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  Open Asset Import Library (assimp)
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  /** @file matrix3x3.h
   *  @brief Definition of a 3x3 matrix, including operators when compiling in C++
   */
  #ifndef AI_MATRIX3x3_H_INC
  #define AI_MATRIX3x3_H_INC
  
  #include "./Compiler/pushpack1.h"
  
  #ifdef __cplusplus
  
  template <typename T> class aiMatrix4x4t;
  template <typename T> class aiVector2t;
  
  // ---------------------------------------------------------------------------
  /** @brief Represents a row-major 3x3 matrix
   *
   *  There's much confusion about matrix layouts (column vs. row order).
   *  This is *always* a row-major matrix. Not even with the
   *  #aiProcess_ConvertToLeftHanded flag, which absolutely does not affect
   *  matrix order - it just affects the handedness of the coordinate system
   *  defined thereby.
   */
  template <typename TReal>
  class aiMatrix3x3t
  {
  public:
  
      aiMatrix3x3t () :
          a1(static_cast<TReal>(1.0f)), a2(), a3(),
          b1(), b2(static_cast<TReal>(1.0f)), b3(),
          c1(), c2(), c3(static_cast<TReal>(1.0f)) {}
  
      aiMatrix3x3t (    TReal _a1, TReal _a2, TReal _a3,
                      TReal _b1, TReal _b2, TReal _b3,
                      TReal _c1, TReal _c2, TReal _c3) :
          a1(_a1), a2(_a2), a3(_a3),
          b1(_b1), b2(_b2), b3(_b3),
          c1(_c1), c2(_c2), c3(_c3)
      {}
  
  public:
  
      // matrix multiplication.
      aiMatrix3x3t& operator *= (const aiMatrix3x3t& m);
      aiMatrix3x3t  operator  * (const aiMatrix3x3t& m) const;
  
      // array access operators
      TReal* operator[]       (unsigned int p_iIndex);
      const TReal* operator[] (unsigned int p_iIndex) const;
  
      // comparison operators
      bool operator== (const aiMatrix4x4t<TReal> m) const;
      bool operator!= (const aiMatrix4x4t<TReal> m) const;
  
      template <typename TOther>
      operator aiMatrix3x3t<TOther> () const;
  
  public:
  
      // -------------------------------------------------------------------
      /** @brief Construction from a 4x4 matrix. The remaining parts
       *  of the matrix are ignored.
       */
      explicit aiMatrix3x3t( const aiMatrix4x4t<TReal>& pMatrix);
  
      // -------------------------------------------------------------------
      /** @brief Transpose the matrix
       */
      aiMatrix3x3t& Transpose();
  
      // -------------------------------------------------------------------
      /** @brief Invert the matrix.
       *  If the matrix is not invertible all elements are set to qnan.
       *  Beware, use (f != f) to check whether a TReal f is qnan.
       */
      aiMatrix3x3t& Inverse();
      TReal Determinant() const;
  
  public:
      // -------------------------------------------------------------------
      /** @brief Returns a rotation matrix for a rotation around z
       *  @param a Rotation angle, in radians
       *  @param out Receives the output matrix
       *  @return Reference to the output matrix
       */
      static aiMatrix3x3t& RotationZ(TReal a, aiMatrix3x3t& out);
  
      // -------------------------------------------------------------------
      /** @brief Returns a rotation matrix for a rotation around
       *    an arbitrary axis.
       *
       *  @param a Rotation angle, in radians
       *  @param axis Axis to rotate around
       *  @param out To be filled
       */
      static aiMatrix3x3t& Rotation( TReal a,
          const aiVector3t<TReal>& axis, aiMatrix3x3t& out);
  
      // -------------------------------------------------------------------
      /** @brief Returns a translation matrix
       *  @param v Translation vector
       *  @param out Receives the output matrix
       *  @return Reference to the output matrix
       */
      static aiMatrix3x3t& Translation( const aiVector2t<TReal>& v, aiMatrix3x3t& out);
  
      // -------------------------------------------------------------------
      /** @brief A function for creating a rotation matrix that rotates a
       *  vector called "from" into another vector called "to".
       * Input : from[3], to[3] which both must be *normalized* non-zero vectors
       * Output: mtx[3][3] -- a 3x3 matrix in colum-major form
       * Authors: Tomas Möller, John Hughes
       *          "Efficiently Building a Matrix to Rotate One Vector to Another"
       *          Journal of Graphics Tools, 4(4):1-4, 1999
       */
      static aiMatrix3x3t& FromToMatrix(const aiVector3t<TReal>& from,
          const aiVector3t<TReal>& to, aiMatrix3x3t& out);
  
  public:
  
  
      TReal a1, a2, a3;
      TReal b1, b2, b3;
      TReal c1, c2, c3;
  } PACK_STRUCT;
  
  typedef aiMatrix3x3t<float> aiMatrix3x3;
  
  #else
  
  struct aiMatrix3x3 {
  
      float a1, a2, a3;
      float b1, b2, b3;
      float c1, c2, c3;
  } PACK_STRUCT;
  
  #endif
  
  #include "./Compiler/poppack1.h"
  
  #endif // AI_MATRIX3x3_H_INC
  