/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
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  following disclaimer in the documentation and/or other
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* Neither the name of the assimp team, nor the names of its
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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----------------------------------------------------------------------
*/

/** Defines a post processing step to limit the number of bones affecting a single vertex. */
#ifndef AI_LIMITBONEWEIGHTSPROCESS_H_INC
#define AI_LIMITBONEWEIGHTSPROCESS_H_INC

#include "Common/BaseProcess.h"

// Forward declarations
struct aiMesh;

class LimitBoneWeightsTest;

namespace Assimp {

// NOTE: If you change these limits, don't forget to change the
// corresponding values in all Assimp ports

// **********************************************************
// Java: ConfigProperty.java,
//  ConfigProperty.DEFAULT_BONE_WEIGHT_LIMIT
// **********************************************************

#if (!defined AI_LMW_MAX_WEIGHTS)
#   define AI_LMW_MAX_WEIGHTS   0x4
#endif // !! AI_LMW_MAX_WEIGHTS

// ---------------------------------------------------------------------------
/** This post processing step limits the number of bones affecting a vertex
* to a certain maximum value. If a vertex is affected by more than that number
* of bones, the bone weight with the least influence on this vertex are removed.
* The other weights on this bone are then renormalized to assure the sum weight
* to be 1.
*/
class ASSIMP_API LimitBoneWeightsProcess : public BaseProcess {
public:
    // -------------------------------------------------------------------
    /// The default class constructor / destructor.
    LimitBoneWeightsProcess();
    ~LimitBoneWeightsProcess() override = default;

    // -------------------------------------------------------------------
    /** 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.
    */
    bool IsActive( unsigned int pFlags) const override;

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

    // -------------------------------------------------------------------
    /** Executes the post processing step on the given imported data.
    * At the moment a process is not supposed to fail.
    * @param pScene The imported data to work at.
    */
    void Execute( aiScene* pScene) override;

    // -------------------------------------------------------------------
    /** Limits the bone weight count for all vertices in the given mesh.
    * @param pMesh The mesh to process.
    */
    void ProcessMesh( aiMesh* pMesh);

    // -------------------------------------------------------------------
    /** Describes a bone weight on a vertex */
    struct Weight {
        unsigned int mBone; ///< Index of the bone
        float mWeight;      ///< Weight of that bone on this vertex
        Weight() AI_NO_EXCEPT
        : mBone(0)
        , mWeight(0.0f) {
            // empty
        }

        Weight( unsigned int pBone, float pWeight)
        : mBone(pBone)
        , mWeight(pWeight) {
            // empty
        }

        /** Comparison operator to sort bone weights by descending weight */
        bool operator < (const Weight& pWeight) const {
            return mWeight > pWeight.mWeight;
        }
    };

    /** Maximum number of bones influencing any single vertex. */
    unsigned int mMaxWeights;
    bool mRemoveEmptyBones;
};

} // end of namespace Assimp

#endif // AI_LIMITBONEWEIGHTSPROCESS_H_INC
