impr: Don't wake up frame rate limiter thread more often than necessary

main/gui/include/window.hpp

@@ -53,6 +53,9 @@ namespace hex {
         void drawImGui();
         void drawWithShader();
 
+        void unlockFrameRate();
+        void forceNewFrame();
+
         GLFWwindow *m_window = nullptr;
 
         std::string m_windowTitle, m_windowTitleFull;
@@ -64,17 +67,22 @@ namespace hex {
         std::list<std::string> m_popupsToOpen;
         std::set<int> m_pressedKeys;
 
-        std::atomic<bool> m_unlockFrameRate = true;
-
         ImGuiExt::ImHexCustomData m_imguiCustomData;
 
         u32 m_searchBarPosition = 0;
         bool m_emergencyPopupOpen = false;
 
         std::jthread m_frameRateThread;
+        std::chrono::duration<double, std::nano> m_remainingUnlockedTime;
+
+        std::mutex m_sleepMutex;
         std::atomic<bool> m_sleepFlag;
         std::condition_variable m_sleepCondVar;
-        std::mutex m_sleepMutex;
+
+        std::mutex m_wakeupMutex;
+        std::atomic<bool> m_wakeupFlag;
+        std::condition_variable m_wakeupCondVar;
+
 
         gl::Shader m_postProcessingShader;
     };

main/gui/source/window/win_window.cpp

@@ -618,7 +618,7 @@ namespace hex {
 
         glfwSetFramebufferSizeCallback(m_window, [](GLFWwindow* window, int width, int height) {
             auto *win = static_cast<Window *>(glfwGetWindowUserPointer(window));
-            win->m_unlockFrameRate = true;
+            win->unlockFrameRate();
 
             glViewport(0, 0, width, height);
             ImHexApi::System::impl::setMainWindowSize(width, height);

main/gui/source/window/window.cpp

@@ -311,7 +311,7 @@ namespace hex {
 
             // Unlock frame rate if any mouse button is being held down to allow drag scrolling to be smooth
             if (ImGui::IsAnyMouseDown())
-                m_unlockFrameRate = true;
+                this->unlockFrameRate();
 
             // Unlock frame rate if any modifier key is held down since they don't generate key repeat events
             if (
@@ -320,12 +320,12 @@ namespace hex {
                 ImGui::IsKeyPressed(ImGuiKey_LeftSuper) || ImGui::IsKeyPressed(ImGuiKey_RightSuper) ||
                 ImGui::IsKeyPressed(ImGuiKey_LeftAlt) || ImGui::IsKeyPressed(ImGuiKey_RightAlt)
             ) {
-                m_unlockFrameRate = true;
+                this->unlockFrameRate();
             }
 
             // Unlock frame rate if there's more than one viewport since these don't call the glfw callbacks registered here
             if (ImGui::GetPlatformIO().Viewports.size() > 1)
-                m_unlockFrameRate = true;
+                this->unlockFrameRate();
         }
 
         // Hide the window as soon as the render loop exits to make the window
@@ -929,6 +929,23 @@ namespace hex {
         #endif
     }
 
+    void Window::unlockFrameRate() {
+        {
+            std::scoped_lock lock(m_wakeupMutex);
+            m_remainingUnlockedTime = std::chrono::seconds(2);
+        }
+
+        this->forceNewFrame();
+    }
+
+    void Window::forceNewFrame() {
+        std::scoped_lock lock(m_wakeupMutex);
+        m_wakeupFlag = true;
+        m_wakeupCondVar.notify_all();
+    }
+
+
+
     void Window::initGLFW() {
         auto initialWindowProperties = ImHexApi::System::getInitialWindowProperties();
         glfwSetErrorCallback([](int error, const char *desc) {
@@ -1029,7 +1046,7 @@ namespace hex {
             if (win == nullptr)
                 return;
 
-            win->m_unlockFrameRate = true;
+            win->unlockFrameRate();
         };
 
         static const auto isMainWindow = [](GLFWwindow *window) {
@@ -1165,7 +1182,7 @@ namespace hex {
             Duration passedTime = {};
 
             std::chrono::steady_clock::time_point startTime = {}, endTime = {};
-            Duration requestedFrameTime = {}, remainingUnlockedTime = {};
+            Duration requestedFrameTime = {};
             float targetFps = 0;
 
             const auto nativeFps = []() -> float {
@@ -1184,32 +1201,36 @@ namespace hex {
 
                 targetFps = ImHexApi::System::getTargetFPS();
 
-                if (m_unlockFrameRate.exchange(false)) {
-                    remainingUnlockedTime = std::chrono::seconds(2);
-                }
-
                 // If the target frame rate is below 15, use the current monitor's refresh rate
                 if (targetFps < 15) {
                     targetFps = nativeFps;
                 }
 
                 passedTime += iterationTime;
-                if (remainingUnlockedTime > std::chrono::nanoseconds(0)) {
-                    remainingUnlockedTime -= iterationTime;
-                } else {
-                    targetFps = 5;
-                }
-
-                requestedFrameTime = (Duration(1.0E9) / targetFps) / 1.3;
-                if (passedTime >= requestedFrameTime) {
+                {
                     std::scoped_lock lock(m_sleepMutex);
-                    m_sleepFlag = true;
-                    m_sleepCondVar.notify_all();
 
-                    passedTime = {};
+                    if (m_remainingUnlockedTime > std::chrono::nanoseconds(0)) {
+                        m_remainingUnlockedTime -= iterationTime;
+                    } else {
+                        targetFps = 0.01;
+                    }
+
+                    requestedFrameTime = (Duration(1.0E9) / targetFps) / 1.3;
+                    if (passedTime >= requestedFrameTime) {
+                        m_sleepFlag = true;
+                        m_sleepCondVar.notify_all();
+
+                        passedTime = {};
+                    }
                 }
 
-                std::this_thread::sleep_for(std::chrono::milliseconds(1));
+                {
+                    std::unique_lock lock(m_wakeupMutex);
+                    m_wakeupCondVar.wait_for(lock, requestedFrameTime, [&] {
+                        return m_wakeupFlag || stopToken.stop_requested();
+                    });
+                }
 
                 endTime = std::chrono::steady_clock::now();
             }