add stopwatch

BasaltPresenter/Presenter/stopwatch.hpp

@@ -0,0 +1,21 @@
+#pragma once
+#include <chrono>
+
+namespace basalt::presenter::stopwatch {
+
+    /**
+     * @brief 一个简单的FPS计算器，每隔指定次数统计一次FPS并输出
+     */
+    class Stopwatch {
+    public:
+        Stopwatch(size_t interval);
+        ~Stopwatch();
+
+        void tick();
+
+    private:
+        std::chrono::steady_clock::time_point start_point;
+        size_t interval, counter;
+    };
+
+} // namespace basalt::presenter::stopwatch