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#ifndef __CGLA_MAT4X4_H__
#define __CGLA_MAT4X4_H__

#include "ExceptionStandard.h"
#include "CGLA.h"
#include "Vec3f.h"
#include "Vec3Hf.h"
#include "Vec4f.h"
#include "ArithSqMat4x4Float.h"


namespace CGLA 
{

  /** \brief 4x4 float matrix.
      This class is useful for transformations such as perspective projections 
      or translation where 3x3 matrices do not suffice. */
  class Mat4x4f: public ArithSqMat4x4Float<Vec4f, Mat4x4f>
    {
    public:
  
      /// Construct a Mat4x4f from four Vec4f vectors
      Mat4x4f(Vec4f _a, Vec4f _b, Vec4f _c, Vec4f _d): 
        ArithSqMat4x4Float<Vec4f, Mat4x4f> (_a,_b,_c,_d) {}
  
      /// Construct the NaN matrix
      Mat4x4f() {}

      /// Construct a matrix with identical elements.
      explicit Mat4x4f(float a) : ArithSqMat4x4Float<Vec4f, Mat4x4f> (a) {}
    };

  /// Create a rotation _matrix. Rotates about one of the major axes.
  Mat4x4f rotation_Mat4x4f(CGLA::Axis axis, float angle);

  /// Create a translation matrix
  Mat4x4f translation_Mat4x4f(const Vec3f&);

  /// Create a scaling matrix.
  Mat4x4f scaling_Mat4x4f(const Vec3f&);

  /// Create an identity matrix.
  inline Mat4x4f identity_Mat4x4f()
    {
      return Mat4x4f(Vec4f(1,0,0,0), 
                     Vec4f(0,1,0,0), 
                     Vec4f(0,0,1,0), 
                     Vec4f(0,0,0,1));
    }

  /** Compute inverse assuming that the upper-left 3x3 sub-matrix is
      orthonormal (which is the case if the transformation is only
      a concatenation of rotations and translations).
  */
  inline Mat4x4f invert_ortho(const Mat4x4f& m)
  {
    Vec3f rx(m[0][0], m[1][0], m[2][0]);
    Vec3f ry(m[0][1], m[1][1], m[2][1]);
    Vec3f rz(m[0][2], m[1][2], m[2][2]);
    Vec3f t(m[0][3], m[1][3], m[2][3]);

    return Mat4x4f(Vec4f(rx, -dot(t, rx)),
                   Vec4f(ry, -dot(t, ry)),
                   Vec4f(rz, -dot(t, rz)),
                   Vec4f(0.0, 0.0, 0.0, 1.0));
  }   
}
#endif