Add embedded window selector & dual game view

This commit allows the `GameView` to select either the "Main Window" (default view of the running game) or a subwindow to become embedded when running the project. This information is communicated to the built game via a new `--swid` (subwindow ID) command line parameter which matches the `--wid` implementation created for the original embedding feature. The subwindow is chosen by matching the name of the window to a user provided name which is given in a text box in the `GameView`.

This is implemented only for Windows and a follow up PR should be able to match the functionality for Linux easily.

Additionally, to utilize this new behavior, there is now the option to enable a second `GameView` that sits above the main one. The second view can embed a different window and has its own embedding controls to improve user debugging. For now, in order to keep the PR smaller, the secondary `GameView` does not utilize its own SceneDebugger, so only the main view can use the runtime selection options. A future PR can open up more functionality for parity with the main view.

Author: RobProductions

core/config/engine.cpp

@@ -423,6 +423,17 @@ bool Engine::is_embedded_in_editor() const {
 	return embedded_in_editor;
 }
 
+void Engine::add_embedded_subwindow(String p_subwindow_title, int64_t p_parent_id) {
+	embedded_subwindows[p_subwindow_title] = p_parent_id;
+}
+
+int64_t Engine::get_embedded_subwindow(String p_subwindow_title) {
+	if (embedded_subwindows.has(p_subwindow_title)) {
+		return embedded_subwindows[p_subwindow_title];
+	}
+	return 0;
+}
+
 Engine::Engine() {
 	singleton = this;
 }

core/config/engine.h

@@ -86,6 +86,7 @@ class Engine {
 	bool project_manager_hint = false;
 	bool extension_reloading = false;
 	bool embedded_in_editor = false;
+	HashMap<String, int64_t> embedded_subwindows;
 	bool recovery_mode_hint = false;
 
 	bool _print_header = true;
@@ -145,6 +146,8 @@ class Engine {
 	void set_frame_delay(uint32_t p_msec);
 	uint32_t get_frame_delay() const;
 
+	void add_embedded_subwindow(String p_subwindow_title, int64_t p_parent_id);
+	int64_t get_embedded_subwindow(String p_subwindow_title);
 	void add_singleton(const Singleton &p_singleton);
 	void get_singletons(List<Singleton> *p_singletons);
 	bool has_singleton(const StringName &p_name) const;

editor/plugins/embedded_process.cpp

@@ -154,7 +154,7 @@ int EmbeddedProcess::get_embedded_pid() const {
 	return current_process_id;
 }
 
-void EmbeddedProcess::embed_process(OS::ProcessID p_pid) {
+void EmbeddedProcess::embed_process(OS::ProcessID p_pid, String p_embedded_window) {
 	if (!window) {
 		return;
 	}
@@ -169,6 +169,7 @@ void EmbeddedProcess::embed_process(OS::ProcessID p_pid) {
 	reset();
 
 	current_process_id = p_pid;
+	current_embedded_window = p_embedded_window;
 	start_embedding_time = OS::get_singleton()->get_ticks_msec();
 	embedding_grab_focus = has_focus();
 	timer_update_embedded_process->start();
@@ -182,7 +183,7 @@ void EmbeddedProcess::embed_process(OS::ProcessID p_pid) {
 
 void EmbeddedProcess::reset() {
 	if (current_process_id != 0 && embedding_completed) {
-		DisplayServer::get_singleton()->remove_embedded_process(current_process_id);
+		DisplayServer::get_singleton()->remove_embedded_process(current_process_id, current_embedded_window);
 	}
 	current_process_id = 0;
 	embedding_completed = false;
@@ -203,7 +204,7 @@ void EmbeddedProcess::request_close() {
 
 void EmbeddedProcess::_try_embed_process() {
 	bool is_visible = is_visible_in_tree();
-	Error err = DisplayServer::get_singleton()->embed_process(window->get_window_id(), current_process_id, get_screen_embedded_window_rect(), is_visible, is_visible && application_has_focus && embedding_grab_focus);
+	Error err = DisplayServer::get_singleton()->embed_process(window->get_window_id(), current_process_id, current_embedded_window, get_screen_embedded_window_rect(), is_visible, is_visible && application_has_focus && embedding_grab_focus);
 	if (err == OK) {
 		embedding_completed = true;
 		queue_redraw();
@@ -262,7 +263,7 @@ void EmbeddedProcess::_update_embedded_process() {
 		last_updated_embedded_process_focused = focus;
 	}
 
-	DisplayServer::get_singleton()->embed_process(window->get_window_id(), current_process_id, get_screen_embedded_window_rect(), is_visible_in_tree(), must_grab_focus);
+	DisplayServer::get_singleton()->embed_process(window->get_window_id(), current_process_id, current_embedded_window, get_screen_embedded_window_rect(), is_visible_in_tree(), must_grab_focus);
 	emit_signal(SNAME("embedded_process_updated"));
 }
 

editor/plugins/embedded_process.h

@@ -39,6 +39,7 @@ class EmbeddedProcess : public Control {
 	uint64_t last_application_focus_time = 0;
 	OS::ProcessID focused_process_id = 0;
 	OS::ProcessID current_process_id = 0;
+	String current_embedded_window = "";
 	bool embedding_grab_focus = false;
 	bool embedding_completed = false;
 	uint64_t start_embedding_time = 0;
@@ -74,7 +75,7 @@ class EmbeddedProcess : public Control {
 	void _notification(int p_what);
 
 public:
-	void embed_process(OS::ProcessID p_pid);
+	void embed_process(OS::ProcessID p_pid, String p_embedded_window);
 	void reset();
 	void request_close();