Add automatic heightmap files removal on Editor shutdown for deleted terrains

#1902

Source/Editor/Managed/ManagedEditor.Internal.cpp

@@ -602,3 +602,13 @@ bool ManagedEditor::CreateAsset(const String& tag, String outputPath)
     FileSystem::NormalizePath(outputPath);
     return AssetsImportingManager::Create(tag, outputPath);
 }
+
+Array<Guid> ManagedEditor::GetAssetReferences(const Guid& assetId)
+{
+    Array<Guid> result;
+    if (auto* asset = Content::Load<Asset>(assetId))
+    {
+        asset->GetReferences(result);
+    }
+    return result;
+}

Source/Editor/Managed/ManagedEditor.h

@@ -218,6 +218,13 @@ public:
     /// <param name="outputPath">Output asset path.</param>
     API_FUNCTION() static bool CreateAsset(const String& tag, String outputPath);
 
+    /// <summary>
+    /// Gets a list of asset references of a given asset.
+    /// </summary>
+    /// <param name="assetId">The asset ID.</param>
+    /// <returns>List of referenced assets.</returns>
+    API_FUNCTION() static Array<Guid> GetAssetReferences(const Guid& assetId);
+
 public:
     API_STRUCT(Internal, NoDefault) struct VisualScriptStackFrame
     {

Source/Editor/SceneGraph/Actors/TerrainNode.cs

@@ -1,5 +1,9 @@
 // Copyright (c) 2012-2024 Wojciech Figat. All rights reserved.
 
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
 using FlaxEngine;
 
 namespace FlaxEditor.SceneGraph.Actors
@@ -10,6 +14,15 @@ namespace FlaxEditor.SceneGraph.Actors
     [HideInEditor]
     public sealed class TerrainNode : ActorNode
     {
+        private struct RemovedTerrain
+        {
+            public Guid SceneId;
+            public Guid TerrainId;
+            public string[] Files;
+        }
+
+        private static List<RemovedTerrain> _cleanupFiles;
+
         /// <inheritdoc />
         public TerrainNode(Actor actor)
         : base(actor)
@@ -18,5 +31,68 @@ namespace FlaxEditor.SceneGraph.Actors
 
         /// <inheritdoc />
         public override bool AffectsNavigation => true;
+
+        /// <inheritdoc />
+        public override void Delete()
+        {
+            // Schedule terrain data files for automatic cleanup
+            if (_cleanupFiles == null)
+            {
+                _cleanupFiles = new List<RemovedTerrain>();
+                Engine.RequestingExit += OnRequestingExit;
+            }
+            if (Actor is Terrain terrain)
+            {
+                var removed = new RemovedTerrain
+                {
+                    SceneId = terrain.Scene?.ID ?? Guid.Empty,
+                    TerrainId = terrain.ID,
+                    Files = new string[4],
+                };
+                for (int i = 0; i < terrain.PatchesCount; i++)
+                {
+                    var patch = terrain.GetPatch(i);
+                    if (patch.Heightmap)
+                        removed.Files[0] = patch.Heightmap.Path;
+                    if (patch.Heightfield)
+                        removed.Files[1] = patch.Heightfield.Path;
+                    if (patch.GetSplatmap(0))
+                        removed.Files[2] = patch.GetSplatmap(0).Path;
+                    if (patch.GetSplatmap(1))
+                        removed.Files[3] = patch.GetSplatmap(1).Path;
+                }
+                _cleanupFiles.Add(removed);
+            }
+
+            base.Delete();
+        }
+
+        void OnRequestingExit()
+        {
+            foreach (var e in _cleanupFiles)
+            {
+                try
+                {
+                    // Skip removing this terrain file sif it's still referenced
+                    var sceneReferences = Editor.GetAssetReferences(e.SceneId);
+                    if (sceneReferences != null && sceneReferences.Contains(e.TerrainId))
+                        continue;
+
+                    // Delete files
+                    foreach (var file in e.Files)
+                    {
+                        if (file != null && File.Exists(file))
+                            File.Delete(file);
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Editor.LogWarning(ex);
+                }
+            }
+            _cleanupFiles.Clear();
+            _cleanupFiles = null;
+            Engine.RequestingExit -= OnRequestingExit;
+        }
     }
 }

Source/Engine/Terrain/TerrainPatch.cpp

@@ -113,6 +113,11 @@ TerrainPatch::~TerrainPatch()
 #endif
 }
 
+RawDataAsset* TerrainPatch::GetHeightfield() const
+{
+    return _heightfield.Get();
+}
+
 void TerrainPatch::RemoveLightmap()
 {
     for (auto& chunk : Chunks)

Source/Engine/Terrain/TerrainPatch.h

@@ -149,6 +149,12 @@ public:
         return GetChunk(z * Terrain::ChunksCountEdge + x);
     }
 
+    /// <summary>
+    /// Gets the heightfield collision data asset.
+    /// </summary>
+    /// <returns>The heightfield data asset.</returns>
+    API_PROPERTY() RawDataAsset* GetHeightfield() const;
+
     /// <summary>
     /// Gets the splatmap assigned to this patch.
     /// </summary>