add stopwatch

BasaltPresenter/Presenter/stopwatch.cpp

@@ -0,0 +1,30 @@
+#include "stopwatch.hpp"
+#include <print>
+
+namespace basalt::presenter::stopwatch {
+
+    Stopwatch::Stopwatch(size_t interval) : start_point(std::chrono::high_resolution_clock::now()), interval(interval), counter(0) {}
+
+    Stopwatch::~Stopwatch() {}
+
+    void Stopwatch::tick() {
+        // 自增计时器
+        ++this->counter;
+        if (this->counter >= this->interval) {
+            // 计数器归零
+            this->counter = 0;
+
+            // 记下当前时刻，计算帧时间和FPS
+            auto stop_point = std::chrono::high_resolution_clock::now();
+            auto time_diff = std::chrono::duration_cast<std::chrono::milliseconds>(stop_point - this->start_point);
+            auto frame_time = static_cast<double>(time_diff.count()) / this->interval;
+            auto fps = 1000.0 / frame_time;
+            // 输出给用户
+            std::print("FPS: {:.2f} Frame Time: {:.4f} ms\n", fps, frame_time);
+
+            // 把结束时间设置为开始时间继续下一轮循环
+            this->start_point = stop_point;
+        }
+    }
+
+} // namespace basalt::presenter::stopwatch