Added Time class

src/core/Time.cpp

@@ -0,0 +1,46 @@
+#include "Time.h"
+
+Uint64 Time::s_lastCounter = 0;
+Uint64 Time::s_freq = 0;
+double Time::s_deltaTime = 0.0;
+
+int Time::s_frames = 0;
+double Time::s_fps = 0.0;
+double Time::s_fpsTimer = 0.0;
+
+void Time::init()
+{
+    s_freq = SDL_GetPerformanceFrequency();
+    s_lastCounter = SDL_GetPerformanceCounter();
+}
+
+void Time::update()
+{
+    Uint64 now = SDL_GetPerformanceCounter();
+    s_deltaTime = (double)(now - s_lastCounter) / s_freq;
+    s_lastCounter = now;
+
+    // 防止切后台
+    if (s_deltaTime > 0.05)
+        s_deltaTime = 0.05;
+
+    // FPS
+    s_frames++;
+    s_fpsTimer += s_deltaTime;
+
+    if (s_fpsTimer >= 1.0) {
+        s_fps = s_frames / s_fpsTimer;
+        s_frames = 0;
+        s_fpsTimer = 0.0;
+    }
+}
+
+double Time::deltaTime()
+{
+    return s_deltaTime;
+}
+
+double Time::fps()
+{
+    return s_fps;
+}

src/core/Time.h

@@ -0,0 +1,20 @@
+#pragma once
+#include <SDL3/SDL.h>
+
+class Time {
+public:
+    static void init();
+    static void update();
+
+    static double deltaTime();
+    static double fps();
+
+private:
+    static Uint64 s_lastCounter;
+    static Uint64 s_freq;
+    static double s_deltaTime;
+
+    static int s_frames;
+    static double s_fps;
+    static double s_fpsTimer;
+};