add framerate control (WIP)

res/texts/ru_RU.txt

@@ -55,6 +55,7 @@ settings.Camera Inertia=Инерция Камеры
 settings.Fog Curve=Кривая Тумана
 settings.FOV=Поле Зрения
 settings.Fullscreen=Полный экран
+settings.Framerate=Частота кадров
 settings.Gamma=Гамма
 settings.Language=Язык
 settings.Load Distance=Дистанция Загрузки

src/engine.cpp

@@ -171,7 +171,8 @@ void Engine::mainloop() {
         if (!Window::isIconified()) {
             renderFrame(batch);
         }
-        Window::swapInterval(Window::isIconified() ? 1 : settings.display.vsync.get());
+        Window::setFramerate(Window::isIconified() ? 20 : 
+                             settings.display.framerate.get());
 
         processPostRunnables();
 

src/files/settings_io.cpp

@@ -48,6 +48,7 @@ SettingsHandler::SettingsHandler(EngineSettings& settings) {
     builder.add("width", &settings.display.width);
     builder.add("height", &settings.display.height);
     builder.add("samples", &settings.display.samples);
+    builder.add("framerate", &settings.display.framerate);
     builder.add("vsync", &settings.display.vsync);
     builder.add("fullscreen", &settings.display.fullscreen);
 

src/settings.hpp

@@ -28,6 +28,8 @@ struct DisplaySettings {
     IntegerSetting height {720};
     /// @brief Anti-aliasing samples
     IntegerSetting samples {0};
+    /// @brief Framerate limit
+    IntegerSetting framerate {-1, -1, 120};
     /// @brief VSync on
     FlagSetting vsync {true};
 };

src/window/Window.cpp

@@ -9,6 +9,8 @@
 
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
+#include <thread>
+#include <chrono>
 
 static debug::Logger logger("window");
 
@@ -20,6 +22,8 @@ uint Window::width = 0;
 uint Window::height = 0;
 int Window::posX = 0;
 int Window::posY = 0;
+int Window::framerate = -1;
+double Window::prevSwap = 0.0;
 bool Window::fullscreen = false;
 
 static util::ObjectsKeeper observers_keeper;
@@ -58,8 +62,7 @@ bool Window::isIconified() {
     return glfwGetWindowAttrib(window, GLFW_ICONIFIED);
 }
 
-bool Window::isFocused()
-{
+bool Window::isFocused() {
     return glfwGetWindowAttrib(window, GLFW_FOCUSED);
 }
 
@@ -182,7 +185,8 @@ int Window::initialize(DisplaySettings* settings){
         }
     }, true));
 
-    glfwSwapInterval(settings->vsync.get());
+    glfwSwapInterval(1);
+    setFramerate(settings->framerate.get());
     const GLubyte* vendor = glGetString(GL_VENDOR);
     const GLubyte* renderer = glGetString(GL_RENDERER);
     logger.info() << "GL Vendor: " << (char*)vendor;
@@ -281,8 +285,11 @@ void Window::setShouldClose(bool flag){
     glfwSetWindowShouldClose(window, flag);
 }
 
-void Window::swapInterval(int interval){
-    glfwSwapInterval(interval);
+void Window::setFramerate(int framerate) {
+    if ((framerate != -1) != (Window::framerate != -1)) {
+        glfwSwapInterval(framerate == -1);
+    }
+    Window::framerate = framerate;
 }
 
 void Window::toggleFullscreen(){
@@ -315,9 +322,16 @@ bool Window::isFullscreen() {
     return fullscreen;
 }
 
-void Window::swapBuffers(){
+void Window::swapBuffers() {
+    double currentTime = time();
+    if (framerate > 0 && currentTime - prevSwap < (1.0 / framerate)) {
+        std::cout << static_cast<int>((1.0/framerate - (currentTime-prevSwap))*1000) << std::endl;
+        std::this_thread::sleep_for(std::chrono::milliseconds(
+            static_cast<int>((1.0/framerate - (currentTime-prevSwap))*1000)));
+    }
     glfwSwapBuffers(window);
     Window::resetScissor();
+    prevSwap = time();
 }
 
 double Window::time() {

src/window/Window.hpp

@@ -19,6 +19,8 @@ class Window {
     static std::stack<glm::vec4> scissorStack;
     static glm::vec4 scissorArea;
     static bool fullscreen;
+    static int framerate;
+    static double prevSwap;
 
     static bool tryToMaximize(GLFWwindow* window, GLFWmonitor* monitor);
 public:
@@ -34,7 +36,7 @@ public:
     static bool isShouldClose();
     static void setShouldClose(bool flag);
     static void swapBuffers();
-    static void swapInterval(int interval);
+    static void setFramerate(int interval);
     static void toggleFullscreen();
     static bool isFullscreen();
     static bool isMaximized();