Overhaul State and StateManager to remove pointers

Removed raw State pointers in favour of unique_ptrs
Avoid allowing control flow to re-enter States that have exited
Defer releasing states until the end of the frame

rwgame/CMakeLists.txt

@@ -15,6 +15,8 @@ set(RWGAME_SOURCES
 	GameConfig.cpp
 	GameWindow.cpp
 
+	StateManager.hpp
+	StateManager.cpp
 	State.cpp
 
 	states/LoadingState.hpp

rwgame/RWGame.cpp

@@ -35,7 +35,6 @@ RWGame::RWGame(Logger& log, int argc, char* argv[])
     : GameBase(log, argc, argv)
     , data(&log, &work, config.getGameDataPath())
     , renderer(&log, &data) {
-
     bool newgame = options.count("newgame");
     bool test = options.count("test");
     std::string startSave(
@@ -81,20 +80,19 @@ RWGame::RWGame(Logger& log, int argc, char* argv[])
         data.loadTXD(name + ".txd");
     }
 
-    auto loading = new LoadingState(this);
+    StateManager::get().enter<LoadingState>(this, [=]() {
         if (!benchFile.empty()) {
-        loading->setNextState(new BenchmarkState(this, benchFile));
+            StateManager::get().enter<BenchmarkState>(this, benchFile);
         } else if (test) {
-        loading->setNextState(new IngameState(this, true, "test"));
+            StateManager::get().enter<IngameState>(this, true, "test");
         } else if (newgame) {
-        loading->setNextState(new IngameState(this, true));
+            StateManager::get().enter<IngameState>(this, true);
         } else if (!startSave.empty()) {
-        loading->setNextState(new IngameState(this, true, startSave));
+            StateManager::get().enter<IngameState>(this, true, startSave);
         } else {
-        loading->setNextState(new MenuState(this));
+            StateManager::get().enter<MenuState>(this);
         }
-
+    });
-    StateManager::get().enter(loading);
 
     log.info("Game", "Started");
 }
@@ -384,8 +382,9 @@ int RWGame::run() {
     last_clock_time = clock.now();
 
     // Loop until we run out of states.
-    while (StateManager::get().states.size()) {
+    bool running = true;
-        State* state = StateManager::get().states.back();
+    while (!StateManager::get().states.empty() && running) {
+        State* state = StateManager::get().states.back().get();
 
         RW_PROFILE_FRAME_BOUNDARY();
 
@@ -394,7 +393,7 @@ int RWGame::run() {
         while (SDL_PollEvent(&event)) {
             switch (event.type) {
                 case SDL_QUIT:
-                    StateManager::get().clear();
+                    running = false;
                     break;
 
                 case SDL_WINDOWEVENT:
@@ -474,8 +473,13 @@ int RWGame::run() {
         renderProfile();
 
         getWindow().swap();
+
+        // Make sure the topmost state is the correct state
+        StateManager::get().updateStack();
     }
 
+    StateManager::get().clear();
+
     return 0;
 }
 
@@ -483,7 +487,7 @@ void RWGame::tick(float dt) {
     // Process the Engine's background work.
     world->_work->update();
 
-    State* currState = StateManager::get().states.back();
+    State* currState = StateManager::get().states.back().get();
 
     world->chase.update(dt);
 

rwgame/State.hpp

@@ -1,8 +1,5 @@
-#ifndef _GAME_STATE_HPP_
+#ifndef RWGAME_STATE_HPP
-#define _GAME_STATE_HPP_
+#define RWGAME_STATE_HPP
-#include <functional>
-#include <glm/gtc/quaternion.hpp>
-#include <queue>
 #include <render/ViewCamera.hpp>
 #include "GameWindow.hpp"
 #include "MenuSystem.hpp"
@@ -11,8 +8,10 @@
 
 class RWGame;
 class GameWorld;
+class StateManager;
 
-struct State {
+class State {
+public:
     // Helper for global menu behaviour
     Menu* currentMenu;
     Menu* nextMenu;
@@ -66,46 +65,15 @@ struct State {
 
     GameWorld* getWorld();
     GameWindow& getWindow();
-};
 
-struct StateManager {
+    bool hasExited() const {
-    static StateManager& get() {
+        return hasexited_;
-        static StateManager m;
-        return m;
     }
 
-    std::deque<State*> states;
+private:
-
+    bool hasexited_ = false;
-    void clear() {
+protected:
-        states.clear();
+    void done() { hasexited_ = true; }
-    }
-
-    void enter(State* state) {
-        states.push_back(state);
-        state->enter();
-    }
-
-    void exec(State* state) {
-        exit();
-        enter(state);
-    }
-
-    void tick(float dt) {
-        states.back()->tick(dt);
-    }
-
-    void draw(GameRenderer* r) {
-        states.back()->draw(r);
-    }
-
-    void exit() {
-        // TODO: Resole states being leaked.
-        states.back()->exit();
-        states.pop_back();
-        if (states.size() > 0) {
-            states.back()->enter();
-        }
-    }
 };
 
 #endif

rwgame/StateManager.hpp

@@ -0,0 +1,70 @@
+#ifndef RWGAME_STATEMANAGER_HPP
+#define RWGAME_STATEMANAGER_HPP
+#include "State.hpp"
+
+#include <memory>
+#include <queue>
+
+/**
+ * @brief Handles current state focus and transitions
+ *
+ * Possible states:
+ * 	Foreground (topmost state)
+ *  Background (any other position)
+ *
+ * Transitions:
+ *  New State (at the top)
+ *  Suspended (a state was created above us)
+ *  Resumed   (blocking state was removed)
+ */
+class StateManager {
+public:
+    static StateManager& get() {
+        static StateManager m;
+        return m;
+    }
+
+    std::deque<std::unique_ptr<State>> states;
+
+    void clear() {
+        cleared = true;
+    }
+
+    template <class T, class... Targs>
+    void enter(Targs&&... args) {
+        // Notify the previous state it has been suspended
+        if (!states.empty()) {
+            states.back()->exit();
+        }
+        states.emplace_back(std::move(std::make_unique<T>(args...)));
+        states.back()->enter();
+    }
+
+    void updateStack() {
+        if (cleared) {
+            states.clear();
+            cleared = false;
+        }
+
+        while (!states.empty() && states.back()->hasExited()) {
+            states.back()->exit();
+            states.pop_back();
+            if (!states.empty()) {
+                states.back()->enter();
+            }
+        }
+    }
+
+    void tick(float dt) {
+        states.back()->tick(dt);
+    }
+
+    void draw(GameRenderer* r) {
+        states.back()->draw(r);
+    }
+
+private:
+    bool cleared = false;
+};
+
+#endif

rwgame/states/BenchmarkState.cpp

@@ -77,7 +77,7 @@ void BenchmarkState::tick(float dt) {
             a = p;
         }
         if (benchmarkTime > duration) {
-            StateManager::get().exit();
+            done();
         }
         if (b.time != a.time) {
             float alpha = (benchmarkTime - a.time) / (b.time - a.time);

rwgame/states/DebugState.cpp

@@ -363,7 +363,7 @@ void DebugState::handleEvent(const SDL_Event& event) {
         case SDL_KEYDOWN:
             switch (event.key.keysym.sym) {
                 case SDLK_ESCAPE:
-                    StateManager::get().exit();
+                    done();
                     break;
                 case SDLK_w:
                     _movement.x = 1.f;

rwgame/states/IngameState.cpp

@@ -412,11 +412,11 @@ void IngameState::handleEvent(const SDL_Event& event) {
         case SDL_KEYDOWN:
             switch (event.key.keysym.sym) {
                 case SDLK_ESCAPE:
-                    StateManager::get().enter(new PauseState(game));
+                    StateManager::get().enter<PauseState>(game);
                     break;
                 case SDLK_m:
-                    StateManager::get().enter(
+                    StateManager::get().enter<DebugState>(game, _look.position,
-                        new DebugState(game, _look.position, _look.rotation));
+                                                          _look.rotation);
                     break;
                 case SDLK_SPACE:
                     if (getWorld()->state->currentCutscene) {

rwgame/states/IngameState.hpp

@@ -1,7 +1,7 @@
 #ifndef INGAMESTATE_HPP
 #define INGAMESTATE_HPP
 
-#include "State.hpp"
+#include "StateManager.hpp"
 
 class PlayerController;
 

rwgame/states/LoadingState.cpp

@@ -1,8 +1,8 @@
 #include "LoadingState.hpp"
-#include <render/OpenGLRenderer.hpp>
 #include "RWGame.hpp"
 
-LoadingState::LoadingState(RWGame* game) : State(game), next(nullptr) {
+LoadingState::LoadingState(RWGame* game, std::function<void(void)> callback)
+    : State(game), complete(callback) {
 }
 
 void LoadingState::enter() {
@@ -15,9 +15,11 @@ void LoadingState::exit() {
 void LoadingState::tick(float dt) {
     RW_UNUSED(dt);
 
-    // If background work is completed, switch to the next state
+    // If background work is completed, do callback
     if (getWorld()->_work->isEmpty()) {
-        StateManager::get().exec(next);
+        // If we ever get back to this state it should be completed
+        done();
+        complete();
     }
 }
 
@@ -25,10 +27,6 @@ bool LoadingState::shouldWorldUpdate() {
     return false;
 }
 
-void LoadingState::setNextState(State* nextState) {
-    next = nextState;
-}
-
 void LoadingState::handleEvent(const SDL_Event& e) {
     State::handleEvent(e);
 }

rwgame/states/LoadingState.hpp

@@ -1,13 +1,14 @@
 #ifndef LOADINGSTATE_HPP
 #define LOADINGSTATE_HPP
+#include "StateManager.hpp"
 
-#include "State.hpp"
+#include <functional>
 
 class LoadingState : public State {
-    State* next;
+    std::function<void(void)> complete;
 
 public:
-    LoadingState(RWGame* game);
+    LoadingState(RWGame* game, std::function<void(void)> callback);
 
     virtual void enter();
     virtual void exit();
@@ -16,8 +17,6 @@ public:
 
     virtual void draw(GameRenderer* r);
 
-    void setNextState(State* nextState);
-
     virtual bool shouldWorldUpdate();
 
     virtual void handleEvent(const SDL_Event& event);

rwgame/states/MenuState.cpp

@@ -16,12 +16,12 @@ void MenuState::enterMainMenu() {
     Menu* m = new Menu;
     m->offset = glm::vec2(200.f, 200.f);
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kStartGameId), [=] {
-        StateManager::get().enter(new IngameState(game));
+        StateManager::get().enter<IngameState>(game);
     }));
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kLoadGameId),
                              [=] { enterLoadMenu(); }));
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kDebugId), [=] {
-        StateManager::get().enter(new IngameState(game, true, "test"));
+        StateManager::get().enter<IngameState>(game, true, "test");
     }));
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kOptionsId),
                              [] { RW_UNIMPLEMENTED("Options Menu"); }));
@@ -45,13 +45,11 @@ void MenuState::enterLoadMenu() {
                << save.basicState.saveTime.minute << "    ";
             auto name = GameStringUtil::fromString(ss.str());
             name += save.basicState.saveName;
-            m->addEntry(Menu::lambda(name,
+            auto loadsave = [=] {
-                                     [=] {
+                StateManager::get().enter<IngameState>(game, false);
-                                         StateManager::get().enter(
-                                             new IngameState(game, false));
                 game->loadGame(save.savePath);
-                                     },
+            };
-                                     20.f));
+            m->addEntry(Menu::lambda(name, loadsave, 20.f));
         } else {
             m->addEntry(Menu::lambda("CORRUPT", [=] {}));
         }
@@ -75,7 +73,7 @@ void MenuState::handleEvent(const SDL_Event& e) {
         case SDL_KEYUP:
             switch (e.key.keysym.sym) {
                 case SDLK_ESCAPE:
-                    StateManager::get().exit();
+                    done();
                 default:
                     break;
             }

rwgame/states/MenuState.hpp

@@ -1,7 +1,7 @@
 #ifndef MENUSTATE_HPP
 #define MENUSTATE_HPP
 
-#include "State.hpp"
+#include "StateManager.hpp"
 
 class MenuState : public State {
 public:

rwgame/states/PauseState.cpp

@@ -1,6 +1,4 @@
 #include "PauseState.hpp"
-#include <ai/PlayerController.hpp>
-#include <objects/CharacterObject.hpp>
 #include "RWGame.hpp"
 
 PauseState::PauseState(RWGame* game) : State(game) {
@@ -9,7 +7,7 @@ PauseState::PauseState(RWGame* game) : State(game) {
     Menu* m = new Menu;
     m->offset = glm::vec2(200.f, 200.f);
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kResumeGameId),
-                             [] { StateManager::get().exit(); }));
+                             [&] { done(); }));
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kOptionsId),
                              [] { std::cout << "Options" << std::endl; }));
     m->addEntry(Menu::lambda(t.text(MenuDefaults::kQuitGameId),
@@ -51,7 +49,7 @@ void PauseState::handleEvent(const SDL_Event& e) {
         case SDL_KEYDOWN:
             switch (e.key.keysym.sym) {
                 case SDLK_ESCAPE:
-                    StateManager::get().exit();
+                    done();
                     break;
                 default:
                     break;

rwgame/states/PauseState.hpp

@@ -1,7 +1,7 @@
 #ifndef PAUSESTATE_HPP
 #define PAUSESTATE_HPP
 
-#include "State.hpp"
+#include "StateManager.hpp"
 
 class PauseState : public State {
 public: