assimp/code/Exporter.cpp

/*
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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).
*/

#include "AssimpPCH.h"

#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"

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
void ExportSceneCollada(const char*,IOSystem*, const aiScene*);
void ExportSceneObj(const char*,IOSystem*, const aiScene*);
void ExportSceneSTL(const char*,IOSystem*, const aiScene*);
void ExportSceneSTLBinary(const char*,IOSystem*, const aiScene*);
void ExportScenePly(const char*,IOSystem*, const aiScene*);
void ExportScene3DS(const char*, IOSystem*, const aiScene*) {}

// ------------------------------------------------------------------------------------------------
// 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_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
	),
#endif

//#ifndef ASSIMP_BUILD_NO_3DS_EXPORTER
//	ExportFormatEntry( "3ds", "Autodesk 3DS (legacy format)", "3ds" , &ExportScene3DS),
//#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 builtin 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;
	boost::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())
{
}


// ------------------------------------------------------------------------------------------------
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 )
{
	if (pimpl->blob) {
		delete pimpl->blob;
		pimpl->blob = NULL;
	}


	boost::shared_ptr<IOSystem> old = pimpl->mIOSystem;

	BlobIOSystem* blobio = new BlobIOSystem();
	pimpl->mIOSystem = boost::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 )
{
	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;
				SceneCombiner::CopyScene(&scenecopy_tmp,pScene);

				std::auto_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 postprocessing 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 postprocessing 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());
				}

				exp.mExportFunction(pPath,pimpl->mIOSystem.get(),scenecopy.get());
			}
			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 pIndex ) const 
{
	if (pIndex >= GetExportFormatCount()) {
		return NULL;
	}

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

// ------------------------------------------------------------------------------------------------
aiReturn Exporter :: RegisterExporter(const ExportFormatEntry& desc)
{
	BOOST_FOREACH(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;
		}
	}
}

#endif // !ASSIMP_BUILD_NO_EXPORT