Simulation: Use dotnet timer

OpenHellion/HiResTime.cs

@@ -0,0 +1,57 @@
+// HiResTime.cs
+//
+// Copyright (C) 2023, OpenHellion contributors
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+using System;
+using System.Diagnostics;
+
+namespace OpenHellion;
+
+/// <summary>
+/// 	High-Resolution time. Counts milliseconds and uses a long.
+/// 	This should make it be able to run continuously for 300 000 000 years.
+/// 	Perhaps slightly overkill.
+/// </summary>
+public static class HiResTime
+{
+	private static Stopwatch _stopwatch;
+
+	public static ulong Milliseconds
+	{
+		get
+		{
+			if (_stopwatch == null)
+			{
+				throw new InvalidOperationException("The HiResTime class has not been started. Call the Start() method first.");
+			}
+
+			return (ulong)_stopwatch.ElapsedMilliseconds;
+		}
+	}
+
+	public static void Start()
+	{
+		_stopwatch = Stopwatch.StartNew();
+	}
+
+	public static void Stop()
+	{
+		_stopwatch.Stop();
+		_stopwatch = null;
+	}
+}

ZeroGravity/Objects/SolarSystem.cs

@@ -5,6 +5,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using OpenHellion.Networking;
+using OpenHellion;
 using ZeroGravity.Data;
 using ZeroGravity.Math;
 using ZeroGravity.Network;