add Timer class

include/td/misc/Time.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <chrono>
+
+namespace td {
+
+class Timer {
+  private:
+	std::chrono::time_point<std::chrono::system_clock> m_LastTime;
+
+  public:
+	Timer() : m_LastTime(std::chrono::system_clock::now()) {}
+
+	float GetDelta() {
+		auto timeElapsed = std::chrono::system_clock::now() - m_LastTime;
+		float timeSeconds = std::chrono::duration<float, std::chrono::seconds::period>(timeElapsed).count();
+		m_LastTime = std::chrono::system_clock::now();
+		return timeSeconds;
+	}
+};
+
+}  // namespace td

src/main.cpp

@@ -1,13 +1,6 @@
 #include <chrono>
 #include <td/display/state/MainMenuState.h>
-
-float GetDelta() {
-	static std::chrono::time_point<std::chrono::system_clock> m_LastTime = std::chrono::system_clock::now();
-	auto timeElapsed = std::chrono::system_clock::now() - m_LastTime;
-	float timeSeconds = std::chrono::duration<float, std::chrono::seconds::period>(timeElapsed).count();
-	m_LastTime = std::chrono::system_clock::now();
-	return timeSeconds;
-}
+#include <td/misc/Time.h>
 
 int main(int argc, char** argv) {
 	// init GL context
@@ -15,10 +8,10 @@ int main(int argc, char** argv) {
 
 	display.ChangeState<td::MainMenuState>();
 
+	td::Timer timer;
 	while (!display.IsCloseRequested()) {
 		display.PollEvents();
-		float delta = GetDelta();
-		display.Update(delta);
+		display.Update(timer.GetDelta());
 	}
 
 	return 0;