assimp/include/assimp/ProgressHandler.hpp

/*
Open Asset Import Library (assimp)
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*/

/** @file ProgressHandler.hpp
 *  @brief Abstract base class 'ProgressHandler'.
 */
#pragma once
#ifndef AI_PROGRESSHANDLER_H_INC
#define AI_PROGRESSHANDLER_H_INC

#ifdef __GNUC__
#   pragma GCC system_header
#endif

#include <assimp/types.h>

namespace Assimp {

// ------------------------------------------------------------------------------------
/** @brief CPP-API: Abstract interface for custom progress report receivers.
 *
 *  Each #Importer instance maintains its own #ProgressHandler. The default
 *  implementation provided by Assimp doesn't do anything at all. */
class ASSIMP_API ProgressHandler
#ifndef SWIG
    : public Intern::AllocateFromAssimpHeap
#endif
{
protected:
    /// @brief  Default constructor
    ProgressHandler () AI_NO_EXCEPT = default;

public:
    /// @brief  Virtual destructor.
    virtual ~ProgressHandler () = default;

    // -------------------------------------------------------------------
    /** @brief Progress callback.
     *  @param percentage An estimate of the current loading progress,
     *    in percent. Or -1.f if such an estimate is not available.
     *
     *  There are restriction on what you may do from within your
     *  implementation of this method: no exceptions may be thrown and no
     *  non-const #Importer methods may be called. It is
     *  not generally possible to predict the number of callbacks
     *  fired during a single import.
     *
     *  @return Return false to abort loading at the next possible
     *   occasion (loaders and Assimp are generally allowed to perform
     *   all needed cleanup tasks prior to returning control to the
     *   caller). If the loading is aborted, #Importer::ReadFile()
     *   returns always nullptr.
     *   */
    virtual bool Update(float percentage = -1.f) = 0;

    // -------------------------------------------------------------------
    /** @brief Progress callback for file loading steps
     *  @param numberOfSteps The number of total post-processing
     *   steps
     *  @param currentStep The index of the current post-processing
     *   step that will run, or equal to numberOfSteps if all of
     *   them has finished. This number is always strictly monotone
     *   increasing, although not necessarily linearly.
     *
     *  @note This is currently only used at the start and the end
     *   of the file parsing.
     *   */
    virtual void UpdateFileRead(int currentStep /*= 0*/, int numberOfSteps /*= 0*/) {
        float f = numberOfSteps ? currentStep / (float)numberOfSteps : 1.0f;
        Update( f * 0.5f );
    }

    // -------------------------------------------------------------------
    /** @brief Progress callback for post-processing steps
     *  @param numberOfSteps The number of total post-processing
     *   steps
     *  @param currentStep The index of the current post-processing
     *   step that will run, or equal to numberOfSteps if all of
     *   them has finished. This number is always strictly monotone
     *   increasing, although not necessarily linearly.
     *   */
    virtual void UpdatePostProcess(int currentStep /*= 0*/, int numberOfSteps /*= 0*/) {
        float f = numberOfSteps ? currentStep / (float)numberOfSteps : 1.0f;
        Update( f * 0.5f + 0.5f );
    }


    // -------------------------------------------------------------------
    /** @brief Progress callback for export steps.
     *  @param numberOfSteps The number of total processing
     *   steps
     *  @param currentStep The index of the current post-processing
     *   step that will run, or equal to numberOfSteps if all of
     *   them has finished. This number is always strictly monotone
     *   increasing, although not necessarily linearly.
     *   */
    virtual void UpdateFileWrite(int currentStep /*= 0*/, int numberOfSteps /*= 0*/) {
        float f = numberOfSteps ? currentStep / (float)numberOfSteps : 1.0f;
        Update(f * 0.5f);
    }
}; // !class ProgressHandler

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

} // Namespace Assimp

#endif // AI_PROGRESSHANDLER_H_INC