +273,7 @@ bool MacPlatform::Init()
         CFRelease(computerName);
     }
 
+#if !PLATFORM_SDL
     // Find the maximum scale of the display to handle high-dpi displays scaling factor
     {
 	    NSArray* screenArray = [NSScreen screens];
@@ -297,6 +298,7 @@ bool MacPlatform::Init()
 
     Input::Mouse = New<MacMouse>();
     Input::Keyboard = New<MacKeyboard>();
+#endif
 
     return false;
 }

Source/Engine/Platform/SDL/SDLInput.cpp

@@ -432,6 +432,12 @@ public:
         Mouse::SetRelativeMode(relativeMode, window);
         if (!SDL_SetWindowRelativeMouseMode(windowHandle, relativeMode))
             LOG(Error, "Failed to set mouse relative mode: {0}", String(SDL_GetError()));
+
+#if PLATFORM_MAC
+        // Warping right before entering relative mode seems to generate motion event for relative mode
+        SDL_PumpEvents();
+        SDL_FlushEvent(SDL_EVENT_MOUSE_MOTION);
+#endif
     }
 
     bool IsRelative(Window* window) const override

Source/Engine/Platform/SDL/SDLPlatform.cpp

@@ -104,7 +104,8 @@ bool SDLPlatform::Init()
     if (InitInternal())
         return true;
 
-    if (UsesWindows() || UsesX11())
+#if !PLATFORM_MAC
+    if (!UsesWayland())
     {
         // Disable SDL clipboard support
         SDL_SetEventEnabled(SDL_EVENT_CLIPBOARD_UPDATE, false);
@@ -116,6 +117,7 @@ bool SDLPlatform::Init()
         SDL_SetEventEnabled(SDL_EVENT_DROP_COMPLETE, false);
         SDL_SetEventEnabled(SDL_EVENT_DROP_POSITION, false);
     }
+#endif
 
     SDLInput::Init();
     SDLWindow::Init();
@@ -225,20 +227,22 @@ void SDLPlatform::OpenUrl(const StringView& url)
 
 Float2 SDLPlatform::GetMousePosition()
 {
-    Float2 pos;
+#if PLATFORM_LINUX
     if (UsesWayland())
     {
         // Wayland doesn't support reporting global mouse position,
         // use the last known reported position we got from received window events.
-        pos = Input::GetMouseScreenPosition();
-        //if (!SDL_GetGlobalMouseState(&pos.X, &pos.Y))
-        //    LOG(Error, "SDL_GetGlobalMouseState() failed");
+        return Input::GetMouseScreenPosition();
     }
-    else if (UsesX11())
+    if (UsesX11())
+#elif PLATFORM_LINUX || PLATFORM_MAC
+    {
+        Float2 pos;
         SDL_GetGlobalMouseState(&pos.X, &pos.Y);
-    else
-        pos = Input::GetMouseScreenPosition();
-    return pos;
+        return pos;
+    }
+#endif
+    return Input::GetMouseScreenPosition();
 }
 
 void SDLPlatform::SetMousePosition(const Float2& pos)

Source/Engine/Platform/SDL/SDLPlatform.h

@@ -50,9 +50,11 @@ private:
     static bool HandleEvent(SDL_Event& event);
 #if PLATFORM_WINDOWS
     static bool EventMessageHook(void* userdata, MSG* msg);
-    static bool SDLPlatform::EventFilterCallback(void* userdata, SDL_Event* event);
+    static bool EventFilterCallback(void* userdata, SDL_Event* event);
 #elif PLATFORM_LINUX
     static bool X11EventHook(void* userdata, _XEvent* xevent);
+#elif PLATFORM_MAC
+    static bool EventFilterCallback(void* userdata, SDL_Event* event);
 #endif
     static void PreHandleEvents();
     static void PostHandleEvents();

Source/Engine/Platform/SDL/SDLWindow.cpp

@@ -31,7 +31,7 @@
 #elif PLATFORM_LINUX
 #include "Engine/Platform/Linux/IncludeX11.h"
 #elif PLATFORM_MAC
-
+#include <Cocoa/Cocoa.h>
 #else
 static_assert(false, "Unsupported Platform");
 #endif
@@ -157,8 +157,18 @@ SDLWindow::SDLWindow(const CreateWindowSettings& settings)
     _dpiScale = SDL_GetWindowDisplayScale(_window);
     _dpi = Math::TruncToInt(_dpiScale * DefaultDPI);
 
-    SDL_SetWindowMinimumSize(_window, Math::TruncToInt(_settings.MinimumSize.X), Math::TruncToInt(_settings.MinimumSize.Y));
-    SDL_SetWindowMaximumSize(_window, Math::TruncToInt(_settings.MaximumSize.X), Math::TruncToInt(_settings.MaximumSize.Y));
+    Int2 minimumSize(Math::TruncToInt(_settings.MinimumSize.X) , Math::TruncToInt(_settings.MinimumSize.Y));
+    Int2 maximumSize(Math::TruncToInt(_settings.MaximumSize.X) , Math::TruncToInt(_settings.MaximumSize.Y));
+
+    SDL_SetWindowMinimumSize(_window, minimumSize.X, minimumSize.Y);
+#if PLATFORM_MAC
+    // BUG: The maximum size is not enforced correctly, set it to real high value instead
+    if (maximumSize.X == 0)
+        maximumSize.X = 999999;
+    if (maximumSize.Y == 0)
+        maximumSize.Y = 999999;
+#endif
+    SDL_SetWindowMaximumSize(_window, maximumSize.X, maximumSize.Y);
     
     SDL_SetWindowHitTest(_window, &OnWindowHitTest, this);
     InitSwapChain();
@@ -182,6 +192,11 @@ SDLWindow::SDLWindow(const CreateWindowSettings& settings)
             if (xdndAware != 0)
                 X11::XChangeProperty(xDisplay, (X11::Window)_handle, xdndAware, (X11::Atom)4, 32, PropModeReplace, (unsigned char*)&xdndVersion, 1);
         }
+#elif PLATFORM_MAC
+        NSWindow* win = ((NSWindow*)_handle);
+        NSView* view = win.contentView;
+        [win unregisterDraggedTypes];
+        [win registerForDraggedTypes:@[NSPasteboardTypeFileURL, NSPasteboardTypeString, (NSString*)kUTTypeFileURL, (NSString*)kUTTypeUTF8PlainText]];
 #endif
     }
 #endif