Limit CPU time given to the server to 60FPS

Also, lay the groundwork for frame lenghtening.

src/lib-app/include/app/AppStateIngame.hpp

@@ -10,6 +10,7 @@
 #include "engine/RenderingEngine.hpp"
 #include "utils/DemoFileHandler.hpp"
 #include "utils/DependencyContainer.hpp"
+#include "utils/Framerate.hpp"
 #include <DGM/dgm.hpp>
 #include <GameLoop.hpp>
 #include <LevelD.hpp>
@@ -90,4 +91,5 @@ class [[nodiscard]] AppStateIngame final : public dgm::AppState
     mem::Box<dgm::Camera> camera;
     bool ready = false;
     size_t lastTick = {};
+    Framerate framerate = Framerate(FPS);
 };

src/lib-app/include/utils/Framerate.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <chrono>
+#include <thread>
+
+class [[nodiscard]] Framerate final
+{
+public:
+    explicit Framerate(const unsigned fps)
+        : targetFrameTime(1'000'000 / fps), clock(), clockStart(clock.now())
+    {
+    }
+
+public:
+    void ensureFramerate(const std::chrono::milliseconds extraDelay = {})
+    {
+        auto&& clockEnd = clock.now();
+        auto&& frameTime = clockEnd - clockStart;
+        if (targetFrameTime > frameTime)
+        {
+            std::this_thread::sleep_for(
+                targetFrameTime - frameTime + extraDelay);
+        }
+        clockStart = clock.now();
+    }
+
+private:
+    std::chrono::microseconds targetFrameTime;
+    std::chrono::high_resolution_clock clock;
+    std::chrono::time_point<std::chrono::high_resolution_clock> clockStart;
+};

src/lib-app/src/app/AppStateIngame.cpp

@@ -3,8 +3,10 @@
 #include "app/AppStateWinnerAnnounced.hpp"
 #include "utils/AppMessage.hpp"
 #include <builder/SceneBuilder.hpp>
+#include <chrono>
 #include <events/EventQueue.hpp>
 #include <print>
+#include <thread>
 
 [[nodiscard]] static std::vector<mem::Rc<ControllerInterface>> createInputs(
     mem::Rc<PhysicalController> physicalController,
@@ -54,7 +56,6 @@ AppStateIngame::AppStateIngame(
               dic->settings->display.resolution.width,
               dic->settings->display.resolution.height)))
 {
-    app.window.getWindowContext().setFramerateLimit(60);
     lockMouse();
     createPlayers();
     dic->jukebox->playIngameSong();
@@ -127,6 +128,8 @@ void AppStateIngame::update()
     ++lastTick;
 
     evaluateWinCondition();
+
+    framerate.ensureFramerate();
 }
 
 void AppStateIngame::draw()
@@ -139,7 +142,6 @@ void AppStateIngame::restoreFocusImpl(const std::string& message)
 {
     handleAppMessage<decltype(this)>(app, message);
 
-    app.window.getWindowContext().setFramerateLimit(60);
     propagateSettings();
     lockMouse();
 }

src/lib-app/src/app/AppStateServerWrapper.cpp

@@ -2,16 +2,20 @@
 #include "Dialogs/YesNoCancelDialog.hpp"
 #include "Server.hpp"
 #include "Shortcuts/ShortcutEngine.hpp"
+#include "utils/Framerate.hpp"
 #include <app/AppStateEditor.hpp>
 #include <app/AppStateGameSetup.hpp>
 #include <app/AppStateServerWrapper.hpp>
+#include <core/Constants.hpp>
 
 void serverLoop(Server server, std::atomic_bool& serverEnabled)
 {
+    auto&& framerate = Framerate(FPS);
     std::cout << "Server loop started" << std::endl;
     while (serverEnabled)
     {
         server.update();
+        framerate.ensureFramerate();
     }
 }