Implemented drag and drop across windows, both OS and embedded.

4 files changed, 69 insertions, 4 deletions

diff --git a/platform/linuxbsd/display_server_x11.cpp b/platform/linuxbsd/display_server_x11.cpp
index 8e225d9b5d..ffe6af41e2 100644
--- a/platform/linuxbsd/display_server_x11.cpp
+++ b/platform/linuxbsd/display_server_x11.cpp
@@ -699,6 +699,26 @@ void DisplayServerX11::delete_sub_window(WindowID p_id) {
 	windows.erase(p_id);
 }
 
+void DisplayServerX11::window_attach_instance_id(ObjectID p_instance, WindowID p_window) {
+
+	ERR_FAIL_COND(!windows.has(p_window));
+	WindowData &wd = windows[p_window];
+
+	wd.instance_id = p_instance;
+}
+
+ObjectID DisplayServerX11::window_get_attached_instance_id(WindowID p_window) const {
+
+	ERR_FAIL_COND_V(!windows.has(p_window), ObjectID());
+	const WindowData &wd = windows[p_window];
+	return wd.instance_id;
+}
+
+DisplayServerX11::WindowID DisplayServerX11::get_window_at_screen_position(const Point2i &p_position) const {
+
+	return INVALID_WINDOW_ID;
+}
+
 void DisplayServerX11::window_set_title(const String &p_title, WindowID p_window) {
 
 	_THREAD_SAFE_METHOD_
diff --git a/platform/linuxbsd/display_server_x11.h b/platform/linuxbsd/display_server_x11.h
index bfce4dc88a..5747ac93ba 100644
--- a/platform/linuxbsd/display_server_x11.h
+++ b/platform/linuxbsd/display_server_x11.h
@@ -130,6 +130,8 @@ class DisplayServerX11 : public DisplayServer {
 		WindowID transient_parent = INVALID_WINDOW_ID;
 		Set<WindowID> transient_children;
 
+		ObjectID instance_id;
+
 		//better to guess on the fly, given WM can change it
 		//WindowMode mode;
 		bool fullscreen = false; //OS can't exit from this mode
@@ -263,11 +265,16 @@ public:
 	virtual int screen_get_dpi(int p_screen = SCREEN_OF_MAIN_WINDOW) const;
 	virtual bool screen_is_touchscreen(int p_screen = SCREEN_OF_MAIN_WINDOW) const;
 
-	virtual Vector<int> get_window_list() const;
+	virtual Vector<DisplayServer::WindowID> get_window_list() const;
 
 	virtual WindowID create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i &p_rect = Rect2i());
 	virtual void delete_sub_window(WindowID p_id);
 
+	virtual WindowID get_window_at_screen_position(const Point2i &p_position) const;
+
+	virtual void window_attach_instance_id(ObjectID p_instance, WindowID p_window = MAIN_WINDOW_ID);
+	virtual ObjectID window_get_attached_instance_id(WindowID p_window = MAIN_WINDOW_ID) const;
+
 	virtual void window_set_title(const String &p_title, WindowID p_window = MAIN_WINDOW_ID);
 	virtual void window_set_rect_changed_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID);
 	virtual void window_set_window_event_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID);
diff --git a/platform/windows/display_server_windows.cpp b/platform/windows/display_server_windows.cpp
index bbf305da3a..707337bc8d 100644
--- a/platform/windows/display_server_windows.cpp
+++ b/platform/windows/display_server_windows.cpp
@@ -435,17 +435,32 @@ bool DisplayServerWindows::screen_is_kept_on() const {
 	return false;
 }
 
-Vector<int> DisplayServerWindows::get_window_list() const {
+Vector<DisplayServer::WindowID> DisplayServerWindows::get_window_list() const {
 
 	_THREAD_SAFE_METHOD_
 
-	Vector<int> ret;
+	Vector<DisplayServer::WindowID> ret;
 	for (Map<WindowID, WindowData>::Element *E = windows.front(); E; E = E->next()) {
 		ret.push_back(E->key());
 	}
 	return ret;
 }
 
+DisplayServer::WindowID DisplayServerWindows::get_window_at_screen_position(const Point2i &p_position) const {
+
+	POINT p;
+	p.x = p_position.x;
+	p.y = p_position.y;
+	HWND hwnd = WindowFromPoint(p);
+	for (Map<WindowID, WindowData>::Element *E = windows.front(); E; E = E->next()) {
+		if (E->get().hWnd == hwnd) {
+			return E->key();
+		}
+	}
+
+	return INVALID_WINDOW_ID;
+}
+
 DisplayServer::WindowID DisplayServerWindows::create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i &p_rect) {
 
 	_THREAD_SAFE_METHOD_
@@ -504,6 +519,22 @@ void DisplayServerWindows::delete_sub_window(WindowID p_window) {
 	windows.erase(p_window);
 }
 
+void DisplayServerWindows::window_attach_instance_id(ObjectID p_instance, WindowID p_window) {
+
+	_THREAD_SAFE_METHOD_
+
+	ERR_FAIL_COND(!windows.has(p_window));
+	windows[p_window].instance_id = p_instance;
+}
+
+ObjectID DisplayServerWindows::window_get_attached_instance_id(WindowID p_window) const {
+
+	_THREAD_SAFE_METHOD_
+
+	ERR_FAIL_COND_V(!windows.has(p_window), ObjectID());
+	return windows[p_window].instance_id;
+}
+
 void DisplayServerWindows::window_set_rect_changed_callback(const Callable &p_callable, WindowID p_window) {
 
 	_THREAD_SAFE_METHOD_
diff --git a/platform/windows/display_server_windows.h b/platform/windows/display_server_windows.h
index c8ee39ecaf..47bb3f59a6 100644
--- a/platform/windows/display_server_windows.h
+++ b/platform/windows/display_server_windows.h
@@ -195,6 +195,8 @@ class DisplayServerWindows : public DisplayServer {
 		Size2 window_rect;
 		Point2 last_pos;
 
+		ObjectID instance_id;
+
 		// IME
 		HIMC im_himc;
 		Vector2 im_position;
@@ -291,11 +293,16 @@ public:
 	virtual void screen_set_keep_on(bool p_enable); //disable screensaver
 	virtual bool screen_is_kept_on() const;
 
-	virtual Vector<int> get_window_list() const;
+	virtual Vector<DisplayServer::WindowID> get_window_list() const;
 
 	virtual WindowID create_sub_window(WindowMode p_mode, uint32_t p_flags, const Rect2i &p_rect = Rect2i());
 	virtual void delete_sub_window(WindowID p_window);
 
+	virtual WindowID get_window_at_screen_position(const Point2i &p_position) const;
+
+	virtual void window_attach_instance_id(ObjectID p_instance, WindowID p_window = MAIN_WINDOW_ID);
+	virtual ObjectID window_get_attached_instance_id(WindowID p_window = MAIN_WINDOW_ID) const;
+
 	virtual void window_set_rect_changed_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID);
 
 	virtual void window_set_window_event_callback(const Callable &p_callable, WindowID p_window = MAIN_WINDOW_ID);