assimp/code/PostProcessing/FindInstancesProcess.h

/*
Open Asset Import Library (assimp)
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*/

/** @file  FindInstancesProcess.h
 *  @brief Declares the aiProcess_FindInstances post-process step
 */
#ifndef AI_FINDINSTANCES_H_INC
#define AI_FINDINSTANCES_H_INC

#include "Common/BaseProcess.h"
#include "PostProcessing/ProcessHelper.h"

class FindInstancesProcessTest;

namespace Assimp {

// -------------------------------------------------------------------------------
/** @brief Get a pseudo(!)-hash representing a mesh.
 *
 *  The hash is built from number of vertices, faces, primitive types,
 *  .... but *not* from the real mesh data. The funcction is not a perfect hash.
 *  @param in Input mesh
 *  @return Hash.
 */
inline uint64_t GetMeshHash(aiMesh* in) {
    ai_assert(nullptr != in);

    // ... get an unique value representing the vertex format of the mesh
    const unsigned int fhash = GetMeshVFormatUnique(in);

    // and bake it with number of vertices/faces/bones/matidx/ptypes
    return ((uint64_t)fhash << 32u) | ((
        (in->mNumBones << 16u) ^  (in->mNumVertices)       ^
        (in->mNumFaces<<4u)    ^  (in->mMaterialIndex<<15) ^
        (in->mPrimitiveTypes<<28)) & 0xffffffff );
}

// -------------------------------------------------------------------------------
/** @brief Perform a component-wise comparison of two arrays
 *
 *  @param first First array
 *  @param second Second array
 *  @param size Size of both arrays
 *  @param e Epsilon
 *  @return true if the arrays are identical
 */
inline bool CompareArrays(const aiVector3D* first, const aiVector3D* second,
        unsigned int size, float e) {
    for (const aiVector3D* end = first+size; first != end; ++first,++second) {
        if ( (*first - *second).SquareLength() >= e)
            return false;
    }
    return true;
}

// and the same for colors ...
inline bool CompareArrays(const aiColor4D* first, const aiColor4D* second,
    unsigned int size, float e)
{
    for (const aiColor4D* end = first+size; first != end; ++first,++second) {
        if ( GetColorDifference(*first,*second) >= e)
            return false;
    }
    return true;
}

// ---------------------------------------------------------------------------
/** @brief A post-processing steps to search for instanced meshes
*/
class FindInstancesProcess : public BaseProcess {
public:
    FindInstancesProcess();
    ~FindInstancesProcess() override = default;

    // -------------------------------------------------------------------
    // Check whether step is active in given flags combination
    bool IsActive( unsigned int pFlags) const override;

    // -------------------------------------------------------------------
    // Execute step on a given scene
    void Execute( aiScene* pScene) override;

    // -------------------------------------------------------------------
    // Setup properties prior to executing the process
    void SetupProperties(const Importer* pImp) override;

private:
    bool configSpeedFlag;
}; // ! end class FindInstancesProcess

}  // ! end namespace Assimp

#endif // !! AI_FINDINSTANCES_H_INC