Esempio n. 1
0
        private void GenerateTerrain(HAPI_NodeId cookNodeId, List <HEU_LoadBufferVolume> terrainBuffers)
        {
            HEU_SessionBase session = GetHoudiniSession(true);
            Transform       parent  = this.gameObject.transform;

            // Directory to store generated terrain files.
            string outputTerrainpath = GetOutputCacheDirectory();

            outputTerrainpath = HEU_Platform.BuildPath(outputTerrainpath, "Terrain");

            int numVolumes = terrainBuffers.Count;

            for (int t = 0; t < numVolumes; ++t)
            {
                if (terrainBuffers[t]._heightMap != null)
                {
                    GameObject newGameObject = new GameObject("heightfield_" + terrainBuffers[t]._tileIndex);

                    HAPI_PartId partId = terrainBuffers[t]._id;
                    ApplyAttributeModifiersOnGameObjectOutput(session, cookNodeId, partId, ref newGameObject);

                    Transform newTransform = newGameObject.transform;
                    newTransform.parent = parent;

                    HEU_GeneratedOutput generatedOutput = new HEU_GeneratedOutput();
                    generatedOutput._outputData._gameObject = newGameObject;

                    Terrain terrain = HEU_GeneralUtility.GetOrCreateComponent <Terrain>(newGameObject);

#if !HEU_TERRAIN_COLLIDER_DISABLED
                    TerrainCollider collider = HEU_GeneralUtility.GetOrCreateComponent <TerrainCollider>(newGameObject);
#endif
                    // The TerrainData and TerrainLayer files needs to be saved out if we create them.
                    // Try user specified path, otherwise use the cache folder
                    string exportTerrainDataPath = terrainBuffers[t]._terrainDataExportPath;
                    if (string.IsNullOrEmpty(exportTerrainDataPath))
                    {
                        // This creates the relative folder path from the Asset's cache folder: {assetCache}/{geo name}/Terrain/Tile{tileIndex}/...
                        exportTerrainDataPath = HEU_Platform.BuildPath(outputTerrainpath, HEU_Defines.HEU_FOLDER_TERRAIN, HEU_Defines.HEU_FOLDER_TILE + terrainBuffers[t]._tileIndex);
                    }

                    bool bFullExportTerrainDataPath = HEU_Platform.DoesFileExist(exportTerrainDataPath);

                    if (!string.IsNullOrEmpty(terrainBuffers[t]._terrainDataPath))
                    {
                        // Load the source TerrainData, then make a unique copy of it in the cache folder

                        TerrainData sourceTerrainData = HEU_AssetDatabase.LoadAssetAtPath(terrainBuffers[t]._terrainDataPath, typeof(TerrainData)) as TerrainData;
                        if (sourceTerrainData == null)
                        {
                            Debug.LogWarningFormat("TerrainData, set via attribute, not found at: {0}", terrainBuffers[t]._terrainDataPath);
                        }

                        if (bFullExportTerrainDataPath)
                        {
                            terrain.terrainData = HEU_AssetDatabase.CopyAndLoadAssetAtGivenPath(sourceTerrainData, exportTerrainDataPath, typeof(TerrainData)) as TerrainData;
                        }
                        else
                        {
                            terrain.terrainData = HEU_AssetDatabase.CopyUniqueAndLoadAssetAtAnyPath(sourceTerrainData, exportTerrainDataPath, typeof(TerrainData)) as TerrainData;
                        }

                        if (terrain.terrainData != null)
                        {
                            // Store path so that it can be deleted on clean up
                            AddGeneratedOutputFilePath(HEU_AssetDatabase.GetAssetPath(terrain.terrainData));
                        }
                    }

                    if (terrain.terrainData == null)
                    {
                        terrain.terrainData = new TerrainData();

                        if (bFullExportTerrainDataPath)
                        {
                            string folderPath = HEU_Platform.GetFolderPath(exportTerrainDataPath, true);
                            HEU_AssetDatabase.CreatePathWithFolders(folderPath);
                            HEU_AssetDatabase.CreateAsset(terrain.terrainData, exportTerrainDataPath);
                        }
                        else
                        {
                            string assetPathName = "TerrainData" + HEU_Defines.HEU_EXT_ASSET;
                            HEU_AssetDatabase.CreateObjectInAssetCacheFolder(terrain.terrainData, exportTerrainDataPath, null, assetPathName, typeof(TerrainData));
                        }
                    }
                    TerrainData terrainData = terrain.terrainData;

#if !HEU_TERRAIN_COLLIDER_DISABLED
                    collider.terrainData = terrainData;
#endif

                    HEU_TerrainUtility.SetTerrainMaterial(terrain, terrainBuffers[t]._specifiedTerrainMaterialName);

#if UNITY_2018_3_OR_NEWER
                    terrain.allowAutoConnect = true;
                    // This has to be set after setting material
                    terrain.drawInstanced = true;
#endif

                    int heightMapSize = terrainBuffers[t]._heightMapWidth;

                    terrainData.heightmapResolution = heightMapSize;
                    if (terrainData.heightmapResolution != heightMapSize)
                    {
                        Debug.LogErrorFormat("Unsupported terrain size: {0}", heightMapSize);
                        continue;
                    }

                    // The terrainData.baseMapResolution is not set here, but rather left to whatever default Unity uses
                    // The terrainData.alphamapResolution is set later when setting the alphamaps.

                    // 32 is the default for resolutionPerPatch
                    const int detailResolution   = 1024;
                    const int resolutionPerPatch = 32;
                    terrainData.SetDetailResolution(detailResolution, resolutionPerPatch);

                    terrainData.SetHeights(0, 0, terrainBuffers[t]._heightMap);

                    // Note that Unity uses a default height range of 600 when a flat terrain is created.
                    // Without a non-zero value for the height range, user isn't able to draw heights.
                    // Therefore, set 600 as the value if height range is currently 0 (due to flat heightfield).
                    float heightRange = terrainBuffers[t]._heightRange;
                    if (heightRange == 0)
                    {
                        heightRange = 600;
                    }

                    terrainData.size = new Vector3(terrainBuffers[t]._terrainSizeX, heightRange, terrainBuffers[t]._terrainSizeY);

                    terrain.Flush();

                    // Set position
                    HAPI_Transform hapiTransformVolume = new HAPI_Transform(true);
                    hapiTransformVolume.position[0] += terrainBuffers[t]._position[0];
                    hapiTransformVolume.position[1] += terrainBuffers[t]._position[1];
                    hapiTransformVolume.position[2] += terrainBuffers[t]._position[2];
                    HEU_HAPIUtility.ApplyLocalTransfromFromHoudiniToUnity(ref hapiTransformVolume, newTransform);

                    // Set layers
                    Texture2D defaultTexture = HEU_VolumeCache.LoadDefaultSplatTexture();
                    int       numLayers      = terrainBuffers[t]._splatLayers.Count;

#if UNITY_2018_3_OR_NEWER
                    // Create TerrainLayer for each heightfield layer.
                    // Note that height and mask layers are ignored (i.e. not created as TerrainLayers).
                    // Since height layer is first, only process layers from 2nd index onwards.
                    if (numLayers > 1)
                    {
                        // Keep existing TerrainLayers, and either update or append to them
                        TerrainLayer[] existingTerrainLayers = terrainData.terrainLayers;

                        // Total layers are existing layers + new alpha maps
                        List <TerrainLayer> finalTerrainLayers = new List <TerrainLayer>(existingTerrainLayers);

                        for (int m = 1; m < numLayers; ++m)
                        {
                            TerrainLayer terrainlayer = null;

                            int terrainLayerIndex = -1;

                            bool bSetTerrainLayerProperties = true;

                            HEU_LoadBufferVolumeLayer layer = terrainBuffers[t]._splatLayers[m];

                            // Look up TerrainLayer file via attribute if user has set it
                            if (!string.IsNullOrEmpty(layer._layerPath))
                            {
                                terrainlayer = HEU_AssetDatabase.LoadAssetAtPath(layer._layerPath, typeof(TerrainLayer)) as TerrainLayer;
                                if (terrainlayer == null)
                                {
                                    Debug.LogWarningFormat("TerrainLayer, set via attribute, not found at: {0}", layer._layerPath);
                                    continue;
                                }
                                else
                                {
                                    // Always check if its part of existing list so as not to add it again
                                    terrainLayerIndex = HEU_TerrainUtility.GetTerrainLayerIndex(terrainlayer, existingTerrainLayers);
                                }
                            }

                            if (terrainlayer == null)
                            {
                                terrainlayer      = new TerrainLayer();
                                terrainLayerIndex = finalTerrainLayers.Count;
                                finalTerrainLayers.Add(terrainlayer);
                            }
                            else
                            {
                                // For existing TerrainLayer, make a copy of it if it has custom layer attributes
                                // because we don't want to change the original TerrainLayer.
                                if (layer._hasLayerAttributes)
                                {
                                    // Copy the TerrainLayer file
                                    TerrainLayer prevTerrainLayer = terrainlayer;
                                    terrainlayer = HEU_AssetDatabase.CopyAndLoadAssetAtAnyPath(terrainlayer, outputTerrainpath, typeof(TerrainLayer), true) as TerrainLayer;
                                    if (terrainlayer != null)
                                    {
                                        if (terrainLayerIndex >= 0)
                                        {
                                            // Update the TerrainLayer reference in the list with this copy
                                            finalTerrainLayers[terrainLayerIndex] = terrainlayer;
                                        }
                                        else
                                        {
                                            // Newly added
                                            terrainLayerIndex = finalTerrainLayers.Count;
                                            finalTerrainLayers.Add(terrainlayer);
                                        }

                                        // Store path for clean up later
                                        AddGeneratedOutputFilePath(HEU_AssetDatabase.GetAssetPath(terrainlayer));
                                    }
                                    else
                                    {
                                        Debug.LogErrorFormat("Unable to copy TerrainLayer '{0}' for generating Terrain. "
                                                             + "Using original TerrainLayer. Will not be able to set any TerrainLayer properties.", layer._layerName);
                                        terrainlayer = prevTerrainLayer;
                                        bSetTerrainLayerProperties = false;
                                        // Again, continuing on to keep proper indexing.
                                    }
                                }
                                else
                                {
                                    // Could be a layer in Assets/ but not part of existing layers in TerrainData
                                    terrainLayerIndex = finalTerrainLayers.Count;
                                    finalTerrainLayers.Add(terrainlayer);
                                    bSetTerrainLayerProperties = false;
                                }
                            }

                            if (bSetTerrainLayerProperties)
                            {
                                if (!string.IsNullOrEmpty(layer._diffuseTexturePath))
                                {
                                    terrainlayer.diffuseTexture = HEU_MaterialFactory.LoadTexture(layer._diffuseTexturePath);
                                }
                                if (terrainlayer.diffuseTexture == null)
                                {
                                    terrainlayer.diffuseTexture = defaultTexture;
                                }

                                terrainlayer.diffuseRemapMin = Vector4.zero;
                                terrainlayer.diffuseRemapMax = Vector4.one;

                                if (!string.IsNullOrEmpty(layer._maskTexturePath))
                                {
                                    terrainlayer.maskMapTexture = HEU_MaterialFactory.LoadTexture(layer._maskTexturePath);
                                }

                                terrainlayer.maskMapRemapMin = Vector4.zero;
                                terrainlayer.maskMapRemapMax = Vector4.one;

                                terrainlayer.metallic = layer._metallic;

                                if (!string.IsNullOrEmpty(layer._normalTexturePath))
                                {
                                    terrainlayer.normalMapTexture = HEU_MaterialFactory.LoadTexture(layer._normalTexturePath);
                                }

                                terrainlayer.normalScale = layer._normalScale;

                                terrainlayer.smoothness = layer._smoothness;
                                terrainlayer.specular   = layer._specularColor;
                                terrainlayer.tileOffset = layer._tileOffset;

                                if (layer._tileSize.magnitude == 0f && terrainlayer.diffuseTexture != null)
                                {
                                    // Use texture size if tile size is 0
                                    layer._tileSize = new Vector2(terrainlayer.diffuseTexture.width, terrainlayer.diffuseTexture.height);
                                }
                                terrainlayer.tileSize = layer._tileSize;
                            }
                        }
                        terrainData.terrainLayers = finalTerrainLayers.ToArray();
                    }
#else
                    // Need to create SplatPrototype for each layer in heightfield, representing the textures.
                    SplatPrototype[] splatPrototypes = new SplatPrototype[numLayers];
                    for (int m = 0; m < numLayers; ++m)
                    {
                        splatPrototypes[m] = new SplatPrototype();

                        HEU_LoadBufferVolumeLayer layer = terrainBuffers[t]._splatLayers[m];

                        Texture2D diffuseTexture = null;
                        if (!string.IsNullOrEmpty(layer._diffuseTexturePath))
                        {
                            diffuseTexture = HEU_MaterialFactory.LoadTexture(layer._diffuseTexturePath);
                        }
                        if (diffuseTexture == null)
                        {
                            diffuseTexture = defaultTexture;
                        }
                        splatPrototypes[m].texture = diffuseTexture;

                        splatPrototypes[m].tileOffset = layer._tileOffset;
                        if (layer._tileSize.magnitude == 0f && diffuseTexture != null)
                        {
                            // Use texture size if tile size is 0
                            layer._tileSize = new Vector2(diffuseTexture.width, diffuseTexture.height);
                        }
                        splatPrototypes[m].tileSize = layer._tileSize;

                        splatPrototypes[m].metallic   = layer._metallic;
                        splatPrototypes[m].smoothness = layer._smoothness;

                        if (!string.IsNullOrEmpty(layer._normalTexturePath))
                        {
                            splatPrototypes[m].normalMap = HEU_MaterialFactory.LoadTexture(layer._normalTexturePath);
                        }
                    }
                    terrainData.splatPrototypes = splatPrototypes;
#endif

                    // Set the splatmaps
                    if (terrainBuffers[t]._splatMaps != null)
                    {
                        // Set the alphamap size before setting the alphamaps to get correct scaling
                        // The alphamap size comes from the first alphamap layer
                        int alphamapResolution = terrainBuffers[t]._heightMapWidth;
                        if (numLayers > 1)
                        {
                            alphamapResolution = terrainBuffers[t]._splatLayers[1]._heightMapWidth;
                        }
                        terrainData.alphamapResolution = alphamapResolution;

                        terrainData.SetAlphamaps(0, 0, terrainBuffers[t]._splatMaps);
                    }

                    // Set the tree scattering
                    if (terrainBuffers[t]._scatterTrees != null)
                    {
                        HEU_TerrainUtility.ApplyScatterTrees(terrainData, terrainBuffers[t]._scatterTrees);
                    }

                    // Set the detail layers
                    if (terrainBuffers[t]._detailPrototypes != null)
                    {
                        HEU_TerrainUtility.ApplyDetailLayers(terrain, terrainData, terrainBuffers[t]._detailProperties,
                                                             terrainBuffers[t]._detailPrototypes, terrainBuffers[t]._detailMaps);
                    }

                    terrainBuffers[t]._generatedOutput = generatedOutput;
                    _generatedOutputs.Add(generatedOutput);

                    SetOutputVisiblity(terrainBuffers[t]);
                }
            }
        }
Esempio n. 2
0
	public void GenerateTerrainWithAlphamaps(HEU_SessionBase session, HEU_HoudiniAsset houdiniAsset, bool bRebuild)
	{
	    if (_layers == null || _layers.Count == 0)
	    {
		Debug.LogError("Unable to generate terrain due to lack of heightfield layers!");
		return;
	    }

	    HEU_VolumeLayer heightLayer = _layers[0];

	    HAPI_VolumeInfo heightVolumeInfo = new HAPI_VolumeInfo();
	    bool bResult = session.GetVolumeInfo(_ownerNode.GeoID, heightLayer._part.PartID, ref heightVolumeInfo);
	    if (!bResult)
	    {
		Debug.LogErrorFormat("Unable to get volume info for height layer: {0}!", heightLayer._layerName);
		return;
	    }

	    // Special handling of volume cache presets. It is applied here (if exists) because it might pertain to TerrainData that exists
	    // in the AssetDatabase. If we don't apply here but rather create a new one, the existing file will get overwritten.
	    // Applying the preset here for terrain ensures the TerrainData is reused.
	    // Get the volume preset for this part
	    HEU_VolumeCachePreset volumeCachePreset = houdiniAsset.GetVolumeCachePreset(_ownerNode.ObjectNode.ObjectName, _ownerNode.GeoName, TileIndex);
	    if (volumeCachePreset != null)
	    {
		ApplyPreset(volumeCachePreset);

		// Remove it so that it doesn't get applied when doing the recook step
		houdiniAsset.RemoveVolumeCachePreset(volumeCachePreset);
	    }

	    // The TerrainData and TerrainLayer files needs to be saved out if we create them. This creates the relative folder
	    // path from the Asset's cache folder: {assetCache}/{geo name}/Terrain/Tile{tileIndex}/...
	    string relativeFolderPath = HEU_Platform.BuildPath(_ownerNode.GeoName, HEU_Defines.HEU_FOLDER_TERRAIN, HEU_Defines.HEU_FOLDER_TILE + TileIndex);

	    if (bRebuild)
	    {
		// For full rebuild, re-create the TerrainData instead of using previous
		_terrainData = null;
	    }

	    //Debug.Log("Generating Terrain with AlphaMaps: " + (_terrainData != null ? _terrainData.name : "NONE"));
	    TerrainData terrainData = _terrainData;
	    Vector3 terrainOffsetPosition = Vector3.zero;

	    // Look up TerrainData export file path via attribute if user has set it
	    string userTerrainDataExportPath = HEU_GeneralUtility.GetAttributeStringValueSingle(session, _ownerNode.GeoID, heightLayer._part.PartID,
		    HEU_Defines.DEFAULT_UNITY_HEIGHTFIELD_TERRAINDATA_EXPORT_FILE_ATTR, HAPI_AttributeOwner.HAPI_ATTROWNER_PRIM);

	    // Look up TerrainData file via attribute if user has set it
	    string terrainDataFile = HEU_GeneralUtility.GetAttributeStringValueSingle(session, _ownerNode.GeoID, heightLayer._part.PartID,
		    HEU_Defines.DEFAULT_UNITY_HEIGHTFIELD_TERRAINDATA_FILE_ATTR, HAPI_AttributeOwner.HAPI_ATTROWNER_PRIM);
	    if (!string.IsNullOrEmpty(terrainDataFile))
	    {
		TerrainData loadedTerrainData = HEU_AssetDatabase.LoadAssetAtPath(terrainDataFile, typeof(TerrainData)) as TerrainData;
		if (loadedTerrainData == null)
		{
		    Debug.LogWarningFormat("TerrainData, set via attribute, not found at: {0}", terrainDataFile);
		}
		else
		{
		    // In the case that the specified TerrainData belongs to another Terrain (i.e. input Terrain), make a copy of it.
		    if (!string.IsNullOrEmpty(userTerrainDataExportPath))
		    {
			// Save it to explicit path specified by user
			terrainData = HEU_AssetDatabase.CopyAndLoadAssetAtGivenPath(loadedTerrainData, userTerrainDataExportPath, typeof(TerrainData)) as TerrainData;
		    }
		    else
		    {
			// Save it into cache
			// Note that this overwrites existing TerrainData in our cache because the workflow is 
			// such that attributes will always override local setting.
			string bakedTerrainPath = HEU_Platform.BuildPath(houdiniAsset.GetValidAssetCacheFolderPath(), relativeFolderPath);
			terrainData = HEU_AssetDatabase.CopyAndLoadAssetAtAnyPath(loadedTerrainData, bakedTerrainPath, typeof(TerrainData), true) as TerrainData;
			if (terrainData == null)
			{
			    Debug.LogErrorFormat("Unable to copy TerrainData from {0} for generating Terrain.", terrainDataFile);
			}
		    }
		}
	    }

	    Terrain terrain = null;

	    // Generate the terrain and terrain data from the height layer. This applies height values.
	    bResult = HEU_TerrainUtility.GenerateTerrainFromVolume(session, ref heightVolumeInfo, heightLayer._part.ParentGeoNode.GeoID,
		    heightLayer._part.PartID, heightLayer._part.OutputGameObject, ref terrainData, out terrainOffsetPosition,
		    ref terrain);
	    if (!bResult || terrainData == null)
	    {
		return;
	    }

	    if (_terrainData != terrainData)
	    {
		_terrainData = terrainData;
		heightLayer._part.SetTerrainData(terrainData, relativeFolderPath, userTerrainDataExportPath);
	    }

	    heightLayer._part.SetTerrainOffsetPosition(terrainOffsetPosition);

	    int terrainSize = terrainData.heightmapResolution;

	    // Now process TerrainLayers and alpha maps

	    // First, preprocess all layers to get heightfield arrays, converted to proper size
	    List<float[]> normalizedHeightfields = new List<float[]>();
	    // Corresponding list of HF volume layers to process as splatmaps
	    List<HEU_VolumeLayer> terrainLayersToProcess = new List<HEU_VolumeLayer>();

	    List<int[,]> convertedDetailMaps = new List<int[,]>();
	    List<HEU_DetailPrototype> detailPrototypes = new List<HEU_DetailPrototype>();

	    int numLayers = _layers.Count;
	    float minHeight = 0;
	    float maxHeight = 0;
	    float heightRange = 0;
	    // This skips the height layer, and processes all other layers.
	    // Note that mask shouldn't be part of _layers at this point.
	    // The layers are normalized and split into detail and terrain layers.
	    for (int i = 1; i < numLayers; ++i)
	    {
		if (_layers[i]._layerType == HFLayerType.DETAIL)
		{
		    if (_detailProperties == null)
		    {
			_detailProperties = new HEU_DetailProperties();
		    }

		    // Convert to detail map, and add to list to set later
		    int[,] normalizedDetail = HEU_TerrainUtility.GetDetailMapFromPart(
			    session, _ownerNode.GeoID, _layers[i]._part.PartID, out _detailProperties._detailResolution);
		    if (normalizedDetail != null && normalizedDetail.Length > 0)
		    {
			convertedDetailMaps.Add(normalizedDetail);
			detailPrototypes.Add(_layers[i]._detailPrototype);
		    }
		}
		else
		{
		    // Convert to normalized heightfield
		    float[] normalizedHF = HEU_TerrainUtility.GetNormalizedHeightmapFromPartWithMinMax(
			    session, _ownerNode.GeoID, _layers[i]._part.PartID, _layers[i]._xLength,
			    _layers[i]._yLength, ref minHeight, ref maxHeight, ref heightRange, false);
		    if (normalizedHF != null && normalizedHF.Length > 0)
		    {
			normalizedHeightfields.Add(normalizedHF);
			terrainLayersToProcess.Add(_layers[i]);
		    }
		}
	    }

	    int numTerrainLayersToProcess = terrainLayersToProcess.Count;

	    HAPI_NodeId geoID;
	    HAPI_PartId partID;

	    Texture2D defaultTexture = LoadDefaultSplatTexture();

#if UNITY_2018_3_OR_NEWER

	    // Create or update the terrain layers based on heightfield layers.

	    // Keep existing TerrainLayers, and either update or append to them
	    TerrainLayer[] existingTerrainLayers = terrainData.terrainLayers;

	    // Total layers are existing layers + new alpha maps
	    List<TerrainLayer> finalTerrainLayers = new List<TerrainLayer>(existingTerrainLayers);

	    // This holds the alpha map indices for each layer that will be added to the TerrainData.
	    // The alpha maps could be a mix of existing and new values, so need to know which to use
	    // Initially set to use existing alpha maps, then override later on if specified via HF layers
	    List<int> alphaMapIndices = new List<int>();
	    for (int a = 0; a < existingTerrainLayers.Length; ++a)
	    {
		// Negative indices for existing alpha map (offset by -1)
		alphaMapIndices.Add(-a - 1);
	    }

	    bool bNewTerrainLayer = false;
	    HEU_VolumeLayer layer = null;
	    TerrainLayer terrainLayer = null;
	    bool bSetTerrainLayerProperties = true;
	    for (int m = 0; m < numTerrainLayersToProcess; ++m)
	    {
		bNewTerrainLayer = false;
		bSetTerrainLayerProperties = true;

		layer = terrainLayersToProcess[m];

		geoID = _ownerNode.GeoID;
		partID = layer._part.PartID;

		terrainLayer = null;

		int terrainLayerIndex = -1;

		// The TerrainLayer attribute overrides existing TerrainLayer. So if its set, load and use it.
		string terrainLayerFile = HEU_GeneralUtility.GetAttributeStringValueSingle(session, geoID, partID,
				HEU_Defines.DEFAULT_UNITY_HEIGHTFIELD_TERRAINLAYER_FILE_ATTR, HAPI_AttributeOwner.HAPI_ATTROWNER_PRIM);
		if (!string.IsNullOrEmpty(terrainLayerFile))
		{
		    terrainLayer = HEU_AssetDatabase.LoadAssetAtPath(terrainLayerFile, typeof(TerrainLayer)) as TerrainLayer;
		    if (terrainLayer == null)
		    {
			Debug.LogWarningFormat("TerrainLayer, set via attribute, not found at: {0}", terrainLayerFile);
			// Not earlying out or skipping this layer due to error because we want to keep proper indexing
			// by creating a new TerrainLayer.
		    }
		    else
		    {
			// TerrainLayer loaded from attribute. 
			// It could be an existing TerrainLayer that is already part of finalTerrainLayers 
			// or could be a new one which needs to be added.

			// If its a different TerrainLayer than existing, update the finalTerrainLayers, and index.
			if (layer._terrainLayer != null && layer._terrainLayer != terrainLayer)
			{
			    terrainLayerIndex = HEU_TerrainUtility.GetTerrainLayerIndex(layer._terrainLayer, existingTerrainLayers);
			    if (terrainLayerIndex >= 0)
			    {
				finalTerrainLayers[terrainLayerIndex] = terrainLayer;
			    }
			}

			if (terrainLayerIndex == -1)
			{
			    // Always check if its part of existing list so as not to add it again
			    terrainLayerIndex = HEU_TerrainUtility.GetTerrainLayerIndex(terrainLayer, existingTerrainLayers);
			}
		    }
		}

		// No terrain layer specified, so try using existing if we have it
		if (terrainLayer == null)
		{
		    terrainLayerIndex = HEU_TerrainUtility.GetTerrainLayerIndex(layer._terrainLayer, existingTerrainLayers);
		    if (terrainLayerIndex >= 0)
		    {
			// Note the terrainLayerIndex is same for finalTerrainLayers as existingTerrainLayers
			terrainLayer = existingTerrainLayers[terrainLayerIndex];
		    }
		}

		// Still not found, so just create a new one
		if (terrainLayer == null)
		{
		    terrainLayer = new TerrainLayer();
		    terrainLayer.name = layer._layerName;
		    //Debug.LogFormat("Created new TerrainLayer with name: {0} ", terrainLayer.name);
		    bNewTerrainLayer = true;
		}

		if (terrainLayerIndex == -1)
		{
		    // Adding to the finalTerrainLayers if this is indeed a newly created or loaded TerrainLayer
		    // (i.e. isn't already part of the TerrainLayers for this Terrain).
		    // Save this layer's index for later on if we make a copy.
		    terrainLayerIndex = finalTerrainLayers.Count;
		    finalTerrainLayers.Add(terrainLayer);

		    // Positive index for alpha map from heightfield (starting at 1)
		    alphaMapIndices.Add(m + 1);
		}
		else
		{
		    // Positive index for alpha map from heightfield (starting at 1)
		    alphaMapIndices[terrainLayerIndex] = m + 1;
		}

		// For existing TerrainLayer, make a copy of it if it has custom layer attributes
		// because we don't want to change the original TerrainLayer.
		if (!bNewTerrainLayer && layer._hasLayerAttributes)
		{
		    string bakedTerrainPath = houdiniAsset.GetValidAssetCacheFolderPath();
		    bakedTerrainPath = HEU_Platform.BuildPath(bakedTerrainPath, relativeFolderPath);
		    TerrainLayer prevTerrainLayer = terrainLayer;
		    terrainLayer = HEU_AssetDatabase.CopyAndLoadAssetAtAnyPath(terrainLayer, bakedTerrainPath, typeof(TerrainLayer), true) as TerrainLayer;
		    if (terrainLayer != null)
		    {
			// Update the TerrainLayer reference in the list with this copy
			finalTerrainLayers[terrainLayerIndex] = terrainLayer;
		    }
		    else
		    {
			Debug.LogErrorFormat("Unable to copy TerrainLayer '{0}' for generating Terrain. "
				+ "Using original TerrainLayer. Will not be able to set any TerrainLayer properties.", layer._layerName);
			terrainLayer = prevTerrainLayer;
			bSetTerrainLayerProperties = false;
			// Again, continuing on to keep proper indexing.
		    }
		}

		// Now override layer properties if they have been set via attributes
		if (bSetTerrainLayerProperties)
		{
		    LoadLayerPropertiesFromAttributes(session, geoID, partID, terrainLayer, bNewTerrainLayer, defaultTexture);
		}

		if (bNewTerrainLayer)
		{
		    // In order to retain the new TerrainLayer, it must be saved to the AssetDatabase.
		    Object savedObject = null;
		    string layerFileNameWithExt = terrainLayer.name;
		    if (!layerFileNameWithExt.EndsWith(HEU_Defines.HEU_EXT_TERRAINLAYER))
		    {
			layerFileNameWithExt += HEU_Defines.HEU_EXT_TERRAINLAYER;
		    }
		    houdiniAsset.AddToAssetDBCache(layerFileNameWithExt, terrainLayer, relativeFolderPath, ref savedObject);
		}

		// Store reference
		layer._terrainLayer = terrainLayer;
	    }

	    // Get existing alpha maps so we can reuse the values if needed
	    float[,,] existingAlphaMaps = terrainData.GetAlphamaps(0, 0, terrainData.alphamapWidth, terrainData.alphamapHeight);

	    terrainData.terrainLayers = finalTerrainLayers.ToArray();

	    int numTotalAlphaMaps = finalTerrainLayers.Count;

#else
			// Create or update the SplatPrototype based on heightfield layers.

			// Need to create or reuse SplatPrototype for each layer in heightfield, representing the textures.
			SplatPrototype[] existingSplats = terrainData.splatPrototypes;

			// A full rebuild clears out existing splats, but a regular cook keeps them.
			List<SplatPrototype> finalSplats = new List<SplatPrototype>(existingSplats);

			// This holds the alpha map indices for each layer that will be added to the TerrainData
			// The alpha maps could be a mix of existing and new values, so need to know which to use
			List<int> alphaMapIndices = new List<int>();

			// Initially set to use existing alpha maps, then override later on if specified via HF layers.
			for (int a = 0; a < existingSplats.Length; ++a)
			{
				// Negative indices for existing alpha map (offset by -1)
				alphaMapIndices.Add(-a - 1);
			}

			bool bNewSplat = false;
			HEU_VolumeLayer layer = null;
			SplatPrototype splatPrototype = null;

			for (int m = 0; m < numTerrainLayersToProcess; ++m)
			{
				bNewSplat = false;

				layer = terrainLayersToProcess[m];

				geoID = _ownerNode.GeoID;
				partID = layer._part.PartID;

				// Try to find existing SplatPrototype for reuse. But not for full rebuild.
				splatPrototype = null;
				if (layer._splatPrototypeIndex >= 0 && layer._splatPrototypeIndex < existingSplats.Length)
				{
					splatPrototype = existingSplats[layer._splatPrototypeIndex];

					// Positive index for alpha map from heightfield (starting at 1)
					alphaMapIndices[layer._splatPrototypeIndex] = m + 1;
				}

				if (splatPrototype == null)
				{
					splatPrototype = new SplatPrototype();
					layer._splatPrototypeIndex = finalSplats.Count;
					finalSplats.Add(splatPrototype);

					// Positive index for alpha map from heightfield (starting at 1)
					alphaMapIndices.Add(m + 1);
				}

				// Now override splat properties if they have been set via attributes
				LoadLayerPropertiesFromAttributes(session, geoID, partID, splatPrototype, bNewSplat, defaultTexture);
			}

			// On regular cook, get existing alpha maps so we can reuse the values if needed.
			float[,,] existingAlphaMaps = terrainData.GetAlphamaps(0, 0, terrainData.alphamapWidth, terrainData.alphamapHeight);

			terrainData.splatPrototypes = finalSplats.ToArray();

			int numTotalAlphaMaps = finalSplats.Count;
#endif

	    // Set alpha maps by combining with existing alpha maps, and appending new heightfields

	    float[,,] alphamap = null;
	    if (numTotalAlphaMaps > 0 && terrainLayersToProcess.Count > 0)
	    {
		// Convert the heightfields into alpha maps with layer strengths
		float[] strengths = new float[terrainLayersToProcess.Count];
		for (int m = 0; m < terrainLayersToProcess.Count; ++m)
		{
		    strengths[m] = terrainLayersToProcess[m]._strength;
		}

		alphamap = HEU_TerrainUtility.AppendConvertedHeightFieldToAlphaMap(
			terrainLayersToProcess[0]._xLength, terrainLayersToProcess[0]._yLength, existingAlphaMaps,
			normalizedHeightfields, strengths, alphaMapIndices);

		// Update the alphamap resolution to the actual size of the first 
		// heightfield layer used for the alphamaps.
		// Setting the size before setting the alphamas applies proper scaling.
		int alphamapResolution = terrainLayersToProcess[0]._xLength;
		terrainData.alphamapResolution = alphamapResolution;

		terrainData.SetAlphamaps(0, 0, alphamap);
	    }

	    // Scattering - trees and details
	    HEU_TerrainUtility.ApplyScatterTrees(terrainData, _scatterTrees);
	    HEU_TerrainUtility.ApplyDetailLayers(terrain, terrainData, _detailProperties, detailPrototypes, convertedDetailMaps);

	    // If the layers were writen out, this saves the asset DB. Otherwise user has to save it themselves.
	    // Not 100% sure this is needed, but without this the editor doesn't know the terrain asset has been updated
	    // and therefore doesn't import and show the terrain layer.
	    HEU_AssetDatabase.SaveAssetDatabase();
	}