Add support for multiple navmeshes on a scene

Source/Engine/Navigation/NavMesh.cpp

@@ -0,0 +1,170 @@
+// Copyright (c) 2012-2021 Wojciech Figat. All rights reserved.
+
+#include "NavMesh.h"
+#include "NavMeshRuntime.h"
+#include "Engine/Level/Scene/Scene.h"
+#include "Engine/Serialization/Serialization.h"
+#if COMPILE_WITH_ASSETS_IMPORTER
+#include "Engine/ContentImporters/AssetsImportingManager.h"
+#include "Engine/Serialization/MemoryWriteStream.h"
+#if USE_EDITOR
+#include "Editor/Editor.h"
+#endif
+#endif
+
+NavMesh::NavMesh(const SpawnParams& params)
+    : Actor(params)
+    , IsDataDirty(false)
+{
+    DataAsset.Loaded.Bind<NavMesh, &NavMesh::OnDataAssetLoaded>(this);
+}
+
+void NavMesh::SaveNavMesh()
+{
+#if COMPILE_WITH_ASSETS_IMPORTER
+
+    // Skip if scene is missing
+    const auto scene = GetScene();
+    if (!scene)
+        return;
+
+#if USE_EDITOR
+    // Skip if game is running in editor (eg. game scripts update dynamic navmesh)
+    if (Editor::IsPlayMode)
+        return;
+#endif
+
+    // Clear flag
+    IsDataDirty = false;
+
+    // Check if has no navmesh data generated (someone could just remove navmesh volumes or generate for empty scene)
+    if (Data.Tiles.IsEmpty())
+    {
+        // Keep asset reference valid
+        DataAsset.Unlink();
+        return;
+    }
+
+    // Prepare
+    Guid assetId = DataAsset.GetID();
+    if (!assetId.IsValid())
+        assetId = Guid::New();
+    const String assetPath = scene->GetDataFolderPath() / TEXT("NavMesh") + Properties.Name + ASSET_FILES_EXTENSION_WITH_DOT;
+
+    // Generate navmesh tiles data
+    const int32 streamInitialCapacity = Math::RoundUpToPowerOf2((Data.Tiles.Count() + 1) * 1024);
+    MemoryWriteStream stream(streamInitialCapacity);
+    Data.Save(stream);
+    BytesContainer bytesContainer;
+    bytesContainer.Link(stream.GetHandle(), stream.GetPosition());
+
+    // Save asset to file
+    if (AssetsImportingManager::Create(AssetsImportingManager::CreateRawDataTag, assetPath, assetId, (void*)&bytesContainer))
+    {
+        LOG(Warning, "Failed to save navmesh tiles data to file.");
+        return;
+    }
+
+    // Link the created asset
+    DataAsset = assetId;
+
+#endif
+}
+
+void NavMesh::ClearData()
+{
+    if (Data.Tiles.HasItems())
+    {
+        IsDataDirty = true;
+        Data.TileSize = 0.0f;
+        Data.Tiles.Resize(0);
+    }
+}
+
+NavMeshRuntime* NavMesh::GetRuntime(bool createIfMissing) const
+{
+    return NavMeshRuntime::Get(Properties, createIfMissing);
+}
+
+void NavMesh::AddTiles()
+{
+    auto navMesh = NavMeshRuntime::Get(Properties, true);
+    navMesh->AddTiles(this);
+}
+
+void NavMesh::RemoveTiles()
+{
+    auto navMesh = NavMeshRuntime::Get(Properties, false);
+    if (navMesh)
+        navMesh->RemoveTiles(this);
+}
+
+void NavMesh::OnDataAssetLoaded()
+{
+    // Skip if already has data (prevent reloading navmesh on saving)
+    if (Data.Tiles.HasItems())
+        return;
+
+    const bool isEnabled = IsDuringPlay() && IsActiveInHierarchy();
+
+    // Remove added tiles
+    if (isEnabled)
+    {
+        RemoveTiles();
+    }
+
+    // Load navmesh tiles
+    BytesContainer data;
+    data.Link(DataAsset->Data);
+    Data.Load(data, false);
+    IsDataDirty = false;
+
+    // Add loaded tiles
+    if (isEnabled)
+    {
+        AddTiles();
+    }
+}
+
+void NavMesh::Serialize(SerializeStream& stream, const void* otherObj)
+{
+    // Base
+    Actor::Serialize(stream, otherObj);
+
+#if USE_EDITOR
+    // Save navmesh tiles to asset (if modified)
+    if (IsDataDirty)
+        SaveNavMesh();
+#endif
+
+    SERIALIZE_GET_OTHER_OBJ(NavMesh);
+    SERIALIZE(DataAsset);
+    SERIALIZE(Properties);
+}
+
+void NavMesh::Deserialize(DeserializeStream& stream, ISerializeModifier* modifier)
+{
+    // Base
+    Actor::Deserialize(stream, modifier);
+
+    DESERIALIZE(DataAsset);
+    DESERIALIZE(Properties);
+}
+
+void NavMesh::OnEnable()
+{
+    // Base
+    Actor::OnEnable();
+
+    GetScene()->NavigationMeshes.Add(this);
+    AddTiles();
+}
+
+void NavMesh::OnDisable()
+{
+    RemoveTiles();
+    GetScene()->NavigationMeshes.Remove(this);
+
+    // Base
+    Actor::OnDisable();
+}