Importer.cpp

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

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All rights reserved.

Redistribution and use of this software in source and binary forms,
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* Redistributions of source code must retain the above
  copyright notice, this list of conditions and the
  following disclaimer.

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  copyright notice, this list of conditions and the
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  derived from this software without specific prior
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*/

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

#include <assimp/version.h>
#include <assimp/config.h>
#include <assimp/importerdesc.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 "Common/Importer.h"
#include "Common/BaseProcess.h"
#include "Common/DefaultProgressHandler.h"
#include "PostProcessing/ProcessHelper.h"
#include "Common/ScenePreprocessor.h"
#include "Common/ScenePrivate.h"

#include <assimp/BaseImporter.h>
#include <assimp/GenericProperty.h>
#include <assimp/MemoryIOWrapper.h>
#include <assimp/Profiler.h>
#include <assimp/TinyFormatter.h>
#include <assimp/Exceptional.h>
#include <assimp/Profiler.h>
#include <assimp/commonMetaData.h>

#include <exception>
#include <set>
#include <memory>
#include <cctype>

#include <assimp/DefaultIOStream.h>
#include <assimp/DefaultIOSystem.h>

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

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

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

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 nullptr;
    }
}

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

// ------------------------------------------------------------------------------------------------
// Importer constructor.
Importer::Importer()
 : pimpl( new ImporterPimpl ) {
    pimpl->mScene = nullptr;
    pimpl->mErrorString = std::string();

    // 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
	DeleteImporterInstanceList(pimpl->mImporter);

    // 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. Destructor's should do that recursively
    delete pimpl->mScene;

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

    // and finally the pimpl itself
    delete pimpl;
}

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

    ASSIMP_BEGIN_EXCEPTION_REGION();

        pimpl->mPostProcessingSteps.push_back(pImp);
        ASSIMP_LOG_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(nullptr != 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 ASSIMP_BUILD_DEBUG
        if (IsExtensionSupported(*it)) {
            ASSIMP_LOG_WARN("The file extension ", *it, " is already in use");
        }
#endif
        baked += *it;
    }

    // add the loader
    pimpl->mImporter.push_back(pImp);
    ASSIMP_LOG_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 nullptr 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);
        ASSIMP_LOG_INFO("Unregistering custom importer: ");
        return AI_SUCCESS;
    }
    ASSIMP_LOG_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 nullptr 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);
        ASSIMP_LOG_INFO("Unregistering custom post-processing step");
        return AI_SUCCESS;
    }
    ASSIMP_LOG_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) {
    ai_assert(nullptr != pimpl);

    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;
    } else if (pimpl->mIOHandler != pIOHandler) { // Otherwise register the custom handler
        delete pimpl->mIOHandler;
        pimpl->mIOHandler = pIOHandler;
        pimpl->mIsDefaultHandler = false;
    }
    ASSIMP_END_EXCEPTION_REGION(void);
}

// ------------------------------------------------------------------------------------------------
// Get the currently set IO handler
IOSystem* Importer::GetIOHandler() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mIOHandler;
}

// ------------------------------------------------------------------------------------------------
// Check whether a custom IO handler is currently set
bool Importer::IsDefaultIOHandler() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mIsDefaultHandler;
}

// ------------------------------------------------------------------------------------------------
// Supplies a custom progress handler to get regular callbacks during importing
void Importer::SetProgressHandler ( ProgressHandler* pHandler ) {
    ai_assert(nullptr != pimpl);

    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;
    } else if (pimpl->mProgressHandler != pHandler) { // Otherwise register the custom handler
        delete pimpl->mProgressHandler;
        pimpl->mProgressHandler = pHandler;
        pimpl->mIsDefaultProgressHandler = false;
    }
    ASSIMP_END_EXCEPTION_REGION(void);
}

// ------------------------------------------------------------------------------------------------
// Get the currently set progress handler
ProgressHandler* Importer::GetProgressHandler() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mProgressHandler;
}

// ------------------------------------------------------------------------------------------------
// Check whether a custom progress handler is currently set
bool Importer::IsDefaultProgressHandler() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mIsDefaultProgressHandler;
}

// ------------------------------------------------------------------------------------------------
// Validate post process step flags
bool _ValidateFlags(unsigned int pFlags) {
    if (pFlags & aiProcess_GenSmoothNormals && pFlags & aiProcess_GenNormals)   {
        ASSIMP_LOG_ERROR("#aiProcess_GenSmoothNormals and #aiProcess_GenNormals are incompatible");
        return false;
    }
    if (pFlags & aiProcess_OptimizeGraph && pFlags & aiProcess_PreTransformVertices)    {
        ASSIMP_LOG_ERROR("#aiProcess_OptimizeGraph and #aiProcess_PreTransformVertices are incompatible");
        return false;
    }
    return true;
}

// ------------------------------------------------------------------------------------------------
// Free the current scene
void Importer::FreeScene( ) {
    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    delete pimpl->mScene;
    pimpl->mScene = nullptr;

    pimpl->mErrorString = std::string();
    pimpl->mException = std::exception_ptr();
    ASSIMP_END_EXCEPTION_REGION(void);
}

// ------------------------------------------------------------------------------------------------
// Get the current error string, if any
const char* Importer::GetErrorString() const {
    ai_assert(nullptr != pimpl);

    // Must remain valid as long as ReadFile() or FreeFile() are not called
    return pimpl->mErrorString.c_str();
}

const std::exception_ptr& Importer::GetException() const {
    ai_assert(nullptr != pimpl);

    // Must remain valid as long as ReadFile() or FreeFile() are not called
    return pimpl->mException;
}

// ------------------------------------------------------------------------------------------------
// Enable extra-verbose mode
void Importer::SetExtraVerbose(bool bDo) {
    ai_assert(nullptr != pimpl);

    pimpl->bExtraVerbose = bDo;
}

// ------------------------------------------------------------------------------------------------
// Get the current scene
const aiScene* Importer::GetScene() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mScene;
}

// ------------------------------------------------------------------------------------------------
// Orphan the current scene and return it.
aiScene* Importer::GetOrphanedScene() {
    ai_assert(nullptr != pimpl);

    aiScene* s = pimpl->mScene;

    ASSIMP_BEGIN_EXCEPTION_REGION();
    pimpl->mScene = nullptr;

    pimpl->mErrorString = std::string();
    pimpl->mException = std::exception_ptr();
    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 /*= ""*/) {
    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();
    if (!pHint) {
        pHint = "";
    }

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

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

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

    // read the file and recover the previous IOSystem
    static const size_t BufSize(Importer::MaxLenHint + 28);
    char fbuff[BufSize];
    ai_snprintf(fbuff, BufSize, "%s.%s",AI_MEMORYIO_MAGIC_FILENAME,pHint);

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

    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString, pimpl->mException);
    return pimpl->mScene;
}

// ------------------------------------------------------------------------------------------------
void WriteLogOpening(const std::string& file) {

    ASSIMP_LOG_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();
    std::stringstream stream;
    stream << "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"
#elif defined(__clang__)
           << "clang"
#elif defined(__EMSCRIPTEN__)
           << "emscripten"
#elif defined(__MINGW32__)
           << "MinGW-w64 32bit"
#elif defined(__MINGW64__)
           << "MinGW-w64 64bit"
#else
           << "<unknown compiler>"
#endif

#ifdef ASSIMP_BUILD_DEBUG
           << " debug"
#endif

           << (flags & ASSIMP_CFLAGS_NOBOOST ? " noboost" : "")
           << (flags & ASSIMP_CFLAGS_SHARED ? " shared" : "")
           << (flags & ASSIMP_CFLAGS_SINGLETHREADED ? " singlethreaded" : "")
           << (flags & ASSIMP_CFLAGS_DOUBLE_SUPPORT ? " double : " : "single : ");

    ASSIMP_LOG_DEBUG(stream.str());
}

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

    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)  {

            ASSIMP_LOG_DEBUG("(Deleting previous scene)");
            FreeScene();
        }

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

            pimpl->mErrorString = "Unable to open file \"" + pFile + "\".";
            ASSIMP_LOG_ERROR(pimpl->mErrorString);
            return nullptr;
        }

        std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);
        if (profiler) {
            profiler->BeginRegion("total");
        }

        // Find an worker class which can handle the file
        BaseImporter* imp = nullptr;
        SetPropertyInteger("importerIndex", -1);
        for( unsigned int a = 0; a < pimpl->mImporter.size(); a++)  {

            if( pimpl->mImporter[a]->CanRead( pFile, pimpl->mIOHandler, false)) {
                imp = pimpl->mImporter[a];
                SetPropertyInteger("importerIndex", 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) {
                ASSIMP_LOG_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];
                        SetPropertyInteger("importerIndex", 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 + "\".";
                ASSIMP_LOG_ERROR(pimpl->mErrorString);
                return nullptr;
            }
        }

        // Get file size for progress handler
        IOStream * fileIO = pimpl->mIOHandler->Open( pFile );
        uint32_t fileSize = 0;
        if (fileIO)
        {
            fileSize = static_cast<uint32_t>(fileIO->FileSize());
            pimpl->mIOHandler->Close( fileIO );
        }

        // Dispatch the reading to the worker class for this format
        const aiImporterDesc *desc( imp->GetInfo() );
        std::string ext( "unknown" );
        if ( nullptr != desc ) {
            ext = desc->mName;
        }
        ASSIMP_LOG_INFO("Found a matching importer for this file format: ", ext, "." );
        pimpl->mProgressHandler->UpdateFileRead( 0, fileSize );

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

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

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

        SetPropertyString("sourceFilePath", pFile);

        // If successful, apply all active post processing steps to the imported data
        if( pimpl->mScene)  {
            if (!pimpl->mScene->mMetaData || !pimpl->mScene->mMetaData->HasKey(AI_METADATA_SOURCE_FORMAT)) {
                if (!pimpl->mScene->mMetaData) {
                    pimpl->mScene->mMetaData = new aiMetadata;
                }
                pimpl->mScene->mMetaData->Add(AI_METADATA_SOURCE_FORMAT, aiString(ext));
            }

#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 nullptr;
                }
            }
#endif // no validation

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

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

            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();
            pimpl->mException = imp->GetException();
        }

        // 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 occurred
        pimpl->mErrorString = std::string(typeid( e ).name()) + ": " + e.what();
#else
        pimpl->mErrorString = std::string("std::exception: ") + e.what();
#endif

        ASSIMP_LOG_ERROR(pimpl->mErrorString);
        delete pimpl->mScene; pimpl->mScene = nullptr;
    }
#endif // ! ASSIMP_CATCH_GLOBAL_EXCEPTIONS

    // either successful or failure - the pointer expresses it anyways
    ASSIMP_END_EXCEPTION_REGION_WITH_ERROR_STRING(const aiScene*, pimpl->mErrorString, pimpl->mException);

    return pimpl->mScene;
}


// ------------------------------------------------------------------------------------------------
// Apply post-processing to the currently bound scene
const aiScene* Importer::ApplyPostProcessing(unsigned int pFlags) {
    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();
    // Return immediately if no scene is active
    if (!pimpl->mScene) {
        return nullptr;
    }

    // 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));
    ASSIMP_LOG_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 nullptr;
        }
    }
#endif // no validation
#ifdef ASSIMP_BUILD_DEBUG
    if (pimpl->bExtraVerbose)
    {
#ifdef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
        ASSIMP_LOG_ERROR("Verbose Import is not available due to build settings");
#endif  // no validation
        pFlags |= aiProcess_ValidateDataStructure;
    }
#else
    if (pimpl->bExtraVerbose) {
        ASSIMP_LOG_WARN("Not a debug build, ignoring extra verbose setting");
    }
#endif // ! DEBUG

    std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);
    for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++)   {
        BaseProcess* process = pimpl->mPostProcessingSteps[a];
        pimpl->mProgressHandler->UpdatePostProcess(static_cast<int>(a), static_cast<int>(pimpl->mPostProcessingSteps.size()) );
        if( process->IsActive( pFlags)) {
            if (profiler) {
                profiler->BeginRegion("postprocess");
            }

            process->ExecuteOnScene ( this );

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

#ifdef 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)   {
            ASSIMP_LOG_DEBUG("Verbose Import: re-validating data structures");

            ValidateDSProcess ds;
            ds.ExecuteOnScene (this);
            if( !pimpl->mScene) {
                ASSIMP_LOG_ERROR("Verbose Import: failed to re-validate data structures");
                break;
            }
        }
#endif // ! DEBUG
    }
    pimpl->mProgressHandler->UpdatePostProcess( static_cast<int>(pimpl->mPostProcessingSteps.size()),
        static_cast<int>(pimpl->mPostProcessingSteps.size()) );

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

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

    ASSIMP_END_EXCEPTION_REGION(const aiScene*);

    return pimpl->mScene;
}

// ------------------------------------------------------------------------------------------------
const aiScene* Importer::ApplyCustomizedPostProcessing( BaseProcess *rootProcess, bool requestValidation ) {
    ai_assert(nullptr != pimpl);

    ASSIMP_BEGIN_EXCEPTION_REGION();

    // Return immediately if no scene is active
    if ( nullptr == pimpl->mScene ) {
        return nullptr;
    }

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

    // In debug builds: run basic flag validation
    ASSIMP_LOG_INFO( "Entering customized 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 ( requestValidation )
    {
        ValidateDSProcess ds;
        ds.ExecuteOnScene( this );
        if ( !pimpl->mScene ) {
            return nullptr;
        }
    }
#endif // no validation
#ifdef ASSIMP_BUILD_DEBUG
    if ( pimpl->bExtraVerbose )
    {
#ifdef ASSIMP_BUILD_NO_VALIDATEDS_PROCESS
        ASSIMP_LOG_ERROR( "Verbose Import is not available due to build settings" );
#endif  // no validation
    }
#else
    if ( pimpl->bExtraVerbose ) {
        ASSIMP_LOG_WARN( "Not a debug build, ignoring extra verbose setting" );
    }
#endif // ! DEBUG

    std::unique_ptr<Profiler> profiler(GetPropertyInteger(AI_CONFIG_GLOB_MEASURE_TIME, 0) ? new Profiler() : nullptr);

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

    rootProcess->ExecuteOnScene( this );

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

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

        ValidateDSProcess ds;
        ds.ExecuteOnScene( this );
        if ( !pimpl->mScene ) {
            ASSIMP_LOG_ERROR( "Verbose Import: failed to revalidate data structures" );
        }
    }

    // clear any data allocated by post-process steps
    pimpl->mPPShared->Clean();
    ASSIMP_LOG_INFO( "Leaving customized 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 nullptr != GetImporter(szExtension);
}

// ------------------------------------------------------------------------------------------------
size_t Importer::GetImporterCount() const {
    ai_assert(nullptr != pimpl);

    return pimpl->mImporter.size();
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc* Importer::GetImporterInfo(size_t index) const {
    ai_assert(nullptr != pimpl);

    if (index >= pimpl->mImporter.size()) {
        return nullptr;
    }
    return pimpl->mImporter[index]->GetInfo();
}


// ------------------------------------------------------------------------------------------------
BaseImporter* Importer::GetImporter (size_t index) const {
    ai_assert(nullptr != pimpl);

    if (index >= pimpl->mImporter.size()) {
        return nullptr;
    }
    return pimpl->mImporter[index];
}

// ------------------------------------------------------------------------------------------------
// Find a loader plugin for a given file extension
BaseImporter* Importer::GetImporter (const char* szExtension) const {
    ai_assert(nullptr != pimpl);

    return GetImporter(GetImporterIndex(szExtension));
}

// ------------------------------------------------------------------------------------------------
// Find a loader plugin for a given file extension
size_t Importer::GetImporterIndex (const char* szExtension) const {
    ai_assert(nullptr != pimpl);
    ai_assert(nullptr != szExtension);

    ASSIMP_BEGIN_EXCEPTION_REGION();

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

    std::string ext(szExtension);
    if (ext.empty()) {
        return static_cast<size_t>(-1);
    }
    ext = ai_tolower(ext);
    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 std::distance(static_cast< std::vector<BaseImporter*>::const_iterator >(pimpl->mImporter.begin()), i);
            }
        }
    }
    ASSIMP_END_EXCEPTION_REGION(size_t);
    return static_cast<size_t>(-1);
}

// ------------------------------------------------------------------------------------------------
// Helper function to build a list of all file extensions supported by ASSIMP
void Importer::GetExtensionList(aiString& szOut) const {
    ai_assert(nullptr != pimpl);

    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);
    }

	// List can be empty
	if( !str.empty() ) {
		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
bool Importer::SetPropertyInteger(const char* szName, int iValue) {
    ai_assert(nullptr != pimpl);

    bool existing;
    ASSIMP_BEGIN_EXCEPTION_REGION();
        existing = SetGenericProperty<int>(pimpl->mIntProperties, szName,iValue);
    ASSIMP_END_EXCEPTION_REGION(bool);
    return existing;
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool Importer::SetPropertyFloat(const char* szName, ai_real iValue) {
    ai_assert(nullptr != pimpl);

    bool existing;
    ASSIMP_BEGIN_EXCEPTION_REGION();
        existing = SetGenericProperty<ai_real>(pimpl->mFloatProperties, szName,iValue);
    ASSIMP_END_EXCEPTION_REGION(bool);
    return existing;
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool Importer::SetPropertyString(const char* szName, const std::string& value) {
    ai_assert(nullptr != pimpl);

    bool existing;
    ASSIMP_BEGIN_EXCEPTION_REGION();
        existing = SetGenericProperty<std::string>(pimpl->mStringProperties, szName,value);
    ASSIMP_END_EXCEPTION_REGION(bool);
    return existing;
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool Importer::SetPropertyMatrix(const char* szName, const aiMatrix4x4& value) {
    ai_assert(nullptr != pimpl);

    bool existing;
    ASSIMP_BEGIN_EXCEPTION_REGION();
        existing = SetGenericProperty<aiMatrix4x4>(pimpl->mMatrixProperties, szName,value);
    ASSIMP_END_EXCEPTION_REGION(bool);
    return existing;
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool Importer::SetPropertyPointer(const char* szName, void* value) {
    ai_assert(nullptr != pimpl);
    
    bool existing;
    ASSIMP_BEGIN_EXCEPTION_REGION();
        existing = SetGenericProperty<void*>(pimpl->mPointerProperties, szName,value);
    ASSIMP_END_EXCEPTION_REGION(bool);
    return existing;
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
int Importer::GetPropertyInteger(const char* szName, int iErrorReturn /*= 0xffffffff*/) const {
    ai_assert(nullptr != pimpl);

    return GetGenericProperty<int>(pimpl->mIntProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
ai_real Importer::GetPropertyFloat(const char* szName, ai_real iErrorReturn /*= 10e10*/) const {
    ai_assert(nullptr != pimpl);

    return GetGenericProperty<ai_real>(pimpl->mFloatProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
std::string Importer::GetPropertyString(const char* szName, const std::string& iErrorReturn /*= ""*/) const {
    ai_assert(nullptr != pimpl);

    return GetGenericProperty<std::string>(pimpl->mStringProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
aiMatrix4x4 Importer::GetPropertyMatrix(const char* szName, const aiMatrix4x4& iErrorReturn /*= aiMatrix4x4()*/) const {
    ai_assert(nullptr != pimpl);

    return GetGenericProperty<aiMatrix4x4>(pimpl->mMatrixProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get a configuration property
void* Importer::GetPropertyPointer(const char* szName, void* iErrorReturn /*= nullptr*/) const {
    ai_assert(nullptr != pimpl);
    
    return GetGenericProperty<void*>(pimpl->mPointerProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Get the memory requirements of a single node
inline
void AddNodeWeight(unsigned int& iScene,const aiNode* pcNode) {
    if ( nullptr == pcNode ) {
        return;
    }
    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 {
    ai_assert(nullptr != pimpl);

    in = aiMemoryInfo();
    aiScene* mScene = pimpl->mScene;

    // return if we have no scene loaded
    if (!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[a];
            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;
}