add stopwatch

BasaltPresenter/Presenter/CMakeLists.txt

@@ -4,6 +4,7 @@ PRIVATE
     main.cpp
     dll_loader.cpp
     cmd_client.cpp
+    stopwatch.cpp
 )
 target_sources(BasaltPresenter
 PUBLIC
@@ -11,6 +12,7 @@ FILE_SET HEADERS
 FILES
     dll_loader.hpp
     cmd_client.hpp
+    stopwatch.hpp
 )
 target_include_directories(BasaltPresenter
 PUBLIC

BasaltPresenter/Presenter/main.cpp

@@ -1,5 +1,6 @@
 #include "dll_loader.hpp"
 #include "cmd_client.hpp"
+#include "stopwatch.hpp"
 #include <basalt/char_types.hpp>
 #include <basalt/engine.hpp>
 #include <basalt/deliver.hpp>
@@ -16,6 +17,7 @@ using dll_loader::DllKind;
 using dll_loader::DllLoader;
 
 using ::basalt::presenter::cmd_client::CmdClient;
+using ::basalt::presenter::stopwatch::Stopwatch;
 
 int main(int argc, char* argv[]) {
     auto engine_dll = DllLoader(DllKind::Engine, BSTEXT("BasaltDirectX11Engine"));
@@ -30,8 +32,10 @@ int main(int argc, char* argv[]) {
     EngineConfig engine_config{.headless = false, .width = payload.width, .height = payload.height};
     engine->startup(std::move(engine_config));
 
+    Stopwatch stopwatch(120);
     while (true) {
         auto req_stop = engine->tick();
+        stopwatch.tick();
         auto can_stop = client.tick(req_stop);
         if (can_stop) break;
     }

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

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