/** Defines the BHV motion capturing loader class */

/*

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*/

/** @file BVHLoader.h

 *  @brief Biovision BVH import

 */

#ifndef AI_BVHLOADER_H_INC

#define AI_BVHLOADER_H_INC

#include <assimp/BaseImporter.h>

struct aiNode;

namespace Assimp {

// --------------------------------------------------------------------------------

/** Loader class to read Motion Capturing data from a .bvh file.

 *

 * This format only contains a hierarchy of joints and a series of keyframes for

 * the hierarchy. It contains no actual mesh data, but we generate a dummy mesh

 * inside the loader just to be able to see something.

*/

class BVHLoader : public BaseImporter {

    /** Possible animation channels for which the motion data holds the values */

    enum ChannelType {

        Channel_PositionX,

        Channel_PositionY,

        Channel_PositionZ,

        Channel_RotationX,

        Channel_RotationY,

        Channel_RotationZ

    };

    /** Collected list of node. Will be bones of the dummy mesh some day, addressed by their array index */

    struct Node {

        const aiNode *mNode;

        std::vector<ChannelType> mChannels;

        std::vector<float> mChannelValues; // motion data values for that node. Of size NumChannels * NumFrames

        Node() : mNode(nullptr) {}

        explicit Node(const aiNode *pNode) :mNode(pNode) {}

    };

public:

    BVHLoader();

    ~BVHLoader() override = default;

    /** Returns whether the class can handle the format of the given file.

     * See BaseImporter::CanRead() for details. */

    bool CanRead(const std::string &pFile, IOSystem *pIOHandler, bool cs) const override;

    void SetupProperties(const Importer *pImp) override;

    const aiImporterDesc *GetInfo() const override;

protected:

    /** Imports the given file into the given scene structure.

     * See BaseImporter::InternReadFile() for details

     */

    void InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) override;

    /** Reads the file */

    void ReadStructure(aiScene *pScene);

    /** Reads the hierarchy */

    void ReadHierarchy(aiScene *pScene);

    /** Reads a node and recursively its children and returns the created node. */

    aiNode *ReadNode();

    /** Reads an end node and returns the created node. */

    aiNode *ReadEndSite(const std::string &pParentName);

    /** Reads a node offset for the given node */

    void ReadNodeOffset(aiNode *pNode);

    /** Reads the animation channels into the given node */

    void ReadNodeChannels(BVHLoader::Node &pNode);

    /** Reads the motion data */

    void ReadMotion(aiScene *pScene);

    /** Retrieves the next token */

    std::string GetNextToken();

    /** Reads the next token as a float */

    float GetNextTokenAsFloat();

    /** Aborts the file reading with an exception */

    template<typename... T>

    AI_WONT_RETURN void ThrowException(T&&... args) AI_WONT_RETURN_SUFFIX;

    /** Constructs an animation for the motion data and stores it in the given scene */

    void CreateAnimation(aiScene *pScene);

protected:

    /** Filename, for a verbose error message */

    std::string mFileName;

    /** Buffer to hold the loaded file */

    std::vector<char> mBuffer;

    /** Next char to read from the buffer */

    std::vector<char>::const_iterator mReader;

    /** Current line, for error messages */

    unsigned int mLine;

    /** Collected list of nodes. Will be bones of the dummy mesh some day, addressed by their array index.

    * Also contain the motion data for the node's channels

    */

    std::vector<Node> mNodes;

    /** basic Animation parameters */

    float mAnimTickDuration;

    unsigned int mAnimNumFrames;

    bool noSkeletonMesh;

};

} // end of namespace Assimp

#endif // AI_BVHLOADER_H_INC