// This code is in the public domain -- castanyo@yahoo.es

#ifndef NV_MATH_MATRIX_H
#define NV_MATH_MATRIX_H

#include <nvmath/nvmath.h>
#include <nvmath/Vector.h>

namespace nv
{

// @@ Use scalar defined in Vector.h, but should use a template instead.

/// 4x4 transformation matrix.
/// -# Matrices are stored in memory in column major order.
/// -# Points are to be though of as column vectors.
/// -# Transformation of a point p by a matrix M is: p' = M * p
class NVMATH_CLASS Matrix
{
public:
	typedef Matrix const & Arg;

	Matrix();
	Matrix(zero_t);
	Matrix(identity_t);
	Matrix(const Matrix & m);

	scalar data(uint idx) const;
	scalar & data(uint idx);
	scalar get(uint row, uint col) const;
	scalar operator()(uint row, uint col) const;
	scalar & operator()(uint row, uint col);
	const scalar * ptr() const;

	Vector4 row(uint i) const;
	Vector4 column(uint i) const;

	void scale(scalar s);
	void scale(Vector3::Arg s);
	void translate(Vector3::Arg t);
	void rotate(scalar theta, scalar v0, scalar v1, scalar v2);
    scalar determinant() const;

	void apply(Matrix::Arg m);

private:
	scalar m_data[16];
};


inline Matrix::Matrix()
{
}

inline Matrix::Matrix(zero_t)
{
	for(int i = 0; i < 16; i++) {
		m_data[i] = 0.0f;
	}
}

inline Matrix::Matrix(identity_t)
{
	for(int i = 0; i < 4; i++) {
		for(int j = 0; j < 4; j++) {
			m_data[4*j+i] = (i == j) ? 1.0f : 0.0f;
		}
	}
}

inline Matrix::Matrix(const Matrix & m)
{
	for(int i = 0; i < 16; i++) {
		m_data[i] = m.m_data[i];
	}
}


// Accessors
inline scalar Matrix::data(uint idx) const
{
	nvDebugCheck(idx < 16);
	return m_data[idx];
}
inline scalar & Matrix::data(uint idx)
{
	nvDebugCheck(idx < 16);
	return m_data[idx];
}
inline scalar Matrix::get(uint row, uint col) const
{
	nvDebugCheck(row < 4 && col < 4);
	return m_data[col * 4 + row];
}
inline scalar Matrix::operator()(uint row, uint col) const
{
	nvDebugCheck(row < 4 && col < 4);
	return m_data[col * 4 + row];
}
inline scalar & Matrix::operator()(uint row, uint col)
{
	nvDebugCheck(row < 4 && col < 4);
	return m_data[col * 4 + row];
}

inline const scalar * Matrix::ptr() const
{
	return m_data;
}

inline Vector4 Matrix::row(uint i) const
{
	nvDebugCheck(i < 4);
	return Vector4(get(i, 0), get(i, 1), get(i, 2), get(i, 3));
}

inline Vector4 Matrix::column(uint i) const
{
	nvDebugCheck(i < 4);
	return Vector4(get(0, i), get(1, i), get(2, i), get(3, i));
}

/// Apply scale.
inline void Matrix::scale(scalar s)
{
	m_data[0] *= s; m_data[1] *= s; m_data[2] *= s; m_data[3] *= s;
	m_data[4] *= s; m_data[5] *= s; m_data[6] *= s; m_data[7] *= s;
	m_data[8] *= s; m_data[9] *= s; m_data[10] *= s; m_data[11] *= s;
    m_data[12] *= s; m_data[13] *= s; m_data[14] *= s; m_data[15] *= s;
}

/// Apply scale.
inline void Matrix::scale(Vector3::Arg s)
{
	m_data[0] *= s.x(); m_data[1] *= s.x(); m_data[2] *= s.x(); m_data[3] *= s.x();
	m_data[4] *= s.y(); m_data[5] *= s.y(); m_data[6] *= s.y(); m_data[7] *= s.y();
	m_data[8] *= s.z(); m_data[9] *= s.z(); m_data[10] *= s.z(); m_data[11] *= s.z();
}

/// Apply translation.
inline void Matrix::translate(Vector3::Arg t)
{
	m_data[12] = m_data[0] * t.x() + m_data[4] * t.y() + m_data[8]  * t.z() + m_data[12];
	m_data[13] = m_data[1] * t.x() + m_data[5] * t.y() + m_data[9]  * t.z() + m_data[13];
	m_data[14] = m_data[2] * t.x() + m_data[6] * t.y() + m_data[10] * t.z() + m_data[14];
	m_data[15] = m_data[3] * t.x() + m_data[7] * t.y() + m_data[11] * t.z() + m_data[15];
}

Matrix rotation(scalar theta, scalar v0, scalar v1, scalar v2);

/// Apply rotation.
inline void Matrix::rotate(scalar theta, scalar v0, scalar v1, scalar v2)
{
	Matrix R(rotation(theta, v0, v1, v2));
	apply(R);
}

/// Apply transform.
inline void Matrix::apply(Matrix::Arg m)
{
	nvDebugCheck(this != &m);

	for(int i = 0; i < 4; i++) {
		const scalar ai0 = get(i,0), ai1 = get(i,1), ai2 = get(i,2), ai3 = get(i,3);
		m_data[0 + i] = ai0 * m(0,0) + ai1 * m(1,0) + ai2 * m(2,0) + ai3 * m(3,0);
		m_data[4 + i] = ai0 * m(0,1) + ai1 * m(1,1) + ai2 * m(2,1) + ai3 * m(3,1);
		m_data[8 + i] = ai0 * m(0,2) + ai1 * m(1,2) + ai2 * m(2,2) + ai3 * m(3,2);
		m_data[12+ i] = ai0 * m(0,3) + ai1 * m(1,3) + ai2 * m(2,3) + ai3 * m(3,3);
	}
}

/// Get scale matrix.
inline Matrix scale(Vector3::Arg s)
{
	Matrix m(identity);
	m(0,0) = s.x();
	m(1,1) = s.y();
	m(2,2) = s.z();
	return m;
}

/// Get scale matrix.
inline Matrix scale(scalar s)
{
	Matrix m(identity);
	m(0,0) = m(1,1) = m(2,2) = s;
	return m;
}

/// Get translation matrix.
inline Matrix translation(Vector3::Arg t)
{
	Matrix m(identity);
	m(0,3) = t.x();
	m(1,3) = t.y();
	m(2,3) = t.z();
	return m;
}

/// Get rotation matrix.
inline Matrix rotation(scalar theta, scalar v0, scalar v1, scalar v2)
{
	scalar cost = cosf(theta);
	scalar sint = sinf(theta);

	Matrix m(identity);

	if( 1 == v0 && 0 == v1 && 0 == v2 ) {
		m(1,1) = cost; m(2,1) = -sint;
		m(1,2) = sint; m(2,2) = cost;
	}
	else if( 0 == v0  && 1 == v1 && 0 == v2 ) {
		m(0,0) = cost; m(2,0) = sint;
		m(1,2) = -sint; m(2,2) = cost;
	}
	else if( 0 == v0 && 0 == v1 && 1 == v2 ) {
		m(0,0) = cost; m(1,0) = -sint;
		m(0,1) = sint; m(1,1) = cost;
	}
	else {
		scalar a2, b2, c2;
		a2 = v0 * v0;
		b2 = v1 * v1;
		c2 = v2 * v2;

		scalar iscale = 1.0f / sqrtf(a2 + b2 + c2);
		v0 *= iscale;
		v1 *= iscale;
		v2 *= iscale;

		scalar abm, acm, bcm;
		scalar mcos, asin, bsin, csin;
		mcos = 1.0f - cost;
		abm = v0 * v1 * mcos;
		acm = v0 * v2 * mcos;
		bcm = v1 * v2 * mcos;
		asin = v0 * sint;
		bsin = v1 * sint;
		csin = v2 * sint;
		m(0,0) = a2 * mcos + cost;
		m(1,0) = abm - csin;
		m(2,0) = acm + bsin;
		m(3,0) = abm + csin;
		m(1,1) = b2 * mcos + cost;
		m(2,1) = bcm - asin;
		m(3,1) = acm - bsin;
		m(1,2) = bcm + asin;
		m(2,2) = c2 * mcos + cost;
	}
	return m;
}

//Matrix rotation(scalar yaw, scalar pitch, scalar roll);
//Matrix skew(scalar angle, Vector3::Arg v1, Vector3::Arg v2);

/// Get frustum matrix.
inline Matrix frustum(scalar xmin, scalar xmax, scalar ymin, scalar ymax, scalar zNear, scalar zFar)
{
	Matrix m(zero);

	scalar doubleznear = 2.0f * zNear;
	scalar one_deltax = 1.0f / (xmax - xmin);
	scalar one_deltay = 1.0f / (ymax - ymin);
	scalar one_deltaz = 1.0f / (zFar - zNear);

	m(0,0) = doubleznear * one_deltax;
	m(1,1) = doubleznear * one_deltay;
	m(0,2) = (xmax + xmin) * one_deltax;
	m(1,2) = (ymax + ymin) * one_deltay;
	m(2,2) = -(zFar + zNear) * one_deltaz;
	m(3,2) = -1.0f;
	m(2,3) = -(zFar * doubleznear) * one_deltaz;

	return m;
}

/// Get infinite frustum matrix.
inline Matrix frustum(scalar xmin, scalar xmax, scalar ymin, scalar ymax, scalar zNear)
{
	Matrix m(zero);

	scalar doubleznear = 2.0f * zNear;
	scalar one_deltax = 1.0f / (xmax - xmin);
	scalar one_deltay = 1.0f / (ymax - ymin);
	scalar nudge = 1.0; // 0.999;

	m(0,0) = doubleznear * one_deltax;
	m(1,1) = doubleznear * one_deltay;
	m(0,2) = (xmax + xmin) * one_deltax;
	m(1,2) = (ymax + ymin) * one_deltay;
	m(2,2) = -1.0f * nudge;
	m(3,2) = -1.0f;
	m(2,3) = -doubleznear * nudge;

	return m;
}

/// Get perspective matrix.
inline Matrix perspective(scalar fovy, scalar aspect, scalar zNear, scalar zFar)
{
	scalar xmax = zNear * tan(fovy / 2);
	scalar xmin = -xmax;

	scalar ymax = xmax / aspect;
	scalar ymin = -ymax;

	return frustum(xmin, xmax, ymin, ymax, zNear, zFar);
}

/// Get infinite perspective matrix.
inline Matrix perspective(scalar fovy, scalar aspect, scalar zNear)
{
	scalar x = zNear * tan(fovy / 2);
	scalar y = x / aspect;
	return frustum( -x, x, -y, y, zNear );
}

/// Get matrix determinant.
inline scalar Matrix::determinant() const
{
	return
		m_data[3] * m_data[6] * m_data[ 9] * m_data[12] - m_data[2] * m_data[7] * m_data[ 9] * m_data[12] - m_data[3] * m_data[5] * m_data[10] * m_data[12] + m_data[1] * m_data[7] * m_data[10] * m_data[12] +
		m_data[2] * m_data[5] * m_data[11] * m_data[12] - m_data[1] * m_data[6] * m_data[11] * m_data[12] - m_data[3] * m_data[6] * m_data[ 8] * m_data[13] + m_data[2] * m_data[7] * m_data[ 8] * m_data[13] +
		m_data[3] * m_data[4] * m_data[10] * m_data[13] - m_data[0] * m_data[7] * m_data[10] * m_data[13] - m_data[2] * m_data[4] * m_data[11] * m_data[13] + m_data[0] * m_data[6] * m_data[11] * m_data[13] +
		m_data[3] * m_data[5] * m_data[ 8] * m_data[14] - m_data[1] * m_data[7] * m_data[ 8] * m_data[14] - m_data[3] * m_data[4] * m_data[ 9] * m_data[14] + m_data[0] * m_data[7] * m_data[ 9] * m_data[14] +
		m_data[1] * m_data[4] * m_data[11] * m_data[14] - m_data[0] * m_data[5] * m_data[11] * m_data[14] - m_data[2] * m_data[5] * m_data[ 8] * m_data[15] + m_data[1] * m_data[6] * m_data[ 8] * m_data[15] +
		m_data[2] * m_data[4] * m_data[ 9] * m_data[15] - m_data[0] * m_data[6] * m_data[ 9] * m_data[15] - m_data[1] * m_data[4] * m_data[10] * m_data[15] + m_data[0] * m_data[5] * m_data[10] * m_data[15];
}

inline Matrix transpose(Matrix::Arg m)
{
	Matrix r;
	for (int i = 0; i < 4; i++)
	{
		for (int j = 0; j < 4; j++)
		{
			r(i, j) = m(j, i);
		}
	}
	return r;
}

inline Matrix inverse(Matrix::Arg m)
{
   Matrix r;
   r.data( 0) = m.data(6)*m.data(11)*m.data(13) - m.data(7)*m.data(10)*m.data(13) + m.data(7)*m.data(9)*m.data(14) - m.data(5)*m.data(11)*m.data(14) - m.data(6)*m.data(9)*m.data(15) + m.data(5)*m.data(10)*m.data(15);
   r.data( 1) = m.data(3)*m.data(10)*m.data(13) - m.data(2)*m.data(11)*m.data(13) - m.data(3)*m.data(9)*m.data(14) + m.data(1)*m.data(11)*m.data(14) + m.data(2)*m.data(9)*m.data(15) - m.data(1)*m.data(10)*m.data(15);
   r.data( 2) = m.data(2)*m.data( 7)*m.data(13) - m.data(3)*m.data( 6)*m.data(13) + m.data(3)*m.data(5)*m.data(14) - m.data(1)*m.data( 7)*m.data(14) - m.data(2)*m.data(5)*m.data(15) + m.data(1)*m.data( 6)*m.data(15);
   r.data( 3) = m.data(3)*m.data( 6)*m.data( 9) - m.data(2)*m.data( 7)*m.data( 9) - m.data(3)*m.data(5)*m.data(10) + m.data(1)*m.data( 7)*m.data(10) + m.data(2)*m.data(5)*m.data(11) - m.data(1)*m.data( 6)*m.data(11);
   r.data( 4) = m.data(7)*m.data(10)*m.data(12) - m.data(6)*m.data(11)*m.data(12) - m.data(7)*m.data(8)*m.data(14) + m.data(4)*m.data(11)*m.data(14) + m.data(6)*m.data(8)*m.data(15) - m.data(4)*m.data(10)*m.data(15);
   r.data( 5) = m.data(2)*m.data(11)*m.data(12) - m.data(3)*m.data(10)*m.data(12) + m.data(3)*m.data(8)*m.data(14) - m.data(0)*m.data(11)*m.data(14) - m.data(2)*m.data(8)*m.data(15) + m.data(0)*m.data(10)*m.data(15);
   r.data( 6) = m.data(3)*m.data( 6)*m.data(12) - m.data(2)*m.data( 7)*m.data(12) - m.data(3)*m.data(4)*m.data(14) + m.data(0)*m.data( 7)*m.data(14) + m.data(2)*m.data(4)*m.data(15) - m.data(0)*m.data( 6)*m.data(15);
   r.data( 7) = m.data(2)*m.data( 7)*m.data( 8) - m.data(3)*m.data( 6)*m.data( 8) + m.data(3)*m.data(4)*m.data(10) - m.data(0)*m.data( 7)*m.data(10) - m.data(2)*m.data(4)*m.data(11) + m.data(0)*m.data( 6)*m.data(11);
   r.data( 8) = m.data(5)*m.data(11)*m.data(12) - m.data(7)*m.data( 9)*m.data(12) + m.data(7)*m.data(8)*m.data(13) - m.data(4)*m.data(11)*m.data(13) - m.data(5)*m.data(8)*m.data(15) + m.data(4)*m.data( 9)*m.data(15);
   r.data( 9) = m.data(3)*m.data( 9)*m.data(12) - m.data(1)*m.data(11)*m.data(12) - m.data(3)*m.data(8)*m.data(13) + m.data(0)*m.data(11)*m.data(13) + m.data(1)*m.data(8)*m.data(15) - m.data(0)*m.data( 9)*m.data(15);
   r.data(10) = m.data(1)*m.data( 7)*m.data(12) - m.data(3)*m.data( 5)*m.data(12) + m.data(3)*m.data(4)*m.data(13) - m.data(0)*m.data( 7)*m.data(13) - m.data(1)*m.data(4)*m.data(15) + m.data(0)*m.data( 5)*m.data(15);
   r.data(11) = m.data(3)*m.data( 5)*m.data( 8) - m.data(1)*m.data( 7)*m.data( 8) - m.data(3)*m.data(4)*m.data( 9) + m.data(0)*m.data( 7)*m.data( 9) + m.data(1)*m.data(4)*m.data(11) - m.data(0)*m.data( 5)*m.data(11);
   r.data(12) = m.data(6)*m.data( 9)*m.data(12) - m.data(5)*m.data(10)*m.data(12) - m.data(6)*m.data(8)*m.data(13) + m.data(4)*m.data(10)*m.data(13) + m.data(5)*m.data(8)*m.data(14) - m.data(4)*m.data( 9)*m.data(14);
   r.data(13) = m.data(1)*m.data(10)*m.data(12) - m.data(2)*m.data( 9)*m.data(12) + m.data(2)*m.data(8)*m.data(13) - m.data(0)*m.data(10)*m.data(13) - m.data(1)*m.data(8)*m.data(14) + m.data(0)*m.data( 9)*m.data(14);
   r.data(14) = m.data(2)*m.data( 5)*m.data(12) - m.data(1)*m.data( 6)*m.data(12) - m.data(2)*m.data(4)*m.data(13) + m.data(0)*m.data( 6)*m.data(13) + m.data(1)*m.data(4)*m.data(14) - m.data(0)*m.data( 5)*m.data(14);
   r.data(15) = m.data(1)*m.data( 6)*m.data( 8) - m.data(2)*m.data( 5)*m.data( 8) + m.data(2)*m.data(4)*m.data( 9) - m.data(0)*m.data( 6)*m.data( 9) - m.data(1)*m.data(4)*m.data(10) + m.data(0)*m.data( 5)*m.data(10);
   r.scale(1.0f / m.determinant());
   return r;
}

inline Matrix isometryInverse(Matrix::Arg m)
{
	Matrix r(identity);

	// transposed 3x3 upper left matrix
	for (int i = 0; i < 3; i++)
	{
		for (int j = 0; j < 3; j++)
		{
			r(i, j) = m(j, i);
		}
	}

	// translate by the negative offsets
	r.translate(-Vector3(m.data(12), m.data(13), m.data(14)));

	return r;
}

//Matrix affineInverse(Matrix::Arg m);

/// Transform the given 3d point with the given matrix.
inline Vector3 transformPoint(Matrix::Arg m, Vector3::Arg p)
{
	return Vector3(
		p.x() * m(0,0) + p.y() * m(0,1) + p.z() * m(0,2) + m(0,3),
		p.x() * m(1,0) + p.y() * m(1,1) + p.z() * m(1,2) + m(1,3),
		p.x() * m(2,0) + p.y() * m(2,1) + p.z() * m(2,2) + m(2,3));
}

/// Transform the given 3d vector with the given matrix.
inline Vector3 transformVector(Matrix::Arg m, Vector3::Arg p)
{
	return Vector3(
		p.x() * m(0,0) + p.y() * m(0,1) + p.z() * m(0,2),
		p.x() * m(1,0) + p.y() * m(1,1) + p.z() * m(1,2),
		p.x() * m(2,0) + p.y() * m(2,1) + p.z() * m(2,2));
}

/// Transform the given 4d vector with the given matrix.
inline Vector4 transform(Matrix::Arg m, Vector4::Arg p)
{
	return Vector4(
		p.x() * m(0,0) + p.y() * m(0,1) + p.z() * m(0,2) + p.w() * m(0,3),
		p.x() * m(1,0) + p.y() * m(1,1) + p.z() * m(1,2) + p.w() * m(1,3),
		p.x() * m(2,0) + p.y() * m(2,1) + p.z() * m(2,2) + p.w() * m(2,3),
		p.x() * m(3,0) + p.y() * m(3,1) + p.z() * m(3,2) + p.w() * m(3,3));
}

inline Matrix mul(Matrix::Arg a, Matrix::Arg b)
{
	// @@ Is this the right order? mul(a, b) = b * a
	Matrix m = a;
	m.apply(b);
	return m;
}

} // nv namespace




#if 0
	/** @name Special matrices. */
	//@{
	/** Generate a translation matrix. */
	void TranslationMatrix(const Vec3 & v) {
		data[0] = 1; data[1] = 0; data[2] = 0; data[3] = 0;
		data[4] = 0; data[5] = 1; data[6] = 0; data[7] = 0;
		data[8] = 0; data[9] = 0; data[10] = 1; data[11] = 0;
		data[12] = v.x; data[13] = v.y; data[14] = v.z; data[15] = 1;
	}

	/** Rotate theta degrees around v. */
	void RotationMatrix( scalar theta, scalar v0, scalar v1, scalar v2 ) {
		scalar cost = cos(theta);
		scalar sint = sin(theta);

		if( 1 == v0 && 0 == v1 && 0 == v2 ) {
			data[0] = 1.0f;	data[1] = 0.0f;	data[2] = 0.0f;	data[3] = 0.0f;
	        data[4] = 0.0f;	data[5] = cost;	data[6] = -sint;data[7] = 0.0f;
		    data[8] = 0.0f;	data[9] = sint;	data[10] = cost;data[11] = 0.0f;
			data[12] = 0.0f;data[13] = 0.0f;data[14] = 0.0f;data[15] = 1.0f;
	    }
		else if( 0 == v0  && 1 == v1 && 0 == v2 ) {
	        data[0] = cost;	data[1] = 0.0f;	data[2] = sint;	data[3] = 0.0f;
		    data[4] = 0.0f;	data[5] = 1.0f;	data[6] = 0.0f;	data[7] = 0.0f;
			data[8] = -sint;data[9] = 0.0f;data[10] = cost;	data[11] = 0.0f;
			data[12] = 0.0f;data[13] = 0.0f;data[14] = 0.0f;data[15] = 1.0f;
	    }
		else if( 0 == v0 && 0 == v1 && 1 == v2 ) {
			data[0] = cost;	data[1] = -sint;data[2] = 0.0f;	data[3] = 0.0f;
	        data[4] = sint; data[5] = cost;	data[6] = 0.0f;	data[7] = 0.0f;
		    data[8] = 0.0f;	data[9] = 0.0f;	data[10] = 1.0f;data[11] = 0.0f;
			data[12] = 0.0f;data[13] = 0.0f;data[14] = 0.0f;data[15] = 1.0f;
	    }
		else {
			//we need scale a,b,c to unit length.
			scalar a2, b2, c2;
	        a2 = v0 * v0;
		    b2 = v1 * v1;
			c2 = v2 * v2;

			scalar iscale = 1.0f / sqrtf(a2 + b2 + c2);
			v0 *= iscale;
			v1 *= iscale;
			v2 *= iscale;

			scalar abm, acm, bcm;
			scalar mcos, asin, bsin, csin;
	        mcos = 1.0f - cost;
		    abm = v0 * v1 * mcos;
			acm = v0 * v2 * mcos;
	        bcm = v1 * v2 * mcos;
		    asin = v0 * sint;
			bsin = v1 * sint;
	        csin = v2 * sint;
		    data[0] = a2 * mcos + cost;
			data[1] = abm - csin;
	        data[2] = acm + bsin;
		    data[3] = abm + csin;
			data[4] = 0.0f;
	        data[5] = b2 * mcos + cost;
		    data[6] = bcm - asin;
			data[7] = acm - bsin;
			data[8] = 0.0f;
		    data[9] = bcm + asin;
			data[10] = c2 * mcos + cost;
			data[11] = 0.0f;
			data[12] = 0.0f;
			data[13] = 0.0f;
			data[14] = 0.0f;
			data[15] = 1.0f;
		}
	}

	/*
	void SkewMatrix(scalar angle, const Vec3 & v1, const Vec3 & v2) {
		v1.Normalize();
		v2.Normalize();

		Vec3 v3;
		v3.Cross(v1, v2);
		v3.Normalize();

		// Get skew factor.
		scalar costheta = Vec3DotProduct(v1, v2);
		scalar sintheta = Real.Sqrt(1 - costheta * costheta);
		scalar skew = tan(Trig.DegreesToRadians(angle) + acos(sintheta)) * sintheta - costheta;

		// Build orthonormal matrix.
		v1 = FXVector3.Cross(v3, v2);
		v1.Normalize();

		Matrix R = Matrix::Identity;
		R[0, 0] = v3.X; // Not sure this is in the correct order...
		R[1, 0] = v3.Y;
		R[2, 0] = v3.Z;
		R[0, 1] = v1.X;
		R[1, 1] = v1.Y;
		R[2, 1] = v1.Z;
		R[0, 2] = v2.X;
		R[1, 2] = v2.Y;
		R[2, 2] = v2.Z;

		// Build skew matrix.
		Matrix S = Matrix::Identity;
		S[2, 1] = -skew;

		// Return skew transform.
		return R * S * R.Transpose;	// Not sure this is in the correct order...
	}
	*/

	/**
	 * Generate rotation matrix for the euler angles. This is the same as computing
	 * 3 rotation matrices and multiplying them together in our custom order.
	 *
	 * @todo Have to recompute this code for our new convention.
	**/
	void RotationMatrix( scalar yaw, scalar pitch, scalar roll ) {
		scalar sy = sin(yaw+ToRadian(90));
		scalar cy = cos(yaw+ToRadian(90));
		scalar sp = sin(pitch-ToRadian(90));
		scalar cp = cos(pitch-ToRadian(90));
		scalar sr = sin(roll);
		scalar cr = cos(roll);

		data[0] = cr*cy + sr*sp*sy;
		data[1] = cp*sy;
		data[2] = -sr*cy + cr*sp*sy;
		data[3] = 0;

		data[4] = -cr*sy + sr*sp*cy;
		data[5] = cp*cy;
		data[6] = sr*sy + cr*sp*cy;
		data[7] = 0;

		data[8] = sr*cp;
		data[9] = -sp;
		data[10] = cr*cp;
		data[11] = 0;

		data[12] = 0;
		data[13] = 0;
		data[14] = 0;
		data[15] = 1;
	}

	/** Create a frustum matrix with the far plane at the infinity. */
	void Frustum( scalar xmin, scalar xmax, scalar ymin, scalar ymax, scalar zNear, scalar zFar ) {
		scalar one_deltax, one_deltay, one_deltaz, doubleznear;

		doubleznear = 2.0f * zNear;
		one_deltax = 1.0f / (xmax - xmin);
		one_deltay = 1.0f / (ymax - ymin);
		one_deltaz = 1.0f / (zFar - zNear);

		data[0] = (scalar)(doubleznear * one_deltax);
		data[1] = 0.0f;
		data[2] = 0.0f;
		data[3] = 0.0f;
		data[4] = 0.0f;
		data[5] = (scalar)(doubleznear * one_deltay);
		data[6] = 0.f;
		data[7] = 0.f;
		data[8] = (scalar)((xmax + xmin) * one_deltax);
		data[9] = (scalar)((ymax + ymin) * one_deltay);
		data[10] = (scalar)(-(zFar + zNear) * one_deltaz);
		data[11] = -1.f;
		data[12] = 0.f;
		data[13] = 0.f;
		data[14] = (scalar)(-(zFar * doubleznear) * one_deltaz);
		data[15] = 0.f;
	}

	/** Create a frustum matrix with the far plane at the infinity. */
	void FrustumInf( scalar xmin, scalar xmax, scalar ymin, scalar ymax, scalar zNear ) {
		scalar one_deltax, one_deltay, doubleznear, nudge;

		doubleznear = 2.0f * zNear;
		one_deltax = 1.0f / (xmax - xmin);
		one_deltay = 1.0f / (ymax - ymin);
	    nudge = 1.0; // 0.999;

		data[0] = doubleznear * one_deltax;
		data[1] = 0.0f;
		data[2] = 0.0f;
		data[3] = 0.0f;

		data[4] = 0.0f;
		data[5] = doubleznear * one_deltay;
		data[6] = 0.f;
		data[7] = 0.f;

		data[8] = (xmax + xmin) * one_deltax;
		data[9] = (ymax + ymin) * one_deltay;
		data[10] = -1.0f * nudge;
		data[11] = -1.0f;

		data[12] = 0.f;
		data[13] = 0.f;
		data[14] = -doubleznear * nudge;
		data[15] = 0.f;
	}

	/** Create an inverse frustum matrix with the far plane at the infinity. */
	void FrustumInfInv( scalar left, scalar right, scalar bottom, scalar top, scalar zNear ) {
		// this matrix is wrong (not tested scalarly) I think it should be transposed.
		data[0] = (right - left) / (2 * zNear);
		data[1] = 0;
		data[2] = 0;
		data[3] = (right + left) / (2 * zNear);
		data[4] = 0;
		data[5] = (top - bottom) / (2 * zNear);
		data[6] = 0;
		data[7] = (top + bottom) / (2 * zNear);
		data[8] = 0;
		data[9] = 0;
		data[10] = 0;
		data[11] = -1;
		data[12] = 0;
		data[13] = 0;
		data[14] = -1 / (2 * zNear);
		data[15] = 1 / (2 * zNear);
	}

	/** Create an homogeneous projection matrix. */
	void Perspective( scalar fov, scalar aspect, scalar zNear, scalar zFar ) {
		scalar xmin, xmax, ymin, ymax;

		xmax = zNear * tan( fov/2 );
		xmin = -xmax;

		ymax = xmax / aspect;
		ymin = -ymax;

		Frustum(xmin, xmax, ymin, ymax, zNear, zFar);
	}

	/** Create a projection matrix with the far plane at the infinity. */
	void PerspectiveInf( scalar fov, scalar aspect, scalar zNear ) {
		scalar x = zNear * tan( fov/2 );
		scalar y = x / aspect;
		FrustumInf( -x, x, -y, y, zNear );
	}

	/** Create an inverse projection matrix with far plane at the infinity. */
	void PerspectiveInfInv( scalar fov, scalar aspect, scalar zNear ) {
		scalar x = zNear * tan( fov/2 );
		scalar y = x / aspect;
		FrustumInfInv( -x, x, -y, y, zNear );
	}

	/** Build bone matrix from quatertion and offset. */
	void BoneMatrix(const Quat & q, const Vec3 & offset) {
		scalar x2, y2, z2, xx, xy, xz, yy, yz, zz, wx, wy, wz;

		// calculate coefficients
		x2 = q.x + q.x;
		y2 = q.y + q.y;
		z2 = q.z + q.z;

		xx = q.x * x2;   xy = q.x * y2;   xz = q.x * z2;
		yy = q.y * y2;   yz = q.y * z2;   zz = q.z * z2;
		wx = q.w * x2;   wy = q.w * y2;   wz = q.w * z2;

		data[0] = 1.0f - (yy + zz);
		data[1] = xy - wz;
		data[2] = xz + wy;
		data[3] = 0.0f;

		data[4] = xy + wz;
		data[5] = 1.0f - (xx + zz);
		data[6] = yz - wx;
		data[7] = 0.0f;

		data[8] = xz - wy;
		data[9] = yz + wx;
		data[10] = 1.0f - (xx + yy);
		data[11] = 0.0f;

		data[12] = offset.x;
		data[13] = offset.y;
		data[14] = offset.z;
		data[15] = 1.0f;
	}

	//@}


	/** @name Transformations: */
	//@{

	/** Apply a general scale. */
	void Scale( scalar x, scalar y, scalar z ) {
		data[0] *= x;	data[4] *= y;	data[8]  *= z;
		data[1] *= x;	data[5] *= y;	data[9]  *= z;
		data[2] *= x;	data[6] *= y;	data[10] *= z;
		data[3] *= x;	data[7] *= y;	data[11] *= z;
	}

	/** Apply a rotation of theta degrees around the axis v*/
	void Rotate( scalar theta, const Vec3 & v ) {
		Matrix b;
		b.RotationMatrix( theta, v[0], v[1], v[2] );
		Multiply4x3( b );
	}

	/** Apply a rotation of theta degrees around the axis v*/
	void Rotate( scalar theta, scalar v0, scalar v1, scalar v2 ) {
		Matrix b;
		b.RotationMatrix( theta, v0, v1, v2 );
		Multiply4x3( b );
	}

	/**
	 * Translate the matrix by t. This is the same as multiplying by a
	 * translation matrix with the given offset.
	 * this = T * this
	 */
	void Translate( const Vec3 &t ) {
		data[12] = data[0] * t.x + data[4] * t.y + data[8]  * t.z + data[12];
		data[13] = data[1] * t.x + data[5] * t.y + data[9]  * t.z + data[13];
		data[14] = data[2] * t.x + data[6] * t.y + data[10] * t.z + data[14];
		data[15] = data[3] * t.x + data[7] * t.y + data[11] * t.z + data[15];
	}

	/**
	 * Translate the matrix by x, y, z. This is the same as multiplying by a
	 * translation matrix with the given offsets.
	 */
	void Translate( scalar x, scalar y, scalar z ) {
		data[12] = data[0] * x + data[4] * y + data[8]  * z + data[12];
		data[13] = data[1] * x + data[5] * y + data[9]  * z + data[13];
		data[14] = data[2] * x + data[6] * y + data[10] * z + data[14];
		data[15] = data[3] * x + data[7] * y + data[11] * z + data[15];
	}

	/** Compute the transposed matrix. */
	void Transpose() {
		piSwap(data[1], data[4]);
		piSwap(data[2], data[8]);
		piSwap(data[6], data[9]);
		piSwap(data[3], data[12]);
		piSwap(data[7], data[13]);
		piSwap(data[11], data[14]);
	}

	/** Compute the inverse of a rigid-body/isometry/orthonormal matrix. */
	void IsometryInverse() {
		// transposed 3x3 upper left matrix
		piSwap(data[1], data[4]);
		piSwap(data[2], data[8]);
		piSwap(data[6], data[9]);

		// translate by the negative offsets
		Vec3 v(-data[12], -data[13], -data[14]);
		data[12] = data[13] = data[14] = 0;
		Translate(v);
	}

	/** Compute the inverse of the affine portion of this matrix. */
	void AffineInverse() {
		data[12] = data[13] = data[14] = 0;
		Transpose();
	}
	//@}

	/** @name Matrix operations: */
	//@{

	/** Return the determinant of this matrix. */
	scalar Determinant() const {
		return	data[0] * data[5] * data[10] * data[15] +
				data[1] * data[6] * data[11] * data[12] +
				data[2] * data[7] * data[ 8] * data[13] +
				data[3] * data[4] * data[ 9] * data[14] -
				data[3] * data[6] * data[ 9] * data[12] -
				data[2] * data[5] * data[ 8] * data[15] -
				data[1] * data[4] * data[11] * data[14] -
				data[0] * data[7] * data[10] * data[12];
	}


	/** Standard matrix product: this *= B. */
	void Multiply4x4( const Matrix & restrict B ) {
		Multiply4x4(*this, B);
	}

	/** Standard matrix product: this = A * B. this != B*/
	void Multiply4x4( const Matrix & A, const Matrix & restrict B ) {
		piDebugCheck(this != &B);

		for(int i = 0; i < 4; i++) {
			const scalar ai0 = A(i,0), ai1 = A(i,1), ai2 = A(i,2), ai3 = A(i,3);
			GetElem(i,0) = ai0 * B(0,0) + ai1 * B(1,0) + ai2 * B(2,0) + ai3 * B(3,0);
			GetElem(i,1) = ai0 * B(0,1) + ai1 * B(1,1) + ai2 * B(2,1) + ai3 * B(3,1);
			GetElem(i,2) = ai0 * B(0,2) + ai1 * B(1,2) + ai2 * B(2,2) + ai3 * B(3,2);
			GetElem(i,3) = ai0 * B(0,3) + ai1 * B(1,3) + ai2 * B(2,3) + ai3 * B(3,3);
		}

		/* Unrolled but does not allow this == A
		data[0] = A.data[0] * B.data[0] + A.data[4] * B.data[1] + A.data[8] * B.data[2] + A.data[12] * B.data[3];
		data[1] = A.data[1] * B.data[0] + A.data[5] * B.data[1] + A.data[9] * B.data[2] + A.data[13] * B.data[3];
		data[2] = A.data[2] * B.data[0] + A.data[6] * B.data[1] + A.data[10] * B.data[2] + A.data[14] * B.data[3];
		data[3] = A.data[3] * B.data[0] + A.data[7] * B.data[1] + A.data[11] * B.data[2] + A.data[15] * B.data[3];
		data[4] = A.data[0] * B.data[4] + A.data[4] * B.data[5] + A.data[8] * B.data[6] + A.data[12] * B.data[7];
		data[5] = A.data[1] * B.data[4] + A.data[5] * B.data[5] + A.data[9] * B.data[6] + A.data[13] * B.data[7];
		data[6] = A.data[2] * B.data[4] + A.data[6] * B.data[5] + A.data[10] * B.data[6] + A.data[14] * B.data[7];
		data[7] = A.data[3] * B.data[4] + A.data[7] * B.data[5] + A.data[11] * B.data[6] + A.data[15] * B.data[7];
		data[8] = A.data[0] * B.data[8] + A.data[4] * B.data[9] + A.data[8] * B.data[10] + A.data[12] * B.data[11];
		data[9] = A.data[1] * B.data[8] + A.data[5] * B.data[9] + A.data[9] * B.data[10] + A.data[13] * B.data[11];
		data[10]= A.data[2] * B.data[8] + A.data[6] * B.data[9] + A.data[10] * B.data[10] + A.data[14] * B.data[11];
		data[11]= A.data[3] * B.data[8] + A.data[7] * B.data[9] + A.data[11] * B.data[10] + A.data[15] * B.data[11];
		data[12]= A.data[0] * B.data[12] + A.data[4] * B.data[13] + A.data[8] * B.data[14] + A.data[12] * B.data[15];
		data[13]= A.data[1] * B.data[12] + A.data[5] * B.data[13] + A.data[9] * B.data[14] + A.data[13] * B.data[15];
		data[14]= A.data[2] * B.data[12] + A.data[6] * B.data[13] + A.data[10] * B.data[14] + A.data[14] * B.data[15];
		data[15]= A.data[3] * B.data[12] + A.data[7] * B.data[13] + A.data[11] * B.data[14] + A.data[15] * B.data[15];
		*/
	}

	/** Standard matrix product: this *= B. */
	void Multiply4x3( const Matrix & restrict B ) {
		Multiply4x3(*this, B);
	}

	/** Standard product of matrices, where the last row is [0 0 0 1]. */
	void Multiply4x3( const Matrix & A, const Matrix & restrict B ) {
		piDebugCheck(this != &B);

		for(int i = 0; i < 3; i++) {
			const scalar ai0 = A(i,0), ai1 = A(i,1), ai2 = A(i,2), ai3 = A(i,3);
			GetElem(i,0) = ai0 * B(0,0) + ai1 * B(1,0) + ai2 * B(2,0) + ai3 * B(3,0);
			GetElem(i,1) = ai0 * B(0,1) + ai1 * B(1,1) + ai2 * B(2,1) + ai3 * B(3,1);
			GetElem(i,2) = ai0 * B(0,2) + ai1 * B(1,2) + ai2 * B(2,2) + ai3 * B(3,2);
			GetElem(i,3) = ai0 * B(0,3) + ai1 * B(1,3) + ai2 * B(2,3) + ai3 * B(3,3);
		}
		data[3] = 0.0f; data[7] = 0.0f; data[11] = 0.0f; data[15] = 1.0f;

		/* Unrolled but does not allow this == A
		data[0] = a.data[0] * b.data[0] + a.data[4] * b.data[1] + a.data[8] * b.data[2] + a.data[12] * b.data[3];
		data[1] = a.data[1] * b.data[0] + a.data[5] * b.data[1] + a.data[9] * b.data[2] + a.data[13] * b.data[3];
		data[2] = a.data[2] * b.data[0] + a.data[6] * b.data[1] + a.data[10] * b.data[2] + a.data[14] * b.data[3];
		data[3] = 0.0f;
		data[4] = a.data[0] * b.data[4] + a.data[4] * b.data[5] + a.data[8] * b.data[6] + a.data[12] * b.data[7];
		data[5] = a.data[1] * b.data[4] + a.data[5] * b.data[5] + a.data[9] * b.data[6] + a.data[13] * b.data[7];
		data[6] = a.data[2] * b.data[4] + a.data[6] * b.data[5] + a.data[10] * b.data[6] + a.data[14] * b.data[7];
		data[7] = 0.0f;
		data[8] = a.data[0] * b.data[8] + a.data[4] * b.data[9] + a.data[8] * b.data[10] + a.data[12] * b.data[11];
		data[9] = a.data[1] * b.data[8] + a.data[5] * b.data[9] + a.data[9] * b.data[10] + a.data[13] * b.data[11];
		data[10]= a.data[2] * b.data[8] + a.data[6] * b.data[9] + a.data[10] * b.data[10] + a.data[14] * b.data[11];
		data[11]= 0.0f;
		data[12]= a.data[0] * b.data[12] + a.data[4] * b.data[13] + a.data[8] * b.data[14] + a.data[12] * b.data[15];
		data[13]= a.data[1] * b.data[12] + a.data[5] * b.data[13] + a.data[9] * b.data[14] + a.data[13] * b.data[15];
		data[14]= a.data[2] * b.data[12] + a.data[6] * b.data[13] + a.data[10] * b.data[14] + a.data[14] * b.data[15];
		data[15]= 1.0f;
		*/
	}
	//@}


	/** @name Vector operations: */
	//@{

	/** Transform 3d vector (w=0). */
	void TransformVec3(const Vec3 & restrict orig, Vec3 * restrict dest) const {
		piDebugCheck(&orig != dest);
		dest->x = orig.x * data[0] + orig.y * data[4] + orig.z * data[8];
		dest->y = orig.x * data[1] + orig.y * data[5] + orig.z * data[9];
		dest->z = orig.x * data[2] + orig.y * data[6] + orig.z * data[10];
	}
	/** Transform 3d vector by the transpose (w=0). */
	void TransformVec3T(const Vec3 & restrict orig, Vec3 * restrict dest) const {
		piDebugCheck(&orig != dest);
		dest->x = orig.x * data[0] + orig.y * data[1] + orig.z * data[2];
		dest->y = orig.x * data[4] + orig.y * data[5] + orig.z * data[6];
		dest->z = orig.x * data[8] + orig.y * data[9] + orig.z * data[10];
	}

	/** Transform a 3d homogeneous vector, where the fourth coordinate is assumed to be 1. */
	void TransformPoint(const Vec3 & restrict orig, Vec3 * restrict dest) const {
		piDebugCheck(&orig != dest);
		dest->x = orig.x * data[0] + orig.y * data[4] + orig.z * data[8] + data[12];
		dest->y = orig.x * data[1] + orig.y * data[5] + orig.z * data[9] + data[13];
		dest->z = orig.x * data[2] + orig.y * data[6] + orig.z * data[10] + data[14];
	}

	/** Transform a point, normalize it, and return w. */
	scalar TransformPointAndNormalize(const Vec3 & restrict orig, Vec3 * restrict dest) const {
		piDebugCheck(&orig != dest);
		scalar w;
		dest->x = orig.x * data[0] + orig.y * data[4] + orig.z * data[8] + data[12];
		dest->y = orig.x * data[1] + orig.y * data[5] + orig.z * data[9] + data[13];
		dest->z = orig.x * data[2] + orig.y * data[6] + orig.z * data[10] + data[14];
		w = 1 / (orig.x * data[3] + orig.y * data[7] + orig.z * data[11] + data[15]);
		*dest *= w;
		return w;
	}

	/** Transform a point and return w. */
	scalar TransformPointReturnW(const Vec3 & restrict orig, Vec3 * restrict dest) const {
		piDebugCheck(&orig != dest);
		dest->x = orig.x * data[0] + orig.y * data[4] + orig.z * data[8] + data[12];
		dest->y = orig.x * data[1] + orig.y * data[5] + orig.z * data[9] + data[13];
		dest->z = orig.x * data[2] + orig.y * data[6] + orig.z * data[10] + data[14];
		return orig.x * data[3] + orig.y * data[7] + orig.z * data[11] + data[15];
	}

	/** Transform a normalized 3d point by a 4d matrix and return the resulting 4d vector. */
	void TransformVec4(const Vec3 & orig, Vec4 * dest) const {
		dest->x = orig.x * data[0] + orig.y * data[4] + orig.z * data[8] + data[12];
		dest->y = orig.x * data[1] + orig.y * data[5] + orig.z * data[9] + data[13];
		dest->z = orig.x * data[2] + orig.y * data[6] + orig.z * data[10] + data[14];
		dest->w = orig.x * data[3] + orig.y * data[7] + orig.z * data[11] + data[15];
	}
	//@}

	/** @name Matrix analysis. */
	//@{

	/** Get the ZYZ euler angles from the matrix. Assumes the matrix is orthonormal. */
	void GetEulerAnglesZYZ(scalar * s, scalar * t, scalar * r) const {
		if( GetElem(2,2) < 1.0f ) {
			if( GetElem(2,2) > -1.0f ) {
				// 	cs*ct*cr-ss*sr 		-ss*ct*cr-cs*sr		st*cr
				//	cs*ct*sr+ss*cr		-ss*ct*sr+cs*cr		st*sr
				//	-cs*st				ss*st				ct
				*s = atan2(GetElem(1,2), -GetElem(0,2));
				*t = acos(GetElem(2,2));
				*r = atan2(GetElem(2,1), GetElem(2,0));
			}
			else {
				// 	-c(s-r)	 	s(s-r)		0
				//	s(s-r)		c(s-r)		0
				//	0			0			-1
				*s = atan2(GetElem(0, 1), -GetElem(0, 0)); // = s-r
				*t = PI;
				*r = 0;
			}
		}
		else {
			// 	c(s+r)		-s(s+r)		0
			//	s(s+r)		c(s+r)		0
			//	0			0			1
			*s = atan2(GetElem(0, 1), GetElem(0, 0)); // = s+r
			*t = 0;
			*r = 0;
		}
	}

	//@}

	MATHLIB_API friend PiStream & operator<< ( PiStream & s, Matrix & m );

	/** Print to debug output. */
	void Print() const {
		piDebug( "[ %5.2f %5.2f %5.2f %5.2f ]\n", data[0], data[4], data[8], data[12] );
		piDebug( "[ %5.2f %5.2f %5.2f %5.2f ]\n", data[1], data[5], data[9], data[13] );
		piDebug( "[ %5.2f %5.2f %5.2f %5.2f ]\n", data[2], data[6], data[10], data[14] );
		piDebug( "[ %5.2f %5.2f %5.2f %5.2f ]\n", data[3], data[7], data[11], data[15] );
	}


public:

	scalar data[16];

};
#endif




#endif // NV_MATH_MATRIX_H
