/*
---------------------------------------------------------------------------
Open Asset Import Library (ASSIMP)
---------------------------------------------------------------------------

Copyright (c) 2006-2010, ASSIMP Development Team

All rights reserved.

Redistribution and use of this software in source and binary forms, 
with or without modification, are permitted provided that the following 
conditions are met:

* Redistributions of source code must retain the above
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following disclaimer.

* Redistributions in binary form must reproduce the above
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following disclaimer in the documentation and/or other
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* Neither the name of the ASSIMP team, nor the names of its
contributors may be used to endorse or promote products
derived from this software without specific prior
written permission of the ASSIMP Development Team.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
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---------------------------------------------------------------------------
*/

/** @file ColladaParser.cpp
 *  @brief Implementation of the Collada parser helper
 */

#include "AssimpPCH.h"
#ifndef ASSIMP_BUILD_NO_DAE_IMPORTER

#include "ColladaParser.h"
#include "fast_atof.h"
#include "ParsingUtils.h"

using namespace Assimp;
using namespace Assimp::Collada;

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
ColladaParser::ColladaParser( IOSystem* pIOHandler, const std::string& pFile)
	: mFileName( pFile)
{
	mRootNode = NULL;
	mUnitSize = 1.0f;
	mUpDirection = UP_Z;

	// We assume the newest file format by default
	mFormat = FV_1_5_n;

  // open the file
  boost::scoped_ptr<IOStream> file( pIOHandler->Open( pFile));
  if( file.get() == NULL)
    throw DeadlyImportError( "Failed to open file " + pFile + ".");

	// generate a XML reader for it
  boost::scoped_ptr<CIrrXML_IOStreamReader> mIOWrapper( new CIrrXML_IOStreamReader( file.get()));
	mReader = irr::io::createIrrXMLReader( mIOWrapper.get());
	if( !mReader)
		ThrowException( "Collada: Unable to open file.");

	// start reading
	ReadContents();
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
ColladaParser::~ColladaParser()
{
	delete mReader;
	for( NodeLibrary::iterator it = mNodeLibrary.begin(); it != mNodeLibrary.end(); ++it)
		delete it->second;
	for( MeshLibrary::iterator it = mMeshLibrary.begin(); it != mMeshLibrary.end(); ++it)
		delete it->second;
}

// ------------------------------------------------------------------------------------------------
// Read bool from text contents of current element
bool ColladaParser::ReadBoolFromTextContent()
{
	const char* cur = GetTextContent();
	return (!ASSIMP_strincmp(cur,"true",4) || '0' != *cur);
}

// ------------------------------------------------------------------------------------------------
// Read float from text contents of current element
float ColladaParser::ReadFloatFromTextContent()
{
	const char* cur = GetTextContent();
	return fast_atof(cur);
}

// ------------------------------------------------------------------------------------------------
// Reads the contents of the file
void ColladaParser::ReadContents()
{
	while( mReader->read())
	{
		// handle the root element "COLLADA"
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "COLLADA"))
			{
				// check for 'version' attribute
				const int attrib = TestAttribute("version");
				if (attrib != -1) {
					const char* version = mReader->getAttributeValue(attrib);
					
					if (!::strncmp(version,"1.5",3)) {
						mFormat =  FV_1_5_n;
						DefaultLogger::get()->debug("Collada schema version is 1.5.n");
					}
					else if (!::strncmp(version,"1.4",3)) {
						mFormat =  FV_1_4_n;
						DefaultLogger::get()->debug("Collada schema version is 1.4.n");
					}
					else if (!::strncmp(version,"1.3",3)) {
						mFormat =  FV_1_3_n;
						DefaultLogger::get()->debug("Collada schema version is 1.3.n");
					}
				}

				ReadStructure();
			} else
			{
				DefaultLogger::get()->debug( boost::str( boost::format( "Ignoring global element \"%s\".") % mReader->getNodeName()));
				SkipElement();
			}
		} else
		{
			// skip everything else silently
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the structure of the file
void ColladaParser::ReadStructure()
{
	while( mReader->read())
	{
		// beginning of elements
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "asset"))
				ReadAssetInfo();
			else if( IsElement( "library_animations"))
				ReadAnimationLibrary();
			else if( IsElement( "library_controllers"))
				ReadControllerLibrary();
			else if( IsElement( "library_images"))
				ReadImageLibrary();
			else if( IsElement( "library_materials"))
				ReadMaterialLibrary();
			else if( IsElement( "library_effects"))
				ReadEffectLibrary();
			else if( IsElement( "library_geometries"))
				ReadGeometryLibrary();
			else if( IsElement( "library_visual_scenes"))
				ReadSceneLibrary();
			else if( IsElement( "library_lights"))
				ReadLightLibrary();
			else if( IsElement( "library_cameras"))
				ReadCameraLibrary();
			else if( IsElement( "library_nodes"))
				ReadSceneNode(NULL); /* some hacking to reuse this piece of code */
			else if( IsElement( "scene"))
				ReadScene();
			else
				SkipElement();
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads asset informations such as coordinate system informations and legal blah
void ColladaParser::ReadAssetInfo()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "unit"))
			{
				// read unit data from the element's attributes
				const int attrIndex = TestAttribute( "meter");
				if (attrIndex == -1) {
					mUnitSize = 1.f;
				}
				else {
					mUnitSize = mReader->getAttributeValueAsFloat( attrIndex);
				}

				// consume the trailing stuff
				if( !mReader->isEmptyElement())
					SkipElement();
			} 
			else if( IsElement( "up_axis"))
			{
				// read content, strip whitespace, compare
				const char* content = GetTextContent();
				if( strncmp( content, "X_UP", 4) == 0)
					mUpDirection = UP_X;
				else if( strncmp( content, "Y_UP", 4) == 0)
					mUpDirection = UP_Y;
				else
					mUpDirection = UP_Z;

				// check element end
				TestClosing( "up_axis");
			} else
			{
				SkipElement();
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "asset") != 0)
				ThrowException( "Expected end of \"asset\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the animation library
void ColladaParser::ReadAnimationLibrary()
{
	if (mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "animation"))
			{
				// delegate the reading. Depending on the inner elements it will be a container or a anim channel
				ReadAnimation( &mAnims);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "library_animations") != 0)
				ThrowException( "Expected end of \"library_animations\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an animation into the given parent structure
void ColladaParser::ReadAnimation( Collada::Animation* pParent)
{
	if( mReader->isEmptyElement())
		return;

	// an <animation> element may be a container for grouping sub-elements or an animation channel
	// this is the channel collection by ID, in case it has channels
	typedef std::map<std::string, AnimationChannel> ChannelMap;
	ChannelMap channels;
	// this is the anim container in case we're a container
	Animation* anim = NULL;

	// optional name given as an attribute
	std::string animName;
	int indexName = TestAttribute( "name");
	int indexID = TestAttribute( "id");
	if( indexName >= 0)
		animName = mReader->getAttributeValue( indexName);
	else if( indexID >= 0)
		animName = mReader->getAttributeValue( indexID);
	else
		animName = "animation";

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			// we have subanimations
			if( IsElement( "animation"))
			{
				// create container from our element
				if( !anim)
				{
					anim = new Animation;
					anim->mName = animName;
					pParent->mSubAnims.push_back( anim);
				}

				// recurse into the subelement
				ReadAnimation( anim);
			} 
			else if( IsElement( "source"))
			{
				// possible animation data - we'll never know. Better store it
				ReadSource();
			} 
			else if( IsElement( "sampler"))
			{
				// read the ID to assign the corresponding collada channel afterwards.
				int indexID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( indexID);
				ChannelMap::iterator newChannel = channels.insert( std::make_pair( id, AnimationChannel())).first;

				// have it read into a channel
				ReadAnimationSampler( newChannel->second);
			} 
			else if( IsElement( "channel"))
			{
				// the binding element whose whole purpose is to provide the target to animate
				// Thanks, Collada! A directly posted information would have been too simple, I guess.
				// Better add another indirection to that! Can't have enough of those.
				int indexTarget = GetAttribute( "target");
				int indexSource = GetAttribute( "source");
				const char* sourceId = mReader->getAttributeValue( indexSource);
				if( sourceId[0] == '#')
					sourceId++;
				ChannelMap::iterator cit = channels.find( sourceId);
				if( cit != channels.end())
					cit->second.mTarget = mReader->getAttributeValue( indexTarget);

				if( !mReader->isEmptyElement())
					SkipElement();
			} 
			else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "animation") != 0)
				ThrowException( "Expected end of \"animation\" element.");

			break;
		}
	}

	// it turned out to have channels - add them
	if( !channels.empty())
	{
		// special filtering for stupid exporters packing each channel into a separate animation
		if( channels.size() == 1)
		{
			pParent->mChannels.push_back( channels.begin()->second);
		} else
		{
			// else create the animation, if not done yet, and store the channels
			if( !anim)
			{
				anim = new Animation;
				anim->mName = animName;
				pParent->mSubAnims.push_back( anim);
			}
			for( ChannelMap::const_iterator it = channels.begin(); it != channels.end(); ++it)
				anim->mChannels.push_back( it->second);
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an animation sampler into the given anim channel
void ColladaParser::ReadAnimationSampler( Collada::AnimationChannel& pChannel)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "input"))
			{
				int indexSemantic = GetAttribute( "semantic");
				const char* semantic = mReader->getAttributeValue( indexSemantic);
				int indexSource = GetAttribute( "source");
				const char* source = mReader->getAttributeValue( indexSource);
				if( source[0] != '#')
					ThrowException( "Unsupported URL format");
				source++;
				
				if( strcmp( semantic, "INPUT") == 0)
					pChannel.mSourceTimes = source;
				else if( strcmp( semantic, "OUTPUT") == 0)
					pChannel.mSourceValues = source;

				if( !mReader->isEmptyElement())
					SkipElement();
			} 
			else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "sampler") != 0)
				ThrowException( "Expected end of \"sampler\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the skeleton controller library
void ColladaParser::ReadControllerLibrary()
{
	if (mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "controller"))
			{
				// read ID. Ask the spec if it's neccessary or optional... you might be surprised.
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				mControllerLibrary[id] = Controller();

				// read on from there
				ReadController( mControllerLibrary[id]);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "library_controllers") != 0)
				ThrowException( "Expected end of \"library_controllers\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a controller into the given mesh structure
void ColladaParser::ReadController( Collada::Controller& pController)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			// two types of controllers: "skin" and "morph". Only the first one is relevant, we skip the other
			if( IsElement( "morph"))
			{
				// should skip everything inside, so there's no danger of catching elements inbetween
				SkipElement();
			} 
			else if( IsElement( "skin"))
			{
				// read the mesh it refers to. According to the spec this could also be another
				// controller, but I refuse to implement every bullshit idea they've come up with
				int sourceIndex = GetAttribute( "source");
				pController.mMeshId = mReader->getAttributeValue( sourceIndex) + 1;
			} 
			else if( IsElement( "bind_shape_matrix"))
			{
				// content is 16 floats to define a matrix... it seems to be important for some models
	      const char* content = GetTextContent();

	      // read the 16 floats
	      for( unsigned int a = 0; a < 16; a++)
	      {
		      // read a number
          content = fast_atof_move( content, pController.mBindShapeMatrix[a]);
		      // skip whitespace after it
		      SkipSpacesAndLineEnd( &content);
	      }

        TestClosing( "bind_shape_matrix");
			} 
			else if( IsElement( "source"))
			{
				// data array - we have specialists to handle this
				ReadSource();
			} 
			else if( IsElement( "joints"))
			{
				ReadControllerJoints( pController);
			}
			else if( IsElement( "vertex_weights"))
			{
				ReadControllerWeights( pController);
			}
			else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "controller") == 0)
				break;
			else if( strcmp( mReader->getNodeName(), "skin") != 0)
				ThrowException( "Expected end of \"controller\" element.");
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the joint definitions for the given controller
void ColladaParser::ReadControllerJoints( Collada::Controller& pController)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			// Input channels for joint data. Two possible semantics: "JOINT" and "INV_BIND_MATRIX"
			if( IsElement( "input"))
			{
				int indexSemantic = GetAttribute( "semantic");
				const char* attrSemantic = mReader->getAttributeValue( indexSemantic);
				int indexSource = GetAttribute( "source");
				const char* attrSource = mReader->getAttributeValue( indexSource);

				// local URLS always start with a '#'. We don't support global URLs
				if( attrSource[0] != '#')
					ThrowException( boost::str( boost::format( "Unsupported URL format in \"%s\"") % attrSource));
				attrSource++;

				// parse source URL to corresponding source
				if( strcmp( attrSemantic, "JOINT") == 0)
					pController.mJointNameSource = attrSource;
				else if( strcmp( attrSemantic, "INV_BIND_MATRIX") == 0)
					pController.mJointOffsetMatrixSource = attrSource;
				else
					ThrowException( boost::str( boost::format( "Unknown semantic \"%s\" in joint data") % attrSemantic));

				// skip inner data, if present
				if( !mReader->isEmptyElement())
					SkipElement();
			}
			else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "joints") != 0)
				ThrowException( "Expected end of \"joints\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the joint weights for the given controller
void ColladaParser::ReadControllerWeights( Collada::Controller& pController)
{
	// read vertex count from attributes and resize the array accordingly
	int indexCount = GetAttribute( "count");
	size_t vertexCount = (size_t) mReader->getAttributeValueAsInt( indexCount);
	pController.mWeightCounts.resize( vertexCount);

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			// Input channels for weight data. Two possible semantics: "JOINT" and "WEIGHT"
			if( IsElement( "input"))
			{
				InputChannel channel;

				int indexSemantic = GetAttribute( "semantic");
				const char* attrSemantic = mReader->getAttributeValue( indexSemantic);
				int indexSource = GetAttribute( "source");
				const char* attrSource = mReader->getAttributeValue( indexSource);
				int indexOffset = TestAttribute( "offset");
				if( indexOffset >= 0)
					channel.mOffset = mReader->getAttributeValueAsInt( indexOffset);

				// local URLS always start with a '#'. We don't support global URLs
				if( attrSource[0] != '#')
					ThrowException( boost::str( boost::format( "Unsupported URL format in \"%s\"") % attrSource));
				channel.mAccessor = attrSource + 1;

				// parse source URL to corresponding source
				if( strcmp( attrSemantic, "JOINT") == 0)
					pController.mWeightInputJoints = channel;
				else if( strcmp( attrSemantic, "WEIGHT") == 0)
					pController.mWeightInputWeights = channel;
				else
					ThrowException( boost::str( boost::format( "Unknown semantic \"%s\" in vertex_weight data") % attrSemantic));

				// skip inner data, if present
				if( !mReader->isEmptyElement())
					SkipElement();
			}
			else if( IsElement( "vcount"))
			{
				// read weight count per vertex
				const char* text = GetTextContent();
				size_t numWeights = 0;
				for( std::vector<size_t>::iterator it = pController.mWeightCounts.begin(); it != pController.mWeightCounts.end(); ++it)
				{
					if( *text == 0)
						ThrowException( "Out of data while reading vcount");

					*it = strtoul10( text, &text);
					numWeights += *it;
					SkipSpacesAndLineEnd( &text);
				}

				TestClosing( "vcount");

				// reserve weight count 
				pController.mWeights.resize( numWeights);
			}
			else if( IsElement( "v"))
			{
				// read JointIndex - WeightIndex pairs
				const char* text = GetTextContent();

				for( std::vector< std::pair<size_t, size_t> >::iterator it = pController.mWeights.begin(); it != pController.mWeights.end(); ++it)
				{
					if( *text == 0)
						ThrowException( "Out of data while reading vertex_weights");
					it->first = strtoul10( text, &text);
					SkipSpacesAndLineEnd( &text);
					if( *text == 0)
						ThrowException( "Out of data while reading vertex_weights");
					it->second = strtoul10( text, &text);
					SkipSpacesAndLineEnd( &text);
				}

				TestClosing( "v");
			}
			else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "vertex_weights") != 0)
				ThrowException( "Expected end of \"vertex_weights\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the image library contents
void ColladaParser::ReadImageLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "image"))
			{
				// read ID. Another entry which is "optional" by design but obligatory in reality
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				mImageLibrary[id] = Image();

				// read on from there
				ReadImage( mImageLibrary[id]);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "library_images") != 0)
				ThrowException( "Expected end of \"library_images\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an image entry into the given image
void ColladaParser::ReadImage( Collada::Image& pImage)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT){
			// Need to run different code paths here, depending on the Collada XSD version
			if (IsElement("image")) {
                SkipElement();
            }
			else if(  IsElement( "init_from"))
			{
				if (mFormat == FV_1_4_n) 
				{
					// FIX: C4D exporter writes empty <init_from/> tags
					if (!mReader->isEmptyElement()) {
						// element content is filename - hopefully
						const char* sz = TestTextContent();
						if (sz)pImage.mFileName = sz;
						TestClosing( "init_from");
					}
					if (!pImage.mFileName.length()) {
						pImage.mFileName = "unknown_texture";
					}
				}
				else if (mFormat == FV_1_5_n) 
				{
					// make sure we skip over mip and array initializations, which
					// we don't support, but which could confuse the loader if 
					// they're not skipped.
					int attrib = TestAttribute("array_index");
					if (attrib != -1 && mReader->getAttributeValueAsInt(attrib) > 0) {
						DefaultLogger::get()->warn("Collada: Ignoring texture array index");
						continue;
					}

					attrib = TestAttribute("mip_index");
					if (attrib != -1 && mReader->getAttributeValueAsInt(attrib) > 0) {
						DefaultLogger::get()->warn("Collada: Ignoring MIP map layer");
						continue;
					}

					// TODO: correctly jump over cube and volume maps?
				}
			}
			else if (mFormat == FV_1_5_n) 
			{
				if( IsElement( "ref"))
				{
					// element content is filename - hopefully
					const char* sz = TestTextContent();
					if (sz)pImage.mFileName = sz;
					TestClosing( "ref");
				} 
				else if( IsElement( "hex") && !pImage.mFileName.length())
				{
					// embedded image. get format
					const int attrib = TestAttribute("format");
					if (-1 == attrib) 
						DefaultLogger::get()->warn("Collada: Unknown image file format");
					else pImage.mEmbeddedFormat = mReader->getAttributeValue(attrib);

					const char* data = GetTextContent();

					// hexadecimal-encoded binary octets. First of all, find the
					// required buffer size to reserve enough storage.
					const char* cur = data;
					while (!IsSpaceOrNewLine(*cur)) cur++;

					const unsigned int size = (unsigned int)(cur-data) * 2;
					pImage.mImageData.resize(size);
					for (unsigned int i = 0; i < size;++i) 
						pImage.mImageData[i] = HexOctetToDecimal(data+(i<<1));

					TestClosing( "hex");
				} 
			}
			else	
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "image") == 0)
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the material library
void ColladaParser::ReadMaterialLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "material"))
			{
				// read ID. By now you propably know my opinion about this "specification"
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				ReadMaterial(mMaterialLibrary[id] = Material());
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "library_materials") != 0)
				ThrowException( "Expected end of \"library_materials\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the light library
void ColladaParser::ReadLightLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "light"))
			{
				// read ID. By now you propably know my opinion about this "specification"
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				ReadLight(mLightLibrary[id] = Light());

			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)	{
			if( strcmp( mReader->getNodeName(), "library_lights") != 0)
				ThrowException( "Expected end of \"library_lights\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the camera library
void ColladaParser::ReadCameraLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "camera"))
			{
				// read ID. By now you propably know my opinion about this "specification"
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				Camera& cam = mCameraLibrary[id]; 
				attrID = TestAttribute( "name");
				if (attrID != -1) 
					cam.mName = mReader->getAttributeValue( attrID);

				ReadCamera(cam);

			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)	{
			if( strcmp( mReader->getNodeName(), "library_cameras") != 0)
				ThrowException( "Expected end of \"library_cameras\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a material entry into the given material
void ColladaParser::ReadMaterial( Collada::Material& pMaterial)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if (IsElement("material")) {
                SkipElement();
            }
			else if( IsElement( "instance_effect"))
			{
				// referred effect by URL
				int attrUrl = GetAttribute( "url");
				const char* url = mReader->getAttributeValue( attrUrl);
				if( url[0] != '#')
					ThrowException( "Unknown reference format");

				pMaterial.mEffect = url+1;

				SkipElement();
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "material") != 0)
				ThrowException( "Expected end of \"material\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a light entry into the given light
void ColladaParser::ReadLight( Collada::Light& pLight)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
            if (IsElement("light")) {
                SkipElement();
            }
			else if (IsElement("spot")) {
				pLight.mType = aiLightSource_SPOT;
			}
			else if (IsElement("ambient")) {
				pLight.mType = aiLightSource_AMBIENT;
			}
			else if (IsElement("directional")) {
				pLight.mType = aiLightSource_DIRECTIONAL;
			}
			else if (IsElement("point")) {
				pLight.mType = aiLightSource_POINT;
			}
			else if (IsElement("color")) {
				// text content contains 3 floats
				const char* content = GetTextContent();
				  
				content = fast_atof_move( content, (float&)pLight.mColor.r);
				SkipSpacesAndLineEnd( &content);
				
				content = fast_atof_move( content, (float&)pLight.mColor.g);
				SkipSpacesAndLineEnd( &content);

				content = fast_atof_move( content, (float&)pLight.mColor.b);
				SkipSpacesAndLineEnd( &content);

				TestClosing( "color");
			}
			else if (IsElement("constant_attenuation")) {
				pLight.mAttConstant = ReadFloatFromTextContent();
				TestClosing("constant_attenuation");
			}
			else if (IsElement("linear_attenuation")) {
				pLight.mAttLinear = ReadFloatFromTextContent();
				TestClosing("linear_attenuation");
			}
			else if (IsElement("quadratic_attenuation")) {
				pLight.mAttQuadratic = ReadFloatFromTextContent();
				TestClosing("quadratic_attenuation");
			}
			else if (IsElement("falloff_angle")) {
				pLight.mFalloffAngle = ReadFloatFromTextContent();
				TestClosing("falloff_angle");
			}
			else if (IsElement("falloff_exponent")) {
				pLight.mFalloffExponent = ReadFloatFromTextContent();
				TestClosing("falloff_exponent");
			}
			// FCOLLADA extensions 
			// -------------------------------------------------------
			else if (IsElement("outer_cone")) {
				pLight.mOuterAngle = ReadFloatFromTextContent();
				TestClosing("outer_cone");
			}
			// ... and this one is even deprecated
			else if (IsElement("penumbra_angle")) {
				pLight.mPenumbraAngle = ReadFloatFromTextContent();
				TestClosing("penumbra_angle");
			}
			else if (IsElement("intensity")) {
				pLight.mIntensity = ReadFloatFromTextContent();
				TestClosing("intensity");
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "light") == 0)
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a camera entry into the given light
void ColladaParser::ReadCamera( Collada::Camera& pCamera)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if (IsElement("camera")) {
                SkipElement();
            }
			else if (IsElement("orthographic")) {
				pCamera.mOrtho = true;
			}
			else if (IsElement("xfov") || IsElement("xmag")) {
				pCamera.mHorFov = ReadFloatFromTextContent();
				TestClosing((pCamera.mOrtho ? "xmag" : "xfov"));
			}
			else if (IsElement("yfov") || IsElement("ymag")) {
				pCamera.mVerFov = ReadFloatFromTextContent();
				TestClosing((pCamera.mOrtho ? "ymag" : "yfov"));
			}
			else if (IsElement("aspect_ratio")) {
				pCamera.mAspect = ReadFloatFromTextContent();
				TestClosing("aspect_ratio");
			}
			else if (IsElement("znear")) {
				pCamera.mZNear = ReadFloatFromTextContent();
				TestClosing("znear");
			}
			else if (IsElement("zfar")) {
				pCamera.mZFar = ReadFloatFromTextContent();
				TestClosing("zfar");
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "camera") == 0)
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the effect library
void ColladaParser::ReadEffectLibrary()
{
	if (mReader->isEmptyElement()) {
		return;
	}

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "effect"))
			{
				// read ID. Do I have to repeat my ranting about "optional" attributes?
				// Alex: .... no, not necessary. Please shut up and leave more space for 
				// me to complain about the fucking Collada spec with its fucking
				// 'optional' attributes ...
				int attrID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( attrID);

				// create an entry and store it in the library under its ID
				mEffectLibrary[id] = Effect();
				// read on from there
				ReadEffect( mEffectLibrary[id]);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "library_effects") != 0)
				ThrowException( "Expected end of \"library_effects\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an effect entry into the given effect
void ColladaParser::ReadEffect( Collada::Effect& pEffect)
{
	// for the moment we don't support any other type of effect.
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "profile_COMMON"))
				ReadEffectProfileCommon( pEffect);
			else
				SkipElement();
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) 
		{
			if( strcmp( mReader->getNodeName(), "effect") != 0)
				ThrowException( "Expected end of \"effect\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an COMMON effect profile
void ColladaParser::ReadEffectProfileCommon( Collada::Effect& pEffect)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "newparam"))	{
				// save ID
				int attrSID = GetAttribute( "sid");
				std::string sid = mReader->getAttributeValue( attrSID);
				pEffect.mParams[sid] = EffectParam();
				ReadEffectParam( pEffect.mParams[sid]);
			} 
			else if( IsElement( "technique") || IsElement( "extra"))
			{
				// just syntactic sugar
			}

			/* Shading modes */
			else if( IsElement( "phong"))
				pEffect.mShadeType = Shade_Phong;
			else if( IsElement( "constant"))
				pEffect.mShadeType = Shade_Constant;
			else if( IsElement( "lambert"))
				pEffect.mShadeType = Shade_Lambert;
			else if( IsElement( "blinn"))
				pEffect.mShadeType = Shade_Blinn;

			/* Color + texture properties */
			else if( IsElement( "emission"))
				ReadEffectColor( pEffect.mEmissive, pEffect.mTexEmissive);
			else if( IsElement( "ambient"))
				ReadEffectColor( pEffect.mAmbient, pEffect.mTexAmbient);
			else if( IsElement( "diffuse"))
				ReadEffectColor( pEffect.mDiffuse, pEffect.mTexDiffuse);
			else if( IsElement( "specular"))
				ReadEffectColor( pEffect.mSpecular, pEffect.mTexSpecular);
			else if( IsElement( "reflective")) {
				ReadEffectColor( pEffect.mReflective, pEffect.mTexReflective);
			}
			else if( IsElement( "transparent")) {
				ReadEffectColor( pEffect.mTransparent,pEffect.mTexTransparent);
			}
			else if( IsElement( "shininess"))
				ReadEffectFloat( pEffect.mShininess);
			else if( IsElement( "reflectivity"))
				ReadEffectFloat( pEffect.mReflectivity);

			/* Single scalar properties */
			else if( IsElement( "transparency"))
				ReadEffectFloat( pEffect.mTransparency);
			else if( IsElement( "index_of_refraction"))
				ReadEffectFloat( pEffect.mRefractIndex);

			// GOOGLEEARTH/OKINO extensions 
			// -------------------------------------------------------
			else if( IsElement( "double_sided"))
				pEffect.mDoubleSided = ReadBoolFromTextContent();

			// FCOLLADA extensions
			// -------------------------------------------------------
			else if( IsElement( "bump")) {
				aiColor4D dummy;
				ReadEffectColor( dummy,pEffect.mTexBump);
			}

			// MAX3D extensions
			// -------------------------------------------------------
			else if( IsElement( "wireframe"))	{
				pEffect.mWireframe = ReadBoolFromTextContent();
				TestClosing( "wireframe");
			}
			else if( IsElement( "faceted"))	{
				pEffect.mFaceted = ReadBoolFromTextContent();
				TestClosing( "faceted");
			}
			else 
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "profile_COMMON") == 0)
			{
				break;
			} 
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Read texture wrapping + UV transform settings from a profile==Maya chunk
void ColladaParser::ReadSamplerProperties( Sampler& out )
{
	if (mReader->isEmptyElement()) {
		return;
	}

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {

			// MAYA extensions
			// -------------------------------------------------------
			if( IsElement( "wrapU"))		{
				out.mWrapU = ReadBoolFromTextContent();
				TestClosing( "wrapU");
			}
			else if( IsElement( "wrapV"))	{
				out.mWrapU = ReadBoolFromTextContent();
				TestClosing( "wrapV");
			}
			else if( IsElement( "mirrorU"))		{
				out.mMirrorU = ReadBoolFromTextContent();
				TestClosing( "mirrorU");
			}
			else if( IsElement( "mirrorV"))	{
				out.mMirrorU = ReadBoolFromTextContent();
				TestClosing( "mirrorV");
			}
			else if( IsElement( "repeatU"))	{
				out.mTransform.mScaling.x = ReadFloatFromTextContent();
				TestClosing( "repeatU");
			}
			else if( IsElement( "repeatV"))	{
				out.mTransform.mScaling.y = ReadFloatFromTextContent();
				TestClosing( "repeatV");
			}
			else if( IsElement( "offsetU"))	{
				out.mTransform.mTranslation.x = ReadFloatFromTextContent();
				TestClosing( "offsetU");
			}
			else if( IsElement( "offsetV"))	{
				out.mTransform.mTranslation.x = ReadFloatFromTextContent();
				TestClosing( "offsetV");
			}
			else if( IsElement( "rotateUV"))	{
				out.mTransform.mRotation = ReadFloatFromTextContent();
				TestClosing( "rotateUV");
			}
			else if( IsElement( "blend_mode"))	{
				
				const char* sz = GetTextContent();
				// http://www.feelingsoftware.com/content/view/55/72/lang,en/
				// NONE, OVER, IN, OUT, ADD, SUBTRACT, MULTIPLY, DIFFERENCE, LIGHTEN, DARKEN, SATURATE, DESATURATE and ILLUMINATE
				if (0 == ASSIMP_strincmp(sz,"ADD",3)) 
					out.mOp = aiTextureOp_Add;

				else if (0 == ASSIMP_strincmp(sz,"SUBTRACT",8)) 
					out.mOp = aiTextureOp_Subtract;

				else if (0 == ASSIMP_strincmp(sz,"MULTIPLY",8)) 
					out.mOp = aiTextureOp_Multiply;

				else  {
					DefaultLogger::get()->warn("Collada: Unsupported MAYA texture blend mode");
				}
				TestClosing( "blend_mode");
			}
			// OKINO extensions
			// -------------------------------------------------------
			else if( IsElement( "weighting"))	{
				out.mWeighting = ReadFloatFromTextContent();
				TestClosing( "weighting");
			}
			else if( IsElement( "mix_with_previous_layer"))	{
				out.mMixWithPrevious = ReadFloatFromTextContent();
				TestClosing( "mix_with_previous_layer");
			}
			// MAX3D extensions
			// -------------------------------------------------------
			else if( IsElement( "amount"))	{
				out.mWeighting = ReadFloatFromTextContent();
				TestClosing( "amount");
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			if( strcmp( mReader->getNodeName(), "technique") == 0)
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an effect entry containing a color or a texture defining that color
void ColladaParser::ReadEffectColor( aiColor4D& pColor, Sampler& pSampler)
{
	if (mReader->isEmptyElement())
		return;

	// Save current element name
	const std::string curElem = mReader->getNodeName();

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "color"))
			{
				// text content contains 4 floats
				const char* content = GetTextContent(); 

				content = fast_atof_move( content, (float&)pColor.r);
				SkipSpacesAndLineEnd( &content);

				content = fast_atof_move( content, (float&)pColor.g);
				SkipSpacesAndLineEnd( &content);

				content = fast_atof_move( content, (float&)pColor.b);
				SkipSpacesAndLineEnd( &content);

				content = fast_atof_move( content, (float&)pColor.a);
				SkipSpacesAndLineEnd( &content);
				TestClosing( "color");
			} 
			else if( IsElement( "texture"))
			{
				// get name of source textur/sampler
				int attrTex = GetAttribute( "texture");
				pSampler.mName = mReader->getAttributeValue( attrTex);

				// get name of UV source channel
				attrTex = GetAttribute( "texcoord");
				pSampler.mUVChannel = mReader->getAttributeValue( attrTex);
				//SkipElement();
			}
			else if( IsElement( "technique"))
			{
				const int _profile = GetAttribute( "profile");
				const char* profile = mReader->getAttributeValue( _profile );

				// Some extensions are quite useful ... ReadSamplerProperties processes
				// several extensions in MAYA, OKINO and MAX3D profiles.
				if (!::strcmp(profile,"MAYA") || !::strcmp(profile,"MAX3D") || !::strcmp(profile,"OKINO"))
				{
					// get more information on this sampler
					ReadSamplerProperties(pSampler);
				}
				else SkipElement();
			}
			else if( !IsElement( "extra"))
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END){
			if (mReader->getNodeName() == curElem)
				break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an effect entry containing a float
void ColladaParser::ReadEffectFloat( float& pFloat)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT){
			if( IsElement( "float"))
			{
				// text content contains a single floats
				const char* content = GetTextContent();
				content = fast_atof_move( content, pFloat);
				SkipSpacesAndLineEnd( &content);

				TestClosing( "float");
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END){
			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads an effect parameter specification of any kind 
void ColladaParser::ReadEffectParam( Collada::EffectParam& pParam)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) {
			if( IsElement( "surface"))
			{
				// image ID given inside <init_from> tags
				TestOpening( "init_from");
				const char* content = GetTextContent();
				pParam.mType = Param_Surface;
				pParam.mReference = content;
				TestClosing( "init_from");

				// don't care for remaining stuff
				SkipElement( "surface");
			} 
			else if( IsElement( "sampler2D"))
			{
				// surface ID is given inside <source> tags
				TestOpening( "source");
				const char* content = GetTextContent();
				pParam.mType = Param_Sampler;
				pParam.mReference = content;
				TestClosing( "source");

				// don't care for remaining stuff
				SkipElement( "sampler2D");
			} else
			{
				// ignore unknown element
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the geometry library contents
void ColladaParser::ReadGeometryLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "geometry"))
			{
				// read ID. Another entry which is "optional" by design but obligatory in reality
				int indexID = GetAttribute( "id");
				std::string id = mReader->getAttributeValue( indexID);

				// TODO: (thom) support SIDs
				// ai_assert( TestAttribute( "sid") == -1);

				// create a mesh and store it in the library under its ID
				Mesh* mesh = new Mesh;
				mMeshLibrary[id] = mesh;

				// read on from there
				ReadGeometry( mesh);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "library_geometries") != 0)
				ThrowException( "Expected end of \"library_geometries\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a geometry from the geometry library.
void ColladaParser::ReadGeometry( Collada::Mesh* pMesh)
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "mesh"))
			{
				// read on from there
				ReadMesh( pMesh);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "geometry") != 0)
				ThrowException( "Expected end of \"geometry\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a mesh from the geometry library
void ColladaParser::ReadMesh( Mesh* pMesh)
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "source"))
			{
				// we have professionals dealing with this
				ReadSource();
			}
			else if( IsElement( "vertices"))
			{
				// read per-vertex mesh data
				ReadVertexData( pMesh);
			}
			else if( IsElement( "triangles") || IsElement( "lines") || IsElement( "linestrips")
				|| IsElement( "polygons") || IsElement( "polylist") || IsElement( "trifans") || IsElement( "tristrips")) 
			{
				// read per-index mesh data and faces setup
				ReadIndexData( pMesh);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "technique_common") == 0)
			{
				// end of another meaningless element - read over it
			} 
			else if( strcmp( mReader->getNodeName(), "mesh") == 0)
			{
				// end of <mesh> element - we're done here
				break;
			} else
			{
				// everything else should be punished
				ThrowException( "Expected end of \"mesh\" element.");
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a source element 
void ColladaParser::ReadSource()
{
	int indexID = GetAttribute( "id");
	std::string sourceID = mReader->getAttributeValue( indexID);

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "float_array") || IsElement( "IDREF_array") || IsElement( "Name_array"))
			{
				ReadDataArray();
			}
			else if( IsElement( "technique_common"))
			{
				// I don't fucking care for your profiles bullshit
			}
			else if( IsElement( "accessor"))
			{
				ReadAccessor( sourceID);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "source") == 0)
			{
				// end of <source> - we're done
				break;
			}
			else if( strcmp( mReader->getNodeName(), "technique_common") == 0)
			{
				// end of another meaningless element - read over it
			} else
			{
				// everything else should be punished
				ThrowException( "Expected end of \"source\" element.");
			}
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a data array holding a number of floats, and stores it in the global library
void ColladaParser::ReadDataArray()
{
	std::string elmName = mReader->getNodeName();
	bool isStringArray = (elmName == "IDREF_array" || elmName == "Name_array");

	// read attributes
	int indexID = GetAttribute( "id");
	std::string id = mReader->getAttributeValue( indexID);
	int indexCount = GetAttribute( "count");
	unsigned int count = (unsigned int) mReader->getAttributeValueAsInt( indexCount);
	const char* content = TestTextContent();
	if (content) { // some exporters write empty data arrays, silently skip over them

		// read values and store inside an array in the data library
		mDataLibrary[id] = Data();
		Data& data = mDataLibrary[id];
		data.mIsStringArray = isStringArray;

		if( isStringArray)
		{
			data.mStrings.reserve( count);
			std::string s;

			for( unsigned int a = 0; a < count; a++)
			{
				if( *content == 0)
					ThrowException( "Expected more values while reading IDREF_array contents.");

				s.clear();
				while( !IsSpaceOrNewLine( *content))
					s += *content++;
				data.mStrings.push_back( s);

				SkipSpacesAndLineEnd( &content);
			}
		} else
		{
			data.mValues.reserve( count);

			for( unsigned int a = 0; a < count; a++)
			{
				if( *content == 0)
					ThrowException( "Expected more values while reading float_array contents.");

				float value;
				// read a number
				content = fast_atof_move( content, value);
				data.mValues.push_back( value);
				// skip whitespace after it
				SkipSpacesAndLineEnd( &content);
			}
		}
	}

	// test for closing tag
	TestClosing( elmName.c_str());
}

// ------------------------------------------------------------------------------------------------
// Reads an accessor and stores it in the global library
void ColladaParser::ReadAccessor( const std::string& pID)
{
	// read accessor attributes
	int attrSource = GetAttribute( "source");
	const char* source = mReader->getAttributeValue( attrSource);
	if( source[0] != '#')
		ThrowException( boost::str( boost::format( "Unknown reference format in url \"%s\".") % source));
	int attrCount = GetAttribute( "count");
	unsigned int count = (unsigned int) mReader->getAttributeValueAsInt( attrCount);
	int attrOffset = TestAttribute( "offset");
	unsigned int offset = 0;
	if( attrOffset > -1)
		offset = (unsigned int) mReader->getAttributeValueAsInt( attrOffset);
	int attrStride = TestAttribute( "stride");
	unsigned int stride = 1;
	if( attrStride > -1)
		stride = (unsigned int) mReader->getAttributeValueAsInt( attrStride);

	// store in the library under the given ID
	mAccessorLibrary[pID] = Accessor();
	Accessor& acc = mAccessorLibrary[pID];
	acc.mCount = count;
	acc.mOffset = offset;
	acc.mStride = stride;
	acc.mSource = source+1; // ignore the leading '#'
	acc.mSize = 0; // gets incremented with every param

	// and read the components
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "param"))
			{
				// read data param
				int attrName = TestAttribute( "name");
				std::string name;
				if( attrName > -1)
				{
					name = mReader->getAttributeValue( attrName);

					// analyse for common type components and store it's sub-offset in the corresponding field

					/* Cartesian coordinates */
					if( name == "X") acc.mSubOffset[0] = acc.mParams.size();
					else if( name == "Y") acc.mSubOffset[1] = acc.mParams.size();
					else if( name == "Z") acc.mSubOffset[2] = acc.mParams.size();

					/* RGBA colors */
					else if( name == "R") acc.mSubOffset[0] = acc.mParams.size();
					else if( name == "G") acc.mSubOffset[1] = acc.mParams.size();
					else if( name == "B") acc.mSubOffset[2] = acc.mParams.size();
					else if( name == "A") acc.mSubOffset[3] = acc.mParams.size();

					/* UVWQ (STPQ) texture coordinates */
					else if( name == "S") acc.mSubOffset[0] = acc.mParams.size();
					else if( name == "T") acc.mSubOffset[1] = acc.mParams.size();
					else if( name == "P") acc.mSubOffset[2] = acc.mParams.size();
				//	else if( name == "Q") acc.mSubOffset[3] = acc.mParams.size(); 
					/* 4D uv coordinates are not supported in Assimp */

					/* Generic extra data, interpreted as UV data, too*/
					else if( name == "U") acc.mSubOffset[0] = acc.mParams.size();
					else if( name == "V") acc.mSubOffset[1] = acc.mParams.size();
					//else
					//	DefaultLogger::get()->warn( boost::str( boost::format( "Unknown accessor parameter \"%s\". Ignoring data channel.") % name));
				}

				// read data type
				int attrType = TestAttribute( "type");
				if( attrType > -1)
				{
					// for the moment we only distinguish between a 4x4 matrix and anything else. 
					// TODO: (thom) I don't have a spec here at work. Check if there are other multi-value types
					// which should be tested for here.
					std::string type = mReader->getAttributeValue( attrType);
					if( type == "float4x4")
						acc.mSize += 16;
					else 
						acc.mSize += 1;
				}

				acc.mParams.push_back( name);

				// skip remaining stuff of this element, if any
				SkipElement();
			} else
			{
				ThrowException( "Unexpected sub element in tag \"accessor\".");
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "accessor") != 0)
				ThrowException( "Expected end of \"accessor\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads input declarations of per-vertex mesh data into the given mesh
void ColladaParser::ReadVertexData( Mesh* pMesh)
{
	// extract the ID of the <vertices> element. Not that we care, but to catch strange referencing schemes we should warn about
	int attrID= GetAttribute( "id");
	pMesh->mVertexID = mReader->getAttributeValue( attrID);

	// a number of <input> elements
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "input"))
			{
				ReadInputChannel( pMesh->mPerVertexData);
			} else
			{
				ThrowException( "Unexpected sub element in tag \"vertices\".");
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "vertices") != 0)
				ThrowException( "Expected end of \"vertices\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads input declarations of per-index mesh data into the given mesh
void ColladaParser::ReadIndexData( Mesh* pMesh)
{
	std::vector<size_t> vcount;
	std::vector<InputChannel> perIndexData;

	// read primitive count from the attribute
	int attrCount = GetAttribute( "count");
	size_t numPrimitives = (size_t) mReader->getAttributeValueAsInt( attrCount);

	// material subgroup 
	int attrMaterial = TestAttribute( "material");
	SubMesh subgroup;
	if( attrMaterial > -1)
		subgroup.mMaterial = mReader->getAttributeValue( attrMaterial);
	subgroup.mNumFaces = numPrimitives;
	pMesh->mSubMeshes.push_back( subgroup);

	// distinguish between polys and triangles
	std::string elementName = mReader->getNodeName();
	PrimitiveType primType = Prim_Invalid;
	if( IsElement( "lines"))
		primType = Prim_Lines;
	else if( IsElement( "linestrips"))
		primType = Prim_LineStrip;
	else if( IsElement( "polygons"))
		primType = Prim_Polygon;
	else if( IsElement( "polylist"))
		primType = Prim_Polylist;
	else if( IsElement( "triangles"))
		primType = Prim_Triangles;
	else if( IsElement( "trifans"))
		primType = Prim_TriFans;
	else if( IsElement( "tristrips"))
		primType = Prim_TriStrips;

	ai_assert( primType != Prim_Invalid);

	// also a number of <input> elements, but in addition a <p> primitive collection and propably index counts for all primitives
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			if( IsElement( "input"))
			{
				ReadInputChannel( perIndexData);
			} 
			else if( IsElement( "vcount"))
			{
				if( !mReader->isEmptyElement())
				{
					// case <polylist> - specifies the number of indices for each polygon
					const char* content = GetTextContent();
					vcount.reserve( numPrimitives);
					for( unsigned int a = 0; a < numPrimitives; a++)
					{
						if( *content == 0)
							ThrowException( "Expected more values while reading vcount contents.");
						// read a number
						vcount.push_back( (size_t) strtoul10( content, &content));
						// skip whitespace after it
						SkipSpacesAndLineEnd( &content);
					}

					TestClosing( "vcount");
				}
			}
			else if( IsElement( "p"))
			{
				if( !mReader->isEmptyElement())
				{
					// now here the actual fun starts - these are the indices to construct the mesh data from
					ReadPrimitives( pMesh, perIndexData, numPrimitives, vcount, primType);
				}
			} else
			{
				ThrowException( "Unexpected sub element in tag \"vertices\".");
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( mReader->getNodeName() != elementName)
				ThrowException( boost::str( boost::format( "Expected end of \"%s\" element.") % elementName));

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a single input channel element and stores it in the given array, if valid 
void ColladaParser::ReadInputChannel( std::vector<InputChannel>& poChannels)
{
	InputChannel channel;
	
	// read semantic
	int attrSemantic = GetAttribute( "semantic");
	std::string semantic = mReader->getAttributeValue( attrSemantic);
	channel.mType = GetTypeForSemantic( semantic);

	// read source
	int attrSource = GetAttribute( "source");
	const char* source = mReader->getAttributeValue( attrSource);
	if( source[0] != '#')
		ThrowException( boost::str( boost::format( "Unknown reference format in url \"%s\".") % source));
	channel.mAccessor = source+1; // skipping the leading #, hopefully the remaining text is the accessor ID only

	// read index offset, if per-index <input>
	int attrOffset = TestAttribute( "offset");
	if( attrOffset > -1)
		channel.mOffset = mReader->getAttributeValueAsInt( attrOffset);

	// read set if texture coordinates
	if(channel.mType == IT_Texcoord || channel.mType == IT_Color){
		int attrSet = TestAttribute("set");
		if(attrSet > -1){
			attrSet = mReader->getAttributeValueAsInt( attrSet);
			if(attrSet < 0)
				ThrowException( boost::str( boost::format( "Invalid index \"%i\" for set attribute") % (attrSet)));
			
			channel.mIndex = attrSet;
		}
	}

	// store, if valid type
	if( channel.mType != IT_Invalid)
		poChannels.push_back( channel);

	// skip remaining stuff of this element, if any
	SkipElement();
}

// ------------------------------------------------------------------------------------------------
// Reads a <p> primitive index list and assembles the mesh data into the given mesh
void ColladaParser::ReadPrimitives( Mesh* pMesh, std::vector<InputChannel>& pPerIndexChannels, 
	size_t pNumPrimitives, const std::vector<size_t>& pVCount, PrimitiveType pPrimType)
{
	// determine number of indices coming per vertex 
	// find the offset index for all per-vertex channels
	size_t numOffsets = 1;
	size_t perVertexOffset = SIZE_MAX; // invalid value
	BOOST_FOREACH( const InputChannel& channel, pPerIndexChannels)
	{
		numOffsets = std::max( numOffsets, channel.mOffset+1);
		if( channel.mType == IT_Vertex)
			perVertexOffset = channel.mOffset;
	}

	// determine the expected number of indices 
	size_t expectedPointCount = 0;
	switch( pPrimType)
	{
		case Prim_Polylist:
		{
			BOOST_FOREACH( size_t i, pVCount)
				expectedPointCount += i;
			break;
		}
		case Prim_Lines:
			expectedPointCount = 2 * pNumPrimitives;
			break;
		case Prim_Triangles:
			expectedPointCount = 3 * pNumPrimitives;
			break;
		default:
			// other primitive types don't state the index count upfront... we need to guess
			break;
	}

	// and read all indices into a temporary array
	std::vector<size_t> indices;
	if( expectedPointCount > 0)
		indices.reserve( expectedPointCount * numOffsets);

	const char* content = GetTextContent();
	while( *content != 0)
	{
		// read a value. 
    // Hack: (thom) Some exporters put negative indices sometimes. We just try to carry on anyways.
    int value = std::max( 0, strtol10( content, &content));
		indices.push_back( size_t( value));
		// skip whitespace after it
		SkipSpacesAndLineEnd( &content);
	}

	// complain if the index count doesn't fit
	if( expectedPointCount > 0 && indices.size() != expectedPointCount * numOffsets)
		ThrowException( "Expected different index count in <p> element.");
	else if( expectedPointCount == 0 && (indices.size() % numOffsets) != 0)
		ThrowException( "Expected different index count in <p> element.");

	// find the data for all sources
  for( std::vector<InputChannel>::iterator it = pMesh->mPerVertexData.begin(); it != pMesh->mPerVertexData.end(); ++it)
	{
    InputChannel& input = *it;
		if( input.mResolved)
			continue;

		// find accessor
		input.mResolved = &ResolveLibraryReference( mAccessorLibrary, input.mAccessor);
		// resolve accessor's data pointer as well, if neccessary
		const Accessor* acc = input.mResolved;
		if( !acc->mData)
			acc->mData = &ResolveLibraryReference( mDataLibrary, acc->mSource);
	}
	// and the same for the per-index channels
  for( std::vector<InputChannel>::iterator it = pPerIndexChannels.begin(); it != pPerIndexChannels.end(); ++it)
  {
    InputChannel& input = *it;
		if( input.mResolved)
			continue;

		// ignore vertex pointer, it doesn't refer to an accessor
		if( input.mType == IT_Vertex)
		{
			// warn if the vertex channel does not refer to the <vertices> element in the same mesh
			if( input.mAccessor != pMesh->mVertexID)
				ThrowException( "Unsupported vertex referencing scheme. I fucking hate Collada.");
			continue;
		}

		// find accessor
		input.mResolved = &ResolveLibraryReference( mAccessorLibrary, input.mAccessor);
		// resolve accessor's data pointer as well, if neccessary
		const Accessor* acc = input.mResolved;
		if( !acc->mData)
			acc->mData = &ResolveLibraryReference( mDataLibrary, acc->mSource);
	}


	// now assemble vertex data according to those indices
	std::vector<size_t>::const_iterator idx = indices.begin();

	// For continued primitives, the given count does not come all in one <p>, but only one primitive per <p>
	size_t numPrimitives = pNumPrimitives;
	if( pPrimType == Prim_TriFans || pPrimType == Prim_Polygon)
		numPrimitives = 1;

	pMesh->mFaceSize.reserve( numPrimitives);
	pMesh->mFacePosIndices.reserve( indices.size() / numOffsets);

	for( size_t a = 0; a < numPrimitives; a++)
	{
		// determine number of points for this primitive
		size_t numPoints = 0;
		switch( pPrimType)
		{
			case Prim_Lines:
				numPoints = 2; 
				break;
			case Prim_Triangles: 
				numPoints = 3; 
				break;
			case Prim_Polylist: 
				numPoints = pVCount[a];
				break;
			case Prim_TriFans: 
			case Prim_Polygon:
				numPoints = indices.size() / numOffsets; 
				break;
			default:
				// LineStrip and TriStrip not supported due to expected index unmangling
				ThrowException( "Unsupported primitive type.");
				break;
		}

		// store the face size to later reconstruct the face from
		pMesh->mFaceSize.push_back( numPoints);

		// gather that number of vertices
		for( size_t b = 0; b < numPoints; b++)
		{
			// read all indices for this vertex. Yes, in a hacky local array
			assert( numOffsets < 20 && perVertexOffset < 20);
			size_t vindex[20];
			for( size_t offsets = 0; offsets < numOffsets; ++offsets)
				vindex[offsets] = *idx++;

			// extract per-vertex channels using the global per-vertex offset
      for( std::vector<InputChannel>::iterator it = pMesh->mPerVertexData.begin(); it != pMesh->mPerVertexData.end(); ++it)
        ExtractDataObjectFromChannel( *it, vindex[perVertexOffset], pMesh);
			// and extract per-index channels using there specified offset
      for( std::vector<InputChannel>::iterator it = pPerIndexChannels.begin(); it != pPerIndexChannels.end(); ++it)
				ExtractDataObjectFromChannel( *it, vindex[it->mOffset], pMesh);

			// store the vertex-data index for later assignment of bone vertex weights
			pMesh->mFacePosIndices.push_back( vindex[perVertexOffset]);
		}
	}


	// if I ever get my hands on that guy who invented this steaming pile of indirection...
	TestClosing( "p");
}

// ------------------------------------------------------------------------------------------------
// Extracts a single object from an input channel and stores it in the appropriate mesh data array 
void ColladaParser::ExtractDataObjectFromChannel( const InputChannel& pInput, size_t pLocalIndex, Mesh* pMesh)
{
	// ignore vertex referrer - we handle them that separate
	if( pInput.mType == IT_Vertex)
		return;

	const Accessor& acc = *pInput.mResolved;
	if( pLocalIndex >= acc.mCount)
		ThrowException( boost::str( boost::format( "Invalid data index (%d/%d) in primitive specification") % pLocalIndex % acc.mCount));

	// get a pointer to the start of the data object referred to by the accessor and the local index
	const float* dataObject = &(acc.mData->mValues[0]) + acc.mOffset + pLocalIndex* acc.mStride;
	
	// assemble according to the accessors component sub-offset list. We don't care, yet,
	// what kind of object exactly we're extracting here
	float obj[4];
	for( size_t c = 0; c < 4; ++c)
		obj[c] = dataObject[acc.mSubOffset[c]];

	// now we reinterpret it according to the type we're reading here
	switch( pInput.mType)
	{
		case IT_Position: // ignore all position streams except 0 - there can be only one position
			if( pInput.mIndex == 0)
				pMesh->mPositions.push_back( aiVector3D( obj[0], obj[1], obj[2])); 
			else 
				DefaultLogger::get()->error("Collada: just one vertex position stream supported");
			break;
		case IT_Normal: 
      // pad to current vertex count if necessary
      if( pMesh->mNormals.size() < pMesh->mPositions.size()-1)
        pMesh->mNormals.insert( pMesh->mNormals.end(), pMesh->mPositions.size() - pMesh->mNormals.size() - 1, aiVector3D( 0, 1, 0));

      // ignore all normal streams except 0 - there can be only one normal
      if( pInput.mIndex == 0)
				pMesh->mNormals.push_back( aiVector3D( obj[0], obj[1], obj[2])); 
			else 
				DefaultLogger::get()->error("Collada: just one vertex normal stream supported");
			break;
		case IT_Tangent: 
      // pad to current vertex count if necessary
      if( pMesh->mTangents.size() < pMesh->mPositions.size()-1)
        pMesh->mTangents.insert( pMesh->mTangents.end(), pMesh->mPositions.size() - pMesh->mTangents.size() - 1, aiVector3D( 1, 0, 0));

      // ignore all tangent streams except 0 - there can be only one tangent
      if( pInput.mIndex == 0)
				pMesh->mTangents.push_back( aiVector3D( obj[0], obj[1], obj[2])); 
			else 
				DefaultLogger::get()->error("Collada: just one vertex tangent stream supported");
			break;
		case IT_Bitangent: 
      // pad to current vertex count if necessary
      if( pMesh->mBitangents.size() < pMesh->mPositions.size()-1)
        pMesh->mBitangents.insert( pMesh->mBitangents.end(), pMesh->mPositions.size() - pMesh->mBitangents.size() - 1, aiVector3D( 0, 0, 1));

      // ignore all bitangent streams except 0 - there can be only one bitangent
      if( pInput.mIndex == 0)
				pMesh->mBitangents.push_back( aiVector3D( obj[0], obj[1], obj[2])); 
			else 
				DefaultLogger::get()->error("Collada: just one vertex bitangent stream supported");
			break;
		case IT_Texcoord: 
      // up to 4 texture coord sets are fine, ignore the others
			if( pInput.mIndex < AI_MAX_NUMBER_OF_TEXTURECOORDS) 
      {
        // pad to current vertex count if necessary
        if( pMesh->mTexCoords[pInput.mIndex].size() < pMesh->mPositions.size()-1)
          pMesh->mTexCoords[pInput.mIndex].insert( pMesh->mTexCoords[pInput.mIndex].end(), 
            pMesh->mPositions.size() - pMesh->mTexCoords[pInput.mIndex].size() - 1, aiVector3D( 0, 0, 0));

				pMesh->mTexCoords[pInput.mIndex].push_back( aiVector3D( obj[0], obj[1], obj[2]));
				if (0 != acc.mSubOffset[2] || 0 != acc.mSubOffset[3]) /* hack ... consider cleaner solution */
					pMesh->mNumUVComponents[pInput.mIndex]=3;
			}	else 
      {
				DefaultLogger::get()->error("Collada: too many texture coordinate sets. Skipping.");
      }
			break;
		case IT_Color: 
      // up to 4 color sets are fine, ignore the others
			if( pInput.mIndex < AI_MAX_NUMBER_OF_COLOR_SETS)
      {
        // pad to current vertex count if necessary
        if( pMesh->mColors[pInput.mIndex].size() < pMesh->mPositions.size()-1)
          pMesh->mColors[pInput.mIndex].insert( pMesh->mColors[pInput.mIndex].end(), 
            pMesh->mPositions.size() - pMesh->mColors[pInput.mIndex].size() - 1, aiColor4D( 0, 0, 0, 1));

				pMesh->mColors[pInput.mIndex].push_back( aiColor4D( obj[0], obj[1], obj[2], obj[3])); 
      } else 
      {
				DefaultLogger::get()->error("Collada: too many vertex color sets. Skipping.");
      }

			break;
	default:
		// IT_Invalid and IT_Vertex 
		ai_assert(false && "shouldn't ever get here");
	}
}

// ------------------------------------------------------------------------------------------------
// Reads the library of node hierarchies and scene parts
void ColladaParser::ReadSceneLibrary()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)
		{
			// a visual scene - generate root node under its ID and let ReadNode() do the recursive work
			if( IsElement( "visual_scene"))
			{
				// read ID. Is optional according to the spec, but how on earth should a scene_instance refer to it then?
				int indexID = GetAttribute( "id");
				const char* attrID = mReader->getAttributeValue( indexID);

				// read name if given. 
				int indexName = TestAttribute( "name");
				const char* attrName = "unnamed";
				if( indexName > -1)
					attrName = mReader->getAttributeValue( indexName);

				// create a node and store it in the library under its ID
				Node* node = new Node;
				node->mID = attrID;
				node->mName = attrName;
				mNodeLibrary[node->mID] = node;

				ReadSceneNode( node);
			} else
			{
				// ignore the rest
				SkipElement();
			}
		}
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
		{
			if( strcmp( mReader->getNodeName(), "library_visual_scenes") == 0)
				//ThrowException( "Expected end of \"library_visual_scenes\" element.");

			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a scene node's contents including children and stores it in the given node
void ColladaParser::ReadSceneNode( Node* pNode)
{
	// quit immediately on <bla/> elements
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT) 
		{
			if( IsElement( "node"))
			{
				Node* child = new Node;
				int attrID = TestAttribute( "id");
				if( attrID > -1)
					child->mID = mReader->getAttributeValue( attrID);
				int attrSID = TestAttribute( "sid");
				if( attrSID > -1)
					child->mSID = mReader->getAttributeValue( attrSID);

				int attrName = TestAttribute( "name");
				if( attrName > -1)
					child->mName = mReader->getAttributeValue( attrName);

				// TODO: (thom) support SIDs
				// assert( TestAttribute( "sid") == -1);

				if (pNode) 
				{
					pNode->mChildren.push_back( child);
					child->mParent = pNode;
				}
				else 
				{
					// no parent node given, probably called from <library_nodes> element.
					// create new node in node library
					mNodeLibrary[child->mID] = child;
				}

				// read on recursively from there
				ReadSceneNode( child);
				continue;
			}
			// For any further stuff we need a valid node to work on
			else if (!pNode)
				continue;

			if( IsElement( "lookat"))
				ReadNodeTransformation( pNode, TF_LOOKAT);
			else if( IsElement( "matrix"))
				ReadNodeTransformation( pNode, TF_MATRIX);
			else if( IsElement( "rotate"))
				ReadNodeTransformation( pNode, TF_ROTATE);
			else if( IsElement( "scale"))
				ReadNodeTransformation( pNode, TF_SCALE);
			else if( IsElement( "skew"))
				ReadNodeTransformation( pNode, TF_SKEW);
			else if( IsElement( "translate"))
				ReadNodeTransformation( pNode, TF_TRANSLATE);
			else if( IsElement( "render") && pNode->mParent == NULL && 0 == pNode->mPrimaryCamera.length())
			{
				// ... scene evaluation or, in other words, postprocessing pipeline,
				// or, again in other words, a turing-complete description how to
				// render a Collada scene. The only thing that is interesting for
				// us is the primary camera.
				int attrId = TestAttribute("camera_node");
				if (-1 != attrId) 
				{
					const char* s = mReader->getAttributeValue(attrId);
					if (s[0] != '#')
						DefaultLogger::get()->error("Collada: Unresolved reference format of camera");
					else 
						pNode->mPrimaryCamera = s+1;
				}
			}
			else if( IsElement( "instance_node")) 
			{
				// find the node in the library
				int attrID = TestAttribute( "url");
				if( attrID != -1) 
				{
					const char* s = mReader->getAttributeValue(attrID);
					if (s[0] != '#')
						DefaultLogger::get()->error("Collada: Unresolved reference format of node");
					else 
					{
						pNode->mNodeInstances.push_back(NodeInstance());
						pNode->mNodeInstances.back().mNode = s+1;
					}
				}
			} 
			else if( IsElement( "instance_geometry") || IsElement( "instance_controller"))
			{
				// Reference to a mesh or controller, with possible material associations
				ReadNodeGeometry( pNode);
			}
			else if( IsElement( "instance_light")) 
			{
				// Reference to a light, name given in 'url' attribute
				int attrID = TestAttribute("url");
				if (-1 == attrID)
					DefaultLogger::get()->warn("Collada: Expected url attribute in <instance_light> element");
				else 
				{
					const char* url = mReader->getAttributeValue( attrID);
					if( url[0] != '#')
						ThrowException( "Unknown reference format in <instance_light> element");

					pNode->mLights.push_back(LightInstance());
					pNode->mLights.back().mLight = url+1;
				}
			}
			else if( IsElement( "instance_camera")) 
			{
				// Reference to a camera, name given in 'url' attribute
				int attrID = TestAttribute("url");
				if (-1 == attrID)
					DefaultLogger::get()->warn("Collada: Expected url attribute in <instance_camera> element");
				else 
				{
					const char* url = mReader->getAttributeValue( attrID);
					if( url[0] != '#')
						ThrowException( "Unknown reference format in <instance_camera> element");

					pNode->mCameras.push_back(CameraInstance());
					pNode->mCameras.back().mCamera = url+1;
				}
			}
			else
			{
				// skip everything else for the moment
				SkipElement();
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END) {
			break;
		}
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a node transformation entry of the given type and adds it to the given node's transformation list.
void ColladaParser::ReadNodeTransformation( Node* pNode, TransformType pType)
{
	if( mReader->isEmptyElement())
		return;

	std::string tagName = mReader->getNodeName();

	Transform tf;
	tf.mType = pType;
	
	// read SID
	int indexSID = TestAttribute( "sid");
	if( indexSID >= 0)
		tf.mID = mReader->getAttributeValue( indexSID);

	// how many parameters to read per transformation type
	static const unsigned int sNumParameters[] = { 9, 4, 3, 3, 7, 16 };
	const char* content = GetTextContent();

	// read as many parameters and store in the transformation
	for( unsigned int a = 0; a < sNumParameters[pType]; a++)
	{
		// read a number
		content = fast_atof_move( content, tf.f[a]);
		// skip whitespace after it
		SkipSpacesAndLineEnd( &content);
	}

	// place the transformation at the queue of the node
	pNode->mTransforms.push_back( tf);

	// and consume the closing tag
	TestClosing( tagName.c_str());
}

// ------------------------------------------------------------------------------------------------
// Processes bind_vertex_input and bind elements
void ColladaParser::ReadMaterialVertexInputBinding( Collada::SemanticMappingTable& tbl)
{
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)	{
			if( IsElement( "bind_vertex_input"))
			{
				Collada::InputSemanticMapEntry vn;

				// effect semantic
				int n = GetAttribute("semantic");
				std::string s = mReader->getAttributeValue(n);

				// input semantic
				n = GetAttribute("input_semantic");
				vn.mType = GetTypeForSemantic( mReader->getAttributeValue(n) );
				
				// index of input set
				n = TestAttribute("input_set");
				if (-1 != n)
					vn.mSet = mReader->getAttributeValueAsInt(n);

				tbl.mMap[s] = vn;
			} 
			else if( IsElement( "bind")) {
				DefaultLogger::get()->warn("Collada: Found unsupported <bind> element");
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)	{
			if( strcmp( mReader->getNodeName(), "instance_material") == 0)
				break;
		} 
	}
}

// ------------------------------------------------------------------------------------------------
// Reads a mesh reference in a node and adds it to the node's mesh list
void ColladaParser::ReadNodeGeometry( Node* pNode)
{
	// referred mesh is given as an attribute of the <instance_geometry> element
	int attrUrl = GetAttribute( "url");
	const char* url = mReader->getAttributeValue( attrUrl);
	if( url[0] != '#')
		ThrowException( "Unknown reference format");
	
	Collada::MeshInstance instance;
	instance.mMeshOrController = url+1; // skipping the leading #

	if( !mReader->isEmptyElement())
	{
		// read material associations. Ignore additional elements inbetween
		while( mReader->read())
		{
			if( mReader->getNodeType() == irr::io::EXN_ELEMENT)	
			{
				if( IsElement( "instance_material"))
				{
					// read ID of the geometry subgroup and the target material
					int attrGroup = GetAttribute( "symbol");
					std::string group = mReader->getAttributeValue( attrGroup);
					int attrMaterial = GetAttribute( "target");
					const char* urlMat = mReader->getAttributeValue( attrMaterial);
					Collada::SemanticMappingTable s;
					if( urlMat[0] == '#')
						urlMat++;

					s.mMatName = urlMat;

					// resolve further material details + THIS UGLY AND NASTY semantic mapping stuff
					if( !mReader->isEmptyElement())
						ReadMaterialVertexInputBinding(s);

					// store the association
					instance.mMaterials[group] = s;
				} 
			} 
			else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)	
			{
				if( strcmp( mReader->getNodeName(), "instance_geometry") == 0 
					|| strcmp( mReader->getNodeName(), "instance_controller") == 0)
					break;
			} 
		}
	}

	// store it
	pNode->mMeshes.push_back( instance);
}

// ------------------------------------------------------------------------------------------------
// Reads the collada scene
void ColladaParser::ReadScene()
{
	if( mReader->isEmptyElement())
		return;

	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT)	{
			if( IsElement( "instance_visual_scene"))
			{
				// should be the first and only occurence
				if( mRootNode)
					ThrowException( "Invalid scene containing multiple root nodes");

				// read the url of the scene to instance. Should be of format "#some_name"
				int urlIndex = GetAttribute( "url");
				const char* url = mReader->getAttributeValue( urlIndex);
				if( url[0] != '#')
					ThrowException( "Unknown reference format");

				// find the referred scene, skip the leading # 
				NodeLibrary::const_iterator sit = mNodeLibrary.find( url+1);
				if( sit == mNodeLibrary.end())
					ThrowException( "Unable to resolve visual_scene reference \"" + std::string(url) + "\".");
				mRootNode = sit->second;
			} else	{
				SkipElement();
			}
		} 
		else if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END){
			break;
		} 
	}
}

// ------------------------------------------------------------------------------------------------
// Aborts the file reading with an exception
void ColladaParser::ThrowException( const std::string& pError) const
{
	throw DeadlyImportError( boost::str( boost::format( "Collada: %s - %s") % mFileName % pError));
}

// ------------------------------------------------------------------------------------------------
// Skips all data until the end node of the current element
void ColladaParser::SkipElement()
{
	// nothing to skip if it's an <element />
	if( mReader->isEmptyElement())
		return;

	// reroute
	SkipElement( mReader->getNodeName());
}

// ------------------------------------------------------------------------------------------------
// Skips all data until the end node of the given element
void ColladaParser::SkipElement( const char* pElement)
{
	// copy the current node's name because it'a pointer to the reader's internal buffer, 
	// which is going to change with the upcoming parsing 
	std::string element = pElement;
	while( mReader->read())
	{
		if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END)
			if( mReader->getNodeName() == element)
				break;
	}
}

// ------------------------------------------------------------------------------------------------
// Tests for an opening element of the given name, throws an exception if not found
void ColladaParser::TestOpening( const char* pName)
{
	// read element start
	if( !mReader->read())
		ThrowException( boost::str( boost::format( "Unexpected end of file while beginning of \"%s\" element.") % pName));
	// whitespace in front is ok, just read again if found
	if( mReader->getNodeType() == irr::io::EXN_TEXT)
		if( !mReader->read())
			ThrowException( boost::str( boost::format( "Unexpected end of file while reading beginning of \"%s\" element.") % pName));

	if( mReader->getNodeType() != irr::io::EXN_ELEMENT || strcmp( mReader->getNodeName(), pName) != 0)
		ThrowException( boost::str( boost::format( "Expected start of \"%s\" element.") % pName));
}

// ------------------------------------------------------------------------------------------------
// Tests for the closing tag of the given element, throws an exception if not found
void ColladaParser::TestClosing( const char* pName)
{
	// check if we're already on the closing tag and return right away
	if( mReader->getNodeType() == irr::io::EXN_ELEMENT_END && strcmp( mReader->getNodeName(), pName) == 0)
		return;

	// if not, read some more
	if( !mReader->read())
		ThrowException( boost::str( boost::format( "Unexpected end of file while reading end of \"%s\" element.") % pName));
	// whitespace in front is ok, just read again if found
	if( mReader->getNodeType() == irr::io::EXN_TEXT)
		if( !mReader->read())
			ThrowException( boost::str( boost::format( "Unexpected end of file while reading end of \"%s\" element.") % pName));

	// but this has the be the closing tag, or we're lost
	if( mReader->getNodeType() != irr::io::EXN_ELEMENT_END || strcmp( mReader->getNodeName(), pName) != 0)
		ThrowException( boost::str( boost::format( "Expected end of \"%s\" element.") % pName));
}

// ------------------------------------------------------------------------------------------------
// Returns the index of the named attribute or -1 if not found. Does not throw, therefore useful for optional attributes
int ColladaParser::GetAttribute( const char* pAttr) const
{
	int index = TestAttribute( pAttr);
	if( index != -1)
		return index;

	// attribute not found -> throw an exception
	ThrowException( boost::str( boost::format( "Expected attribute \"%s\" at element \"%s\".") % pAttr % mReader->getNodeName()));
	return -1;
}

// ------------------------------------------------------------------------------------------------
// Tests the present element for the presence of one attribute, returns its index or throws an exception if not found
int ColladaParser::TestAttribute( const char* pAttr) const
{
	for( int a = 0; a < mReader->getAttributeCount(); a++)
		if( strcmp( mReader->getAttributeName( a), pAttr) == 0)
			return a;

	return -1;
}

// ------------------------------------------------------------------------------------------------
// Reads the text contents of an element, throws an exception if not given. Skips leading whitespace.
const char* ColladaParser::GetTextContent()
{
	const char* sz = TestTextContent();
	if(!sz) {
		ThrowException( "Invalid contents in element \"n\".");
	}
	return sz;
}

// ------------------------------------------------------------------------------------------------
// Reads the text contents of an element, returns NULL if not given. Skips leading whitespace.
const char* ColladaParser::TestTextContent()
{
	// present node should be the beginning of an element
	if( mReader->getNodeType() != irr::io::EXN_ELEMENT || mReader->isEmptyElement())
		ThrowException( "Expected opening element");

	// read contents of the element
	if( !mReader->read())
		ThrowException( "Unexpected end of file while reading n element.");
	if( mReader->getNodeType() != irr::io::EXN_TEXT)
		return NULL;

	// skip leading whitespace
	const char* text = mReader->getNodeData();
	SkipSpacesAndLineEnd( &text);

	return text;
}

// ------------------------------------------------------------------------------------------------
// Calculates the resulting transformation fromm all the given transform steps
aiMatrix4x4 ColladaParser::CalculateResultTransform( const std::vector<Transform>& pTransforms) const
{
	aiMatrix4x4 res;

	for( std::vector<Transform>::const_iterator it = pTransforms.begin(); it != pTransforms.end(); ++it)
	{
		const Transform& tf = *it;
		switch( tf.mType)
		{
			case TF_LOOKAT:
      {
        aiVector3D pos( tf.f[0], tf.f[1], tf.f[2]);
        aiVector3D dstPos( tf.f[3], tf.f[4], tf.f[5]);
        aiVector3D up = aiVector3D( tf.f[6], tf.f[7], tf.f[8]).Normalize();
        aiVector3D dir = aiVector3D( dstPos - pos).Normalize();
        aiVector3D right = (dir ^ up).Normalize();

        res *= aiMatrix4x4( 
          right.x, up.x, -dir.x, pos.x, 
          right.y, up.y, -dir.y, pos.y,
          right.z, up.z, -dir.z, pos.z,
          0, 0, 0, 1);
				break;
      }
			case TF_ROTATE:
			{
				aiMatrix4x4 rot;
				float angle = tf.f[3] * float( AI_MATH_PI) / 180.0f;
				aiVector3D axis( tf.f[0], tf.f[1], tf.f[2]);
				aiMatrix4x4::Rotation( angle, axis, rot);
				res *= rot;
				break;
			}
			case TF_TRANSLATE:
			{
				aiMatrix4x4 trans;
				aiMatrix4x4::Translation( aiVector3D( tf.f[0], tf.f[1], tf.f[2]), trans);
				res *= trans;
				break;
			}
			case TF_SCALE:
			{
				aiMatrix4x4 scale( tf.f[0], 0.0f, 0.0f, 0.0f, 0.0f, tf.f[1], 0.0f, 0.0f, 0.0f, 0.0f, tf.f[2], 0.0f, 
					0.0f, 0.0f, 0.0f, 1.0f);
				res *= scale;
				break;
			}
			case TF_SKEW:
				// TODO: (thom)
				ai_assert( false);
				break;
			case TF_MATRIX:
			{
				aiMatrix4x4 mat( tf.f[0], tf.f[1], tf.f[2], tf.f[3], tf.f[4], tf.f[5], tf.f[6], tf.f[7],
					tf.f[8], tf.f[9], tf.f[10], tf.f[11], tf.f[12], tf.f[13], tf.f[14], tf.f[15]);
				res *= mat;
				break;
			}
			default: 
				assert( false);
				break;
		}
	}

	return res;
}

// ------------------------------------------------------------------------------------------------
// Determines the input data type for the given semantic string
Collada::InputType ColladaParser::GetTypeForSemantic( const std::string& pSemantic)
{
	if( pSemantic == "POSITION")
		return IT_Position;
	else if( pSemantic == "TEXCOORD")
		return IT_Texcoord;
	else if( pSemantic == "NORMAL")
		return IT_Normal;
	else if( pSemantic == "COLOR")
		return IT_Color;
	else if( pSemantic == "VERTEX")
		return IT_Vertex;
	else if( pSemantic == "BINORMAL" || pSemantic ==  "TEXBINORMAL")
		return IT_Bitangent;
	else if( pSemantic == "TANGENT" || pSemantic == "TEXTANGENT")
		return IT_Tangent;

	DefaultLogger::get()->warn( boost::str( boost::format( "Unknown vertex input type \"%s\". Ignoring.") % pSemantic));
	return IT_Invalid;
}

#endif // !! ASSIMP_BUILD_NO_DAE_IMPORTER