assimp/code/Importer.cpp

/*
---------------------------------------------------------------------------
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
  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  Importer.cpp
 *  @brief Implementation of the CPP-API class #Importer
 */

#include "AssimpPCH.h"
#include "../include/aiVersion.h"

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

// ------------------------------------------------------------------------------------------------
// Internal headers
// ------------------------------------------------------------------------------------------------
#include "Importer.h"
#include "BaseProcess.h"

#include "DefaultIOStream.h"
#include "DefaultIOSystem.h"
#include "DefaultProgressHandler.h"
#include "GenericProperty.h"
#include "ProcessHelper.h"
#include "ScenePreprocessor.h"
#include "MemoryIOWrapper.h"
#include "Profiler.h"
#include "TinyFormatter.h"

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
#	include "ValidateDataStructure.h"
#endif

using namespace Assimp::Profiling;
using namespace Assimp::Formatter;

namespace Assimp {
	// ImporterRegistry.cpp
	void GetImporterInstanceList(std::vector< BaseImporter* >& out);
	// PostStepRegistry.cpp
	void GetPostProcessingStepInstanceList(std::vector< BaseProcess* >& out);
}

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.
// See http://www.gotw.ca/publications/mill15.htm
// ------------------------------------------------------------------------------------------------
void* AllocateFromAssimpHeap::operator new ( size_t num_bytes)	{
	return ::operator new(num_bytes);
}

void* AllocateFromAssimpHeap::operator new ( size_t num_bytes, const std::nothrow_t& ) throw()	{
	try	{
		return AllocateFromAssimpHeap::operator new( num_bytes );
	}
	catch( ... )	{
		return NULL;
	}
}

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 new[] ( size_t num_bytes, const std::nothrow_t& ) throw() {
	try	{
		return AllocateFromAssimpHeap::operator new[]( num_bytes );
	}
	catch( ... )	{
		return NULL;
	}
}

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

// ------------------------------------------------------------------------------------------------
// Importer constructor. 
Importer::Importer() 
{
	// allocate the pimpl first
	pimpl = new ImporterPimpl();

	pimpl->mScene = NULL;
	pimpl->mErrorString = "";

	// Allocate a default IO handler
	pimpl->mIOHandler = new DefaultIOSystem;
	pimpl->mIsDefaultHandler = true; 
	pimpl->bExtraVerbose     = false; // disable extra verbose mode by default

	pimpl->mProgressHandler = new DefaultProgressHandler();
	pimpl->mIsDefaultProgressHandler = true;

	GetImporterInstanceList(pimpl->mImporter);
	GetPostProcessingStepInstanceList(pimpl->mPostProcessingSteps);

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

		(*it)->SetSharedData(pimpl->mPPShared);
	}
}

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

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

	// Delete the assigned IO and progress handler
	delete pimpl->mIOHandler;
	delete pimpl->mProgressHandler;

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

	// Delete shared post-processing data
	delete pimpl->mPPShared;

	// and finally the pimpl itself
	delete pimpl;
}

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

	pimpl->mIntProperties    = other.pimpl->mIntProperties;
	pimpl->mFloatProperties  = other.pimpl->mFloatProperties;
	pimpl->mStringProperties = other.pimpl->mStringProperties;
}

// ------------------------------------------------------------------------------------------------
// Register a custom post-processing step
aiReturn Importer::RegisterPPStep(BaseProcess* pImp)
{
	ai_assert(NULL != pImp);
	ASSIMP_BEGIN_EXCEPTION_REGION();

		pimpl->mPostProcessingSteps.push_back(pImp);
		DefaultLogger::get()->info("Registering custom post-processing step");
	
	ASSIMP_END_EXCEPTION_REGION(aiReturn);
	return AI_SUCCESS;
}

// ------------------------------------------------------------------------------------------------
// Register a custom loader plugin
aiReturn Importer::RegisterLoader(BaseImporter* pImp)
{
	ai_assert(NULL != pImp);
	ASSIMP_BEGIN_EXCEPTION_REGION();

	// --------------------------------------------------------------------
	// 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 probably never be called if the first 
	// loader is a bit too lazy in his file checking.
	// --------------------------------------------------------------------
	std::set<std::string> st;
	std::string baked;
	pImp->GetExtensionList(st);

	for(std::set<std::string>::const_iterator it = st.begin(); it != st.end(); ++it) {

#ifdef _DEBUG
		if (IsExtensionSupported(*it)) {
			DefaultLogger::get()->warn("The file extension " + *it + " is already in use");
		}
#endif
		baked += *it;
	}

	// add the loader
	pimpl->mImporter.push_back(pImp);
	DefaultLogger::get()->info("Registering custom importer for these file extensions: " + baked);
	ASSIMP_END_EXCEPTION_REGION(aiReturn);
	return AI_SUCCESS;
}

// ------------------------------------------------------------------------------------------------
// Unregister a custom loader plugin
aiReturn Importer::UnregisterLoader(BaseImporter* pImp)
{
	if(!pImp) {
		// unregistering a NULL importer is no problem for us ... really!
		return AI_SUCCESS;
	}

	ASSIMP_BEGIN_EXCEPTION_REGION();
	std::vector<BaseImporter*>::iterator it = std::find(pimpl->mImporter.begin(),
		pimpl->mImporter.end(),pImp);

	if (it != pimpl->mImporter.end())	{
		pimpl->mImporter.erase(it);

		std::set<std::string> st;
		pImp->GetExtensionList(st);

		DefaultLogger::get()->info("Unregistering custom importer: ");
		return AI_SUCCESS;
	}
	DefaultLogger::get()->warn("Unable to remove custom importer: I can't find you ...");
	ASSIMP_END_EXCEPTION_REGION(aiReturn);
	return AI_FAILURE;
}

// ------------------------------------------------------------------------------------------------
// Unregister a custom loader plugin
aiReturn Importer::UnregisterPPStep(BaseProcess* pImp)
{
	if(!pImp) {
		// unregistering a NULL ppstep is no problem for us ... really!
		return AI_SUCCESS;
	}

	ASSIMP_BEGIN_EXCEPTION_REGION();
	std::vector<BaseProcess*>::iterator it = std::find(pimpl->mPostProcessingSteps.begin(),
		pimpl->mPostProcessingSteps.end(),pImp);

	if (it != pimpl->mPostProcessingSteps.end())	{
		pimpl->mPostProcessingSteps.erase(it);
		DefaultLogger::get()->info("Unregistering custom post-processing step");
		return AI_SUCCESS;
	}
	DefaultLogger::get()->warn("Unable to remove custom post-processing step: I can't find you ..");
	ASSIMP_END_EXCEPTION_REGION(aiReturn);
	return AI_FAILURE;
}

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

// ------------------------------------------------------------------------------------------------
// Get the currently set IO handler
IOSystem* Importer::GetIOHandler() const
{
	return pimpl->mIOHandler;
}

// ------------------------------------------------------------------------------------------------
// Check whether a custom IO handler is currently set
bool Importer::IsDefaultIOHandler() const
{
	return pimpl->mIsDefaultHandler;
}

// ------------------------------------------------------------------------------------------------
// Supplies a custom progress handler to get regular callbacks during importing
void Importer::SetProgressHandler ( ProgressHandler* pHandler )
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	// If the new handler is zero, allocate a default implementation.
	if (!pHandler)
	{
		// Release pointer in the possession of the caller
		pimpl->mProgressHandler = new DefaultProgressHandler();
		pimpl->mIsDefaultProgressHandler = true;
	}
	// Otherwise register the custom handler
	else if (pimpl->mProgressHandler != pHandler)
	{
		delete pimpl->mProgressHandler;
		pimpl->mProgressHandler = pHandler;
		pimpl->mIsDefaultProgressHandler = false;
	}
	ASSIMP_END_EXCEPTION_REGION(void);
}

// ------------------------------------------------------------------------------------------------
// Get the currently set progress handler
ProgressHandler* Importer::GetProgressHandler() const
{
	return pimpl->mProgressHandler;
}

// ------------------------------------------------------------------------------------------------
// Check whether a custom progress handler is currently set
bool Importer::IsDefaultProgressHandler() const
{
	return pimpl->mIsDefaultProgressHandler;
}

// ------------------------------------------------------------------------------------------------
// 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 are incompatible");
		return false;
	}
	if (pFlags & aiProcess_OptimizeGraph && pFlags & aiProcess_PreTransformVertices)	{
		DefaultLogger::get()->error("#aiProcess_OptimizeGraph and #aiProcess_PreTransformVertices are incompatible");
		return false;
	}
	return true;
}

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

	pimpl->mErrorString = "";
	ASSIMP_END_EXCEPTION_REGION(void);
}

// ------------------------------------------------------------------------------------------------
// Get the current error string, if any
const char* Importer::GetErrorString() const 
{ 
	 /* Must remain valid as long as ReadFile() or FreeFile() are not called */
	return pimpl->mErrorString.c_str();
}

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

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

// ------------------------------------------------------------------------------------------------
// Orphan the current scene and return it.
aiScene* Importer::GetOrphanedScene()
{
	aiScene* s = pimpl->mScene;

	ASSIMP_BEGIN_EXCEPTION_REGION();
	pimpl->mScene = NULL;

	pimpl->mErrorString = ""; /* reset error string */
	ASSIMP_END_EXCEPTION_REGION(aiScene*);
	return s;
}

// ------------------------------------------------------------------------------------------------
// Validate post-processing flags
bool Importer::ValidateFlags(unsigned int pFlags) const
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	// 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 ASSIMP_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 < (1u << (sizeof(unsigned int)*8-1));mask <<= 1) {
		
		if (pFlags & mask) {
		
			bool have = false;
			for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++)	{
				if (pimpl->mPostProcessingSteps[a]-> IsActive(mask) ) {
				
					have = true;
					break;
				}
			}
			if (!have) {
				return false;
			}
		}
	}
	ASSIMP_END_EXCEPTION_REGION(bool);
	return true;
}

// ------------------------------------------------------------------------------------------------
const aiScene* Importer::ReadFileFromMemory( const void* pBuffer,
	size_t pLength,
	unsigned int pFlags,
	const char* pHint /*= ""*/)
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	if (!pHint) {
		pHint = "";
	}

	if (!pBuffer || !pLength || strlen(pHint) > 100) {
		pimpl->mErrorString = "Invalid parameters passed to ReadFileFromMemory()";
		return NULL;
	}

	// prevent deletion of the previous IOHandler
	IOSystem* io = pimpl->mIOHandler;
	pimpl->mIOHandler = NULL;

	SetIOHandler(new MemoryIOSystem((const uint8_t*)pBuffer,pLength));

	// read the file and recover the previous IOSystem
	char fbuff[128];
	sprintf(fbuff,"%s.%s",AI_MEMORYIO_MAGIC_FILENAME,pHint);

	ReadFile(fbuff,pFlags);
	SetIOHandler(io);

	ASSIMP_END_EXCEPTION_REGION(const aiScene*);
	return pimpl->mScene;
}

// ------------------------------------------------------------------------------------------------
void WriteLogOpening(const std::string& file)
{
	Logger* l = DefaultLogger::get();
	if (!l) {
		return;
	}
	l->info("Load " + file);

	// print a full version dump. This is nice because we don't
	// need to ask the authors of incoming bug reports for
	// the library version they're using - a log dump is
	// sufficient.
	const unsigned int flags = aiGetCompileFlags();
	l->debug(format()
		<< "Assimp "
		<< aiGetVersionMajor() 
		<< "." 
		<< aiGetVersionMinor() 
		<< "." 
		<< aiGetVersionRevision()

		<< " "
#if defined(ASSIMP_BUILD_ARCHITECTURE)
		<< ASSIMP_BUILD_ARCHITECTURE
#elif defined(_M_IX86) || defined(__x86_32__) || defined(__i386__)
		<< "x86"
#elif defined(_M_X64) || defined(__x86_64__) 
		<< "amd64"
#elif defined(_M_IA64) || defined(__ia64__)
		<< "itanium"
#elif defined(__ppc__) || defined(__powerpc__)
		<< "ppc32"
#elif defined(__powerpc64__)
		<< "ppc64"
#elif defined(__arm__)
		<< "arm"
#else
	<< "<unknown architecture>"
#endif

		<< " "
#if defined(ASSIMP_BUILD_COMPILER)
		<< ASSIMP_BUILD_COMPILER
#elif defined(_MSC_VER)
		<< "msvc"
#elif defined(__GNUC__)
		<< "gcc"
#else
		<< "<unknown compiler>"
#endif

#ifndef NDEBUG
		<< " debug"
#endif

		<< (flags & ASSIMP_CFLAGS_NOBOOST ? " noboost" : "")
		<< (flags & ASSIMP_CFLAGS_SHARED  ? " shared" : "")
		<< (flags & ASSIMP_CFLAGS_SINGLETHREADED  ? " singlethreaded" : "")
		);
}

// ------------------------------------------------------------------------------------------------
// Reads the given file and returns its contents if successful.
const aiScene* Importer::ReadFile( const char* _pFile, unsigned int pFlags)
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	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.
	//-----------------------------------------------------------------------

	WriteLogOpening(pFile);

#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 (pimpl->mScene)	{

			DefaultLogger::get()->debug("(Deleting previous scene)");
			FreeScene();
		}

		// First check if the file is accessable at all
		if( !pimpl->mIOHandler->Exists( pFile))	{

			pimpl->mErrorString = "Unable to open file \"" + pFile + "\".";
			DefaultLogger::get()->error(pimpl->mErrorString);
			return NULL;
		}

		boost::scoped_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME,0)?new Profiler():NULL);
		if (profiler) {
			profiler->BeginRegion("total");
		}

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

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

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

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

		// Dispatch the reading to the worker class for this format
		DefaultLogger::get()->info("Found a matching importer for this file format");
		pimpl->mProgressHandler->Update();

		if (profiler) {
			profiler->BeginRegion("import");
		}

		pimpl->mScene = imp->ReadFile( this, pFile, pimpl->mIOHandler);
		pimpl->mProgressHandler->Update();

		if (profiler) {
			profiler->EndRegion("import");
		}

		// If successful, apply all active post processing steps to the imported data
		if( pimpl->mScene)	{

#ifndef ASSIMP_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 (!pimpl->mScene) {
					return NULL;
				}
			}
#endif // no validation

			// Preprocess the scene and prepare it for post-processing 
			if (profiler) {
				profiler->BeginRegion("preprocess");
			}

			ScenePreprocessor pre(pimpl->mScene);
			pre.ProcessScene();

			pimpl->mProgressHandler->Update();
			if (profiler) {
				profiler->EndRegion("preprocess");
			}

			// Ensure that the validation process won't be called twice
			ApplyPostProcessing(pFlags & (~aiProcess_ValidateDataStructure));
		}
		// if failed, extract the error string
		else if( !pimpl->mScene) {
			pimpl->mErrorString = imp->GetErrorText();
		}

		// clear any data allocated by post-process steps
		pimpl->mPPShared->Clean();

		if (profiler) {
			profiler->EndRegion("total");
		}
	}
#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
		pimpl->mErrorString = std::string(typeid( e ).name()) + ": " + e.what();
#else
		pimpl->mErrorString = std::string("std::exception: ") + e.what();
#endif

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

	// either successful or failure - the pointer expresses it anyways
	ASSIMP_END_EXCEPTION_REGION(const aiScene*);
	return pimpl->mScene;
}


// ------------------------------------------------------------------------------------------------
// Apply post-processing to the currently bound scene
const aiScene* Importer::ApplyPostProcessing(unsigned int pFlags)
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	// Return immediately if no scene is active
	if (!pimpl->mScene) {
		return NULL;
	}

	// If no flags are given, return the current scene with no further action
	if (!pFlags) {
		return pimpl->mScene;
	}

	// In debug builds: run basic flag validation
	ai_assert(_ValidateFlags(pFlags));
	DefaultLogger::get()->info("Entering post processing pipeline");

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
	// The ValidateDS process plays an exceptional role. It isn't contained in the global
	// list of post-processing steps, so we need to call it manually.
	if (pFlags & aiProcess_ValidateDataStructure)
	{
		ValidateDSProcess ds;
		ds.ExecuteOnScene (this);
		if (!pimpl->mScene) {
			return NULL;
		}
	}
#endif // no validation
#ifdef _DEBUG
	if (pimpl->bExtraVerbose)
	{
#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
		DefaultLogger::get()->error("Verbose Import is not available due to build settings");
#endif  // no validation
		pFlags |= aiProcess_ValidateDataStructure;
	}
#else
	if (pimpl->bExtraVerbose) {
		DefaultLogger::get()->warn("Not a debug build, ignoring extra verbose setting");
	}
#endif // ! DEBUG

	boost::scoped_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME,0)?new Profiler():NULL);
	for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++)	{

		BaseProcess* process = pimpl->mPostProcessingSteps[a];
		if( process->IsActive( pFlags))	{

			if (profiler) {
				profiler->BeginRegion("postprocess");
			}

			process->ExecuteOnScene	( this );
			pimpl->mProgressHandler->Update();

			if (profiler) {
				profiler->EndRegion("postprocess");
			}
		}
		if( !pimpl->mScene) {
			break; 
		}
#ifdef _DEBUG

#ifndef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
		continue;
#endif  // no validation

		// If the extra verbose mode is active, execute the ValidateDataStructureStep again - after each step
		if (pimpl->bExtraVerbose)	{
			DefaultLogger::get()->debug("Verbose Import: revalidating data structures");

			ValidateDSProcess ds; 
			ds.ExecuteOnScene (this);
			if( !pimpl->mScene)	{
				DefaultLogger::get()->error("Verbose Import: failed to revalidate data structures");
				break; 
			}
		}
#endif // ! DEBUG
	}

	// update private scene flags
	ScenePriv(pimpl->mScene)->mPPStepsApplied |= pFlags;

	// clear any data allocated by post-process steps
	pimpl->mPPShared->Clean();
	DefaultLogger::get()->info("Leaving post processing pipeline");

	ASSIMP_END_EXCEPTION_REGION(const aiScene*);
	return pimpl->mScene;
}

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

// ------------------------------------------------------------------------------------------------
// Find a loader plugin for a given file extension
BaseImporter* Importer::FindLoader (const char* szExtension) const
{
	ai_assert(szExtension);
	ASSIMP_BEGIN_EXCEPTION_REGION();

	// skip over wildcard and dot characters at string head --
	for(;*szExtension == '*' || *szExtension == '.'; ++szExtension);

	std::string ext(szExtension);
	if (ext.empty()) {
		return NULL;
	}
	std::transform(ext.begin(),ext.end(), ext.begin(), tolower);

	std::set<std::string> str;
	for (std::vector<BaseImporter*>::const_iterator i =  pimpl->mImporter.begin();i != pimpl->mImporter.end();++i)	{
		str.clear();

		(*i)->GetExtensionList(str);
		for (std::set<std::string>::const_iterator it = str.begin(); it != str.end(); ++it) {
			if (ext == *it) {
				return (*i);
			}
		}
	}
	ASSIMP_END_EXCEPTION_REGION(BaseImporter*);
	return NULL;
}

// ------------------------------------------------------------------------------------------------
// Helper function to build a list of all file extensions supported by ASSIMP
void Importer::GetExtensionList(aiString& szOut) const
{
	ASSIMP_BEGIN_EXCEPTION_REGION();
	std::set<std::string> str;
	for (std::vector<BaseImporter*>::const_iterator i =  pimpl->mImporter.begin();i != pimpl->mImporter.end();++i)	{
		(*i)->GetExtensionList(str);
	}

	for (std::set<std::string>::const_iterator it = str.begin();; ) {
		szOut.Append("*.");
		szOut.Append((*it).c_str());

		if (++it == str.end()) {
			break;
		}
		szOut.Append(";");
	}
	ASSIMP_END_EXCEPTION_REGION(void);
}

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

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

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

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

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

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

	// return if we have no scene loaded
	if (!pimpl->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;
}