Change Unloading bucket to unloading sqr distance based on the tolera…

…nce added to the maximum loading distance (#236)

Explorer/Assets/Scripts/ECS/Prioritization/Settings/IRealmPartitionSettings.cs

@@ -25,10 +25,11 @@ public interface IRealmPartitionSettings
         int MaxLoadingDistanceInParcels { get; }
 
         /// <summary>
-        ///     Bucket from which the scenes start to unload, the distance corresponding to this bucket should be bigger than <see cref="MaxLoadingDistanceInParcels" />
-        ///     so distant parcels will start unloading gradually
+        ///     Tolerance that is added to <see cref="MaxLoadingDistanceInParcels" /> to determine the distance at which scenes start unloading.
+        ///     It should be slightly bigger than 0 to avoid scenes unloading and loading back immediately when the player moves back and forth
+        ///     when the <see cref="MaxLoadingDistanceInParcels" /> is reached
         /// </summary>
-        int UnloadBucket { get; }
+        int UnloadingDistanceToleranceInParcels { get; }
 
         /// <summary>
         ///     The number of closest scenes that can be requested at a time

Explorer/Assets/Scripts/ECS/Prioritization/Settings/RealmPartitionSettingsAsset.cs

@@ -16,8 +16,8 @@ public class RealmPartitionSettingsAsset : ScriptableObject, IRealmPartitionSett
         [field: SerializeField]
         public int MaxLoadingDistanceInParcels { get; private set; }
 
-        [field: SerializeField]
-        public int UnloadBucket { get; private set; }
+        [field: SerializeField] [field: Min(1)]
+        public int UnloadingDistanceToleranceInParcels { get; private set; } = 1;
 
         [field: SerializeField]
         public int ScenesRequestBatchSize { get; private set; }

Explorer/Assets/Scripts/ECS/SceneLifeCycle/IncreasingRadius/ResolveSceneStateByIncreasingRadiusSystem.cs

@@ -14,6 +14,7 @@
 using SceneRunner.Scene;
 using System.Collections.Generic;
 using System.Runtime.CompilerServices;
+using UnityEngine;
 using UnityEngine.Pool;
 using Utility;
 
@@ -65,7 +66,12 @@ protected override void Update(float t)
                 ProcessesFixedRealmQuery(World, maxLoadingSqrDistance);
             }
 
-            StartUnloadingQuery(World);
+            float unloadingDistance = (Mathf.Max(1, realmPartitionSettings.UnloadingDistanceToleranceInParcels) + realmPartitionSettings.MaxLoadingDistanceInParcels)
+                                      * ParcelMathHelper.PARCEL_SIZE;
+
+            float unloadingSqrDistance = unloadingDistance * unloadingDistance;
+
+            StartUnloadingQuery(World, unloadingSqrDistance);
         }
 
         [Query]
@@ -145,17 +151,17 @@ private void StartScenesLoading(ref RealmComponent realmComponent, float maxLoad
         [Query]
         [All(typeof(SceneDefinitionComponent))]
         [None(typeof(DeleteEntityIntention))]
-        private void StartUnloading(in Entity entity, ref PartitionComponent partitionComponent)
+        private void StartUnloading([Data] float unloadingSqrDistance, in Entity entity, ref PartitionComponent partitionComponent)
         {
-            if (partitionComponent.Bucket < realmPartitionSettings.UnloadBucket) return;
+            if (partitionComponent.RawSqrDistance < unloadingSqrDistance) return;
             World.Add(entity, DeleteEntityIntention.DeferredDeletion);
         }
 
         private struct OrderedData
         {
-            public Entity Entity;
             public PartitionComponent PartitionComponent;
             public SceneDefinitionComponent DefinitionComponent;
+            public Entity Entity;
         }
     }
 }

Explorer/Assets/Scripts/ECS/SceneLifeCycle/Tests/ResolveSceneStateByIncreasingRadiusSystemShould.cs

@@ -68,7 +68,8 @@ public void LimitScenesLoading()
         [Test]
         public void StartUnloading()
         {
-            realmPartitionSettings.UnloadBucket.Returns(3);
+            realmPartitionSettings.UnloadingDistanceToleranceInParcels.Returns(1);
+            realmPartitionSettings.MaxLoadingDistanceInParcels.Returns(1);
 
             for (byte i = 2; i <= 4; i++)
             {
@@ -83,7 +84,7 @@ public void StartUnloading()
                             },
                         },
                     },
-                    new IpfsTypes.IpfsPath()), new PartitionComponent { Bucket = i });
+                    new IpfsTypes.IpfsPath()), new PartitionComponent { Bucket = i, RawSqrDistance = (ParcelMathHelper.PARCEL_SIZE * i * ParcelMathHelper.PARCEL_SIZE * i) - 1f });
             }
 
             system.Update(0f);