assimp.assimp/code/AssetLib/FBX/FBXExporter.h

/*
Open Asset Import Library (assimp)
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* Redistributions in binary form must reproduce the above
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*/

/** @file FBXExporter.h
* Declares the exporter class to write a scene to an fbx file
*/
#ifndef AI_FBXEXPORTER_H_INC
#define AI_FBXEXPORTER_H_INC

#ifndef ASSIMP_BUILD_NO_FBX_EXPORTER

#include "FBXExportNode.h" // FBX::Node
#include "FBXCommon.h" // FBX::TransformInheritance

#include <assimp/types.h>
#include <assimp/StreamWriter.h> // StreamWriterLE
#include <assimp/Exceptional.h> // DeadlyExportError

#include <vector>
#include <map>
#include <unordered_set>
#include <memory> // shared_ptr
#include <sstream> // stringstream

struct aiScene;
struct aiNode;
struct aiLight;

namespace Assimp {
    class IOSystem;
    class IOStream;
    class ExportProperties;

    // ---------------------------------------------------------------------
    /** Helper class to export a given scene to an FBX file. */
    // ---------------------------------------------------------------------
    class FBXExporter
    {
    public:
        /// Constructor for a specific scene to export
        FBXExporter(const aiScene* pScene, const ExportProperties* pProperties);

        // call one of these methods to export
        void ExportBinary(const char* pFile, IOSystem* pIOSystem);
        void ExportAscii(const char* pFile, IOSystem* pIOSystem);

    private:
        bool binary; // whether current export is in binary or ascii format
        const aiScene* mScene; // the scene to export
        const ExportProperties* mProperties; // currently unused
        std::shared_ptr<IOStream> outfile; // file to write to

        std::vector<FBX::Node> connections; // connection storage

        std::map<const aiNode*, int64_t> mesh_uids;
        std::vector<int64_t> blendshape_uids;
        std::vector<int64_t> material_uids;
        std::map<const aiNode*,int64_t> node_uids;
        std::map<std::string,int64_t> lights_uids;

        // this crude unique-ID system is actually fine
        int64_t last_uid = 999999;
        int64_t generate_uid() { return ++last_uid; }

        // binary files have a specific header and footer,
        // in addition to the actual data
        void WriteBinaryHeader();
        void WriteBinaryFooter();

        // ascii files have a comment at the top
        void WriteAsciiHeader();

        // WriteAllNodes does the actual export.
        // It just calls all the Write<Section> methods below in order.
        void WriteAllNodes();

        // Methods to write individual sections.
        // The order here matches the order inside an FBX file.
        // Each method corresponds to a top-level FBX section,
        // except WriteHeader which also includes some binary-only sections
        // and WriteFooter which is binary data only.
        void WriteHeaderExtension();
        // WriteFileId(); // binary-only, included in WriteHeader
        // WriteCreationTime(); // binary-only, included in WriteHeader
        // WriteCreator(); // binary-only, included in WriteHeader
        void WriteGlobalSettings();
        void WriteDocuments();
        void WriteReferences();
        void WriteDefinitions();
        void WriteObjects();
        void WriteConnections();
        // WriteTakes(); // deprecated since at least 2015 (fbx 7.4)

        // helpers
        void WriteAsciiSectionHeader(const std::string& title);
        void WriteModelNodes(
            Assimp::StreamWriterLE& s,
            const aiNode* node,
            int64_t parent_uid,
            const std::unordered_set<const aiNode*>& limbnodes
        );
        void WriteModelNodes( // usually don't call this directly
            StreamWriterLE& s,
            const aiNode* node,
            int64_t parent_uid,
            const std::unordered_set<const aiNode*>& limbnodes,
            std::vector<std::pair<std::string,aiVector3D>>& transform_chain
        );
        void WriteModelNode( // nor this
            StreamWriterLE& s,
            bool binary,
            const aiNode* node,
            int64_t node_uid,
            const std::string& type,
            const std::vector<std::pair<std::string,aiVector3D>>& xfm_chain,
            FBX::TransformInheritance ti_type=FBX::TransformInheritance_RSrs
        );
        void WriteAnimationCurveNode(
                StreamWriterLE &outstream,
                int64_t uid,
                const std::string &name, // "T", "R", or "S"
                aiVector3D default_value,
                const std::string &property_name, // "Lcl Translation" etc
                int64_t animation_layer_uid,
                int64_t node_uid);
        void WriteAnimationCurve(
            StreamWriterLE& outstream,
            double default_value,
            const std::vector<int64_t>& times,
            const std::vector<float>& values,
            int64_t curvenode_id,
            const std::string& property_link // "d|X", "d|Y", etc
        );
    };
}

#endif // ASSIMP_BUILD_NO_FBX_EXPORTER

#endif // AI_FBXEXPORTER_H_INC