Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

utilities/Timer.h

@@ -0,0 +1,73 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#pragma once
+
+namespace Timer {
+
+double GetTime();
+double GetRenderTime();
+
+double GetDeltaTime();
+double GetDeltaRenderTime();
+
+void set_delta_override(double v);
+
+void ResetTimers();
+
+void UpdateTimers(bool pause);
+
+class stopwatch {
+
+public:
+// constructors
+    stopwatch() = default;
+// methods
+    void
+        start() {
+            m_start = std::chrono::steady_clock::now(); }
+	std::chrono::duration<float, std::milli>
+        stop() {
+		    m_last = std::chrono::duration_cast<std::chrono::microseconds>( ( std::chrono::steady_clock::now() - m_start ) );
+			m_accumulator = 0.95f * m_accumulator + m_last.count() / 1000.f;
+			return m_last; }
+    float
+        average() const {
+            return m_accumulator / 20.f;}
+	std::chrono::microseconds
+	    last() const {
+		    return m_last; }
+
+private:
+// members
+    std::chrono::time_point<std::chrono::steady_clock> m_start { std::chrono::steady_clock::now() };
+    float m_accumulator { 1000.f / 30.f * 20.f }; // 20 last samples, initial 'neutral' rate of 30 fps
+    std::chrono::microseconds m_last;
+};
+
+struct subsystem_stopwatches {
+    stopwatch gfx_total;
+    stopwatch gfx_color;
+    stopwatch gfx_shadows;
+    stopwatch gfx_reflections;
+    stopwatch gfx_swap;
+    stopwatch gfx_gui;
+    stopwatch gfx_animate;
+    stopwatch sim_total;
+    stopwatch sim_dynamics;
+    stopwatch sim_events;
+    stopwatch sim_ai;
+    stopwatch mainloop_total;
+};
+
+extern subsystem_stopwatches subsystem;
+
+};
+
+//---------------------------------------------------------------------------