Add AbstractGameRule.cs & derived classes

PckStudio.Core/GameRule/SpawnPositionSet.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Numerics;
+using System.Text;
+using System.Threading.Tasks;
+using OMI.Formats.GameRule;
+
+namespace PckStudio.Core.GameRule
+{
+    internal sealed class SpawnPositionSet : AbstractGameRule
+    {
+        internal enum SpanPositionMethod
+        {
+            OnStart,
+            OnRespawn
+        }
+        private SpanPositionMethod _method;
+
+        internal SpawnPositionSet(SpanPositionMethod method) => _method = method;
+
+        public void AddSpawnPosition(int x, int y, int z, int xRot, int yRot) => AddRule(new UpdatePlayer(new Vector3(x, y, z), new Vector2(xRot, yRot)));
+
+        protected override GameRuleFile.GameRule GetGameRule()
+        {
+            var gameRule = new GameRuleFile.GameRule("SpawnPositionSet");
+            gameRule.AddParameter(new GameRuleFile.IntParameter("method", (int)_method));
+            return gameRule;
+        }
+    }
+}