assimp/code/Exporter.cpp

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

/** @file Exporter.cpp

Assimp export interface. While it's public interface bears many similarities
to the import interface (in fact, it is largely symmetric), the internal
implementations differs a lot. Exporters are considered stateless and are
simple callbacks which we maintain in a global list along with their
description strings.

Here we implement only the C++ interface (Assimp::Exporter).
*/

#ifndef ASSIMP_BUILD_NO_EXPORT

#include "DefaultIOSystem.h"
#include "BlobIOSystem.h"
#include "SceneCombiner.h"
#include "BaseProcess.h"
#include "Importer.h" // need this for GetPostProcessingStepInstanceList()

#include "JoinVerticesProcess.h"
#include "MakeVerboseFormat.h"
#include "ConvertToLHProcess.h"
#include "Exceptional.h"
#include "ScenePrivate.h"
#include <memory>
#include <assimp/Exporter.hpp>
#include <assimp/mesh.h>
#include <assimp/postprocess.h>
#include <assimp/scene.h>

namespace Assimp {

// PostStepRegistry.cpp
void GetPostProcessingStepInstanceList(std::vector< BaseProcess* >& out);

// ------------------------------------------------------------------------------------------------
// Exporter worker function prototypes. Should not be necessary to #ifndef them, it's just a prototype
// do not use const, because some exporter need to convert the scene temporary
void ExportSceneCollada(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneXFile(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneStep(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneObj(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneSTL(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneSTLBinary(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportScenePly(const char*,IOSystem*, const aiScene*, const ExportProperties*);
void ExportScenePlyBinary(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportScene3DS(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneGLTF(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneGLB(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneAssbin(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneAssxml(const char*, IOSystem*, const aiScene*, const ExportProperties*);
void ExportSceneX3D(const char*, IOSystem*, const aiScene*, const ExportProperties*);

// ------------------------------------------------------------------------------------------------
// global array of all export formats which Assimp supports in its current build
Exporter::ExportFormatEntry gExporters[] =
{
#ifndef ASSIMP_BUILD_NO_COLLADA_EXPORTER
    Exporter::ExportFormatEntry( "collada", "COLLADA - Digital Asset Exchange Schema", "dae", &ExportSceneCollada),
#endif

#ifndef ASSIMP_BUILD_NO_X_EXPORTER
    Exporter::ExportFormatEntry( "x", "X Files", "x", &ExportSceneXFile,
        aiProcess_MakeLeftHanded | aiProcess_FlipWindingOrder | aiProcess_FlipUVs),
#endif

#ifndef ASSIMP_BUILD_NO_STEP_EXPORTER
    Exporter::ExportFormatEntry( "stp", "Step Files", "stp", &ExportSceneStep, 0),
#endif

#ifndef ASSIMP_BUILD_NO_OBJ_EXPORTER
    Exporter::ExportFormatEntry( "obj", "Wavefront OBJ format", "obj", &ExportSceneObj,
        aiProcess_GenSmoothNormals /*| aiProcess_PreTransformVertices */),
#endif

#ifndef ASSIMP_BUILD_NO_STL_EXPORTER
    Exporter::ExportFormatEntry( "stl", "Stereolithography", "stl" , &ExportSceneSTL,
        aiProcess_Triangulate | aiProcess_GenNormals | aiProcess_PreTransformVertices
    ),
    Exporter::ExportFormatEntry( "stlb", "Stereolithography (binary)", "stl" , &ExportSceneSTLBinary,
        aiProcess_Triangulate | aiProcess_GenNormals | aiProcess_PreTransformVertices
    ),
#endif

#ifndef ASSIMP_BUILD_NO_PLY_EXPORTER
    Exporter::ExportFormatEntry( "ply", "Stanford Polygon Library", "ply" , &ExportScenePly,
        aiProcess_PreTransformVertices
    ),
    Exporter::ExportFormatEntry( "plyb", "Stanford Polygon Library (binary)", "ply", &ExportScenePlyBinary,
        aiProcess_PreTransformVertices
    ),
#endif

#ifndef ASSIMP_BUILD_NO_3DS_EXPORTER
    Exporter::ExportFormatEntry( "3ds", "Autodesk 3DS (legacy)", "3ds" , &ExportScene3DS,
        aiProcess_Triangulate | aiProcess_SortByPType | aiProcess_JoinIdenticalVertices),
#endif

#ifndef ASSIMP_BUILD_NO_GLTF_EXPORTER
    Exporter::ExportFormatEntry( "gltf", "GL Transmission Format", "gltf", &ExportSceneGLTF,
        aiProcess_JoinIdenticalVertices | aiProcess_Triangulate | aiProcess_SortByPType),
    Exporter::ExportFormatEntry( "glb", "GL Transmission Format (binary)", "glb", &ExportSceneGLB,
        aiProcess_JoinIdenticalVertices | aiProcess_Triangulate | aiProcess_SortByPType),
#endif

#ifndef ASSIMP_BUILD_NO_ASSBIN_EXPORTER
    Exporter::ExportFormatEntry( "assbin", "Assimp Binary", "assbin" , &ExportSceneAssbin, 0),
#endif

#ifndef ASSIMP_BUILD_NO_ASSXML_EXPORTER
    Exporter::ExportFormatEntry( "assxml", "Assxml Document", "assxml" , &ExportSceneAssxml, 0),
#endif

#ifndef ASSIMP_BUILD_NO_X3D_EXPORTER
	Exporter::ExportFormatEntry( "x3d", "Extensible 3D", "x3d" , &ExportSceneX3D, 0),
#endif
};

#define ASSIMP_NUM_EXPORTERS (sizeof(gExporters)/sizeof(gExporters[0]))


class ExporterPimpl {
public:
    ExporterPimpl()
        : blob()
        , mIOSystem(new Assimp::DefaultIOSystem())
        , mIsDefaultIOHandler(true)
    {
        GetPostProcessingStepInstanceList(mPostProcessingSteps);

        // grab all built-in exporters
        mExporters.resize(ASSIMP_NUM_EXPORTERS);
        std::copy(gExporters,gExporters+ASSIMP_NUM_EXPORTERS,mExporters.begin());
    }

    ~ExporterPimpl()
    {
        delete blob;

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

public:

    aiExportDataBlob* blob;
    std::shared_ptr< Assimp::IOSystem > mIOSystem;
    bool mIsDefaultIOHandler;

    /** Post processing steps we can apply at the imported data. */
    std::vector< BaseProcess* > mPostProcessingSteps;

    /** Last fatal export error */
    std::string mError;

    /** Exporters, this includes those registered using #Assimp::Exporter::RegisterExporter */
    std::vector<Exporter::ExportFormatEntry> mExporters;
};

} // end of namespace Assimp

using namespace Assimp;

// ------------------------------------------------------------------------------------------------
Exporter :: Exporter()
: pimpl(new ExporterPimpl()) {
    // empty
}

// ------------------------------------------------------------------------------------------------
Exporter::~Exporter() {
    FreeBlob();

    delete pimpl;
}

// ------------------------------------------------------------------------------------------------
void Exporter::SetIOHandler( IOSystem* pIOHandler) {
    pimpl->mIsDefaultIOHandler = !pIOHandler;
    pimpl->mIOSystem.reset(pIOHandler);
}

// ------------------------------------------------------------------------------------------------
IOSystem* Exporter::GetIOHandler() const {
    return pimpl->mIOSystem.get();
}

// ------------------------------------------------------------------------------------------------
bool Exporter::IsDefaultIOHandler() const {
    return pimpl->mIsDefaultIOHandler;
}

// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter::ExportToBlob( const aiScene* pScene, const char* pFormatId, 
                                                unsigned int, const ExportProperties* pProperties ) {
    if (pimpl->blob) {
        delete pimpl->blob;
        pimpl->blob = NULL;
    }

    std::shared_ptr<IOSystem> old = pimpl->mIOSystem;
    BlobIOSystem* blobio = new BlobIOSystem();
    pimpl->mIOSystem = std::shared_ptr<IOSystem>( blobio );

    if (AI_SUCCESS != Export(pScene,pFormatId,blobio->GetMagicFileName())) {
        pimpl->mIOSystem = old;
        return NULL;
    }

    pimpl->blob = blobio->GetBlobChain();
    pimpl->mIOSystem = old;

    return pimpl->blob;
}

// ------------------------------------------------------------------------------------------------
bool IsVerboseFormat(const aiMesh* mesh) {
    // avoid slow vector<bool> specialization
    std::vector<unsigned int> seen(mesh->mNumVertices,0);
    for(unsigned int i = 0; i < mesh->mNumFaces; ++i) {
        const aiFace& f = mesh->mFaces[i];
        for(unsigned int j = 0; j < f.mNumIndices; ++j) {
            if(++seen[f.mIndices[j]] == 2) {
                // found a duplicate index
                return false;
            }
        }
    }
    return true;
}

// ------------------------------------------------------------------------------------------------
bool IsVerboseFormat(const aiScene* pScene) {
    for(unsigned int i = 0; i < pScene->mNumMeshes; ++i) {
        if(!IsVerboseFormat(pScene->mMeshes[i])) {
            return false;
        }
    }
    return true;
}

// ------------------------------------------------------------------------------------------------
aiReturn Exporter::Export( const aiScene* pScene, const char* pFormatId, const char* pPath, unsigned int pPreprocessing, const ExportProperties* pProperties) {
    ASSIMP_BEGIN_EXCEPTION_REGION();

    // when they create scenes from scratch, users will likely create them not in verbose
    // format. They will likely not be aware that there is a flag in the scene to indicate
    // this, however. To avoid surprises and bug reports, we check for duplicates in
    // meshes upfront.
    const bool is_verbose_format = !(pScene->mFlags & AI_SCENE_FLAGS_NON_VERBOSE_FORMAT) || IsVerboseFormat(pScene);

    pimpl->mError = "";
    for (size_t i = 0; i < pimpl->mExporters.size(); ++i) {
        const Exporter::ExportFormatEntry& exp = pimpl->mExporters[i];
        if (!strcmp(exp.mDescription.id,pFormatId)) {
            try {
                // Always create a full copy of the scene. We might optimize this one day,
                // but for now it is the most pragmatic way.
                aiScene* scenecopy_tmp = NULL;
                SceneCombiner::CopyScene(&scenecopy_tmp,pScene);

                std::unique_ptr<aiScene> scenecopy(scenecopy_tmp);
                const ScenePrivateData* const priv = ScenePriv(pScene);

                // steps that are not idempotent, i.e. we might need to run them again, usually to get back to the
                // original state before the step was applied first. When checking which steps we don't need
                // to run, those are excluded.
                const unsigned int nonIdempotentSteps = aiProcess_FlipWindingOrder | aiProcess_FlipUVs | aiProcess_MakeLeftHanded;

                // Erase all pp steps that were already applied to this scene
                const unsigned int pp = (exp.mEnforcePP | pPreprocessing) & ~(priv && !priv->mIsCopy
                    ? (priv->mPPStepsApplied & ~nonIdempotentSteps)
                    : 0u);

                // If no extra post-processing was specified, and we obtained this scene from an
                // Assimp importer, apply the reverse steps automatically.
                // TODO: either drop this, or document it. Otherwise it is just a bad surprise.
                //if (!pPreprocessing && priv) {
                //  pp |= (nonIdempotentSteps & priv->mPPStepsApplied);
                //}

                // If the input scene is not in verbose format, but there is at least post-processing step that relies on it,
                // we need to run the MakeVerboseFormat step first.
                bool must_join_again = false;
                if (!is_verbose_format) {
                    bool verbosify = false;
                    for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++) {
                        BaseProcess* const p = pimpl->mPostProcessingSteps[a];

                        if (p->IsActive(pp) && p->RequireVerboseFormat()) {
                            verbosify = true;
                            break;
                        }
                    }

                    if (verbosify || (exp.mEnforcePP & aiProcess_JoinIdenticalVertices)) {
                        DefaultLogger::get()->debug("export: Scene data not in verbose format, applying MakeVerboseFormat step first");

                        MakeVerboseFormatProcess proc;
                        proc.Execute(scenecopy.get());

                        if(!(exp.mEnforcePP & aiProcess_JoinIdenticalVertices)) {
                            must_join_again = true;
                        }
                    }
                }

                if (pp) {
                    // the three 'conversion' steps need to be executed first because all other steps rely on the standard data layout
                    {
                        FlipWindingOrderProcess step;
                        if (step.IsActive(pp)) {
                            step.Execute(scenecopy.get());
                        }
                    }

                    {
                        FlipUVsProcess step;
                        if (step.IsActive(pp)) {
                            step.Execute(scenecopy.get());
                        }
                    }

                    {
                        MakeLeftHandedProcess step;
                        if (step.IsActive(pp)) {
                            step.Execute(scenecopy.get());
                        }
                    }

                    // dispatch other processes
                    for( unsigned int a = 0; a < pimpl->mPostProcessingSteps.size(); a++) {
                        BaseProcess* const p = pimpl->mPostProcessingSteps[a];

                        if (p->IsActive(pp)
                            && !dynamic_cast<FlipUVsProcess*>(p)
                            && !dynamic_cast<FlipWindingOrderProcess*>(p)
                            && !dynamic_cast<MakeLeftHandedProcess*>(p)) {

                            p->Execute(scenecopy.get());
                        }
                    }
                    ScenePrivateData* const privOut = ScenePriv(scenecopy.get());
                    ai_assert(privOut);

                    privOut->mPPStepsApplied |= pp;
                }

                if(must_join_again) {
                    JoinVerticesProcess proc;
                    proc.Execute(scenecopy.get());
                }

                ExportProperties emptyProperties;  // Never pass NULL ExportProperties so Exporters don't have to worry.
                exp.mExportFunction(pPath,pimpl->mIOSystem.get(),scenecopy.get(), pProperties ? pProperties : &emptyProperties);
            } catch (DeadlyExportError& err) {
                pimpl->mError = err.what();
                return AI_FAILURE;
            }
            return AI_SUCCESS;
        }
    }

    pimpl->mError = std::string("Found no exporter to handle this file format: ") + pFormatId;
    ASSIMP_END_EXCEPTION_REGION(aiReturn);
    return AI_FAILURE;
}

// ------------------------------------------------------------------------------------------------
const char* Exporter::GetErrorString() const {
    return pimpl->mError.c_str();
}


// ------------------------------------------------------------------------------------------------
void Exporter::FreeBlob() {
    delete pimpl->blob;
    pimpl->blob = NULL;

    pimpl->mError = "";
}

// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter::GetBlob() const {
    return pimpl->blob;
}

// ------------------------------------------------------------------------------------------------
const aiExportDataBlob* Exporter::GetOrphanedBlob() const {
    const aiExportDataBlob* tmp = pimpl->blob;
    pimpl->blob = NULL;
    return tmp;
}

// ------------------------------------------------------------------------------------------------
size_t Exporter::GetExportFormatCount() const {
    return pimpl->mExporters.size();
}

// ------------------------------------------------------------------------------------------------
const aiExportFormatDesc* Exporter::GetExportFormatDescription( size_t index ) const {
    if (index >= GetExportFormatCount()) {
        return NULL;
    }

    // Return from static storage if the requested index is built-in.
    if (index < sizeof(gExporters) / sizeof(gExporters[0])) {
        return &gExporters[index].mDescription;
    }

    return &pimpl->mExporters[index].mDescription;
}

// ------------------------------------------------------------------------------------------------
aiReturn Exporter::RegisterExporter(const ExportFormatEntry& desc) {
    for(const ExportFormatEntry& e : pimpl->mExporters) {
        if (!strcmp(e.mDescription.id,desc.mDescription.id)) {
            return aiReturn_FAILURE;
        }
    }

    pimpl->mExporters.push_back(desc);
    return aiReturn_SUCCESS;
}

// ------------------------------------------------------------------------------------------------
void Exporter::UnregisterExporter(const char* id) {
    for(std::vector<ExportFormatEntry>::iterator it = pimpl->mExporters.begin(); it != pimpl->mExporters.end(); ++it) {
        if (!strcmp((*it).mDescription.id,id)) {
            pimpl->mExporters.erase(it);
            break;
        }
    }
}

// ------------------------------------------------------------------------------------------------
ExportProperties::ExportProperties() {
    // empty
}

// ------------------------------------------------------------------------------------------------
ExportProperties::ExportProperties(const ExportProperties &other)
: mIntProperties(other.mIntProperties)
, mFloatProperties(other.mFloatProperties)
, mStringProperties(other.mStringProperties)
, mMatrixProperties(other.mMatrixProperties) {
    // empty
}


// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool ExportProperties::SetPropertyInteger(const char* szName, int iValue) {
    return SetGenericProperty<int>(mIntProperties, szName,iValue);
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool ExportProperties::SetPropertyFloat(const char* szName, ai_real iValue) {
    return SetGenericProperty<ai_real>(mFloatProperties, szName,iValue);
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool ExportProperties :: SetPropertyString(const char* szName, const std::string& value)
{
    return SetGenericProperty<std::string>(mStringProperties, szName,value);
}

// ------------------------------------------------------------------------------------------------
// Set a configuration property
bool ExportProperties :: SetPropertyMatrix(const char* szName, const aiMatrix4x4& value)
{
    return SetGenericProperty<aiMatrix4x4>(mMatrixProperties, szName,value);
}

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

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

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

// ------------------------------------------------------------------------------------------------
// Has a configuration property
const aiMatrix4x4 ExportProperties :: GetPropertyMatrix(const char* szName,
    const aiMatrix4x4& iErrorReturn /*= aiMatrix4x4()*/) const
{
    return GetGenericProperty<aiMatrix4x4>(mMatrixProperties,szName,iErrorReturn);
}

// ------------------------------------------------------------------------------------------------
// Has a configuration property
bool ExportProperties :: HasPropertyInteger(const char* szName) const
{
    return HasGenericProperty<int>(mIntProperties, szName);
}

// ------------------------------------------------------------------------------------------------
// Has a configuration property
bool ExportProperties :: HasPropertyBool(const char* szName) const
{
    return HasGenericProperty<int>(mIntProperties, szName);
}

// ------------------------------------------------------------------------------------------------
// Has a configuration property
bool ExportProperties :: HasPropertyFloat(const char* szName) const
{
    return HasGenericProperty<ai_real>(mFloatProperties, szName);
}

// ------------------------------------------------------------------------------------------------
// Has a configuration property
bool ExportProperties :: HasPropertyString(const char* szName) const
{
    return HasGenericProperty<std::string>(mStringProperties, szName);
}

// ------------------------------------------------------------------------------------------------
// Has a configuration property
bool ExportProperties :: HasPropertyMatrix(const char* szName) const
{
    return HasGenericProperty<aiMatrix4x4>(mMatrixProperties, szName);
}


#endif // !ASSIMP_BUILD_NO_EXPORT