Implemented SDL event listener class and HUD toggle key (#4)

* Implemented SDL event listener class

* Add HUD toggle.

* frontend_listener: clean-up

* window: invoke all listener callbacks at once

* window: use raw pointers for listeners

* Rename WindowListener to SDLEventListener, reduce virtual functions

---------

Co-authored-by: RadiantDerg <jayvier13@gmail.com>

UnleashedRecomp/ui/sdl_listener.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "ui/window.h"
+
+class ISDLEventListener
+{
+public:
+    virtual ~ISDLEventListener() = default;
+    virtual void OnSDLEvent(SDL_Event* event) = 0;
+};
+
+class SDLEventListener : public ISDLEventListener
+{
+public:
+    SDLEventListener()
+    {
+        Window::s_eventListeners.emplace_back(this);
+    }
+
+    void OnSDLEvent(SDL_Event* event) override {}
+};

UnleashedRecomp/ui/window.cpp

@@ -1,4 +1,5 @@
 #include "window.h"
+#include "sdl_listener.h"
 #include <config.h>
 #include <kernel/function.h>
 #include <SDL_syswm.h>
@@ -107,6 +108,9 @@ int Window_OnSDLEvent(void*, SDL_Event* event)
         }
     }
 
+    for (auto listener : Window::s_eventListeners)
+        listener->OnSDLEvent(event);
+
     return 0;
 }
 

UnleashedRecomp/ui/window.h

@@ -7,7 +7,9 @@
 #define DEFAULT_WIDTH 1280
 #define DEFAULT_HEIGHT 720
 
-struct Window
+class SDLEventListener;
+
+class Window
 {
 public:
     inline static SDL_Window* s_pWindow;
@@ -20,6 +22,8 @@ public:
 
     inline static bool s_isFocused;
 
+    inline static std::vector<SDLEventListener*> s_eventListeners;
+
     static SDL_Surface* GetIconSurface(void* pIconBmp = nullptr, size_t iconSize = 0)
     {
         auto rw = SDL_RWFromMem(pIconBmp ? pIconBmp : (void*)g_icon, pIconBmp ? iconSize : g_icon_size);