assimp/code/Common/BaseProcess.h

/*
Open Asset Import Library (assimp)
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  following disclaimer.

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*/

/** @file Base class of all import post processing steps */
#ifndef INCLUDED_AI_BASEPROCESS_H
#define INCLUDED_AI_BASEPROCESS_H

#include <assimp/GenericProperty.h>

#include <map>

struct aiScene;

namespace Assimp {

class Importer;

// ---------------------------------------------------------------------------
/** Helper class to allow post-processing steps to interact with each other.
 *
 *  The class maintains a simple property list that can be used by pp-steps
 *  to provide additional information to other steps. This is primarily
 *  intended for cross-step optimizations.
 */
class SharedPostProcessInfo {
public:
    struct Base {
        virtual ~Base() = default;
    };

    //! Represents data that is allocated on the heap, thus needs to be deleted
    template <typename T>
    struct THeapData : public Base {
        explicit THeapData(T *in) :
                data(in) {}

        ~THeapData() {
            delete data;
        }
        T *data;
    };

    //! Represents static, by-value data not allocated on the heap
    template <typename T>
    struct TStaticData : public Base {
        explicit TStaticData(T in) :
                data(in) {}

        ~TStaticData() = default;

        T data;
    };

    // some typedefs for cleaner code
    typedef unsigned int KeyType;
    typedef std::map<KeyType, Base *> PropertyMap;

public:
    //! Destructor
    ~SharedPostProcessInfo() {
        Clean();
    }

    //! Remove all stored properties from the table
    void Clean() {
        // invoke the virtual destructor for all stored properties
        for (PropertyMap::iterator it = pmap.begin(), end = pmap.end();
                it != end; ++it) {
            delete (*it).second;
        }
        pmap.clear();
    }

    //! Add a heap property to the list
    template <typename T>
    void AddProperty(const char *name, T *in) {
        AddProperty(name, (Base *)new THeapData<T>(in));
    }

    //! Add a static by-value property to the list
    template <typename T>
    void AddProperty(const char *name, T in) {
        AddProperty(name, (Base *)new TStaticData<T>(in));
    }

    //! Get a heap property
    template <typename T>
    bool GetProperty(const char *name, T *&out) const {
        THeapData<T> *t = (THeapData<T> *)GetPropertyInternal(name);
        if (!t) {
            out = nullptr;
            return false;
        }
        out = t->data;
        return true;
    }

    //! Get a static, by-value property
    template <typename T>
    bool GetProperty(const char *name, T &out) const {
        TStaticData<T> *t = (TStaticData<T> *)GetPropertyInternal(name);
        if ( nullptr == t) {
            return false;
        }
        out = t->data;
        return true;
    }

    //! Remove a property of a specific type
    void RemoveProperty(const char *name) {
        SetGenericPropertyPtr<Base>(pmap, name, nullptr );
    }

private:
    void AddProperty(const char *name, Base *data) {
        SetGenericPropertyPtr<Base>(pmap, name, data);
    }

    Base *GetPropertyInternal(const char *name) const {
        return GetGenericProperty<Base *>(pmap, name, nullptr );
    }

private:
    //! Map of all stored properties
    PropertyMap pmap;
};

#define AI_SPP_SPATIAL_SORT "$Spat"

// ---------------------------------------------------------------------------
/** The BaseProcess defines a common interface for all post processing steps.
 * A post processing step is run after a successful import if the caller
 * specified the corresponding flag when calling ReadFile().
 * Enum #aiPostProcessSteps defines which flags are available.
 * After a successful import the Importer iterates over its internal array
 * of processes and calls IsActive() on each process to evaluate if the step
 * should be executed. If the function returns true, the class' Execute()
 * function is called subsequently.
 */
class ASSIMP_API BaseProcess {
    friend class Importer;

public:
    /** @brief onstructor to be privately used by Importer */
    BaseProcess() AI_NO_EXCEPT;

    /** @brief Destructor, private as well */
    virtual ~BaseProcess();

    // -------------------------------------------------------------------
    /**
     * @brief Returns whether the processing step is present in the given flag.
     * @param pFlags The processing flags the importer was called with. A
     *   bitwise combination of #aiPostProcessSteps.
     * @return true if the process is present in this flag fields,
     *   false if not.
     */
    virtual bool IsActive(unsigned int pFlags) const = 0;

    // -------------------------------------------------------------------
    /** Check whether this step expects its input vertex data to be
     *  in verbose format. */
    virtual bool RequireVerboseFormat() const;

    // -------------------------------------------------------------------
    /**
     * @brief Executes the post processing step on the given imported data.
     * The function deletes the scene if the post-process step fails (
     * the object pointer will be set to nullptr).
     * @param pImp Importer instance (pImp->mScene must be valid)
     */
    void ExecuteOnScene(Importer *pImp);

    // -------------------------------------------------------------------
    /**
     * @brief Called prior to ExecuteOnScene().
     * The function is a request to the process to update its configuration
     * basing on the Importer's configuration property list.
     */
    virtual void SetupProperties(const Importer *pImp);

    // -------------------------------------------------------------------
    /**
     * @brief Executes the post processing step on the given imported data.
     * A process should throw an ImportErrorException* if it fails.
     * This method must be implemented by deriving classes.
     * @param pScene The imported data to work at.
     */
    virtual void Execute(aiScene *pScene) = 0;

    // -------------------------------------------------------------------
    /** Assign a new SharedPostProcessInfo to the step. This object
     *  allows multiple post-process steps to share data.
     * @param sh May be nullptr
     */
    inline void SetSharedData(SharedPostProcessInfo *sh) {
        shared = sh;
    }

    // -------------------------------------------------------------------
    /** Get the shared data that is assigned to the step.
    */
    inline SharedPostProcessInfo *GetSharedData() {
        return shared;
    }

protected:
    /** See the doc of #SharedPostProcessInfo for more details */
    SharedPostProcessInfo *shared;

    /** Currently active progress handler */
    ProgressHandler *progress;
};

} // end of namespace Assimp

#endif // AI_BASEPROCESS_H_INC