assimp.assimp/code/LWOLoader.cpp

/*
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Open Asset Import Library (ASSIMP)
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/** @file  LWOLoader.cpp
 *  @brief Implementation of the LWO importer class
 */

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_LWO_IMPORTER

// internal headers
#include "LWOLoader.h"
#include "MaterialSystem.h"
#include "StringComparison.h"
#include "SGSpatialSort.h"
#include "ByteSwap.h"
#include "ProcessHelper.h"
#include "ConvertToLHProcess.h"

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
LWOImporter::LWOImporter()
{}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well 
LWOImporter::~LWOImporter()
{}

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file. 
bool LWOImporter::CanRead( const std::string& pFile, IOSystem* pIOHandler, bool checkSig) const
{
	const std::string extension = GetExtension(pFile);
	if (extension == "lwo" || extension == "lxo")
		return true;

	// if check for extension is not enough, check for the magic tokens 
	if (!extension.length() || checkSig) {
		uint32_t tokens[3]; 
		tokens[0] = AI_LWO_FOURCC_LWOB;
		tokens[1] = AI_LWO_FOURCC_LWO2;
		tokens[2] = AI_LWO_FOURCC_LXOB;
		return CheckMagicToken(pIOHandler,pFile,tokens,3,8);
	}
	return false;
}

// ------------------------------------------------------------------------------------------------
// Setup configuration properties
void LWOImporter::SetupProperties(const Importer* pImp)
{
	configSpeedFlag  = ( 0 != pImp->GetPropertyInteger(AI_CONFIG_FAVOUR_SPEED,0) ? true : false);
	configLayerIndex = pImp->GetPropertyInteger (AI_CONFIG_IMPORT_LWO_ONE_LAYER_ONLY,0xffffffff); 
	configLayerName  = pImp->GetPropertyString  (AI_CONFIG_IMPORT_LWO_ONE_LAYER_ONLY,"");
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure. 
void LWOImporter::InternReadFile( const std::string& pFile, 
	aiScene* pScene, 
	IOSystem* pIOHandler)
{
	boost::scoped_ptr<IOStream> file( pIOHandler->Open( pFile, "rb"));

	// Check whether we can read from the file
	if( file.get() == NULL)
		throw new ImportErrorException( "Failed to open LWO file " + pFile + ".");

	if((this->fileSize = (unsigned int)file->FileSize()) < 12)
		throw new ImportErrorException("LWO: The file is too small to contain the IFF header");

	// Allocate storage and copy the contents of the file to a memory buffer
	std::vector< uint8_t > mBuffer(fileSize);
	file->Read( &mBuffer[0], 1, fileSize);
	this->pScene = pScene;

	// Determine the type of the file
	uint32_t fileType;
	const char* sz = IFF::ReadHeader(&mBuffer[0],fileType);
	if (sz)throw new ImportErrorException(sz);

	mFileBuffer = &mBuffer[0] + 12;
	fileSize -= 12;

	// Initialize some members with their default values
	hasNamedLayer   = false;

	// Create temporary storage on the stack but store pointers to it in the class 
	// instance. Therefore everything will be destructed properly if an exception 
	// is thrown and we needn't take care of that.
	LayerList		_mLayers;
	SurfaceList		_mSurfaces;		
	TagList			_mTags;		
	TagMappingTable _mMapping;	

	mLayers			= &_mLayers;
	mTags			= &_mTags;
	mMapping		= &_mMapping;
	mSurfaces		= &_mSurfaces;

	// Allocate a default layer (layer indices are 1-based from now)
	mLayers->push_back(Layer());
	mCurLayer = &mLayers->back();
	mCurLayer->mName = "<LWODefault>";

	// old lightwave file format (prior to v6)
	if (AI_LWO_FOURCC_LWOB == fileType)	{
		DefaultLogger::get()->info("LWO file format: LWOB (<= LightWave 5.5)");

		mIsLWO2 = false;
		LoadLWOBFile();
	}

	// New lightwave format
	else if (AI_LWO_FOURCC_LWO2 == fileType)	{
		DefaultLogger::get()->info("LWO file format: LWO2 (>= LightWave 6)");
	}
	// MODO file format
	else if (AI_LWO_FOURCC_LXOB == fileType)	{
		DefaultLogger::get()->info("LWO file format: LXOB (Modo)");
	}
	// we don't know this format
	else 
	{
		char szBuff[5];
		szBuff[0] = (char)(fileType >> 24u);
		szBuff[1] = (char)(fileType >> 16u);
		szBuff[2] = (char)(fileType >> 8u);
		szBuff[3] = (char)(fileType);
		throw new ImportErrorException(std::string("Unknown LWO sub format: ") + szBuff);
	}

	if (AI_LWO_FOURCC_LWOB != fileType)	{
		mIsLWO2 = true;
		LoadLWO2File();

		// The newer lightwave format allows the user to configure the
		// loader that just one layer is used. If this is the case
		// we need to check now whether the requested layer has been found.
		if (0xffffffff != configLayerIndex && configLayerIndex > mLayers->size())
			throw new ImportErrorException("LWO2: The requested layer was not found");

		if (configLayerName.length() && !hasNamedLayer)	{
			throw new ImportErrorException("LWO2: Unable to find the requested layer: " 
				+ configLayerName);
		}
	}

	// now, as we have loaded all data, we can resolve cross-referenced tags and clips
	ResolveTags();
	ResolveClips();

	// now process all layers and build meshes and nodes
	std::vector<aiMesh*> apcMeshes;
	std::vector<aiNode*> apcNodes;
	apcNodes. reserve(mLayers->size());
	apcMeshes.reserve(mLayers->size()*std::min(((unsigned int)mSurfaces->size()/2u), 1u));

	unsigned int iDefaultSurface = 0xffffffff; // index of the default surface
	for (LayerList::iterator lit = mLayers->begin(), lend = mLayers->end();lit != lend;++lit)	{
		LWO::Layer& layer = *lit;
		if (layer.skip)
			continue;

		// I don't know whether there could be dummy layers, but it would be possible
		const unsigned int meshStart = (unsigned int)apcMeshes.size();
		if (!layer.mFaces.empty() && !layer.mTempPoints.empty())	{

			// now sort all faces by the surfaces assigned to them
			std::vector<SortedRep> pSorted(mSurfaces->size()+1);

			unsigned int i = 0;
			for (FaceList::iterator it = layer.mFaces.begin(), end = layer.mFaces.end();it != end;++it,++i)	{
				// Check whether we support this face's type
				if ((*it).type != AI_LWO_FACE && (*it).type != AI_LWO_PTCH) {
					continue;
				}

				unsigned int idx = (*it).surfaceIndex;
				if (idx >= mTags->size())
				{
					DefaultLogger::get()->warn("LWO: Invalid face surface index");
					idx = 0xffffffff;
				}
				if(0xffffffff == idx || 0xffffffff == (idx = _mMapping[idx]))	{
					if (0xffffffff == iDefaultSurface)	{
						iDefaultSurface = (unsigned int)mSurfaces->size();
						mSurfaces->push_back(LWO::Surface());
						LWO::Surface& surf = mSurfaces->back();
						surf.mColor.r = surf.mColor.g = surf.mColor.b = 0.6f; 
						surf.mName = "LWODefaultSurface";
					}
					idx = iDefaultSurface;
				}
				pSorted[idx].push_back(i);
			}
			if (0xffffffff == iDefaultSurface) {
				pSorted.erase(pSorted.end()-1);
			}
			for (unsigned int p = 0,i = 0;i < mSurfaces->size();++i)	{
				SortedRep& sorted = pSorted[i];
				if (sorted.empty())
					continue;

				// generate the mesh 
				aiMesh* mesh = new aiMesh();
				apcMeshes.push_back(mesh);
				mesh->mNumFaces = (unsigned int)sorted.size();

				// count the number of vertices
				SortedRep::const_iterator it = sorted.begin(), end = sorted.end();
				for (;it != end;++it)	{
					mesh->mNumVertices += layer.mFaces[*it].mNumIndices;
				}

				aiVector3D *nrm = NULL, * pv = mesh->mVertices = new aiVector3D[mesh->mNumVertices];
				aiFace* pf = mesh->mFaces = new aiFace[mesh->mNumFaces];
				mesh->mMaterialIndex = i;

				// find out which vertex color channels and which texture coordinate
				// channels are really required by the material attached to this mesh
				unsigned int vUVChannelIndices[AI_MAX_NUMBER_OF_TEXTURECOORDS];
				unsigned int vVColorIndices[AI_MAX_NUMBER_OF_COLOR_SETS];

#if _DEBUG
				for (unsigned int mui = 0; mui < AI_MAX_NUMBER_OF_TEXTURECOORDS;++mui )
					vUVChannelIndices[mui] = 0xffffffff;
				for (unsigned int mui = 0; mui < AI_MAX_NUMBER_OF_COLOR_SETS;++mui )
					vVColorIndices[mui] = 0xffffffff;
#endif

				FindUVChannels(_mSurfaces[i],sorted,layer,vUVChannelIndices);
				FindVCChannels(_mSurfaces[i],sorted,layer,vVColorIndices);

				// allocate storage for UV and CV channels
				aiVector3D* pvUV[AI_MAX_NUMBER_OF_TEXTURECOORDS];
				for (unsigned int mui = 0; mui < AI_MAX_NUMBER_OF_TEXTURECOORDS;++mui )	{
					if (0xffffffff == vUVChannelIndices[mui])
						break;
					
					pvUV[mui] = mesh->mTextureCoords[mui] = new aiVector3D[mesh->mNumVertices];

					// LightWave doesn't support more than 2 UV components (?)
					mesh->mNumUVComponents[0] = 2;
				}

				if (layer.mNormals.name.length())
					nrm = mesh->mNormals = new aiVector3D[mesh->mNumVertices];
		
				aiColor4D* pvVC[AI_MAX_NUMBER_OF_COLOR_SETS];
				for (unsigned int mui = 0; mui < AI_MAX_NUMBER_OF_COLOR_SETS;++mui)	{
					if (0xffffffff == vVColorIndices[mui])break;
					pvVC[mui] = mesh->mColors[mui] = new aiColor4D[mesh->mNumVertices];
				}

				// we would not need this extra array, but the code is much cleaner if we use it
				std::vector<unsigned int>& smoothingGroups = layer.mPointReferrers;
				smoothingGroups.erase (smoothingGroups.begin(),smoothingGroups.end());
				smoothingGroups.resize(mesh->mNumFaces,0);

				// now convert all faces
				unsigned int vert = 0;
				std::vector<unsigned int>::iterator outIt = smoothingGroups.begin();
				for (it = sorted.begin(); it != end;++it,++outIt)	{
					const LWO::Face& face = layer.mFaces[*it];
					*outIt = face.smoothGroup;

					// copy all vertices
					for (unsigned int q = 0; q  < face.mNumIndices;++q,++vert)	{
						register unsigned int idx = face.mIndices[q];
						*pv++ = layer.mTempPoints[idx] /*- layer.mPivot*/;

						// process UV coordinates
						for (unsigned int w = 0; w < AI_MAX_NUMBER_OF_TEXTURECOORDS;++w)	{
							if (0xffffffff == vUVChannelIndices[w])
								break;
							aiVector3D*& pp = pvUV[w];
							const aiVector2D& src = ((aiVector2D*)&layer.mUVChannels[vUVChannelIndices[w]].rawData[0])[idx];
							pp->x = src.x;
							pp->y = src.y; 
							pp++;
						}

						// process normals (MODO extension)
						if (nrm)	{
							*nrm = ((aiVector3D*)&layer.mNormals.rawData[0])[idx];
							nrm->z *= -1.f;
							++nrm;
						}

						// process vertex colors
						for (unsigned int w = 0; w < AI_MAX_NUMBER_OF_COLOR_SETS;++w)	{
							if (0xffffffff == vVColorIndices[w])
								break;
							*pvVC[w] = ((aiColor4D*)&layer.mVColorChannels[vVColorIndices[w]].rawData[0])[idx];

							// If a RGB color map is explicitly requested delete the
							// alpha channel - it could theoretically be != 1.
							if(_mSurfaces[i].mVCMapType == AI_LWO_RGB)
								pvVC[w]->a = 1.f;

							pvVC[w]++;
						}

#if 0
						// process vertex weights - not yet supported
						for (unsigned int w = 0; w < layer.mWeightChannels.size();++w)
						{
						}
#endif
						face.mIndices[q] = vert;
					}
					pf->mIndices = face.mIndices;
					pf->mNumIndices = face.mNumIndices;
					unsigned int** p = (unsigned int**)&face.mIndices;*p = NULL; // HACK: make sure it won't be deleted
					pf++;
				}

				if (!mesh->mNormals)	{
					// Compute normal vectors for the mesh - we can't use our GenSmoothNormal-
					// Step here since it wouldn't handle smoothing groups correctly for LWO.
					// So we use a separate implementation. 
					ComputeNormals(mesh,smoothingGroups,_mSurfaces[i]);
				}
				else DefaultLogger::get()->debug("LWO2: No need to compute normals, they're already there");
				++p;
			}
		}

		// Generate nodes to render the mesh. Store the source layer in the mParent member of the nodes
		unsigned int num = apcMeshes.size() - meshStart;
		if (layer.mName != "<LWODefault>" || num > 0) {
			aiNode* pcNode = new aiNode();
			apcNodes.push_back(pcNode);
			pcNode->mName.Set(layer.mName);
			pcNode->mParent = (aiNode*)&layer;
			pcNode->mNumMeshes = num;

			if (pcNode->mNumMeshes) {
				pcNode->mMeshes = new unsigned int[pcNode->mNumMeshes];
				for (unsigned int p = 0; p < pcNode->mNumMeshes;++p)
					pcNode->mMeshes[p] = p + meshStart;
			}
		}
	}

	if (apcNodes.empty() || apcMeshes.empty())
		throw new ImportErrorException("LWO: No meshes loaded");

	// The RemoveRedundantMaterials step will clean this up later
	pScene->mMaterials = new aiMaterial*[pScene->mNumMaterials = (unsigned int)mSurfaces->size()];
	for (unsigned int mat = 0; mat < pScene->mNumMaterials;++mat)	{
		MaterialHelper* pcMat = new MaterialHelper();
		pScene->mMaterials[mat] = pcMat;
		ConvertMaterial((*mSurfaces)[mat],pcMat);
	}

	// copy the meshes to the output structure
	pScene->mMeshes = new aiMesh*[ pScene->mNumMeshes = (unsigned int)apcMeshes.size() ];
	::memcpy(pScene->mMeshes,&apcMeshes[0],pScene->mNumMeshes*sizeof(void*));

	// generate the final node graph
	GenerateNodeGraph(apcNodes);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ComputeNormals(aiMesh* mesh, const std::vector<unsigned int>& smoothingGroups,
	const LWO::Surface& surface)
{
	// Allocate output storage
	mesh->mNormals = new aiVector3D[mesh->mNumVertices];

	// First generate per-face normals
	aiVector3D* out;
	std::vector<aiVector3D> faceNormals;

	// ... in some cases that's already enough
	if (!surface.mMaximumSmoothAngle)
		out = mesh->mNormals;
	else	{
		faceNormals.resize(mesh->mNumVertices);
		out = &faceNormals[0];
	}

	aiFace* begin = mesh->mFaces, *const end = mesh->mFaces+mesh->mNumFaces;
	for (; begin != end; ++begin)	{
		aiFace& face = *begin;

		// LWO doc: "the normal is defined as the cross product of the first and last edges"
		aiVector3D* pV1 = mesh->mVertices + face.mIndices[0];
		aiVector3D* pV2 = mesh->mVertices + face.mIndices[1];
		aiVector3D* pV3 = mesh->mVertices + face.mIndices[face.mNumIndices-1];

		aiVector3D vNor = ((*pV2 - *pV1) ^(*pV3 - *pV1)).Normalize();
		for (unsigned int i = 0; i < face.mNumIndices;++i)
			out[face.mIndices[i]] = vNor;
	}
	if (!surface.mMaximumSmoothAngle)return;
	const float posEpsilon = ComputePositionEpsilon(mesh);
	
	// Now generate the spatial sort tree
	SGSpatialSort sSort;
	std::vector<unsigned int>::const_iterator it = smoothingGroups.begin();
	for( begin =  mesh->mFaces; begin != end; ++begin, ++it)
	{
		aiFace& face = *begin;
		for (unsigned int i = 0; i < face.mNumIndices;++i)
		{
			register unsigned int tt = face.mIndices[i];
			sSort.Add(mesh->mVertices[tt],tt,*it);
		}
	}
	// Sort everything - this takes O(nlogn) time
	sSort.Prepare();
	std::vector<unsigned int> poResult;
	poResult.reserve(20);

	// Generate vertex normals. We have O(logn) for the binary lookup, which we need
	// for n elements, thus the EXPECTED complexity is O(nlogn)
	if (surface.mMaximumSmoothAngle < 3.f && !configSpeedFlag)	{
		const float fLimit = cos(surface.mMaximumSmoothAngle);

		for( begin =  mesh->mFaces, it = smoothingGroups.begin(); begin != end; ++begin, ++it)	{
			const aiFace& face = *begin;
			unsigned int* beginIdx = face.mIndices, *const endIdx = face.mIndices+face.mNumIndices;
			for (; beginIdx != endIdx; ++beginIdx)
			{
				register unsigned int idx = *beginIdx;
				sSort.FindPositions(mesh->mVertices[idx],*it,posEpsilon,poResult,true);
				std::vector<unsigned int>::const_iterator a, end = poResult.end();

				aiVector3D vNormals;
				for (a =  poResult.begin();a != end;++a)	{
					const aiVector3D& v = faceNormals[*a];
					if (v * faceNormals[idx] < fLimit)
						continue;
					vNormals += v;
				}
				mesh->mNormals[idx] = vNormals.Normalize();
			}
		}
	}
	 // faster code path in case there is no smooth angle
	else	{
		std::vector<bool> vertexDone(mesh->mNumVertices,false);
		for( begin =  mesh->mFaces, it = smoothingGroups.begin(); begin != end; ++begin, ++it)	{
			const aiFace& face = *begin;
			unsigned int* beginIdx = face.mIndices, *const endIdx = face.mIndices+face.mNumIndices;
			for (; beginIdx != endIdx; ++beginIdx)
			{
				register unsigned int idx = *beginIdx;
				if (vertexDone[idx])
					continue;
				sSort.FindPositions(mesh->mVertices[idx],*it,posEpsilon,poResult,true);
				std::vector<unsigned int>::const_iterator a, end = poResult.end();

				aiVector3D vNormals;
				for (a =  poResult.begin();a != end;++a)	{
					const aiVector3D& v = faceNormals[*a];
					vNormals += v;
				}
				vNormals.Normalize();
				for (a =  poResult.begin();a != end;++a)	{
					mesh->mNormals[*a] = vNormals;
					vertexDone[*a] = true;
				}
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::AddChildren(aiNode* node, uint16_t parent, std::vector<aiNode*>& apcNodes)
{
	for (std::vector<aiNode*>::iterator it = apcNodes.begin(); it != apcNodes.end(); ++it)	{
		if (*it) {
			LWO::Layer* layer = (LWO::Layer*)(*it)->mParent;
			if (layer->mParent == parent && layer->mIndex != parent)
				++node->mNumChildren;
		}
	}

	if (node->mNumChildren)	{
		unsigned int p = 0;

		node->mChildren = new aiNode* [ node->mNumChildren ];
		for (std::vector<aiNode*>::iterator it = apcNodes.begin(); it != apcNodes.end(); ++it)	{
			if (*it) {
				LWO::Layer* layer = (LWO::Layer*)(*it)->mParent;
				if (layer->mParent == parent && layer->mIndex != parent)	{
					aiNode* nd = node->mChildren[p++] = *it;
					nd->mParent = node;

					// fixme: ignore pivot points for the moment
					//nd->mTransformation.a4 = layer->mPivot.x;
					//nd->mTransformation.b4 = layer->mPivot.y;
					//nd->mTransformation.c4 = layer->mPivot.z;

					// recursively add more children
					(*it) = NULL;
					AddChildren(nd,layer->mIndex,apcNodes);
				}
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::GenerateNodeGraph(std::vector<aiNode*>& apcNodes)
{
	// now generate the final nodegraph - generate a root node and attach children
	aiNode* root = pScene->mRootNode = new aiNode();
	root->mName.Set("<LWORoot>");
	AddChildren(root,0,apcNodes);

	// check whether we added all layers with meshes assigned to the output graph.
	// if not, add them to the root node
	unsigned int extra = 0;
	for (std::vector<aiNode*>::iterator it = apcNodes.begin(); it != apcNodes.end(); ++it) {
		if ((*it) && (*it)->mNumMeshes) 
			++extra;
	}

	if (extra)	{
		const unsigned int newSize = extra + pScene->mRootNode->mNumChildren;
		aiNode** const apcNewNodes = new aiNode*[newSize];
		if((extra = root->mNumChildren))
			::memcpy(apcNewNodes,root->mChildren,extra*sizeof(void*));

		aiNode** cc = apcNewNodes+extra;
		for (std::vector<aiNode*>::iterator it = apcNodes.begin(); it != apcNodes.end(); ++it) {
			if ((*it) && (*it)->mNumMeshes) {
				aiNode* nd = *cc++ = *it;
				nd->mParent = pScene->mRootNode;

				// recursively add more children
				(*it) = NULL;
				AddChildren(nd,((LWO::Layer*)nd->mParent)->mIndex,apcNodes);
			}
		}
		delete[] root->mChildren;
		root->mChildren = apcNewNodes;
		root->mNumChildren = newSize;
	}
	if (!pScene->mRootNode->mNumChildren)
		throw new ImportErrorException("LWO: Unable to build a valid node graph");

	// Remove a single root node with no meshes assigned to it ... 
	if (1 == pScene->mRootNode->mNumChildren)	{
		aiNode* pc = pScene->mRootNode->mChildren[0];
		pc->mParent = pScene->mRootNode->mChildren[0] = NULL;
		delete pScene->mRootNode;
		pScene->mRootNode = pc;
	}

	// convert the whole stuff to RH with CCW winding
	MakeLeftHandedProcess maker;
	maker.Execute(pScene);

	FlipWindingOrderProcess flipper;
	flipper.Execute(pScene);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ResolveTags()
{
	// --- this function is used for both LWO2 and LWOB
	mMapping->resize(mTags->size(),0xffffffff);
	for (unsigned int a = 0; a  < mTags->size();++a)
	{
		const std::string& c = (*mTags)[a];
		for (unsigned int i = 0; i < mSurfaces->size();++i)
		{
			const std::string& d = (*mSurfaces)[i].mName;
			if (!ASSIMP_stricmp(c,d))
			{
				(*mMapping)[a] = i;
				break;
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::ResolveClips()
{
	for( unsigned int i = 0; i < mClips.size();++i)
	{
		Clip& clip = mClips[i];
		if (Clip::REF == clip.type)
		{
			if (clip.clipRef >= mClips.size())
			{
				DefaultLogger::get()->error("LWO2: Clip referrer index is out of range");
				clip.clipRef = 0;
			}
			Clip& dest = mClips[clip.clipRef];
			if (Clip::REF == dest.type)
			{
				DefaultLogger::get()->error("LWO2: Clip references another clip reference");
				clip.type = Clip::UNSUPPORTED;
			}
			else
			{
				clip.path = dest.path;
				clip.type = dest.type;
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::AdjustTexturePath(std::string& out)
{
	// --- this function is used for both LWO2 and LWOB
	if (!mIsLWO2 && ::strstr(out.c_str(), "(sequence)"))
	{
		// remove the (sequence) and append 000
		DefaultLogger::get()->info("LWOB: Sequence of animated texture found. It will be ignored");
		out = out.substr(0,out.length()-10) + "000";
	}

	// format: drive:path/file - we need to insert a slash after the drive
	std::string::size_type n = out.find_first_of(':');
	if (std::string::npos != n)
	{
		out.insert(n+1,"/");
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOTags(unsigned int size)
{
	// --- this function is used for both LWO2 and LWOB

	const char* szCur = (const char*)mFileBuffer, *szLast = szCur;
	const char* const szEnd = szLast+size;
	while (szCur < szEnd)
	{
		if (!(*szCur))
		{
			const size_t len = (size_t)(szCur-szLast);
			// FIX: skip empty-sized tags
			if (len)
				mTags->push_back(std::string(szLast,len));
			szCur += (len&0x1 ? 1 : 2);
			szLast = szCur;
		}
		szCur++;
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWOPoints(unsigned int length)
{
	// --- this function is used for both LWO2 and LWOB but for
	// LWO2 we need to allocate 25% more storage - it could be we'll 
	// need to duplicate some points later.
	register unsigned int regularSize = (unsigned int)mCurLayer->mTempPoints.size() + length / 12;
	if (mIsLWO2)
	{
		mCurLayer->mTempPoints.reserve	( regularSize + (regularSize>>2u) );
		mCurLayer->mTempPoints.resize	( regularSize );

		// initialize all point referrers with the default values
		mCurLayer->mPointReferrers.reserve	( regularSize + (regularSize>>2u) );
		mCurLayer->mPointReferrers.resize	( regularSize, 0xffffffff );
	}
	else mCurLayer->mTempPoints.resize( regularSize );

	// perform endianess conversions
#ifndef AI_BUILD_BIG_ENDIAN
	for (unsigned int i = 0; i < length>>2;++i)
		ByteSwap::Swap4( mFileBuffer + (i << 2));
#endif
	::memcpy(&mCurLayer->mTempPoints[0],mFileBuffer,length);
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2Polygons(unsigned int length)
{
	LE_NCONST uint16_t* const end	= (LE_NCONST uint16_t*)(mFileBuffer+length);
	const uint32_t type = GetU4();

	// Determine the type of the polygons
	switch (type)
	{
		// read unsupported stuff too (although we wont process it)
	case  AI_LWO_BONE:
		DefaultLogger::get()->warn("LWO2: Encountered unsupported primitive chunk (BONE)");
		break;
	case  AI_LWO_MBAL:
		DefaultLogger::get()->warn("LWO2: Encountered unsupported primitive chunk (METABALL)");
		break;
	case  AI_LWO_CURV:
		DefaultLogger::get()->warn("LWO2: Encountered unsupported primitive chunk (SPLINE)");;
		break;

		// These are ok with no restrictions
	case  AI_LWO_PTCH:
	case  AI_LWO_FACE:
		break;
	default:

		// hm!? wtf is this? ok ...
		DefaultLogger::get()->error("LWO2: Encountered unknown polygon type");
		break;
	}

	// first find out how many faces and vertices we'll finally need
	uint16_t* cursor= (uint16_t*)mFileBuffer;

	unsigned int iNumFaces = 0,iNumVertices = 0;
	CountVertsAndFacesLWO2(iNumVertices,iNumFaces,cursor,end);

	// allocate the output array and copy face indices
	if (iNumFaces)	{
		cursor = (uint16_t*)mFileBuffer;

		mCurLayer->mFaces.resize(iNumFaces,LWO::Face(type));
		FaceList::iterator it = mCurLayer->mFaces.begin();
		CopyFaceIndicesLWO2(it,cursor,end);
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CountVertsAndFacesLWO2(unsigned int& verts, unsigned int& faces,
	uint16_t*& cursor, const uint16_t* const end, unsigned int max)
{
	while (cursor < end && max--)
	{
		AI_LSWAP2P(cursor);
		uint16_t numIndices = *cursor++;
		numIndices &= 0x03FF;
		verts += numIndices;++faces;

		for(uint16_t i = 0; i < numIndices; i++)
			ReadVSizedIntLWO2((uint8_t*&)cursor);
	}
}

// ------------------------------------------------------------------------------------------------
void LWOImporter::CopyFaceIndicesLWO2(FaceList::iterator& it,
	uint16_t*& cursor, 
	const uint16_t* const end)
{
	while (cursor < end)
	{
		LWO::Face& face = *it;++it;
		if((face.mNumIndices = (*cursor++) & 0x03FF)) // swapping has already been done
		{
			face.mIndices = new unsigned int[face.mNumIndices];
			for(unsigned int i = 0; i < face.mNumIndices; i++)
			{
				face.mIndices[i] = ReadVSizedIntLWO2((uint8_t*&)cursor) + mCurLayer->mPointIDXOfs;
				if(face.mIndices[i] > mCurLayer->mTempPoints.size())
				{
					DefaultLogger::get()->warn("LWO2: face index is out of range");
					face.mIndices[i] = (unsigned int)mCurLayer->mTempPoints.size()-1;
				}
			}
		}
		else throw new ImportErrorException("LWO2: face has 0 indices");
	}
}


// ------------------------------------------------------------------------------------------------
void LWOImporter::LoadLWO2PolygonTags(unsigned int length)
{
	LE_NCONST uint8_t* const end = mFileBuffer+length;

	AI_LWO_VALIDATE_CHUNK_LENGTH(length,PTAG,4);
	uint32_t type = GetU4();

	if (type != AI_LWO_SURF && type != AI_LWO_SMGP)
		return;

	while (mFileBuffer < end)
	{
		unsigned int i = ReadVSizedIntLWO2(mFileBuffer) + mCurLayer->mFaceIDXOfs;
		unsigned int j = GetU2();

		if (i >= mCurLayer->mFaces.size())
		{
			DefaultLogger::get()->warn("LWO2: face index in PTAG is out of range");
			continue;
		}

		switch (type)
		{
		case AI_LWO_SURF:
			mCurLayer->mFaces[i].surfaceIndex = j;
			break;
		case AI_LWO_SMGP:
			mCurLayer->mFaces[i].smoothGroup = j;
			break;
		};
	}
}

// ------------------------------------------------------------------------------------------------
template <class T>
VMapEntry* FindEntry(std::vector< T >& list,const std::string& name, bool perPoly)
{
	for (typename std::vector< T >::iterator it = list.begin(), end = list.end();it != end; ++it)	{
		if ((*it).name == name)
		{
			if (!perPoly)
			{
				DefaultLogger::get()->warn("LWO2: Found two VMAP sections with equal names");
			}
			return &(*it);
		}
	}
	list.push_back( T() );
	VMapEntry* p = &list.back();
	p->name = name;
	return p;
}

// ------------------------------------------------------------------------------------------------
template <class T>
inline void CreateNewEntry(T& chan, unsigned int srcIdx)
{
	if (!chan.name.length())return;

	chan.abAssigned[srcIdx] = true;
	chan.abAssigned.resize(chan.abAssigned.size()+1,false);

	for (unsigned int a = 0; a < chan.dims;++a)
		chan.rawData.push_back(chan.rawData[srcIdx*chan.dims+a]);
}

// ------------------------------------------------------------------------------------------------
template <class T>
inline void CreateNewEntry(std::vector< T >& list, unsigned int srcIdx)
{
	for (typename std::vector< T >::iterator it =  list.begin(), end = list.end();it != end;++it)	{
		CreateNewEntry( *it, srcIdx );
	}
}

// ------------------------------------------------------------------------------------------------
inline void LWOImporter::DoRecursiveVMAPAssignment(VMapEntry* base, unsigned int numRead, 
	unsigned int idx, float* data)
{
	ai_assert(NULL != data);
	LWO::ReferrerList& refList	= mCurLayer->mPointReferrers;
	unsigned int i;

	base->abAssigned[idx] = true;
	for (i = 0; i < numRead;++i) 
		base->rawData[idx*base->dims+i]= data[i];

	if (0xffffffff != (i = refList[idx]))
		DoRecursiveVMAPAssignment(base,numRead,i,data);
}

// ------------------------------------------------------------------------------------------------
inline void AddToSingleLinkedList(ReferrerList& refList, unsigned int srcIdx, unsigned int destIdx)
{
	if(0xffffffff == refList[srcIdx])	{
		refList[srcIdx] = destIdx;
		return;
	}
	AddToSingleLinkedList(refList,refList[srcIdx],destIdx);
}

// ------------------------------------------------------------------------------------------------
// Load LWO2 vertex map
void LWOImporter::LoadLWO2VertexMap(unsigned int length, bool perPoly)
{
	LE_NCONST uint8_t* const end = mFileBuffer+length;

	AI_LWO_VALIDATE_CHUNK_LENGTH(length,VMAP,6);
	unsigned int type = GetU4();
	unsigned int dims = GetU2();

	VMapEntry* base;

	// read the name of the vertex map 
	std::string name;
	GetS0(name,length);

	switch (type)
	{
	case AI_LWO_TXUV:
		if (dims != 2)	{
			DefaultLogger::get()->warn("LWO2: Found UV channel with != 2 components"); 
			return;
		}
		base = FindEntry(mCurLayer->mUVChannels,name,perPoly);
		break;
	case AI_LWO_WGHT:
		if (dims != 1)	{
			DefaultLogger::get()->warn("LWO2: found vertex weight map with != 1 components"); 
			return;
		}
		base = FindEntry(mCurLayer->mWeightChannels,name,perPoly);
		break;
	case AI_LWO_RGB:
	case AI_LWO_RGBA:
		if (dims != 3 && dims != 4)	{
			DefaultLogger::get()->warn("LWO2: found vertex color map with != 3&4 components"); 
			return;
		}
		base = FindEntry(mCurLayer->mVColorChannels,name,perPoly);
		break;

	case AI_LWO_MODO_NORM:

		/*  This is a non-standard extension chunk used by Luxology's MODO.
		 *  It stores per-vertex normals. This VMAP exists just once, has
		 *  3 dimensions and is btw extremely beautiful.
		 */
		if (name != "vert_normals" || dims != 3 || mCurLayer->mNormals.name.length())
			return;

		DefaultLogger::get()->info("Non-standard extension: MODO VMAP.NORM.vert_normals");
		
		mCurLayer->mNormals.name = name;
		base = & mCurLayer->mNormals;
		break;

	default: 
		return;
	};
	base->Allocate((unsigned int)mCurLayer->mTempPoints.size());

	// now read all entries in the map
	type = std::min(dims,base->dims); 
	const unsigned int diff = (dims - type)<<2;

	LWO::FaceList& list	= mCurLayer->mFaces;
	LWO::PointList& pointList = mCurLayer->mTempPoints;
	LWO::ReferrerList& refList = mCurLayer->mPointReferrers;

	float temp[4];

	const unsigned int numPoints = (unsigned int)pointList.size();
	const unsigned int numFaces  = (unsigned int)list.size();

	while (mFileBuffer < end)
	{
		unsigned int idx = ReadVSizedIntLWO2(mFileBuffer) + mCurLayer->mPointIDXOfs;
		if (idx >= numPoints)	{
			DefaultLogger::get()->warn("LWO2: vertex index in vmap/vmad is out of range");
			mFileBuffer += base->dims*4;continue;
		}
		if (perPoly)	{
			unsigned int polyIdx = ReadVSizedIntLWO2(mFileBuffer) + mCurLayer->mFaceIDXOfs;
			if (base->abAssigned[idx])	{
				// we have already a VMAP entry for this vertex - thus
				// we need to duplicate the corresponding polygon.
				if (polyIdx >= numFaces)	{
					DefaultLogger::get()->warn("LWO2: VMAD polygon index is out of range");
					mFileBuffer += base->dims*4;
					continue;
				}

				LWO::Face& src = list[polyIdx];

				// generate a new unique vertex for the corresponding index - but only
				// if we can find the index in the face
				for (unsigned int i = 0; i < src.mNumIndices;++i)	{
					register unsigned int srcIdx = src.mIndices[i];
					if (idx != srcIdx)
						continue;

					refList.resize(refList.size()+1, 0xffffffff);
						
					idx = (unsigned int)pointList.size();
					src.mIndices[i] = (unsigned int)pointList.size();

					// store the index of the new vertex in the old vertex
					// so we get a single linked list we can traverse in
					// only one direction
					AddToSingleLinkedList(refList,srcIdx,src.mIndices[i]);
					pointList.push_back(pointList[srcIdx]);

					CreateNewEntry(mCurLayer->mVColorChannels,	srcIdx );
					CreateNewEntry(mCurLayer->mUVChannels,		srcIdx );
					CreateNewEntry(mCurLayer->mWeightChannels,	srcIdx );
					CreateNewEntry(mCurLayer->mNormals,	srcIdx );
				}
			}
		}
		for (unsigned int l = 0; l < type;++l)
			temp[l] = GetF4();

		DoRecursiveVMAPAssignment(base,type,idx, temp);
		mFileBuffer += diff;
	}
}

// ------------------------------------------------------------------------------------------------
// Load LWO2 clip
void LWOImporter::LoadLWO2Clip(unsigned int length)
{
	AI_LWO_VALIDATE_CHUNK_LENGTH(length,CLIP,10);

	mClips.push_back(LWO::Clip());
	LWO::Clip& clip = mClips.back();

	// first - get the index of the clip
	clip.idx = GetU4();

	IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);
	switch (head->type)
	{
	case AI_LWO_STIL:
		AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,STIL,1);

		// "Normal" texture
		GetS0(clip.path,head->length);
		clip.type = Clip::STILL;
		break;

	case AI_LWO_ISEQ:
		AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,ISEQ,16);
		// Image sequence. We'll later take the first.
		{
			uint8_t digits = GetU1();  mFileBuffer++;
			int16_t offset = GetU2();  mFileBuffer+=4;
			int16_t start  = GetU2();  mFileBuffer+=4;

			std::string s;std::stringstream ss;
			GetS0(s,head->length);

			head->length -= (unsigned int)s.length()+1;
			ss << s;
			ss << std::setw(digits) << offset + start;
			GetS0(s,head->length);
			ss << s;
			clip.path = ss.str();
			clip.type = Clip::SEQ;
		}
		break;

	case AI_LWO_STCC:
		DefaultLogger::get()->warn("LWO2: Color shifted images are not supported");
		break;

	case AI_LWO_ANIM:
		DefaultLogger::get()->warn("LWO2: Animated textures are not supported");
		break;

	case AI_LWO_XREF:
		AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,XREF,4);

		// Just a cross-reference to another CLIp
		clip.type = Clip::REF;
		clip.clipRef = GetU4();
		break;

	case AI_LWO_NEGA:
		AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,NEGA,2);
		clip.negate = (0 != GetU2());
		break;

	default:
		DefaultLogger::get()->warn("LWO2: Encountered unknown CLIP subchunk");
	}
}

// ------------------------------------------------------------------------------------------------
// Load envelope description
void LWOImporter::LoadLWO2Envelope(unsigned int length)
{
	LE_NCONST uint8_t* const end = mFileBuffer + length;
	AI_LWO_VALIDATE_CHUNK_LENGTH(length,ENVL,4);

	mEnvelopes.push_back(LWO::Envelope());
	LWO::Envelope& envelope = mEnvelopes.back();

	// Get the index of the envelope
	envelope.index = ReadVSizedIntLWO2(mFileBuffer);

	// ... and read all subchunks
	while (true)
	{
		if (mFileBuffer + 6 >= end)break;
		LE_NCONST IFF::SubChunkHeader* const head = IFF::LoadSubChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
			throw new ImportErrorException("LWO2: Invalid envelope chunk length");

		uint8_t* const next = mFileBuffer+head->length;
		switch (head->type)
		{
			// Type & representation of the envelope
		case AI_LWO_TYPE:
			AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,TYPE,2);
			mFileBuffer++; // skip user format

			// Determine type of envelope
			envelope.type  = (LWO::EnvelopeType)*mFileBuffer;
			++mFileBuffer;
			break;

			// precondition
		case AI_LWO_PRE:
			AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,PRE,2);
			envelope.pre = (LWO::PrePostBehaviour)GetU2();
			break;
		
			// postcondition
		case AI_LWO_POST:
			AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,POST,2);
			envelope.post = (LWO::PrePostBehaviour)GetU2();
			break;

			// keyframe
		case AI_LWO_KEY: 
			{
			AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,KEY,8);
			
			envelope.keys.push_back(LWO::Key());
			LWO::Key& key = envelope.keys.back();

			key.time = GetF4();
			key.value = GetF4();
			break;
			}

			// interval interpolation
		case AI_LWO_SPAN: 
			{
				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,SPAN,4);
				if (envelope.keys.size()<2)
					DefaultLogger::get()->warn("LWO2: Unexpected SPAN chunk");
				else {
					LWO::Key& key = envelope.keys.back();
					switch (GetU4())
					{
						case AI_LWO_STEP:
							key.inter = LWO::IT_STEP;break;
						case AI_LWO_LINE:
							key.inter = LWO::IT_LINE;break;
						case AI_LWO_TCB:
							key.inter = LWO::IT_TCB;break;
						case AI_LWO_HERM:
							key.inter = LWO::IT_HERM;break;
						case AI_LWO_BEZI:
							key.inter = LWO::IT_BEZI;break;
						case AI_LWO_BEZ2:
							key.inter = LWO::IT_BEZ2;break;
						default:
							DefaultLogger::get()->warn("LWO2: Unknown interval interpolation mode");
					};

					// todo ... read params
				}
				break;
			}

		default:
			DefaultLogger::get()->warn("LWO2: Encountered unknown ENVL subchunk");
		}
		// regardless how much we did actually read, go to the next chunk
		mFileBuffer = next;
	}
}

// ------------------------------------------------------------------------------------------------
// Load file - master function
void LWOImporter::LoadLWO2File()
{
	bool skip = false;

	LE_NCONST uint8_t* const end = mFileBuffer + fileSize;
	while (true)
	{
		if (mFileBuffer + sizeof(IFF::ChunkHeader) > end)break;
		IFF::ChunkHeader* const head = IFF::LoadChunk(mFileBuffer);

		if (mFileBuffer + head->length > end)
		{
			throw new ImportErrorException("LWO2: Chunk length points behind the file");
			break;
		}
		uint8_t* const next = mFileBuffer+head->length;
		unsigned int iUnnamed = 0;

		switch (head->type)
		{
			// new layer
		case AI_LWO_LAYR:
			{
				// add a new layer to the list ....
				mLayers->push_back ( LWO::Layer() );
				LWO::Layer& layer = mLayers->back();
				mCurLayer = &layer;

				AI_LWO_VALIDATE_CHUNK_LENGTH(head->length,LAYR,16);

				// Continue loading this layer or ignore it? Check the layer index property
				// NOTE: The first layer is the default layer, so the layer index is one-based now
				if (0xffffffff != configLayerIndex && configLayerIndex != mLayers->size()-1)	{
					skip = true;
				}
				else skip = false;

				// layer index. that's just for internal parenting, from the scope of a LWS file
				// all layers are numbered in the oder in which they appear in the file
				layer.mIndex = GetU2();

				// pivot point
				mFileBuffer += 2; /* unknown */
				mCurLayer->mPivot.x = GetF4();
				mCurLayer->mPivot.y = GetF4();
				mCurLayer->mPivot.z = GetF4();
				GetS0(layer.mName,head->length-16);

				// if the name is empty, generate a default name
				if (layer.mName.empty())	{
					char buffer[128]; // should be sufficiently large
					::sprintf(buffer,"Layer_%i", iUnnamed++);
					layer.mName = buffer;
				}

				// load this layer or ignore it? Check the layer name property
				if (configLayerName.length() && configLayerName != layer.mName)	{
					skip = true;
				}
				else hasNamedLayer = true;

				// optional: parent of this layer
				if (mFileBuffer + 2 <= next)
					layer.mParent = GetU2();

				break;
			}

			// vertex list
		case AI_LWO_PNTS:
			{
				if (skip)
					break;

				unsigned int old = (unsigned int)mCurLayer->mTempPoints.size();
				LoadLWOPoints(head->length);
				mCurLayer->mPointIDXOfs = old;
				break;
			}
			// vertex tags
		case AI_LWO_VMAD:
			if (mCurLayer->mFaces.empty())
			{
				DefaultLogger::get()->warn("LWO2: Unexpected VMAD chunk");
				break;
			}
			// --- intentionally no break here
		case AI_LWO_VMAP:
			{
				if (skip)
					break;

				if (mCurLayer->mTempPoints.empty())
					DefaultLogger::get()->warn("LWO2: Unexpected VMAP chunk");
				else LoadLWO2VertexMap(head->length,head->type == AI_LWO_VMAD);
				break;
			}
			// face list
		case AI_LWO_POLS:
			{
				if (skip)
					break;

				unsigned int old = (unsigned int)mCurLayer->mFaces.size();
				LoadLWO2Polygons(head->length);
				mCurLayer->mFaceIDXOfs = old;
				break;
			}
			// polygon tags 
		case AI_LWO_PTAG:
			{
				if (skip)
					break;

				if (mCurLayer->mFaces.empty())
					DefaultLogger::get()->warn("LWO2: Unexpected PTAG");
				else LoadLWO2PolygonTags(head->length);
				break;
			}
			// list of tags
		case AI_LWO_TAGS:
			{
				if (!mTags->empty())
					DefaultLogger::get()->warn("LWO2: SRFS chunk encountered twice");
				else LoadLWOTags(head->length);
				break;
			}

			// surface chunk
		case AI_LWO_SURF:
			{
				LoadLWO2Surface(head->length);
				break;
			}

			// clip chunk
		case AI_LWO_CLIP:
			{
				LoadLWO2Clip(head->length);
				break;
			}

			// envelope chunk
		case AI_LWO_ENVL:
			{
				LoadLWO2Envelope(head->length);
				break;
			}
		}
		mFileBuffer = next;
	}
}

#endif // !! ASSIMP_BUILD_NO_LWO_IMPORTER