init

framework/timer.h

@@ -0,0 +1,127 @@
+/* Copyright (c) 2019-2020, Arm Limited and Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 the "License";
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <chrono>
+
+namespace vkb
+{
+/**
+ * @brief Encapsulates basic usage of chrono, providing a means to calculate float
+ *        durations between time points via function calls.
+ */
+class Timer
+{
+  public:
+	using Seconds      = std::ratio<1>;
+	using Milliseconds = std::ratio<1, 1000>;
+	using Microseconds = std::ratio<1, 1000000>;
+	using Nanoseconds  = std::ratio<1, 1000000000>;
+
+	// Configure
+	using Clock             = std::chrono::steady_clock;
+	using DefaultResolution = Seconds;
+
+	Timer();
+
+	virtual ~Timer() = default;
+
+	/**
+	 * @brief Starts the timer, elapsed() now returns the duration since start()
+	 */
+	void start();
+
+	/**
+	 * @brief Laps the timer, elapsed() now returns the duration since the last lap()
+	 */
+	void lap();
+
+	/**
+	 * @brief Stops the timer, elapsed() now returns 0
+	 * @return The total execution time between `start()` and `stop()`
+	 */
+	template <typename T = DefaultResolution>
+	double stop()
+	{
+		if (!running)
+		{
+			return 0;
+		}
+
+		running       = false;
+		lapping       = false;
+		auto duration = std::chrono::duration<double, T>(Clock::now() - start_time);
+		start_time    = Clock::now();
+		lap_time      = Clock::now();
+
+		return duration.count();
+	}
+
+	/**
+	 * @brief Calculates the time difference between now and when the timer was started
+	 *        if lap() was called, then between now and when the timer was last lapped
+	 * @return The duration between the two time points (default in seconds)
+	 */
+	template <typename T = DefaultResolution>
+	double elapsed()
+	{
+		if (!running)
+		{
+			return 0;
+		}
+
+		Clock::time_point start = start_time;
+
+		if (lapping)
+		{
+			start = lap_time;
+		}
+
+		return std::chrono::duration<double, T>(Clock::now() - start).count();
+	}
+
+	/**
+	 * @brief Calculates the time difference between now and the last time this function was called
+	 * @return The duration between the two time points (default in seconds)
+	 */
+	template <typename T = DefaultResolution>
+	double tick()
+	{
+		auto now      = Clock::now();
+		auto duration = std::chrono::duration<double, T>(now - previous_tick);
+		previous_tick = now;
+		return duration.count();
+	}
+
+	/**
+	 * @brief Check if the timer is running
+	 */
+	bool is_running() const;
+
+  private:
+	bool running{false};
+
+	bool lapping{false};
+
+	Clock::time_point start_time;
+
+	Clock::time_point lap_time;
+
+	Clock::time_point previous_tick;
+};
+}        // namespace vkb