assimp/code/Importer.cpp

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

Copyright (c) 2006-2008, 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
  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
  copyright notice, this list of conditions and the
  following disclaimer in the documentation and/or other
  materials provided with the distribution.

* 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,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
---------------------------------------------------------------------------
*/

/** @file Implementation of the CPP-API class #Importer */

#include "AssimpPCH.h"

/* Uncomment this line to prevent Assimp from catching unknown exceptions.
 *
 * Note that any Exception except ImportErrorException may lead to 
 * undefined behaviour -> loaders could remain in an unusable state and
 * further imports with the same Importer instance could fail/crash/burn ...
 */
#define ASSIMP_CATCH_GLOBAL_EXCEPTIONS

// =======================================================================================
// Internal headers
// =======================================================================================
#include "BaseImporter.h"
#include "BaseProcess.h"
#include "DefaultIOStream.h"
#include "DefaultIOSystem.h"
#include "GenericProperty.h"
#include "ProcessHelper.h"
#include "ScenePreprocessor.h"

// =======================================================================================
// Importers
// =======================================================================================
#ifndef AI_BUILD_NO_X_IMPORTER
#	include "XFileImporter.h"
#endif
#ifndef AI_BUILD_NO_3DS_IMPORTER
#	include "3DSLoader.h"
#endif
#ifndef AI_BUILD_NO_MD3_IMPORTER
#	include "MD3Loader.h"
#endif
#ifndef AI_BUILD_NO_MDL_IMPORTER
#	include "MDLLoader.h"
#endif
#ifndef AI_BUILD_NO_MD2_IMPORTER
#	include "MD2Loader.h"
#endif
#ifndef AI_BUILD_NO_PLY_IMPORTER
#	include "PlyLoader.h"
#endif
#ifndef AI_BUILD_NO_ASE_IMPORTER
#	include "ASELoader.h"
#endif
#ifndef AI_BUILD_NO_OBJ_IMPORTER
#	include "ObjFileImporter.h"
#endif
#ifndef AI_BUILD_NO_HMP_IMPORTER
#	include "HMPLoader.h"
#endif
#ifndef AI_BUILD_NO_SMD_IMPORTER
#	include "SMDLoader.h"
#endif
#ifndef AI_BUILD_NO_MDC_IMPORTER
#	include "MDCLoader.h"
#endif
#ifndef AI_BUILD_NO_MD5_IMPORTER
#	include "MD5Loader.h"
#endif
#ifndef AI_BUILD_NO_STL_IMPORTER
#	include "STLLoader.h"
#endif
#ifndef AI_BUILD_NO_LWO_IMPORTER
#	include "LWOLoader.h"
#endif
#ifndef AI_BUILD_NO_DXF_IMPORTER
#	include "DXFLoader.h"
#endif
#ifndef AI_BUILD_NO_NFF_IMPORTER
#	include "NFFLoader.h"
#endif
#ifndef AI_BUILD_NO_RAW_IMPORTER
#	include "RawLoader.h"
#endif
#ifndef AI_BUILD_NO_OFF_IMPORTER
#	include "OFFLoader.h"
#endif
#ifndef AI_BUILD_NO_AC_IMPORTER
#	include "ACLoader.h"
#endif
#ifndef AI_BUILD_NO_BVH_IMPORTER
#	include "BVHLoader.h"
#endif
#ifndef AI_BUILD_NO_IRRMESH_IMPORTER
#	include "IRRMeshLoader.h"
#endif
#ifndef AI_BUILD_NO_IRR_IMPORTER
#	include "IRRLoader.h"
#endif
#ifndef AI_BUILD_NO_Q3D_IMPORTER
#	include "Q3DLoader.h"
#endif
#ifndef AI_BUILD_NO_B3D_IMPORTER
#	include "B3DImporter.h"
#endif
#ifndef AI_BUILD_NO_COLLADA_IMPORTER
#	include "ColladaLoader.h"
#endif
#ifndef AI_BUILD_NO_TERRAGEN_IMPORTER
#	include "TerragenLoader.h"
#endif
//#ifndef AI_BUILD_NO_CSM_IMPORTER
//#	include "CSMLoader.h"
//#endif
#ifndef AI_BUILD_NO_3D_IMPORTER
#	include "UnrealLoader.h"
#endif




#ifndef AI_BUILD_NO_LWS_IMPORTER
#	include "LWSLoader.h"
#endif


// =======================================================================================
// PostProcess-Steps
// =======================================================================================
#ifndef AI_BUILD_NO_CALCTANGENTS_PROCESS
#	include "CalcTangentsProcess.h"
#endif
#ifndef AI_BUILD_NO_JOINVERTICES_PROCESS
#	include "JoinVerticesProcess.h"
#endif
#if !(defined AI_BUILD_NO_MAKELEFTHANDED_PROCESS && defined AI_BUILD_NO_FLIPUVS_PROCESS && defined AI_BUILD_NO_FLIPWINDINGORDER_PROCESS)
#	include "ConvertToLHProcess.h"
#endif
#ifndef AI_BUILD_NO_TRIANGULATE_PROCESS
#	include "TriangulateProcess.h"
#endif
#ifndef AI_BUILD_NO_GENFACENORMALS_PROCESS
#	include "GenFaceNormalsProcess.h"
#endif
#ifndef AI_BUILD_NO_GENVERTEXNORMALS_PROCESS
#	include "GenVertexNormalsProcess.h"
#endif
#ifndef AI_BUILD_NO_REMOVEVC_PROCESS
#	include "RemoveVCProcess.h"
#endif
#ifndef AI_BUILD_NO_SPLITLARGEMESHES_PROCESS
#	include "SplitLargeMeshes.h"
#endif
#ifndef AI_BUILD_NO_PRETRANSFORMVERTICES_PROCESS
#	include "PretransformVertices.h"
#endif
#ifndef AI_BUILD_NO_LIMITBONEWEIGHTS_PROCESS
#	include "LimitBoneWeightsProcess.h"
#endif
#ifndef AI_BUILD_NO_VALIDATEDS_PROCESS
#	include "ValidateDataStructure.h"
#endif
#ifndef AI_BUILD_NO_IMPROVECACHELOCALITY_PROCESS
#	include "ImproveCacheLocality.h"
#endif
#ifndef AI_BUILD_NO_FIXINFACINGNORMALS_PROCESS
#	include "FixNormalsStep.h"
#endif
#ifndef AI_BUILD_NO_REMOVE_REDUNDANTMATERIALS_PROCESS
#	include "RemoveRedundantMaterials.h"
#endif
#ifndef AI_BUILD_NO_FINDINVALIDDATA_PROCESS
#	include "FindInvalidDataProcess.h"
#endif
#ifndef AI_BUILD_NO_FINDDEGENERATES_PROCESS
#	include "FindDegenerates.h"
#endif
#ifndef AI_BUILD_NO_SORTBYPTYPE_PROCESS
#	include "SortByPTypeProcess.h"
#endif
#ifndef AI_BUILD_NO_GENUVCOORDS_PROCESS
#	include "ComputeUVMappingProcess.h"
#endif
#ifndef AI_BUILD_NO_TRANSFORMTEXCOORDS_PROCESS
#	include "TextureTransform.h"
#endif
#ifndef AI_BUILD_NO_FINDINSTANCES_PROCESS
#	include "FindInstancesProcess.h"
#endif

using namespace Assimp;
using namespace Assimp::Intern;

// =======================================================================================
// Intern::AllocateFromAssimpHeap serves as abstract base class. It overrides
// new and delete (and their array counterparts) of public API classes (e.g. Logger) to
// utilize our DLL heap
// =======================================================================================
void* AllocateFromAssimpHeap::operator new ( size_t num_bytes)	
{
	return ::operator new(num_bytes);
}

void AllocateFromAssimpHeap::operator delete ( void* data)	
{
	return ::operator delete(data);
}

void* AllocateFromAssimpHeap::operator new[] ( size_t num_bytes)	
{
	return ::operator new[](num_bytes);
}

void AllocateFromAssimpHeap::operator delete[] ( void* data)
{
	return ::operator delete[](data);
}

// ------------------------------------------------------------------------------------------------
// Importer Constructor. 
Importer::Importer() 
	:	mIOHandler		(NULL)
	,	mScene			(NULL)
	,	mErrorString	("")	
{
	// Allocate a default IO handler
	mIOHandler = new DefaultIOSystem;
	mIsDefaultHandler = true; 
	bExtraVerbose     = false; // disable extra verbose mode by default

	// ======================================================================
	// Add an instance of each worker class here
	// The order doesn't really care, however file formats that are
	// used more frequently than others should be at the beginning.
	// ======================================================================
	mImporter.reserve(25);

#if (!defined AI_BUILD_NO_X_IMPORTER)
	mImporter.push_back( new XFileImporter());
#endif
#if (!defined AI_BUILD_NO_OBJ_IMPORTER)
	mImporter.push_back( new ObjFileImporter());
#endif
#if (!defined AI_BUILD_NO_3DS_IMPORTER)
	mImporter.push_back( new Discreet3DSImporter());
#endif
#if (!defined AI_BUILD_NO_MD3_IMPORTER)
	mImporter.push_back( new MD3Importer());
#endif
#if (!defined AI_BUILD_NO_MD2_IMPORTER)
	mImporter.push_back( new MD2Importer());
#endif
#if (!defined AI_BUILD_NO_PLY_IMPORTER)
	mImporter.push_back( new PLYImporter());
#endif
#if (!defined AI_BUILD_NO_MDL_IMPORTER)
	mImporter.push_back( new MDLImporter());
#endif
#if (!defined AI_BUILD_NO_ASE_IMPORTER)
	mImporter.push_back( new ASEImporter());
#endif
#if (!defined AI_BUILD_NO_HMP_IMPORTER)
	mImporter.push_back( new HMPImporter());
#endif
#if (!defined AI_BUILD_NO_SMD_IMPORTER)
	mImporter.push_back( new SMDImporter());
#endif
#if (!defined AI_BUILD_NO_MDC_IMPORTER)
	mImporter.push_back( new MDCImporter());
#endif
#if (!defined AI_BUILD_NO_MD5_IMPORTER)
	mImporter.push_back( new MD5Importer());
#endif
#if (!defined AI_BUILD_NO_STL_IMPORTER)
	mImporter.push_back( new STLImporter());
#endif
#if (!defined AI_BUILD_NO_LWO_IMPORTER)
	mImporter.push_back( new LWOImporter());
#endif
#if (!defined AI_BUILD_NO_DXF_IMPORTER)
	mImporter.push_back( new DXFImporter());
#endif
#if (!defined AI_BUILD_NO_NFF_IMPORTER)
	mImporter.push_back( new NFFImporter());
#endif
#if (!defined AI_BUILD_NO_RAW_IMPORTER)
	mImporter.push_back( new RAWImporter());
#endif
#if (!defined AI_BUILD_NO_OFF_IMPORTER)
	mImporter.push_back( new OFFImporter());
#endif
#if (!defined AI_BUILD_NO_AC_IMPORTER)
	mImporter.push_back( new AC3DImporter());
#endif
#if (!defined AI_BUILD_NO_BVH_IMPORTER)
	mImporter.push_back( new BVHLoader());
#endif
#if (!defined AI_BUILD_NO_IRRMESH_IMPORTER)
	mImporter.push_back( new IRRMeshImporter());
#endif
#if (!defined AI_BUILD_NO_IRR_IMPORTER)
	mImporter.push_back( new IRRImporter());
#endif
#if (!defined AI_BUILD_NO_Q3D_IMPORTER)
	mImporter.push_back( new Q3DImporter());
#endif
#if (!defined AI_BUILD_NO_B3D_IMPORTER)
	mImporter.push_back( new B3DImporter());
#endif
#if (!defined AI_BUILD_NO_COLLADA_IMPORTER)
	mImporter.push_back( new ColladaLoader());
#endif
#if (!defined AI_BUILD_NO_TERRAGEN_IMPORTER)
	mImporter.push_back( new TerragenImporter());
#endif
//#if (!defined AI_BUILD_NO_CSM_IMPORTER)
//	mImporter.push_back( new CSMImporter());
//#endif
#if (!defined AI_BUILD_NO_3D_IMPORTER)
	mImporter.push_back( new UnrealImporter());
#endif



#if (!defined AI_BUILD_NO_LWS_IMPORTER)
	mImporter.push_back( new LWSImporter());
#endif

	// ======================================================================
	// Add an instance of each post processing step here in the order 
	// of sequence it is executed. Steps that are added here are not
	// validated - as RegisterPPStep() does - all dependencies must be there.
	// ======================================================================
	mPostProcessingSteps.reserve(25);

#if (!defined AI_BUILD_NO_REMOVEVC_PROCESS)
	mPostProcessingSteps.push_back( new RemoveVCProcess());
#endif

#if (!defined AI_BUILD_NO_REMOVE_REDUNDANTMATERIALS_PROCESS)
	mPostProcessingSteps.push_back( new RemoveRedundantMatsProcess());
#endif

#if (!defined AI_BUILD_NO_FINDINSTANCES_PROCESS)
	mPostProcessingSteps.push_back( new FindInstancesProcess());
#endif

#if (!defined AI_BUILD_NO_FINDDEGENERATES_PROCESS)
	mPostProcessingSteps.push_back( new FindDegeneratesProcess());
#endif


	
#ifndef AI_BUILD_NO_GENUVCOORDS_PROCESS
	mPostProcessingSteps.push_back( new ComputeUVMappingProcess());
#endif
#ifndef AI_BUILD_NO_TRANSFORMTEXCOORDS_PROCESS
	mPostProcessingSteps.push_back( new TextureTransformStep());
#endif

#if (!defined AI_BUILD_NO_PRETRANSFORMVERTICES_PROCESS)
	mPostProcessingSteps.push_back( new PretransformVertices());
#endif
#if (!defined AI_BUILD_NO_TRIANGULATE_PROCESS)
	mPostProcessingSteps.push_back( new TriangulateProcess());
#endif
	
#if (!defined AI_BUILD_NO_SORTBYPTYPE_PROCESS)
	mPostProcessingSteps.push_back( new SortByPTypeProcess());
#endif

#if (!defined AI_BUILD_NO_FINDINVALIDDATA_PROCESS)
	mPostProcessingSteps.push_back( new FindInvalidDataProcess());
#endif

#if (!defined AI_BUILD_NO_FIXINFACINGNORMALS_PROCESS)
	mPostProcessingSteps.push_back( new FixInfacingNormalsProcess());
#endif
#if (!defined AI_BUILD_NO_SPLITLARGEMESHES_PROCESS)
	mPostProcessingSteps.push_back( new SplitLargeMeshesProcess_Triangle());
#endif
#if (!defined AI_BUILD_NO_GENFACENORMALS_PROCESS)
	mPostProcessingSteps.push_back( new GenFaceNormalsProcess());
#endif


	// DON'T change the order of these five!
	mPostProcessingSteps.push_back( new ComputeSpatialSortProcess());

#if (!defined AI_BUILD_NO_GENVERTEXNORMALS_PROCESS)
	mPostProcessingSteps.push_back( new GenVertexNormalsProcess());
#endif
#if (!defined AI_BUILD_NO_CALCTANGENTS_PROCESS)
	mPostProcessingSteps.push_back( new CalcTangentsProcess());
#endif
#if (!defined AI_BUILD_NO_JOINVERTICES_PROCESS)
	mPostProcessingSteps.push_back( new JoinVerticesProcess());
#endif

	mPostProcessingSteps.push_back( new DestroySpatialSortProcess());


#if (!defined AI_BUILD_NO_SPLITLARGEMESHES_PROCESS)
	mPostProcessingSteps.push_back( new SplitLargeMeshesProcess_Vertex());
#endif
#if (!defined AI_BUILD_NO_MAKELEFTHANDED_PROCESS)
	mPostProcessingSteps.push_back( new MakeLeftHandedProcess());
#endif
#if (!defined AI_BUILD_NO_FLIPUVS_PROCESS)
	mPostProcessingSteps.push_back( new FlipUVsProcess());
#endif
#if (!defined AI_BUILD_NO_FLIPWINDINGORDER_PROCESS)
	mPostProcessingSteps.push_back( new FlipWindingOrderProcess());
#endif
#if (!defined AI_BUILD_NO_LIMITBONEWEIGHTS_PROCESS)
	mPostProcessingSteps.push_back( new LimitBoneWeightsProcess());
#endif
#if (!defined AI_BUILD_NO_IMPROVECACHELOCALITY_PROCESS)
	mPostProcessingSteps.push_back( new ImproveCacheLocalityProcess());
#endif


	// Allocate a SharedPostProcessInfo object and store pointers to it
	// in all post-process steps in the list.
	mPPShared = new SharedPostProcessInfo();
	for (std::vector<BaseProcess*>::iterator it = mPostProcessingSteps.begin(),
		 end =  mPostProcessingSteps.end(); it != end; ++it)
	{
		(*it)->SetSharedData(mPPShared);
	}
}

// ------------------------------------------------------------------------------------------------
// Destructor. 
Importer::~Importer()
{
	// Delete all import plugins
	for( unsigned int a = 0; a < mImporter.size(); a++)
		delete mImporter[a];

	// Delete all post-processing plug-ins
	for( unsigned int a = 0; a < mPostProcessingSteps.size(); a++)
		delete mPostProcessingSteps[a];

	// Delete the assigned IO handler
	delete mIOHandler;

	// Kill imported scene. Destructors should do that recursivly
	delete mScene;

	// Delete shared post-processing data
	delete mPPShared;
}

// ------------------------------------------------------------------------------------------------
//	Copy constructor - copies the config of another Importer, not the scene
Importer::Importer(const Importer &other)
{
	// Call the default constructor
	new(this) Importer();

	// Copy the property table
	mIntProperties    = other.mIntProperties;
	mFloatProperties  = other.mFloatProperties;
	mStringProperties = other.mStringProperties;
}

// ------------------------------------------------------------------------------------------------
// Register a custom loader plugin
aiReturn Importer::RegisterLoader(BaseImporter* pImp)
{
	ai_assert(NULL != pImp);
	// ======================================================================
	// Check whether we would have two loaders for the same file extension 
	// This is absolutely OK, but we should warn the developer of the new
	// loader that his code will propably never be called.
	// ======================================================================
	std::string st;
	pImp->GetExtensionList(st);

#ifdef _DEBUG
	const char* sz = ::strtok(const_cast<char*>(st.c_str()),";");
	while (sz)
	{
		if (IsExtensionSupported(std::string(sz)))
			DefaultLogger::get()->warn(std::string( "The file extension " ) + sz + " is already in use");
		
		sz = ::strtok(NULL,";");
	}
#endif

	// add the loader
	mImporter.push_back(pImp);
	DefaultLogger::get()->info("Registering custom importer: " + st);
	return AI_SUCCESS;
}

// ------------------------------------------------------------------------------------------------
// Unregister a custom loader
aiReturn Importer::UnregisterLoader(BaseImporter* pImp)
{
	ai_assert(NULL != pImp);
	for (std::vector<BaseImporter*>::iterator
		it = mImporter.begin(),end = mImporter.end();
		it != end;++it)
	{
		if (pImp == (*it))
		{
			mImporter.erase(it);

			std::string st;
			pImp->GetExtensionList(st);
			DefaultLogger::get()->info("Unregistering custom importer: " + st);
			return AI_SUCCESS;
		}
	}
	DefaultLogger::get()->warn("Unable to remove importer: importer not found");
	return AI_FAILURE;
}

// ------------------------------------------------------------------------------------------------
// Supplies a custom IO handler to the importer to open and access files.
void Importer::SetIOHandler( IOSystem* pIOHandler)
{
	// If the new handler is zero, allocate a default IO implementation.
	if (!pIOHandler)
	{
		// Release pointer in the possession of the caller
		// delete mIOHandler; 
		mIOHandler = new DefaultIOSystem();
		mIsDefaultHandler = true;
	}
	// Otherwise register the custom handler
	else if (mIOHandler != pIOHandler)
	{
		delete mIOHandler;
		mIOHandler = pIOHandler;
		mIsDefaultHandler = false;
	}
	return;
}

// ------------------------------------------------------------------------------------------------
IOSystem* Importer::GetIOHandler()
{
	return mIOHandler;
}

// ------------------------------------------------------------------------------------------------
bool Importer::IsDefaultIOHandler()
{
	return mIsDefaultHandler;
}

// ------------------------------------------------------------------------------------------------
// Validate post process step flags 
bool _ValidateFlags(unsigned int pFlags)
{
	if (pFlags & aiProcess_GenSmoothNormals &&
		pFlags & aiProcess_GenNormals)
	{
		DefaultLogger::get()->error("aiProcess_GenSmoothNormals and "
			"aiProcess_GenNormals may not be specified together");
		return false;
	}
	return true;
}

// ------------------------------------------------------------------------------------------------
// Free the current scene
void Importer::FreeScene( )
{
	delete mScene;
	mScene = NULL;
}

// ------------------------------------------------------------------------------------------------
// Get the current error string, if any
const std::string& Importer::GetErrorString() const 
{ 
	return mErrorString;
}

// ------------------------------------------------------------------------------------------------
// Enable extra-verbose mode
void Importer::SetExtraVerbose(bool bDo)
{
	bExtraVerbose = bDo;
}

// ------------------------------------------------------------------------------------------------
// Get the current scene
const aiScene* Importer::GetScene() const
{
	return mScene;
}

// ------------------------------------------------------------------------------------------------
// Orphan the current scene
aiScene* Importer::GetOrphanedScene()
{
	aiScene* s = mScene;
	mScene = NULL;
	return s;
}

// ------------------------------------------------------------------------------------------------
// Validate post-processing flags
bool Importer::ValidateFlags(unsigned int pFlags)
{
	// run basic checks for mutually exclusive flags
	if(!_ValidateFlags(pFlags))
		return false;

	// ValidateDS does not anymore occur in the pp list, it plays
	// an awesome extra role ...
#ifdef AI_BUILD_NO_VALIDATEDS_PROCESS
	if (pFlags & aiProcess_ValidateDataStructure)
		return false;
#endif
	pFlags &= ~aiProcess_ValidateDataStructure;

	// Now iterate through all bits which are set in
	// the flags and check whether we find at least
	// one pp plugin which handles it.
	for (unsigned int mask = 1; mask < (1 << (sizeof(unsigned int)*8-1));mask <<= 1) {
		
		if (pFlags & mask) {
		
			bool have = false;
			for( unsigned int a = 0; a < mPostProcessingSteps.size(); a++)	{
				if (mPostProcessingSteps[a]-> IsActive(mask) ) {
				
					have = true;
					break;
				}
			}
			if (!have)
				return false;
		}
	}
	return true;
}

// ------------------------------------------------------------------------------------------------
// Reads the given file and returns its contents if successful. 
const aiScene* Importer::ReadFile( const char* _pFile, unsigned int pFlags)
{
	// In debug builds, run a basic flag validation
	ai_assert(_ValidateFlags(pFlags));

	const std::string pFile(_pFile);

	// ======================================================================
	// Put a large try block around everything to catch all std::exception's
	// that might be thrown by STL containers or by new(). 
	// ImportErrorException's are throw by ourselves and caught elsewhere.
	// ======================================================================
#ifdef ASSIMP_CATCH_GLOBAL_EXCEPTIONS
	try
#endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS
	{
		// Check whether this Importer instance has already loaded
		// a scene. In this case we need to delete the old one
		if (mScene)
		{
			DefaultLogger::get()->debug("Deleting previous scene");
			FreeScene();
		}

		// First check if the file is accessable at all
		if( !mIOHandler->Exists( pFile))
		{
			mErrorString = "Unable to open file \"" + pFile + "\".";
			DefaultLogger::get()->error(mErrorString);
			return NULL;
		}

		// Find an worker class which can handle the file
		BaseImporter* imp = NULL;
		for( unsigned int a = 0; a < mImporter.size(); a++)	{

			if( mImporter[a]->CanRead( pFile, mIOHandler, false)) {
				imp = mImporter[a];
				break;
			}
		}

		if (!imp)
		{
			// not so bad yet ... try format auto detection.
			std::string::size_type s = pFile.find_last_of('.');
			if (s != std::string::npos) {
				DefaultLogger::get()->info("File extension now known, trying signature-based detection");
				for( unsigned int a = 0; a < mImporter.size(); a++)	{

					if( mImporter[a]->CanRead( pFile, mIOHandler, true)) {
						imp = mImporter[a];
						break;
					}
				}
			}
			// Put a proper error message if no suitable importer was found
			if( !imp)
			{
				mErrorString = "No suitable reader found for the file format of file \"" + pFile + "\".";
				DefaultLogger::get()->error(mErrorString);
				return NULL;
			}
		}

		// Dispatch the reading to the worker class for this format
		DefaultLogger::get()->info("Found a matching importer for this file format");
		imp->SetupProperties( this );
		mScene = imp->ReadFile( pFile, mIOHandler);

		// If successful, apply all active post processing steps to the imported data
		if( mScene)
		{
#ifndef AI_BUILD_NO_VALIDATEDS_PROCESS
			// The ValidateDS process is an exception. It is executed first,
			// even before ScenePreprocessor is called.
			if (pFlags & aiProcess_ValidateDataStructure)
			{
				ValidateDSProcess ds;
				ds.ExecuteOnScene (this);
				if (!mScene)
					return NULL;
			}
#endif // no validation

			// Preprocess the scene 
			ScenePreprocessor pre(mScene);
			pre.ProcessScene();

			DefaultLogger::get()->info("Import successful, entering postprocessing-steps");
#ifdef _DEBUG
			if (bExtraVerbose)
			{
#ifndef AI_BUILD_NO_VALIDATEDS_PROCESS

				DefaultLogger::get()->error("Extra verbose mode not available, library"
					" wasn't build with the ValidateDS-Step");
#endif  // no validation


				pFlags |= aiProcess_ValidateDataStructure;
			}
#else
			if (bExtraVerbose)DefaultLogger::get()->warn("Not a debug build, ignoring extra verbose setting");
#endif // ! DEBUG
			for( unsigned int a = 0; a < mPostProcessingSteps.size(); a++)
			{
				BaseProcess* process = mPostProcessingSteps[a];
				if( process->IsActive( pFlags))
				{
					process->SetupProperties( this );
					process->ExecuteOnScene	( this );
				}
				if( !mScene)break; 
#ifdef _DEBUG

#ifndef AI_BUILD_NO_VALIDATEDS_PROCESS
				continue;
#endif  // no validation

				// If the extra verbose mode is active execute the
				// VaidateDataStructureStep again after each step
				if (bExtraVerbose)
				{
					DefaultLogger::get()->debug("Extra verbose: revalidating data structures");
					
					ValidateDSProcess ds; 
					ds.ExecuteOnScene (this);
					if( !mScene)
					{
						DefaultLogger::get()->error("Extra verbose: failed to revalidate data structures");
						break; 
					}
				}
#endif // ! DEBUG
			}
		}
		// if failed, extract the error string
		else if( !mScene)
			mErrorString = imp->GetErrorText();

		// clear any data allocated by post-process steps
		mPPShared->Clean();
	}
#ifdef ASSIMP_CATCH_GLOBAL_EXCEPTIONS
	catch (std::exception &e)
	{
#if (defined _MSC_VER) &&	(defined _CPPRTTI) 
		// if we have RTTI get the full name of the exception that occured
		mErrorString = std::string(typeid( e ).name()) + ": " + e.what();
#else
		mErrorString = std::string("std::exception: ") + e.what();
#endif

		DefaultLogger::get()->error(mErrorString);
		delete mScene;mScene = NULL;
	}
#endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS

	// either successful or failure - the pointer expresses it anyways
	return mScene;
}

// ------------------------------------------------------------------------------------------------
// Helper function to check whether an extension is supported by ASSIMP
bool Importer::IsExtensionSupported(const char* szExtension)
{
	return NULL != FindLoader(szExtension);
}

// ------------------------------------------------------------------------------------------------
BaseImporter* Importer::FindLoader (const char* _szExtension)
{
	const std::string szExtension(_szExtension);
	for (std::vector<BaseImporter*>::const_iterator
		i =  mImporter.begin();
		i != mImporter.end();++i)
	{
		// pass the file extension to the CanRead(..,NULL)-method
		if ((*i)->CanRead(szExtension,NULL,false))return *i;
	}
	return NULL;
}

// ------------------------------------------------------------------------------------------------
// Helper function to build a list of all file extensions supported by ASSIMP
void Importer::GetExtensionList(aiString& szOut)
{
	unsigned int iNum = 0;
	std::string tmp; // todo: Rewrite baseImporter::GetExtensionList to use aiString, too
	for (std::vector<BaseImporter*>::const_iterator
		i =  mImporter.begin();
		i != mImporter.end();++i,++iNum)
	{
		// Insert a comma as delimiter character
		// FIX: to take lazy loader implementations into account, we are
		// slightly more tolerant here than we'd need to be.
		if (0 != iNum && ';' != *(tmp.end()-1))
			tmp.append(";");

		(*i)->GetExtensionList(tmp);
	}
	szOut.Set(tmp);
	return;
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
void Importer::SetPropertyInteger(const char* szName, int iValue, 
	bool* bWasExisting /*= NULL*/)
{
	SetGenericProperty<int>(mIntProperties, szName,iValue,bWasExisting);	
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
void Importer::SetPropertyFloat(const char* szName, float iValue, 
	bool* bWasExisting /*= NULL*/)
{
	SetGenericProperty<float>(mFloatProperties, szName,iValue,bWasExisting);	
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
void Importer::SetPropertyString(const char* szName, const std::string& value, 
	bool* bWasExisting /*= NULL*/)
{
	SetGenericProperty<std::string>(mStringProperties, szName,value,bWasExisting);	
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
int Importer::GetPropertyInteger(const char* szName, 
	int iErrorReturn /*= 0xffffffff*/) const
{
	return GetGenericProperty<int>(mIntProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
float Importer::GetPropertyFloat(const char* szName, 
	float iErrorReturn /*= 10e10*/) const
{
	return GetGenericProperty<float>(mFloatProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
const std::string& Importer::GetPropertyString(const char* szName, 
	const std::string& iErrorReturn /*= ""*/) const
{
	return GetGenericProperty<std::string>(mStringProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get the memory requirements of a single node
inline void AddNodeWeight(unsigned int& iScene,const aiNode* pcNode)
{
	iScene += sizeof(aiNode);
	iScene += sizeof(unsigned int) * pcNode->mNumMeshes;
	iScene += sizeof(void*) * pcNode->mNumChildren;
	for (unsigned int i = 0; i < pcNode->mNumChildren;++i)
		AddNodeWeight(iScene,pcNode->mChildren[i]);
}

// ------------------------------------------------------------------------------------------------
// Get the memory requirements of the scene
void Importer::GetMemoryRequirements(aiMemoryInfo& in) const
{
	in = aiMemoryInfo();

	// return if we have no scene loaded
	if (!this->mScene)return;
	in.total = sizeof(aiScene);

	// add all meshes
	for (unsigned int i = 0; i < mScene->mNumMeshes;++i)
	{
		in.meshes += sizeof(aiMesh);
		if (mScene->mMeshes[i]->HasPositions())
			in.meshes += sizeof(aiVector3D) * mScene->mMeshes[i]->mNumVertices;

		if (mScene->mMeshes[i]->HasNormals())
			in.meshes += sizeof(aiVector3D) * mScene->mMeshes[i]->mNumVertices;

		if (mScene->mMeshes[i]->HasTangentsAndBitangents())
			in.meshes += sizeof(aiVector3D) * mScene->mMeshes[i]->mNumVertices * 2;

		for (unsigned int a = 0; a < AI_MAX_NUMBER_OF_COLOR_SETS;++a)
		{
			if (mScene->mMeshes[i]->HasVertexColors(a))
				in.meshes += sizeof(aiColor4D) * mScene->mMeshes[i]->mNumVertices;
			else break;
		}
		for (unsigned int a = 0; a < AI_MAX_NUMBER_OF_TEXTURECOORDS;++a)
		{
			if (mScene->mMeshes[i]->HasTextureCoords(a))
				in.meshes += sizeof(aiVector3D) * mScene->mMeshes[i]->mNumVertices;
			else break;
		}
		if (mScene->mMeshes[i]->HasBones())
		{
			in.meshes += sizeof(void*) * mScene->mMeshes[i]->mNumBones;
			for (unsigned int p = 0; p < mScene->mMeshes[i]->mNumBones;++p)
			{
				in.meshes += sizeof(aiBone);
				in.meshes += mScene->mMeshes[i]->mBones[p]->mNumWeights * sizeof(aiVertexWeight);
			}
		}
		in.meshes += (sizeof(aiFace) + 3 * sizeof(unsigned int))*mScene->mMeshes[i]->mNumFaces;
	}
    in.total += in.meshes;

	// add all embedded textures
	for (unsigned int i = 0; i < mScene->mNumTextures;++i)
	{
		const aiTexture* pc = mScene->mTextures[i];
		in.textures += sizeof(aiTexture);
		if (pc->mHeight)
		{
			in.textures += 4 * pc->mHeight * pc->mWidth;
		}
		else in.textures += pc->mWidth;
	}
	in.total += in.textures;

	// add all animations
	for (unsigned int i = 0; i < mScene->mNumAnimations;++i)
	{
		const aiAnimation* pc = mScene->mAnimations[i];
		in.animations += sizeof(aiAnimation);

		// add all bone anims
		for (unsigned int a = 0; a < pc->mNumChannels; ++a)
		{
			const aiNodeAnim* pc2 = pc->mChannels[i];
			in.animations += sizeof(aiNodeAnim);
			in.animations += pc2->mNumPositionKeys * sizeof(aiVectorKey);
			in.animations += pc2->mNumScalingKeys * sizeof(aiVectorKey);
			in.animations += pc2->mNumRotationKeys * sizeof(aiQuatKey);
		}
	}
	in.total += in.animations;

	// add all cameras and all lights
	in.total += in.cameras = sizeof(aiCamera) *  mScene->mNumCameras;
	in.total += in.lights  = sizeof(aiLight)  *  mScene->mNumLights;

	// add all nodes
	AddNodeWeight(in.nodes,mScene->mRootNode);
	in.total += in.nodes;

	// add all materials
	for (unsigned int i = 0; i < mScene->mNumMaterials;++i)
	{
		const aiMaterial* pc = mScene->mMaterials[i];
		in.materials += sizeof(aiMaterial);
		in.materials += pc->mNumAllocated * sizeof(void*);
		for (unsigned int a = 0; a < pc->mNumProperties;++a)
		{
			in.materials += pc->mProperties[a]->mDataLength;
		}
	}
	in.total += in.materials;
}