belongs to previous commit, add deltatime to application

Author: Floyd Huizinga

src/Cpp/Framework/Application.cpp

@@ -3,6 +3,7 @@
 #include <GLFW/glfw3.h>
 
 #include <iostream>
+#include <ratio>
 
 Application::Application(const std::string& title)
     : _title(title)
@@ -49,6 +50,8 @@ bool Application::Initialize()
 
     glfwSetWindowUserPointer(_window, this);
     glfwSetFramebufferSizeCallback(_window, HandleResize);
+
+    _currentTime = std::chrono::high_resolution_clock::now();
     return true;
 }
 
@@ -111,5 +114,10 @@ int32_t Application::GetWindowHeight() const
 
 void Application::Update()
 {
+    auto oldTime = _currentTime;
+    _currentTime = std::chrono::high_resolution_clock::now();
+
+    std::chrono::duration<double, std::milli> timeSpan = (_currentTime - oldTime);
+    _deltaTime = static_cast<float>(timeSpan.count() / 1000.0);
     glfwPollEvents();
 }

src/Cpp/Framework/Application.hpp

@@ -2,6 +2,7 @@
 
 #include <cstdint>
 #include <string>
+#include <chrono>
 
 // ReSharper disable once CppInconsistentNaming
 struct GLFWwindow;
@@ -33,9 +34,11 @@ class Application
     [[nodiscard]] int32_t GetWindowWidth() const;
     [[nodiscard]] int32_t GetWindowHeight() const;
 
-private:
-    GLFWwindow* _window = nullptr;
     int32_t _width = 0;
     int32_t _height = 0;
+    float _deltaTime = 0.016f;
+private:
+    std::chrono::high_resolution_clock::time_point _currentTime;
+    GLFWwindow* _window = nullptr;
     std::string _title;
 };