feat: add pauzing of the running game

destrum/include/destrum/App.h

@@ -55,7 +55,9 @@ public:
     virtual void onPlayModeChanged(bool) {}
 
     [[nodiscard]] bool isPlaying() const { return playing; }
+    [[nodiscard]] bool isPaused() const { return paused; }
     void requestPlayModeToggle() { playModeToggleRequested = true; }
+    void setPaused(bool pause);
 
     virtual void customWindowsMenu() {}
 
@@ -75,7 +77,6 @@ protected:
     bool cleanedUp{false};
     bool cleaningUp{false};
     bool customInitStarted{false};
-    bool gamePaused{false};
 
     bool frameLimit{false};
     float frameTime{0.f};
@@ -110,6 +111,8 @@ private:
     void exitPlayMode();
 
     bool playing{true};
+    bool paused{false};
+    bool mouseCapturedBeforePause{false};
     bool playModeToggleRequested{false};
     std::optional<nlohmann::json> editSnapshot;
     std::weak_ptr<Scene> editScene;

destrum/include/destrum/Scene/SceneManager.h

@@ -20,6 +20,8 @@ public:
 
     void SetPlaying(bool playing) { m_playing = playing; }
     [[nodiscard]] bool IsPlaying() const { return m_playing; }
+    void SetPaused(bool paused) { m_paused = paused; }
+    [[nodiscard]] bool IsPaused() const { return m_paused; }
 
     void Update(float dt);
     void FixedUpdate(float dt);
@@ -55,7 +57,11 @@ private:
 
     std::vector<std::shared_ptr<Scene>> m_activeScenes;
     std::vector<std::shared_ptr<Scene>> m_scenes;
+
+    [[nodiscard]] bool IsTicking() const { return m_playing && !m_paused; }
+
     bool m_playing{true};
+    bool m_paused{false};
 };
 
 #endif //SCENEMANAGER_H

destrum/src/App.cpp

@@ -188,6 +188,10 @@ if (!isRunning) break;
         {
             playModeToggleRequested = true;
         }
+        if (playing && InputManager::GetInstance().WasKeyPressed(SDL_SCANCODE_F7))
+        {
+            setPaused(!paused);
+        }
 
         // Consume SDL events before updating the base camera so held and
         // newly pressed inputs are applied in the same frame.
@@ -431,21 +435,57 @@ void App::drawWindowsMenu()
 
 void App::drawPlayControls()
 {
-    const char* state = playing ? "PLAYING" : "EDIT";
+    const char* state = !playing ? "EDIT" : paused ? "PAUSED" : "PLAYING";
     const char* action = playing ? "Stop (F5)" : "Play (F5)";
+    const char* pauseAction = paused ? "Resume (F7)" : "Pause (F7)";
     const ImGuiStyle& style = ImGui::GetStyle();
-    const float width = ImGui::CalcTextSize(state).x + ImGui::CalcTextSize(action).x +
-                        style.ItemSpacing.x * 2.0f + style.FramePadding.x * 2.0f;
+    float width = ImGui::CalcTextSize(state).x + ImGui::CalcTextSize(action).x +
+                  style.ItemSpacing.x * 2.0f + style.FramePadding.x * 2.0f;
+    if (playing)
+    {
+        width += ImGui::CalcTextSize(pauseAction).x + style.ItemSpacing.x + style.FramePadding.x * 2.0f;
+    }
 
     // Centered like Godot's run buttons, unless the menus already reach past the middle
     ImGui::SetCursorPosX(std::max(ImGui::GetCursorPosX(), (ImGui::GetWindowWidth() - width) * 0.5f));
-    ImGui::TextColored(playing ? ImVec4{0.4f, 0.9f, 0.4f, 1.0f} : ImVec4{0.7f, 0.7f, 0.7f, 1.0f}, "%s", state);
+    const ImVec4 stateColor = !playing ? ImVec4{0.7f, 0.7f, 0.7f, 1.0f}
+                            : paused   ? ImVec4{0.95f, 0.75f, 0.3f, 1.0f}
+                                       : ImVec4{0.4f, 0.9f, 0.4f, 1.0f};
+    ImGui::TextColored(stateColor, "%s", state);
+    if (playing && ImGui::MenuItem(pauseAction))
+    {
+        setPaused(!paused);
+    }
     if (ImGui::MenuItem(action))
     {
         playModeToggleRequested = true;
     }
 }
 
+void App::setPaused(bool pause)
+{
+    if (!playing || pause == paused)
+    {
+        return;
+    }
+
+    paused = pause;
+    SceneManager::GetInstance().SetPaused(paused);
+
+    // Hand the mouse to the editor while paused, give it back to the game on resume
+    auto& input = InputManager::GetInstance();
+    if (paused)
+    {
+        mouseCapturedBeforePause = input.IsMouseCaptured();
+        input.SetMouseCaptured(false);
+    }
+    else
+    {
+        input.SetMouseCaptured(mouseCapturedBeforePause);
+    }
+    spdlog::info(paused ? "Paused play mode" : "Resumed play mode");
+}
+
 void App::applyPlayModeToggle()
 {
     if (playing)
@@ -500,7 +540,9 @@ void App::exitPlayMode()
 {
     auto& sceneManager = SceneManager::GetInstance();
     playing = false;
+    paused = false;
     sceneManager.SetPlaying(false);
+    sceneManager.SetPaused(false);
     InputManager::GetInstance().SetMouseCaptured(false);
 
     const std::shared_ptr<Scene> scene = editScene.lock();

destrum/src/Scene/SceneManager.cpp

@@ -16,7 +16,7 @@ Scene& SceneManager::GetCurrentScene() const {
 
 void SceneManager::Update(float dt) {
     for (const auto& scene : m_activeScenes) {
-        if (m_playing) {
+        if (IsTicking()) {
             scene->Update(dt);
         } else {
             scene->CommitPendingAdditions();
@@ -25,7 +25,7 @@ void SceneManager::Update(float dt) {
 }
 
 void SceneManager::FixedUpdate(float dt) {
-    if (!m_playing) {
+    if (!IsTicking()) {
         return;
     }
     for (const auto& scene : m_activeScenes) {
@@ -34,7 +34,7 @@ void SceneManager::FixedUpdate(float dt) {
 }
 
 void SceneManager::LateUpdate(float dt) {
-    if (!m_playing) {
+    if (!IsTicking()) {
         return;
     }
     for (const auto& scene : m_activeScenes) {