include/assimp/Exporter.hpp

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/** @file  Exporter.hpp
*  @brief Defines the CPP-API for the Assimp export interface
*/
#pragma once
#ifndef AI_EXPORT_HPP_INC
#define AI_EXPORT_HPP_INC

#ifdef __GNUC__
#pragma GCC system_header
#endif

#ifndef ASSIMP_BUILD_NO_EXPORT

#include "cexport.h"
#include <map>
#include <functional>

namespace Assimp {

class ExporterPimpl;
class IOSystem;
class ProgressHandler;

// ----------------------------------------------------------------------------------
/** CPP-API: The Exporter class forms an C++ interface to the export functionality
 * of the Open Asset Import Library. Note that the export interface is available
 * only if Assimp has been built with ASSIMP_BUILD_NO_EXPORT not defined.
 *
 * The interface is modeled after the importer interface and mostly
 * symmetric. The same rules for threading etc. apply.
 *
 * In a nutshell, there are two export interfaces: #Export, which writes the
 * output file(s) either to the regular file system or to a user-supplied
 * #IOSystem, and #ExportToBlob which returns a linked list of memory
 * buffers (blob), each referring to one output file (in most cases
 * there will be only one output file of course, but this extra complexity is
 * needed since Assimp aims at supporting a wide range of file formats).
 *
 * #ExportToBlob is especially useful if you intend to work
 * with the data in-memory.
*/
class ASSIMP_API ExportProperties;

class ASSIMP_API Exporter {
public:
    /** Function pointer type of a Export worker function */
    typedef void (*fpExportFunc)(const char *, IOSystem *, const aiScene *, const ExportProperties *);

    /** Internal description of an Assimp export format option */
    struct ExportFormatEntry {
        /// Public description structure to be returned by aiGetExportFormatDescription()
        aiExportFormatDesc mDescription;

        // Worker function to do the actual exporting
        fpExportFunc mExportFunction;

        // Post-processing steps to be executed PRIOR to invoking mExportFunction
        unsigned int mEnforcePP;

        // Constructor to fill all entries
        ExportFormatEntry(const char *pId, const char *pDesc, const char *pExtension, fpExportFunc pFunction, unsigned int pEnforcePP = 0u) {
            mDescription.id = pId;
            mDescription.description = pDesc;
            mDescription.fileExtension = pExtension;
            mExportFunction = pFunction;
            mEnforcePP = pEnforcePP;
        }

        ExportFormatEntry() :
                mExportFunction(),
                mEnforcePP() {
            mDescription.id = nullptr;
            mDescription.description = nullptr;
            mDescription.fileExtension = nullptr;
        }
    };

    /**
     *  @brief  The class constructor.
     */
    Exporter();

    /**
    *  @brief  The class destructor.
    */
    ~Exporter();

    // -------------------------------------------------------------------
    /** Supplies a custom IO handler to the exporter to use to open and
     * access files.
     *
     * If you need #Export to use custom IO logic to access the files,
     * you need to supply a custom implementation of IOSystem and
     * IOFile to the exporter.
     *
     * #Exporter takes ownership of the object and will destroy it
     * afterwards. The previously assigned handler will be deleted.
     * Pass NULL to take again ownership of your IOSystem and reset Assimp
     * to use its default implementation, which uses plain file IO.
     *
     * @param pIOHandler The IO handler to be used in all file accesses
     *   of the Importer. */
    void SetIOHandler(IOSystem *pIOHandler);

    // -------------------------------------------------------------------
    /** Retrieves the IO handler that is currently set.
     * You can use #IsDefaultIOHandler() to check whether the returned
     * interface is the default IO handler provided by ASSIMP. The default
     * handler is active as long the application doesn't supply its own
     * custom IO handler via #SetIOHandler().
     * @return A valid IOSystem interface, never NULL. */
    IOSystem *GetIOHandler() const;

    // -------------------------------------------------------------------
    /** Checks whether a default IO handler is active
     * A default handler is active as long the application doesn't
     * supply its own custom IO handler via #SetIOHandler().
     * @return true by default */
    bool IsDefaultIOHandler() const;

    // -------------------------------------------------------------------
    /** Supplies a custom progress handler to the exporter. This
     *  interface exposes an #Update() callback, which is called
     *  more or less periodically (please don't sue us if it
     *  isn't as periodically as you'd like it to have ...).
     *  This can be used to implement progress bars and loading
     *  timeouts.
     *  @param pHandler Progress callback interface. Pass nullptr to
     *    disable progress reporting.
     *  @note Progress handlers can be used to abort the loading
     *    at almost any time.*/
    void SetProgressHandler(ProgressHandler *pHandler);

    // -------------------------------------------------------------------
    /** Exports the given scene to a chosen file format. Returns the exported
    * data as a binary blob which you can write into a file or something.
    * When you're done with the data, simply let the #Exporter instance go
    * out of scope to have it released automatically.
    * @param pScene The scene to export. Stays in possession of the caller,
    *   is not changed by the function.
    * @param pFormatId ID string to specify to which format you want to
    *   export to. Use
    * #GetExportFormatCount / #GetExportFormatDescription to learn which
    *   export formats are available.
    * @param pPreprocessing See the documentation for #Export
    * @return the exported data or nullptr in case of error.
    * @note If the Exporter instance did already hold a blob from
    *   a previous call to #ExportToBlob, it will be disposed.
    *   Any IO handlers set via #SetIOHandler are ignored here.
    * @note Use aiCopyScene() to get a modifiable copy of a previously
    *   imported scene. */
    const aiExportDataBlob *ExportToBlob(const aiScene *pScene, const char *pFormatId,
            unsigned int pPreprocessing = 0u, const ExportProperties *pProperties = nullptr);
    const aiExportDataBlob *ExportToBlob(const aiScene *pScene, const std::string &pFormatId,
            unsigned int pPreprocessing = 0u, const ExportProperties *pProperties = nullptr);

    // -------------------------------------------------------------------
    /** Convenience function to export directly to a file. Use
     *  #SetIOSystem to supply a custom IOSystem to gain fine-grained control
     *  about the output data flow of the export process.
     * @param pBlob A data blob obtained from a previous call to #aiExportScene. Must not be nullptr.
     * @param pPath Full target file name. Target must be accessible.
     * @param pPreprocessing Accepts any choice of the #aiPostProcessSteps enumerated
     *   flags, but in reality only a subset of them makes sense here. Specifying
     *   'preprocessing' flags is useful if the input scene does not conform to
     *   Assimp's default conventions as specified in the @link data Data Structures Page @endlink.
     *   In short, this means the geometry data should use a right-handed coordinate systems, face
     *   winding should be counter-clockwise and the UV coordinate origin is assumed to be in
     *   the upper left. The #aiProcess_MakeLeftHanded, #aiProcess_FlipUVs and
     *   #aiProcess_FlipWindingOrder flags are used in the import side to allow users
     *   to have those defaults automatically adapted to their conventions. Specifying those flags
     *   for exporting has the opposite effect, respectively. Some other of the
     *   #aiPostProcessSteps enumerated values may be useful as well, but you'll need
     *   to try out what their effect on the exported file is. Many formats impose
     *   their own restrictions on the structure of the geometry stored therein,
     *   so some preprocessing may have little or no effect at all, or may be
     *   redundant as exporters would apply them anyhow. A good example
     *   is triangulation - whilst you can enforce it by specifying
     *   the #aiProcess_Triangulate flag, most export formats support only
     *   triangulate data so they would run the step even if it wasn't requested.
     *
     *   If assimp detects that the input scene was directly taken from the importer side of
     *   the library (i.e. not copied using aiCopyScene and potentially modified afterwards),
     *   any post-processing steps already applied to the scene will not be applied again, unless
     *   they show non-idempotent behavior (#aiProcess_MakeLeftHanded, #aiProcess_FlipUVs and
     *   #aiProcess_FlipWindingOrder).
     * @return AI_SUCCESS if everything was fine.
     * @note Use aiCopyScene() to get a modifiable copy of a previously
     *   imported scene.*/
    aiReturn Export(const aiScene *pScene, const char *pFormatId, const char *pPath,
            unsigned int pPreprocessing = 0u, const ExportProperties *pProperties = nullptr);
    aiReturn Export(const aiScene *pScene, const std::string &pFormatId, const std::string &pPath,
            unsigned int pPreprocessing = 0u, const ExportProperties *pProperties = nullptr);

    // -------------------------------------------------------------------
    /** Returns an error description of an error that occurred in #Export
     *    or #ExportToBlob
     *
     * Returns an empty string if no error occurred.
     * @return A description of the last error, an empty string if no
     *   error occurred. The string is never nullptr.
     *
     * @note The returned function remains valid until one of the
     * following methods is called: #Export, #ExportToBlob, #FreeBlob */
    const char *GetErrorString() const;

    // -------------------------------------------------------------------
    /** Return the blob obtained from the last call to #ExportToBlob */
    const aiExportDataBlob *GetBlob() const;

    // -------------------------------------------------------------------
    /** Orphan the blob from the last call to #ExportToBlob. This means
     *  the caller takes ownership and is thus responsible for calling
     *  the C API function #aiReleaseExportBlob to release it. */
    const aiExportDataBlob *GetOrphanedBlob() const;

    // -------------------------------------------------------------------
    /** Frees the current blob.
     *
     *  The function does nothing if no blob has previously been
     *  previously produced via #ExportToBlob. #FreeBlob is called
     *  automatically by the destructor. The only reason to call
     *  it manually would be to reclaim as much storage as possible
     *  without giving up the #Exporter instance yet. */
    void FreeBlob();

    // -------------------------------------------------------------------
    /** Returns the number of export file formats available in the current
     *  Assimp build. Use #Exporter::GetExportFormatDescription to
     *  retrieve infos of a specific export format.
     *
     *  This includes built-in exporters as well as exporters registered
     *  using #RegisterExporter.
     **/
    size_t GetExportFormatCount() const;

    // -------------------------------------------------------------------
    /** Returns a description of the nth export file format. Use #
     *  #Exporter::GetExportFormatCount to learn how many export
     *  formats are supported.
     *
     * The returned pointer is of static storage duration if the
     * pIndex pertains to a built-in exporter (i.e. one not registered
     * via #RegistrerExporter). It is restricted to the life-time of the
     * #Exporter instance otherwise.
     *
     * @param pIndex Index of the export format to retrieve information
     *  for. Valid range is 0 to #Exporter::GetExportFormatCount
     * @return A description of that specific export format.
     *  NULL if pIndex is out of range. */
    const aiExportFormatDesc *GetExportFormatDescription(size_t pIndex) const;

    // -------------------------------------------------------------------
    /** Register a custom exporter. Custom export formats are limited to
     *    to the current #Exporter instance and do not affect the
     *    library globally. The indexes under which the format's
     *    export format description can be queried are assigned
     *    monotonously.
     *  @param desc Exporter description.
     *  @return aiReturn_SUCCESS if the export format was successfully
     *    registered. A common cause that would prevent an exporter
     *    from being registered is that its format id is already
     *    occupied by another format. */
    aiReturn RegisterExporter(const ExportFormatEntry &desc);

    // -------------------------------------------------------------------
    /** Remove an export format previously registered with #RegisterExporter
     *  from the #Exporter instance (this can also be used to drop
     *  built-in exporters because those are implicitly registered
     *  using #RegisterExporter).
     *  @param id Format id to be unregistered, this refers to the
     *    'id' field of #aiExportFormatDesc.
     *  @note Calling this method on a format description not yet registered
     *    has no effect.*/
    void UnregisterExporter(const char *id);

protected:
    // Just because we don't want you to know how we're hacking around.
    ExporterPimpl *pimpl;
};

class ASSIMP_API ExportProperties {
public:
    // Data type to store the key hash
    typedef unsigned int KeyType;

    // typedefs for our four configuration maps.
    // We don't need more, so there is no need for a generic solution
    typedef std::map<KeyType, int> IntPropertyMap;
    typedef std::map<KeyType, ai_real> FloatPropertyMap;
    typedef std::map<KeyType, std::string> StringPropertyMap;
    typedef std::map<KeyType, aiMatrix4x4> MatrixPropertyMap;
    typedef std::map<KeyType, std::function<void *(void *)>> CallbackPropertyMap;

public:
    /** Standard constructor
    * @see ExportProperties()
    */
    ExportProperties();

    // -------------------------------------------------------------------
    /** Copy constructor.
     *
     * This copies the configuration properties of another ExportProperties.
     * @see ExportProperties(const ExportProperties& other)
     */
    ExportProperties(const ExportProperties &other);

    // -------------------------------------------------------------------
    /** Set an integer configuration property.
     * @param szName Name of the property. All supported properties
     *   are defined in the aiConfig.g header (all constants share the
     *   prefix AI_CONFIG_XXX and are simple strings).
     * @param iValue New value of the property
     * @return true if the property was set before. The new value replaces
     *   the previous value in this case.
     * @note Property of different types (float, int, string ..) are kept
     *   on different stacks, so calling SetPropertyInteger() for a
     *   floating-point property has no effect - the loader will call
     *   GetPropertyFloat() to read the property, but it won't be there.
     */
    bool SetPropertyInteger(const char *szName, int iValue);

    // -------------------------------------------------------------------
    /** Set a boolean configuration property. Boolean properties
     *  are stored on the integer stack internally so it's possible
     *  to set them via #SetPropertyBool and query them with
     *  #GetPropertyBool and vice versa.
     * @see SetPropertyInteger()
     */
    bool SetPropertyBool(const char *szName, bool value) {
        return SetPropertyInteger(szName, value);
    }

    // -------------------------------------------------------------------
    /** Set a floating-point configuration property.
     * @see SetPropertyInteger()
     */
    bool SetPropertyFloat(const char *szName, ai_real fValue);

    // -------------------------------------------------------------------
    /** Set a string configuration property.
     * @see SetPropertyInteger()
     */
    bool SetPropertyString(const char *szName, const std::string &sValue);

    // -------------------------------------------------------------------
    /** Set a matrix configuration property.
     * @see SetPropertyInteger()
     */
    bool SetPropertyMatrix(const char *szName, const aiMatrix4x4 &sValue);

    bool SetPropertyCallback(const char *szName, const std::function<void *(void *)> &f);

    // -------------------------------------------------------------------
    /** Get a configuration property.
     * @param szName Name of the property. All supported properties
     *   are defined in the aiConfig.g header (all constants share the
     *   prefix AI_CONFIG_XXX).
     * @param iErrorReturn Value that is returned if the property
     *   is not found.
     * @return Current value of the property
     * @note Property of different types (float, int, string ..) are kept
     *   on different lists, so calling SetPropertyInteger() for a
     *   floating-point property has no effect - the loader will call
     *   GetPropertyFloat() to read the property, but it won't be there.
     */
    int GetPropertyInteger(const char *szName,
            int iErrorReturn = 0xffffffff) const;

    // -------------------------------------------------------------------
    /** Get a boolean configuration property. Boolean properties
     *  are stored on the integer stack internally so it's possible
     *  to set them via #SetPropertyBool and query them with
     *  #GetPropertyBool and vice versa.
     * @see GetPropertyInteger()
     */
    bool GetPropertyBool(const char *szName, bool bErrorReturn = false) const {
        return GetPropertyInteger(szName, bErrorReturn) != 0;
    }

    // -------------------------------------------------------------------
    /** Get a floating-point configuration property
     * @see GetPropertyInteger()
     */
    ai_real GetPropertyFloat(const char *szName,
            ai_real fErrorReturn = 10e10f) const;

    // -------------------------------------------------------------------
    /** Get a string configuration property
     *
     *  The return value remains valid until the property is modified.
     * @see GetPropertyInteger()
     */
    const std::string GetPropertyString(const char *szName,
            const std::string &sErrorReturn = "") const;

    // -------------------------------------------------------------------
    /** Get a matrix configuration property
     *
     *  The return value remains valid until the property is modified.
     * @see GetPropertyInteger()
     */
    const aiMatrix4x4 GetPropertyMatrix(const char *szName,
            const aiMatrix4x4 &sErrorReturn = aiMatrix4x4()) const;

    std::function<void *(void *)> GetPropertyCallback(const char* szName) const;

    // -------------------------------------------------------------------
    /** Determine a integer configuration property has been set.
    * @see HasPropertyInteger()
     */
    bool HasPropertyInteger(const char *szName) const;

    /** Determine a boolean configuration property has been set.
    * @see HasPropertyBool()
     */
    bool HasPropertyBool(const char *szName) const;

    /** Determine a boolean configuration property has been set.
    * @see HasPropertyFloat()
     */
    bool HasPropertyFloat(const char *szName) const;

    /** Determine a String configuration property has been set.
    * @see HasPropertyString()
     */
    bool HasPropertyString(const char *szName) const;

    /** Determine a Matrix configuration property has been set.
    * @see HasPropertyMatrix()
     */
    bool HasPropertyMatrix(const char *szName) const;

    bool HasPropertyCallback(const char *szName) const;

    /** List of integer properties */
    IntPropertyMap mIntProperties;

    /** List of floating-point properties */
    FloatPropertyMap mFloatProperties;

    /** List of string properties */
    StringPropertyMap mStringProperties;

    /** List of Matrix properties */
    MatrixPropertyMap mMatrixProperties;

    CallbackPropertyMap mCallbackProperties;
};

// ----------------------------------------------------------------------------------
inline const aiExportDataBlob *Exporter::ExportToBlob(const aiScene *pScene, const std::string &pFormatId,
        unsigned int pPreprocessing, const ExportProperties *pProperties) {
    return ExportToBlob(pScene, pFormatId.c_str(), pPreprocessing, pProperties);
}

// ----------------------------------------------------------------------------------
inline aiReturn Exporter ::Export(const aiScene *pScene, const std::string &pFormatId,
        const std::string &pPath, unsigned int pPreprocessing,
        const ExportProperties *pProperties) {
    return Export(pScene, pFormatId.c_str(), pPath.c_str(), pPreprocessing, pProperties);
}

} // namespace Assimp

#endif // ASSIMP_BUILD_NO_EXPORT
#endif // AI_EXPORT_HPP_INC