/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: some of this file.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/blenlib/intern/math_matrix.c
 *  \ingroup bli
 */


#include <assert.h>
#include "BLI_math.h"

#include "BLI_strict_flags.h"

/********************************* Init **************************************/

void zero_m2(float m[2][2])
{
	memset(m, 0, sizeof(float[2][2]));
}

void zero_m3(float m[3][3])
{
	memset(m, 0, sizeof(float[3][3]));
}

void zero_m4(float m[4][4])
{
	memset(m, 0, sizeof(float[4][4]));
}

void unit_m2(float m[2][2])
{
	m[0][0] = m[1][1] = 1.0f;
	m[0][1] = 0.0f;
	m[1][0] = 0.0f;
}

void unit_m3(float m[3][3])
{
	m[0][0] = m[1][1] = m[2][2] = 1.0f;
	m[0][1] = m[0][2] = 0.0f;
	m[1][0] = m[1][2] = 0.0f;
	m[2][0] = m[2][1] = 0.0f;
}

void unit_m4(float m[4][4])
{
	m[0][0] = m[1][1] = m[2][2] = m[3][3] = 1.0f;
	m[0][1] = m[0][2] = m[0][3] = 0.0f;
	m[1][0] = m[1][2] = m[1][3] = 0.0f;
	m[2][0] = m[2][1] = m[2][3] = 0.0f;
	m[3][0] = m[3][1] = m[3][2] = 0.0f;
}

void copy_m2_m2(float m1[2][2], float m2[2][2])
{
	memcpy(m1, m2, sizeof(float[2][2]));
}

void copy_m3_m3(float m1[3][3], float m2[3][3])
{
	/* destination comes first: */
	memcpy(m1, m2, sizeof(float[3][3]));
}

void copy_m4_m4(float m1[4][4], float m2[4][4])
{
	memcpy(m1, m2, sizeof(float[4][4]));
}

void copy_m3_m4(float m1[3][3], float m2[4][4])
{
	m1[0][0] = m2[0][0];
	m1[0][1] = m2[0][1];
	m1[0][2] = m2[0][2];

	m1[1][0] = m2[1][0];
	m1[1][1] = m2[1][1];
	m1[1][2] = m2[1][2];

	m1[2][0] = m2[2][0];
	m1[2][1] = m2[2][1];
	m1[2][2] = m2[2][2];
}

void copy_m4_m3(float m1[4][4], float m2[3][3]) /* no clear */
{
	m1[0][0] = m2[0][0];
	m1[0][1] = m2[0][1];
	m1[0][2] = m2[0][2];

	m1[1][0] = m2[1][0];
	m1[1][1] = m2[1][1];
	m1[1][2] = m2[1][2];

	m1[2][0] = m2[2][0];
	m1[2][1] = m2[2][1];
	m1[2][2] = m2[2][2];

	/*	Reevan's Bugfix */
	m1[0][3] = 0.0f;
	m1[1][3] = 0.0f;
	m1[2][3] = 0.0f;

	m1[3][0] = 0.0f;
	m1[3][1] = 0.0f;
	m1[3][2] = 0.0f;
	m1[3][3] = 1.0f;

}

void copy_m3_m3d(float R[3][3], double A[3][3])
{
	/* Keep it stupid simple for better data flow in CPU. */
	R[0][0] = (float)A[0][0];
	R[0][1] = (float)A[0][1];
	R[0][2] = (float)A[0][2];

	R[1][0] = (float)A[1][0];
	R[1][1] = (float)A[1][1];
	R[1][2] = (float)A[1][2];

	R[2][0] = (float)A[2][0];
	R[2][1] = (float)A[2][1];
	R[2][2] = (float)A[2][2];
}

void swap_m3m3(float m1[3][3], float m2[3][3])
{
	float t;
	int i, j;

	for (i = 0; i < 3; i++) {
		for (j = 0; j < 3; j++) {
			t = m1[i][j];
			m1[i][j] = m2[i][j];
			m2[i][j] = t;
		}
	}
}

void swap_m4m4(float m1[4][4], float m2[4][4])
{
	float t;
	int i, j;

	for (i = 0; i < 4; i++) {
		for (j = 0; j < 4; j++) {
			t = m1[i][j];
			m1[i][j] = m2[i][j];
			m2[i][j] = t;
		}
	}
}

/******************************** Arithmetic *********************************/

void mul_m4_m4m4(float m1[4][4], float m3_[4][4], float m2_[4][4])
{
	float m2[4][4], m3[4][4];

	/* copy so it works when m1 is the same pointer as m2 or m3 */
	copy_m4_m4(m2, m2_);
	copy_m4_m4(m3, m3_);

	/* matrix product: m1[j][k] = m2[j][i].m3[i][k] */
	m1[0][0] = m2[0][0] * m3[0][0] + m2[0][1] * m3[1][0] + m2[0][2] * m3[2][0] + m2[0][3] * m3[3][0];
	m1[0][1] = m2[0][0] * m3[0][1] + m2[0][1] * m3[1][1] + m2[0][2] * m3[2][1] + m2[0][3] * m3[3][1];
	m1[0][2] = m2[0][0] * m3[0][2] + m2[0][1] * m3[1][2] + m2[0][2] * m3[2][2] + m2[0][3] * m3[3][2];
	m1[0][3] = m2[0][0] * m3[0][3] + m2[0][1] * m3[1][3] + m2[0][2] * m3[2][3] + m2[0][3] * m3[3][3];

	m1[1][0] = m2[1][0] * m3[0][0] + m2[1][1] * m3[1][0] + m2[1][2] * m3[2][0] + m2[1][3] * m3[3][0];
	m1[1][1] = m2[1][0] * m3[0][1] + m2[1][1] * m3[1][1] + m2[1][2] * m3[2][1] + m2[1][3] * m3[3][1];
	m1[1][2] = m2[1][0] * m3[0][2] + m2[1][1] * m3[1][2] + m2[1][2] * m3[2][2] + m2[1][3] * m3[3][2];
	m1[1][3] = m2[1][0] * m3[0][3] + m2[1][1] * m3[1][3] + m2[1][2] * m3[2][3] + m2[1][3] * m3[3][3];

	m1[2][0] = m2[2][0] * m3[0][0] + m2[2][1] * m3[1][0] + m2[2][2] * m3[2][0] + m2[2][3] * m3[3][0];
	m1[2][1] = m2[2][0] * m3[0][1] + m2[2][1] * m3[1][1] + m2[2][2] * m3[2][1] + m2[2][3] * m3[3][1];
	m1[2][2] = m2[2][0] * m3[0][2] + m2[2][1] * m3[1][2] + m2[2][2] * m3[2][2] + m2[2][3] * m3[3][2];
	m1[2][3] = m2[2][0] * m3[0][3] + m2[2][1] * m3[1][3] + m2[2][2] * m3[2][3] + m2[2][3] * m3[3][3];

	m1[3][0] = m2[3][0] * m3[0][0] + m2[3][1] * m3[1][0] + m2[3][2] * m3[2][0] + m2[3][3] * m3[3][0];
	m1[3][1] = m2[3][0] * m3[0][1] + m2[3][1] * m3[1][1] + m2[3][2] * m3[2][1] + m2[3][3] * m3[3][1];
	m1[3][2] = m2[3][0] * m3[0][2] + m2[3][1] * m3[1][2] + m2[3][2] * m3[2][2] + m2[3][3] * m3[3][2];
	m1[3][3] = m2[3][0] * m3[0][3] + m2[3][1] * m3[1][3] + m2[3][2] * m3[2][3] + m2[3][3] * m3[3][3];

}

void mul_m3_m3m3(float m1[3][3], float m3_[3][3], float m2_[3][3])
{
	float m2[3][3], m3[3][3];

	/* copy so it works when m1 is the same pointer as m2 or m3 */
	copy_m3_m3(m2, m2_);
	copy_m3_m3(m3, m3_);

	/* m1[i][j] = m2[i][k] * m3[k][j], args are flipped!  */
	m1[0][0] = m2[0][0] * m3[0][0] + m2[0][1] * m3[1][0] + m2[0][2] * m3[2][0];
	m1[0][1] = m2[0][0] * m3[0][1] + m2[0][1] * m3[1][1] + m2[0][2] * m3[2][1];
	m1[0][2] = m2[0][0] * m3[0][2] + m2[0][1] * m3[1][2] + m2[0][2] * m3[2][2];

	m1[1][0] = m2[1][0] * m3[0][0] + m2[1][1] * m3[1][0] + m2[1][2] * m3[2][0];
	m1[1][1] = m2[1][0] * m3[0][1] + m2[1][1] * m3[1][1] + m2[1][2] * m3[2][1];
	m1[1][2] = m2[1][0] * m3[0][2] + m2[1][1] * m3[1][2] + m2[1][2] * m3[2][2];

	m1[2][0] = m2[2][0] * m3[0][0] + m2[2][1] * m3[1][0] + m2[2][2] * m3[2][0];
	m1[2][1] = m2[2][0] * m3[0][1] + m2[2][1] * m3[1][1] + m2[2][2] * m3[2][1];
	m1[2][2] = m2[2][0] * m3[0][2] + m2[2][1] * m3[1][2] + m2[2][2] * m3[2][2];
}

void mul_m4_m4m3(float m1[4][4], float m3_[4][4], float m2_[3][3])
{
	float m2[3][3], m3[4][4];

	/* copy so it works when m1 is the same pointer as m2 or m3 */
	copy_m3_m3(m2, m2_);
	copy_m4_m4(m3, m3_);

	m1[0][0] = m2[0][0] * m3[0][0] + m2[0][1] * m3[1][0] + m2[0][2] * m3[2][0];
	m1[0][1] = m2[0][0] * m3[0][1] + m2[0][1] * m3[1][1] + m2[0][2] * m3[2][1];
	m1[0][2] = m2[0][0] * m3[0][2] + m2[0][1] * m3[1][2] + m2[0][2] * m3[2][2];
	m1[1][0] = m2[1][0] * m3[0][0] + m2[1][1] * m3[1][0] + m2[1][2] * m3[2][0];
	m1[1][1] = m2[1][0] * m3[0][1] + m2[1][1] * m3[1][1] + m2[1][2] * m3[2][1];
	m1[1][2] = m2[1][0] * m3[0][2] + m2[1][1] * m3[1][2] + m2[1][2] * m3[2][2];
	m1[2][0] = m2[2][0] * m3[0][0] + m2[2][1] * m3[1][0] + m2[2][2] * m3[2][0];
	m1[2][1] = m2[2][0] * m3[0][1] + m2[2][1] * m3[1][1] + m2[2][2] * m3[2][1];
	m1[2][2] = m2[2][0] * m3[0][2] + m2[2][1] * m3[1][2] + m2[2][2] * m3[2][2];
}

/* m1 = m2 * m3, ignore the elements on the 4th row/column of m3 */
void mul_m3_m3m4(float m1[3][3], float m3_[4][4], float m2_[3][3])
{
	float m2[3][3], m3[4][4];

	/* copy so it works when m1 is the same pointer as m2 or m3 */
	copy_m3_m3(m2, m2_);
	copy_m4_m4(m3, m3_);

	/* m1[i][j] = m2[i][k] * m3[k][j] */
	m1[0][0] = m2[0][0] * m3[0][0] + m2[0][1] * m3[1][0] + m2[0][2] * m3[2][0];
	m1[0][1] = m2[0][0] * m3[0][1] + m2[0][1] * m3[1][1] + m2[0][2] * m3[2][1];
	m1[0][2] = m2[0][0] * m3[0][2] + m2[0][1] * m3[1][2] + m2[0][2] * m3[2][2];

	m1[1][0] = m2[1][0] * m3[0][0] + m2[1][1] * m3[1][0] + m2[1][2] * m3[2][0];
	m1[1][1] = m2[1][0] * m3[0][1] + m2[1][1] * m3[1][1] + m2[1][2] * m3[2][1];
	m1[1][2] = m2[1][0] * m3[0][2] + m2[1][1] * m3[1][2] + m2[1][2] * m3[2][2];

	m1[2][0] = m2[2][0] * m3[0][0] + m2[2][1] * m3[1][0] + m2[2][2] * m3[2][0];
	m1[2][1] = m2[2][0] * m3[0][1] + m2[2][1] * m3[1][1] + m2[2][2] * m3[2][1];
	m1[2][2] = m2[2][0] * m3[0][2] + m2[2][1] * m3[1][2] + m2[2][2] * m3[2][2];
}

void mul_m4_m3m4(float m1[4][4], float m3_[3][3], float m2_[4][4])
{
	float m2[4][4], m3[3][3];

	/* copy so it works when m1 is the same pointer as m2 or m3 */
	copy_m4_m4(m2, m2_);
	copy_m3_m3(m3, m3_);

	m1[0][0] = m2[0][0] * m3[0][0] + m2[0][1] * m3[1][0] + m2[0][2] * m3[2][0];
	m1[0][1] = m2[0][0] * m3[0][1] + m2[0][1] * m3[1][1] + m2[0][2] * m3[2][1];
	m1[0][2] = m2[0][0] * m3[0][2] + m2[0][1] * m3[1][2] + m2[0][2] * m3[2][2];
	m1[1][0] = m2[1][0] * m3[0][0] + m2[1][1] * m3[1][0] + m2[1][2] * m3[2][0];
	m1[1][1] = m2[1][0] * m3[0][1] + m2[1][1] * m3[1][1] + m2[1][2] * m3[2][1];
	m1[1][2] = m2[1][0] * m3[0][2] + m2[1][1] * m3[1][2] + m2[1][2] * m3[2][2];
	m1[2][0] = m2[2][0] * m3[0][0] + m2[2][1] * m3[1][0] + m2[2][2] * m3[2][0];
	m1[2][1] = m2[2][0] * m3[0][1] + m2[2][1] * m3[1][1] + m2[2][2] * m3[2][1];
	m1[2][2] = m2[2][0] * m3[0][2] + m2[2][1] * m3[1][2] + m2[2][2] * m3[2][2];
}


/** \name Macro helpers for: mul_m3_series
 * \{ */
void _va_mul_m3_series_3(
        float r[3][3],
        float m1[3][3], float m2[3][3])
{
	mul_m3_m3m3(r, m1, m2);
}
void _va_mul_m3_series_4(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
}
void _va_mul_m3_series_5(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3], float m4[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
	mul_m3_m3m3(r, r, m4);
}
void _va_mul_m3_series_6(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3], float m4[3][3],
        float m5[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
	mul_m3_m3m3(r, r, m4);
	mul_m3_m3m3(r, r, m5);
}
void _va_mul_m3_series_7(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3], float m4[3][3],
        float m5[3][3], float m6[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
	mul_m3_m3m3(r, r, m4);
	mul_m3_m3m3(r, r, m5);
	mul_m3_m3m3(r, r, m6);
}
void _va_mul_m3_series_8(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3], float m4[3][3],
        float m5[3][3], float m6[3][3], float m7[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
	mul_m3_m3m3(r, r, m4);
	mul_m3_m3m3(r, r, m5);
	mul_m3_m3m3(r, r, m6);
	mul_m3_m3m3(r, r, m7);
}
void _va_mul_m3_series_9(
        float r[3][3],
        float m1[3][3], float m2[3][3], float m3[3][3], float m4[3][3],
        float m5[3][3], float m6[3][3], float m7[3][3], float m8[3][3])
{
	mul_m3_m3m3(r, m1, m2);
	mul_m3_m3m3(r, r, m3);
	mul_m3_m3m3(r, r, m4);
	mul_m3_m3m3(r, r, m5);
	mul_m3_m3m3(r, r, m6);
	mul_m3_m3m3(r, r, m7);
	mul_m3_m3m3(r, r, m8);
}
/** \} */

/** \name Macro helpers for: mul_m4_series
 * \{ */
void _va_mul_m4_series_3(
        float r[4][4],
        float m1[4][4], float m2[4][4])
{
	mul_m4_m4m4(r, m1, m2);
}
void _va_mul_m4_series_4(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
}
void _va_mul_m4_series_5(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4], float m4[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
	mul_m4_m4m4(r, r, m4);
}
void _va_mul_m4_series_6(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4], float m4[4][4],
        float m5[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
	mul_m4_m4m4(r, r, m4);
	mul_m4_m4m4(r, r, m5);
}
void _va_mul_m4_series_7(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4], float m4[4][4],
        float m5[4][4], float m6[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
	mul_m4_m4m4(r, r, m4);
	mul_m4_m4m4(r, r, m5);
	mul_m4_m4m4(r, r, m6);
}
void _va_mul_m4_series_8(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4], float m4[4][4],
        float m5[4][4], float m6[4][4], float m7[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
	mul_m4_m4m4(r, r, m4);
	mul_m4_m4m4(r, r, m5);
	mul_m4_m4m4(r, r, m6);
	mul_m4_m4m4(r, r, m7);
}
void _va_mul_m4_series_9(
        float r[4][4],
        float m1[4][4], float m2[4][4], float m3[4][4], float m4[4][4],
        float m5[4][4], float m6[4][4], float m7[4][4], float m8[4][4])
{
	mul_m4_m4m4(r, m1, m2);
	mul_m4_m4m4(r, r, m3);
	mul_m4_m4m4(r, r, m4);
	mul_m4_m4m4(r, r, m5);
	mul_m4_m4m4(r, r, m6);
	mul_m4_m4m4(r, r, m7);
	mul_m4_m4m4(r, r, m8);
}
/** \} */

void mul_v2_m3v2(float r[2], float m[3][3], float v[2])
{
	float temp[3], warped[3];

	copy_v2_v2(temp, v);
	temp[2] = 1.0f;

	mul_v3_m3v3(warped, m, temp);

	r[0] = warped[0] / warped[2];
	r[1] = warped[1] / warped[2];
}

void mul_m3_v2(float m[3][3], float r[2])
{
	mul_v2_m3v2(r, m, r);
}

void mul_m4_v3(float mat[4][4], float vec[3])
{
	const float x = vec[0];
	const float y = vec[1];

	vec[0] = x * mat[0][0] + y * mat[1][0] + mat[2][0] * vec[2] + mat[3][0];
	vec[1] = x * mat[0][1] + y * mat[1][1] + mat[2][1] * vec[2] + mat[3][1];
	vec[2] = x * mat[0][2] + y * mat[1][2] + mat[2][2] * vec[2] + mat[3][2];
}

void mul_v3_m4v3(float r[3], float mat[4][4], const float vec[3])
{
	const float x = vec[0];
	const float y = vec[1];

	r[0] = x * mat[0][0] + y * mat[1][0] + mat[2][0] * vec[2] + mat[3][0];
	r[1] = x * mat[0][1] + y * mat[1][1] + mat[2][1] * vec[2] + mat[3][1];
	r[2] = x * mat[0][2] + y * mat[1][2] + mat[2][2] * vec[2] + mat[3][2];
}

void mul_v2_m4v3(float r[2], float mat[4][4], const float vec[3])
{
	const float x = vec[0];

	r[0] = x * mat[0][0] + vec[1] * mat[1][0] + mat[2][0] * vec[2] + mat[3][0];
	r[1] = x * mat[0][1] + vec[1] * mat[1][1] + mat[2][1] * vec[2] + mat[3][1];
}

void mul_v2_m2v2(float r[2], float mat[2][2], const float vec[2])
{
	const float x = vec[0];

	r[0] = mat[0][0] * x + mat[1][0] * vec[1];
	r[1] = mat[0][1] * x + mat[1][1] * vec[1];
}

void mul_m2v2(float mat[2][2], float vec[2])
{
	mul_v2_m2v2(vec, mat, vec);
}

/* same as mul_m4_v3() but doesnt apply translation component */
void mul_mat3_m4_v3(float mat[4][4], float vec[3])
{
	const float x = vec[0];
	const float y = vec[1];

	vec[0] = x * mat[0][0] + y * mat[1][0] + mat[2][0] * vec[2];
	vec[1] = x * mat[0][1] + y * mat[1][1] + mat[2][1] * vec[2];
	vec[2] = x * mat[0][2] + y * mat[1][2] + mat[2][2] * vec[2];
}

void mul_project_m4_v3(float mat[4][4], float vec[3])
{
	const float w = mul_project_m4_v3_zfac(mat, vec);
	mul_m4_v3(mat, vec);

	vec[0] /= w;
	vec[1] /= w;
	vec[2] /= w;
}

void mul_v3_project_m4_v3(float r[3], float mat[4][4], const float vec[3])
{
	const float w = mul_project_m4_v3_zfac(mat, vec);
	mul_v3_m4v3(r, mat, vec);

	r[0] /= w;
	r[1] /= w;
	r[2] /= w;
}

void mul_v2_project_m4_v3(float r[2], float mat[4][4], const float vec[3])
{
	const float w = mul_project_m4_v3_zfac(mat, vec);
	mul_v2_m4v3(r, mat, vec);

	r[0] /= w;
	r[1] /= w;
}

void mul_v4_m4v4(float r[4], float mat[4][4], const float v[4])
{
	const float x = v[0];
	const float y = v[1];
	const float z = v[2];

	r[0] = x * mat[0][0] + y * mat[1][0] + z * mat[2][0] + mat[3][0] * v[3];
	r[1] = x * mat[0][1] + y * mat[1][1] + z * mat[2][1] + mat[3][1] * v[3];
	r[2] = x * mat[0][2] + y * mat[1][2] + z * mat[2][2] + mat[3][2] * v[3];
	r[3] = x * mat[0][3] + y * mat[1][3] + z * mat[2][3] + mat[3][3] * v[3];
}

void mul_m4_v4(float mat[4][4], float r[4])
{
	mul_v4_m4v4(r, mat, r);
}

void mul_v4d_m4v4d(double r[4], float mat[4][4], double v[4])
{
	const double x = v[0];
	const double y = v[1];
	const double z = v[2];

	r[0] = x * (double)mat[0][0] + y * (double)mat[1][0] + z * (double)mat[2][0] + (double)mat[3][0] * v[3];
	r[1] = x * (double)mat[0][1] + y * (double)mat[1][1] + z * (double)mat[2][1] + (double)mat[3][1] * v[3];
	r[2] = x * (double)mat[0][2] + y * (double)mat[1][2] + z * (double)mat[2][2] + (double)mat[3][2] * v[3];
	r[3] = x * (double)mat[0][3] + y * (double)mat[1][3] + z * (double)mat[2][3] + (double)mat[3][3] * v[3];
}

void mul_m4_v4d(float mat[4][4], double r[4])
{
	mul_v4d_m4v4d(r, mat, r);
}

void mul_v3_m3v3(float r[3], float M[3][3], const float a[3])
{
	BLI_assert(r != a);

	r[0] = M[0][0] * a[0] + M[1][0] * a[1] + M[2][0] * a[2];
	r[1] = M[0][1] * a[0] + M[1][1] * a[1] + M[2][1] * a[2];
	r[2] = M[0][2] * a[0] + M[1][2] * a[1] + M[2][2] * a[2];
}

void mul_v2_m3v3(float r[2], float M[3][3], const float a[3])
{
	BLI_assert(r != a);

	r[0] = M[0][0] * a[0] + M[1][0] * a[1] + M[2][0] * a[2];
	r[1] = M[0][1] * a[0] + M[1][1] * a[1] + M[2][1] * a[2];
}

void mul_m3_v3(float M[3][3], float r[3])
{
	float tmp[3];

	mul_v3_m3v3(tmp, M, r);
	copy_v3_v3(r, tmp);
}

void mul_transposed_m3_v3(float mat[3][3], float vec[3])
{
	const float x = vec[0];
	const float y = vec[1];

	vec[0] = x * mat[0][0] + y * mat[0][1] + mat[0][2] * vec[2];
	vec[1] = x * mat[1][0] + y * mat[1][1] + mat[1][2] * vec[2];
	vec[2] = x * mat[2][0] + y * mat[2][1] + mat[2][2] * vec[2];
}

void mul_transposed_mat3_m4_v3(float mat[4][4], float vec[3])
{
	const float x = vec[0];
	const float y = vec[1];

	vec[0] = x * mat[0][0] + y * mat[0][1] + mat[0][2] * vec[2];
	vec[1] = x * mat[1][0] + y * mat[1][1] + mat[1][2] * vec[2];
	vec[2] = x * mat[2][0] + y * mat[2][1] + mat[2][2] * vec[2];
}

void mul_m3_fl(float m[3][3], float f)
{
	int i, j;

	for (i = 0; i < 3; i++)
		for (j = 0; j < 3; j++)
			m[i][j] *= f;
}

void mul_m4_fl(float m[4][4], float f)
{
	int i, j;

	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			m[i][j] *= f;
}

void mul_mat3_m4_fl(float m[4][4], float f)
{
	int i, j;

	for (i = 0; i < 3; i++)
		for (j = 0; j < 3; j++)
			m[i][j] *= f;
}

void negate_m3(float m[4][4])
{
	int i, j;

	for (i = 0; i < 3; i++)
		for (j = 0; j < 3; j++)
			m[i][j] *= -1.0f;
}

void negate_m4(float m[4][4])
{
	int i, j;

	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			m[i][j] *= -1.0f;
}

void mul_m3_v3_double(float mat[3][3], double vec[3])
{
	const double x = vec[0];
	const double y = vec[1];

	vec[0] = x * (double)mat[0][0] + y * (double)mat[1][0] + (double)mat[2][0] * vec[2];
	vec[1] = x * (double)mat[0][1] + y * (double)mat[1][1] + (double)mat[2][1] * vec[2];
	vec[2] = x * (double)mat[0][2] + y * (double)mat[1][2] + (double)mat[2][2] * vec[2];
}

void add_m3_m3m3(float m1[3][3], float m2[3][3], float m3[3][3])
{
	int i, j;

	for (i = 0; i < 3; i++)
		for (j = 0; j < 3; j++)
			m1[i][j] = m2[i][j] + m3[i][j];
}

void add_m4_m4m4(float m1[4][4], float m2[4][4], float m3[4][4])
{
	int i, j;

	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			m1[i][j] = m2[i][j] + m3[i][j];
}

void sub_m3_m3m3(float m1[3][3], float m2[3][3], float m3[3][3])
{
	int i, j;

	for (i = 0; i < 3; i++)
		for (j = 0; j < 3; j++)
			m1[i][j] = m2[i][j] - m3[i][j];
}

void sub_m4_m4m4(float m1[4][4], float m2[4][4], float m3[4][4])
{
	int i, j;

	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			m1[i][j] = m2[i][j] - m3[i][j];
}

float determinant_m3_array(float m[3][3])
{
	return (m[0][0] * (m[1][1] * m[2][2] - m[1][2] * m[2][1]) -
	        m[1][0] * (m[0][1] * m[2][2] - m[0][2] * m[2][1]) +
	        m[2][0] * (m[0][1] * m[1][2] - m[0][2] * m[1][1]));
}

bool invert_m3_ex(float m[3][3], const float epsilon)
{
	float tmp[3][3];
	const bool success = invert_m3_m3_ex(tmp, m, epsilon);

	copy_m3_m3(m, tmp);
	return success;
}

bool invert_m3_m3_ex(float m1[3][3], float m2[3][3], const float epsilon)
{
	float det;
	int a, b;
	bool success;

	BLI_assert(epsilon >= 0.0f);

	/* calc adjoint */
	adjoint_m3_m3(m1, m2);

	/* then determinant old matrix! */
	det = determinant_m3_array(m2);

	success = (fabsf(det) > epsilon);

	if (LIKELY(det != 0.0f)) {
		det = 1.0f / det;
		for (a = 0; a < 3; a++) {
			for (b = 0; b < 3; b++) {
				m1[a][b] *= det;
			}
		}
	}
	return success;
}

bool invert_m3(float m[3][3])
{
	float tmp[3][3];
	const bool success = invert_m3_m3(tmp, m);

	copy_m3_m3(m, tmp);
	return success;
}

bool invert_m3_m3(float m1[3][3], float m2[3][3])
{
	float det;
	int a, b;
	bool success;

	/* calc adjoint */
	adjoint_m3_m3(m1, m2);

	/* then determinant old matrix! */
	det = determinant_m3_array(m2);

	success = (det != 0.0f);

	if (LIKELY(det != 0.0f)) {
		det = 1.0f / det;
		for (a = 0; a < 3; a++) {
			for (b = 0; b < 3; b++) {
				m1[a][b] *= det;
			}
		}
	}

	return success;
}

bool invert_m4(float m[4][4])
{
	float tmp[4][4];
	const bool success = invert_m4_m4(tmp, m);

	copy_m4_m4(m, tmp);
	return success;
}

/*
 * invertmat -
 *      computes the inverse of mat and puts it in inverse.  Returns
 *  true on success (i.e. can always find a pivot) and false on failure.
 *  Uses Gaussian Elimination with partial (maximal column) pivoting.
 *
 *					Mark Segal - 1992
 */

bool invert_m4_m4(float inverse[4][4], float mat[4][4])
{
	int i, j, k;
	double temp;
	float tempmat[4][4];
	float max;
	int maxj;

	BLI_assert(inverse != mat);

	/* Set inverse to identity */
	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			inverse[i][j] = 0;
	for (i = 0; i < 4; i++)
		inverse[i][i] = 1;

	/* Copy original matrix so we don't mess it up */
	for (i = 0; i < 4; i++)
		for (j = 0; j < 4; j++)
			tempmat[i][j] = mat[i][j];

	for (i = 0; i < 4; i++) {
		/* Look for row with max pivot */
		max = fabsf(tempmat[i][i]);
		maxj = i;
		for (j = i + 1; j < 4; j++) {
			if (fabsf(tempmat[j][i]) > max) {
				max = fabsf(tempmat[j][i]);
				maxj = j;
			}
		}
		/* Swap rows if necessary */
		if (maxj != i) {
			for (k = 0; k < 4; k++) {
				SWAP(float, tempmat[i][k], tempmat[maxj][k]);
				SWAP(float, inverse[i][k], inverse[maxj][k]);
			}
		}

		temp = tempmat[i][i];
		if (temp == 0)
			return 0;  /* No non-zero pivot */
		for (k = 0; k < 4; k++) {
			tempmat[i][k] = (float)((double)tempmat[i][k] / temp);
			inverse[i][k] = (float)((double)inverse[i][k] / temp);
		}
		for (j = 0; j < 4; j++) {
			if (j != i) {
				temp = tempmat[j][i];
				for (k = 0; k < 4; k++) {
					tempmat[j][k] -= (float)((double)tempmat[i][k] * temp);
					inverse[j][k] -= (float)((double)inverse[i][k] * temp);
				}
			}
		}
	}
	return 1;
}

/****************************** Linear Algebra *******************************/

void transpose_m3(float mat[3][3])
{
	float t;

	t = mat[0][1];
	mat[0][1] = mat[1][0];
	mat[1][0] = t;
	t = mat[0][2];
	mat[0][2] = mat[2][0];
	mat[2][0] = t;
	t = mat[1][2];
	mat[1][2] = mat[2][1];
	mat[2][1] = t;
}

void transpose_m4(float mat[4][4])
{
	float t;

	t = mat[0][1];
	mat[0][1] = mat[1][0];
	mat[1][0] = t;
	t = mat[0][2];
	mat[0][2] = mat[2][0];
	mat[2][0] = t;
	t = mat[0][3];
	mat[0][3] = mat[3][0];
	mat[3][0] = t;

	t = mat[1][2];
	mat[1][2] = mat[2][1];
	mat[2][1] = t;
	t = mat[1][3];
	mat[1][3] = mat[3][1];
	mat[3][1] = t;

	t = mat[2][3];
	mat[2][3] = mat[3][2];
	mat[3][2] = t;
}

int compare_m4m4(float mat1[4][4], float mat2[4][4], float limit)
{
	if (compare_v4v4(mat1[0], mat2[0], limit))
		if (compare_v4v4(mat1[1], mat2[1], limit))
			if (compare_v4v4(mat1[2], mat2[2], limit))
				if (compare_v4v4(mat1[3], mat2[3], limit))
					return 1;
	return 0;
}

void orthogonalize_m3(float mat[3][3], int axis)
{
	float size[3];
	mat3_to_size(size, mat);
	normalize_v3(mat[axis]);
	switch (axis) {
		case 0:
			if (dot_v3v3(mat[0], mat[1]) < 1) {
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			else if (dot_v3v3(mat[0], mat[2]) < 1) {
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
				normalize_v3(mat[1]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			else {
				float vec[3];

				vec[0] = mat[0][1];
				vec[1] = mat[0][2];
				vec[2] = mat[0][0];

				cross_v3_v3v3(mat[2], mat[0], vec);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			break;
		case 1:
			if (dot_v3v3(mat[1], mat[0]) < 1) {
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
			}
			else if (dot_v3v3(mat[0], mat[2]) < 1) {
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			else {
				float vec[3];

				vec[0] = mat[1][1];
				vec[1] = mat[1][2];
				vec[2] = mat[1][0];

				cross_v3_v3v3(mat[0], mat[1], vec);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			break;
		case 2:
			if (dot_v3v3(mat[2], mat[0]) < 1) {
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
				normalize_v3(mat[1]);
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
			}
			else if (dot_v3v3(mat[2], mat[1]) < 1) {
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			else {
				float vec[3];

				vec[0] = mat[2][1];
				vec[1] = mat[2][2];
				vec[2] = mat[2][0];

				cross_v3_v3v3(mat[0], vec, mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			break;
		default:
			BLI_assert(0);
			break;
	}
	mul_v3_fl(mat[0], size[0]);
	mul_v3_fl(mat[1], size[1]);
	mul_v3_fl(mat[2], size[2]);
}

void orthogonalize_m4(float mat[4][4], int axis)
{
	float size[3];
	mat4_to_size(size, mat);
	normalize_v3(mat[axis]);
	switch (axis) {
		case 0:
			if (dot_v3v3(mat[0], mat[1]) < 1) {
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			else if (dot_v3v3(mat[0], mat[2]) < 1) {
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
				normalize_v3(mat[1]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			else {
				float vec[3];

				vec[0] = mat[0][1];
				vec[1] = mat[0][2];
				vec[2] = mat[0][0];

				cross_v3_v3v3(mat[2], mat[0], vec);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			break;
		case 1:
			if (dot_v3v3(mat[1], mat[0]) < 1) {
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
				normalize_v3(mat[2]);
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
			}
			else if (dot_v3v3(mat[0], mat[2]) < 1) {
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			else {
				float vec[3];

				vec[0] = mat[1][1];
				vec[1] = mat[1][2];
				vec[2] = mat[1][0];

				cross_v3_v3v3(mat[0], mat[1], vec);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[2], mat[0], mat[1]);
			}
			break;
		case 2:
			if (dot_v3v3(mat[2], mat[0]) < 1) {
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
				normalize_v3(mat[1]);
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
			}
			else if (dot_v3v3(mat[2], mat[1]) < 1) {
				cross_v3_v3v3(mat[0], mat[1], mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			else {
				float vec[3];

				vec[0] = mat[2][1];
				vec[1] = mat[2][2];
				vec[2] = mat[2][0];

				cross_v3_v3v3(mat[0], vec, mat[2]);
				normalize_v3(mat[0]);
				cross_v3_v3v3(mat[1], mat[2], mat[0]);
			}
			break;
		default:
			BLI_assert(0);
			break;
	}
	mul_v3_fl(mat[0], size[0]);
	mul_v3_fl(mat[1], size[1]);
	mul_v3_fl(mat[2], size[2]);
}

bool is_orthogonal_m3(float m[3][3])
{
	int i, j;

	for (i = 0; i < 3; i++) {
		for (j = 0; j < i; j++) {
			if (fabsf(dot_v3v3(m[i], m[j])) > 1.5f * FLT_EPSILON)
				return 0;
		}
	}

	return 1;
}

bool is_orthogonal_m4(float m[4][4])
{
	int i, j;

	for (i = 0; i < 4; i++) {
		for (j = 0; j < i; j++) {
			if (fabsf(dot_v4v4(m[i], m[j])) > 1.5f * FLT_EPSILON)
				return 0;
		}

	}

	return 1;
}

bool is_orthonormal_m3(float m[3][3])
{
	if (is_orthogonal_m3(m)) {
		int i;

		for (i = 0; i < 3; i++)
			if (fabsf(dot_v3v3(m[i], m[i]) - 1) > 1.5f * FLT_EPSILON)
				return 0;

		return 1;
	}

	return 0;
}

bool is_orthonormal_m4(float m[4][4])
{
	if (is_orthogonal_m4(m)) {
		int i;

		for (i = 0; i < 4; i++)
			if (fabsf(dot_v4v4(m[i], m[i]) - 1) > 1.5f * FLT_EPSILON)
				return 0;

		return 1;
	}

	return 0;
}

bool is_uniform_scaled_m3(float m[3][3])
{
	const float eps = 1e-7f;
	float t[3][3];
	float l1, l2, l3, l4, l5, l6;

	copy_m3_m3(t, m);
	transpose_m3(t);

	l1 = len_squared_v3(m[0]);
	l2 = len_squared_v3(m[1]);
	l3 = len_squared_v3(m[2]);

	l4 = len_squared_v3(t[0]);
	l5 = len_squared_v3(t[1]);
	l6 = len_squared_v3(t[2]);

	if (fabsf(l2 - l1) <= eps &&
	    fabsf(l3 - l1) <= eps &&
	    fabsf(l4 - l1) <= eps &&
	    fabsf(l5 - l1) <= eps &&
	    fabsf(l6 - l1) <= eps)
	{
		return true;
	}

	return false;
}

bool is_uniform_scaled_m4(float m[4][4])
{
	float t[3][3];
	copy_m3_m4(t, m);
	return is_uniform_scaled_m3(t);
}

void normalize_m3(float mat[3][3])
{
	normalize_v3(mat[0]);
	normalize_v3(mat[1]);
	normalize_v3(mat[2]);
}

void normalize_m3_m3(float rmat[3][3], float mat[3][3])
{
	normalize_v3_v3(rmat[0], mat[0]);
	normalize_v3_v3(rmat[1], mat[1]);
	normalize_v3_v3(rmat[2], mat[2]);
}

void normalize_m4(float mat[4][4])
{
	float len;

	len = normalize_v3(mat[0]);
	if (len != 0.0f) mat[0][3] /= len;
	len = normalize_v3(mat[1]);
	if (len != 0.0f) mat[1][3] /= len;
	len = normalize_v3(mat[2]);
	if (len != 0.0f) mat[2][3] /= len;
}

void normalize_m4_m4(float rmat[4][4], float mat[4][4])
{
	copy_m4_m4(rmat, mat);
	normalize_m4(rmat);
}

void adjoint_m2_m2(float m1[2][2], float m[2][2])
{
	BLI_assert(m1 != m);
	m1[0][0] =  m[1][1];
	m1[0][1] = -m[0][1];
	m1[1][0] = -m[1][0];
	m1[1][1] =  m[0][0];
}

void adjoint_m3_m3(float m1[3][3], float m[3][3])
{
	BLI_assert(m1 != m);
	m1[0][0] = m[1][1] * m[2][2] - m[1][2] * m[2][1];
	m1[0][1] = -m[0][1] * m[2][2] + m[0][2] * m[2][1];
	m1[0][2] = m[0][1] * m[1][2] - m[0][2] * m[1][1];

	m1[1][0] = -m[1][0] * m[2][2] + m[1][2] * m[2][0];
	m1[1][1] = m[0][0] * m[2][2] - m[0][2] * m[2][0];
	m1[1][2] = -m[0][0] * m[1][2] + m[0][2] * m[1][0];

	m1[2][0] = m[1][0] * m[2][1] - m[1][1] * m[2][0];
	m1[2][1] = -m[0][0] * m[2][1] + m[0][1] * m[2][0];
	m1[2][2] = m[0][0] * m[1][1] - m[0][1] * m[1][0];
}

void adjoint_m4_m4(float out[4][4], float in[4][4]) /* out = ADJ(in) */
{
	float a1, a2, a3, a4, b1, b2, b3, b4;
	float c1, c2, c3, c4, d1, d2, d3, d4;

	a1 = in[0][0];
	b1 = in[0][1];
	c1 = in[0][2];
	d1 = in[0][3];

	a2 = in[1][0];
	b2 = in[1][1];
	c2 = in[1][2];
	d2 = in[1][3];

	a3 = in[2][0];
	b3 = in[2][1];
	c3 = in[2][2];
	d3 = in[2][3];

	a4 = in[3][0];
	b4 = in[3][1];
	c4 = in[3][2];
	d4 = in[3][3];


	out[0][0] = determinant_m3(b2, b3, b4, c2, c3, c4, d2, d3, d4);
	out[1][0] = -determinant_m3(a2, a3, a4, c2, c3, c4, d2, d3, d4);
	out[2][0] = determinant_m3(a2, a3, a4, b2, b3, b4, d2, d3, d4);
	out[3][0] = -determinant_m3(a2, a3, a4, b2, b3, b4, c2, c3, c4);

	out[0][1] = -determinant_m3(b1, b3, b4, c1, c3, c4, d1, d3, d4);
	out[1][1] = determinant_m3(a1, a3, a4, c1, c3, c4, d1, d3, d4);
	out[2][1] = -determinant_m3(a1, a3, a4, b1, b3, b4, d1, d3, d4);
	out[3][1] = determinant_m3(a1, a3, a4, b1, b3, b4, c1, c3, c4);

	out[0][2] = determinant_m3(b1, b2, b4, c1, c2, c4, d1, d2, d4);
	out[1][2] = -determinant_m3(a1, a2, a4, c1, c2, c4, d1, d2, d4);
	out[2][2] = determinant_m3(a1, a2, a4, b1, b2, b4, d1, d2, d4);
	out[3][2] = -determinant_m3(a1, a2, a4, b1, b2, b4, c1, c2, c4);

	out[0][3] = -determinant_m3(b1, b2, b3, c1, c2, c3, d1, d2, d3);
	out[1][3] = determinant_m3(a1, a2, a3, c1, c2, c3, d1, d2, d3);
	out[2][3] = -determinant_m3(a1, a2, a3, b1, b2, b3, d1, d2, d3);
	out[3][3] = determinant_m3(a1, a2, a3, b1, b2, b3, c1, c2, c3);
}

float determinant_m2(float a, float b, float c, float d)
{

	return a * d - b * c;
}

float determinant_m3(float a1, float a2, float a3,
                     float b1, float b2, float b3,
                     float c1, float c2, float c3)
{
	float ans;

	ans = (a1 * determinant_m2(b2, b3, c2, c3) -
	       b1 * determinant_m2(a2, a3, c2, c3) +
	       c1 * determinant_m2(a2, a3, b2, b3));

	return ans;
}

float determinant_m4(float m[4][4])
{
	float ans;
	float a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4, d1, d2, d3, d4;

	a1 = m[0][0];
	b1 = m[0][1];
	c1 = m[0][2];
	d1 = m[0][3];

	a2 = m[1][0];
	b2 = m[1][1];
	c2 = m[1][2];
	d2 = m[1][3];

	a3 = m[2][0];
	b3 = m[2][1];
	c3 = m[2][2];
	d3 = m[2][3];

	a4 = m[3][0];
	b4 = m[3][1];
	c4 = m[3][2];
	d4 = m[3][3];

	ans = (a1 * determinant_m3(b2, b3, b4, c2, c3, c4, d2, d3, d4) -
	       b1 * determinant_m3(a2, a3, a4, c2, c3, c4, d2, d3, d4) +
	       c1 * determinant_m3(a2, a3, a4, b2, b3, b4, d2, d3, d4) -
	       d1 * determinant_m3(a2, a3, a4, b2, b3, b4, c2, c3, c4));

	return ans;
}

/****************************** Transformations ******************************/

void size_to_mat3(float mat[3][3], const float size[3])
{
	mat[0][0] = size[0];
	mat[0][1] = 0.0f;
	mat[0][2] = 0.0f;
	mat[1][1] = size[1];
	mat[1][0] = 0.0f;
	mat[1][2] = 0.0f;
	mat[2][2] = size[2];
	mat[2][1] = 0.0f;
	mat[2][0] = 0.0f;
}

void size_to_mat4(float mat[4][4], const float size[3])
{
	mat[0][0] = size[0];
	mat[0][1] = 0.0f;
	mat[0][2] = 0.0f;
	mat[0][3] = 0.0f;
	mat[1][0] = 0.0f;
	mat[1][1] = size[1];
	mat[1][2] = 0.0f;
	mat[1][3] = 0.0f;
	mat[2][0] = 0.0f;
	mat[2][1] = 0.0f;
	mat[2][2] = size[2];
	mat[2][3] = 0.0f;
	mat[3][0] = 0.0f;
	mat[3][1] = 0.0f;
	mat[3][2] = 0.0f;
	mat[3][3] = 1.0f;
}

void mat3_to_size(float size[3], float mat[3][3])
{
	size[0] = len_v3(mat[0]);
	size[1] = len_v3(mat[1]);
	size[2] = len_v3(mat[2]);
}

void mat4_to_size(float size[3], float mat[4][4])
{
	size[0] = len_v3(mat[0]);
	size[1] = len_v3(mat[1]);
	size[2] = len_v3(mat[2]);
}

/* this gets the average scale of a matrix, only use when your scaling
 * data that has no idea of scale axis, examples are bone-envelope-radius
 * and curve radius */
float mat3_to_scale(float mat[3][3])
{
	/* unit length vector */
	float unit_vec[3];
	copy_v3_fl(unit_vec, (float)(1.0 / M_SQRT3));
	mul_m3_v3(mat, unit_vec);
	return len_v3(unit_vec);
}

float mat4_to_scale(float mat[4][4])
{
	/* unit length vector */
	float unit_vec[3];
	copy_v3_fl(unit_vec, (float)(1.0 / M_SQRT3));
	mul_mat3_m4_v3(mat, unit_vec);
	return len_v3(unit_vec);
}

void mat3_to_rot_size(float rot[3][3], float size[3], float mat3[3][3])
{
	float mat3_n[3][3]; /* mat3 -> normalized, 3x3 */
	float imat3_n[3][3]; /* mat3 -> normalized & inverted, 3x3 */

	/* rotation & scale are linked, we need to create the mat's
	 * for these together since they are related. */

	/* so scale doesn't interfere with rotation [#24291] */
	/* note: this is a workaround for negative matrix not working for rotation conversion, FIXME */
	normalize_m3_m3(mat3_n, mat3);
	if (is_negative_m3(mat3)) {
		negate_v3(mat3_n[0]);
		negate_v3(mat3_n[1]);
		negate_v3(mat3_n[2]);
	}

	/* rotation */
	/* keep rot as a 3x3 matrix, the caller can convert into a quat or euler */
	copy_m3_m3(rot, mat3_n);

	/* scale */
	/* note: mat4_to_size(ob->size, mat) fails for negative scale */
	invert_m3_m3(imat3_n, mat3_n);
	mul_m3_m3m3(mat3, imat3_n, mat3);

	size[0] = mat3[0][0];
	size[1] = mat3[1][1];
	size[2] = mat3[2][2];
}

void mat4_to_loc_rot_size(float loc[3], float rot[3][3], float size[3], float wmat[4][4])
{
	float mat3[3][3]; /* wmat -> 3x3 */

	copy_m3_m4(mat3, wmat);
	mat3_to_rot_size(rot, size, mat3);

	/* location */
	copy_v3_v3(loc, wmat[3]);
}

void mat4_to_loc_quat(float loc[3], float quat[4], float wmat[4][4])
{
	float mat3[3][3];
	float mat3_n[3][3]; /* normalized mat3 */

	copy_m3_m4(mat3, wmat);
	normalize_m3_m3(mat3_n, mat3);

	/* so scale doesn't interfere with rotation [#24291] */
	/* note: this is a workaround for negative matrix not working for rotation conversion, FIXME */
	if (is_negative_m3(mat3)) {
		negate_v3(mat3_n[0]);
		negate_v3(mat3_n[1]);
		negate_v3(mat3_n[2]);
	}

	mat3_to_quat(quat, mat3_n);
	copy_v3_v3(loc, wmat[3]);
}

void mat4_decompose(float loc[3], float quat[4], float size[3], float wmat[4][4])
{
	float rot[3][3];
	mat4_to_loc_rot_size(loc, rot, size, wmat);
	mat3_to_quat(quat, rot);
}

void scale_m3_fl(float m[3][3], float scale)
{
	m[0][0] = m[1][1] = m[2][2] = scale;
	m[0][1] = m[0][2] = 0.0;
	m[1][0] = m[1][2] = 0.0;
	m[2][0] = m[2][1] = 0.0;
}

void scale_m4_fl(float m[4][4], float scale)
{
	m[0][0] = m[1][1] = m[2][2] = scale;
	m[3][3] = 1.0;
	m[0][1] = m[0][2] = m[0][3] = 0.0;
	m[1][0] = m[1][2] = m[1][3] = 0.0;
	m[2][0] = m[2][1] = m[2][3] = 0.0;
	m[3][0] = m[3][1] = m[3][2] = 0.0;
}

void translate_m4(float mat[4][4], float Tx, float Ty, float Tz)
{
	mat[3][0] += (Tx * mat[0][0] + Ty * mat[1][0] + Tz * mat[2][0]);
	mat[3][1] += (Tx * mat[0][1] + Ty * mat[1][1] + Tz * mat[2][1]);
	mat[3][2] += (Tx * mat[0][2] + Ty * mat[1][2] + Tz * mat[2][2]);
}

void rotate_m4(float mat[4][4], const char axis, const float angle)
{
	int col;
	float temp[4] = {0.0f, 0.0f, 0.0f, 0.0f};
	float cosine, sine;

	assert(axis >= 'X' && axis <= 'Z');

	cosine = cosf(angle);
	sine   = sinf(angle);
	switch (axis) {
		case 'X':
			for (col = 0; col < 4; col++)
				temp[col] = cosine * mat[1][col] + sine * mat[2][col];
			for (col = 0; col < 4; col++) {
				mat[2][col] = -sine * mat[1][col] + cosine * mat[2][col];
				mat[1][col] = temp[col];
			}
			break;

		case 'Y':
			for (col = 0; col < 4; col++)
				temp[col] = cosine * mat[0][col] - sine * mat[2][col];
			for (col = 0; col < 4; col++) {
				mat[2][col] = sine * mat[0][col] + cosine * mat[2][col];
				mat[0][col] = temp[col];
			}
			break;

		case 'Z':
			for (col = 0; col < 4; col++)
				temp[col] = cosine * mat[0][col] + sine * mat[1][col];
			for (col = 0; col < 4; col++) {
				mat[1][col] = -sine * mat[0][col] + cosine * mat[1][col];
				mat[0][col] = temp[col];
			}
			break;
	}
}

void rotate_m2(float mat[2][2], const float angle)
{
	mat[0][0] = mat[1][1] = cosf(angle);
	mat[0][1] = sinf(angle);
	mat[1][0] = -mat[0][1];
}

/**
 * Scale or rotate around a pivot point,
 * a convenience function to avoid having to do inline.
 *
 * Since its common to make a scale/rotation matrix that pivots around an arbitrary point.
 *
 * Typical use case is to make 3x3 matrix, copy to 4x4, then pass to this function.
 */
void transform_pivot_set_m4(float mat[4][4], const float pivot[3])
{
	float tmat[4][4];

	unit_m4(tmat);

	copy_v3_v3(tmat[3], pivot);
	mul_m4_m4m4(mat, tmat, mat);

	/* invert the matrix */
	negate_v3(tmat[3]);
	mul_m4_m4m4(mat, mat, tmat);
}

void blend_m3_m3m3(float out[3][3], float dst[3][3], float src[3][3], const float srcweight)
{
	float srot[3][3], drot[3][3];
	float squat[4], dquat[4], fquat[4];
	float sscale[3], dscale[3], fsize[3];
	float rmat[3][3], smat[3][3];

	mat3_to_rot_size(drot, dscale, dst);
	mat3_to_rot_size(srot, sscale, src);

	mat3_to_quat(dquat, drot);
	mat3_to_quat(squat, srot);

	/* do blending */
	interp_qt_qtqt(fquat, dquat, squat, srcweight);
	interp_v3_v3v3(fsize, dscale, sscale, srcweight);

	/* compose new matrix */
	quat_to_mat3(rmat, fquat);
	size_to_mat3(smat, fsize);
	mul_m3_m3m3(out, rmat, smat);
}

void blend_m4_m4m4(float out[4][4], float dst[4][4], float src[4][4], const float srcweight)
{
	float sloc[3], dloc[3], floc[3];
	float srot[3][3], drot[3][3];
	float squat[4], dquat[4], fquat[4];
	float sscale[3], dscale[3], fsize[3];

	mat4_to_loc_rot_size(dloc, drot, dscale, dst);
	mat4_to_loc_rot_size(sloc, srot, sscale, src);

	mat3_to_quat(dquat, drot);
	mat3_to_quat(squat, srot);

	/* do blending */
	interp_v3_v3v3(floc, dloc, sloc, srcweight);
	interp_qt_qtqt(fquat, dquat, squat, srcweight);
	interp_v3_v3v3(fsize, dscale, sscale, srcweight);

	/* compose new matrix */
	loc_quat_size_to_mat4(out, floc, fquat, fsize);
}

bool is_negative_m3(float mat[3][3])
{
	float vec[3];
	cross_v3_v3v3(vec, mat[0], mat[1]);
	return (dot_v3v3(vec, mat[2]) < 0.0f);
}

bool is_negative_m4(float mat[4][4])
{
	float vec[3];
	cross_v3_v3v3(vec, mat[0], mat[1]);
	return (dot_v3v3(vec, mat[2]) < 0.0f);
}

bool is_zero_m3(float mat[3][3])
{
	return (is_zero_v3(mat[0]) &&
	        is_zero_v3(mat[1]) &&
	        is_zero_v3(mat[2]));
}
bool is_zero_m4(float mat[4][4])
{
	return (is_zero_v4(mat[0]) &&
	        is_zero_v4(mat[1]) &&
	        is_zero_v4(mat[2]) &&
	        is_zero_v4(mat[3]));
}

/* make a 4x4 matrix out of 3 transform components */
/* matrices are made in the order: scale * rot * loc */
/* TODO: need to have a version that allows for rotation order... */

void loc_eul_size_to_mat4(float mat[4][4], const float loc[3], const float eul[3], const float size[3])
{
	float rmat[3][3], smat[3][3], tmat[3][3];

	/* initialize new matrix */
	unit_m4(mat);

	/* make rotation + scaling part */
	eul_to_mat3(rmat, eul);
	size_to_mat3(smat, size);
	mul_m3_m3m3(tmat, rmat, smat);

	/* copy rot/scale part to output matrix*/
	copy_m4_m3(mat, tmat);

	/* copy location to matrix */
	mat[3][0] = loc[0];
	mat[3][1] = loc[1];
	mat[3][2] = loc[2];
}

/* make a 4x4 matrix out of 3 transform components */

/* matrices are made in the order: scale * rot * loc */
void loc_eulO_size_to_mat4(float mat[4][4], const float loc[3], const float eul[3], const float size[3], const short rotOrder)
{
	float rmat[3][3], smat[3][3], tmat[3][3];

	/* initialize new matrix */
	unit_m4(mat);

	/* make rotation + scaling part */
	eulO_to_mat3(rmat, eul, rotOrder);
	size_to_mat3(smat, size);
	mul_m3_m3m3(tmat, rmat, smat);

	/* copy rot/scale part to output matrix*/
	copy_m4_m3(mat, tmat);

	/* copy location to matrix */
	mat[3][0] = loc[0];
	mat[3][1] = loc[1];
	mat[3][2] = loc[2];
}


/* make a 4x4 matrix out of 3 transform components */

/* matrices are made in the order: scale * rot * loc */
void loc_quat_size_to_mat4(float mat[4][4], const float loc[3], const float quat[4], const float size[3])
{
	float rmat[3][3], smat[3][3], tmat[3][3];

	/* initialize new matrix */
	unit_m4(mat);

	/* make rotation + scaling part */
	quat_to_mat3(rmat, quat);
	size_to_mat3(smat, size);
	mul_m3_m3m3(tmat, rmat, smat);

	/* copy rot/scale part to output matrix*/
	copy_m4_m3(mat, tmat);

	/* copy location to matrix */
	mat[3][0] = loc[0];
	mat[3][1] = loc[1];
	mat[3][2] = loc[2];
}

void loc_axisangle_size_to_mat4(float mat[4][4], const float loc[3], const float axis[3], const float angle, const float size[3])
{
	float q[4];
	axis_angle_to_quat(q, axis, angle);
	loc_quat_size_to_mat4(mat, loc, q, size);
}

/*********************************** Other ***********************************/

void print_m3(const char *str, float m[3][3])
{
	printf("%s\n", str);
	printf("%f %f %f\n", m[0][0], m[1][0], m[2][0]);
	printf("%f %f %f\n", m[0][1], m[1][1], m[2][1]);
	printf("%f %f %f\n", m[0][2], m[1][2], m[2][2]);
	printf("\n");
}

void print_m4(const char *str, float m[4][4])
{
	printf("%s\n", str);
	printf("%f %f %f %f\n", m[0][0], m[1][0], m[2][0], m[3][0]);
	printf("%f %f %f %f\n", m[0][1], m[1][1], m[2][1], m[3][1]);
	printf("%f %f %f %f\n", m[0][2], m[1][2], m[2][2], m[3][2]);
	printf("%f %f %f %f\n", m[0][3], m[1][3], m[2][3], m[3][3]);
	printf("\n");
}

/*********************************** SVD ************************************
 * from TNT matrix library
 *
 * Compute the Single Value Decomposition of an arbitrary matrix A
 * That is compute the 3 matrices U,W,V with U column orthogonal (m,n)
 * ,W a diagonal matrix and V an orthogonal square matrix s.t.
 * A = U.W.Vt. From this decomposition it is trivial to compute the
 * (pseudo-inverse) of A as Ainv = V.Winv.tranpose(U).
 */

void svd_m4(float U[4][4], float s[4], float V[4][4], float A_[4][4])
{
	float A[4][4];
	float work1[4], work2[4];
	int m = 4;
	int n = 4;
	int maxiter = 200;
	int nu = min_ii(m, n);

	float *work = work1;
	float *e = work2;
	float eps;

	int i = 0, j = 0, k = 0, p, pp, iter;

	/* Reduce A to bidiagonal form, storing the diagonal elements
	 * in s and the super-diagonal elements in e. */

	int nct = min_ii(m - 1, n);
	int nrt = max_ii(0, min_ii(n - 2, m));

	copy_m4_m4(A, A_);
	zero_m4(U);
	zero_v4(s);

	for (k = 0; k < max_ii(nct, nrt); k++) {
		if (k < nct) {

			/* Compute the transformation for the k-th column and
			 * place the k-th diagonal in s[k].
			 * Compute 2-norm of k-th column without under/overflow. */
			s[k] = 0;
			for (i = k; i < m; i++) {
				s[k] = hypotf(s[k], A[i][k]);
			}
			if (s[k] != 0.0f) {
				float invsk;
				if (A[k][k] < 0.0f) {
					s[k] = -s[k];
				}
				invsk = 1.0f / s[k];
				for (i = k; i < m; i++) {
					A[i][k] *= invsk;
				}
				A[k][k] += 1.0f;
			}
			s[k] = -s[k];
		}
		for (j = k + 1; j < n; j++) {
			if ((k < nct) && (s[k] != 0.0f)) {

				/* Apply the transformation. */

				float t = 0;
				for (i = k; i < m; i++) {
					t += A[i][k] * A[i][j];
				}
				t = -t / A[k][k];
				for (i = k; i < m; i++) {
					A[i][j] += t * A[i][k];
				}
			}

			/* Place the k-th row of A into e for the */
			/* subsequent calculation of the row transformation. */

			e[j] = A[k][j];
		}
		if (k < nct) {

			/* Place the transformation in U for subsequent back
			 * multiplication. */

			for (i = k; i < m; i++)
				U[i][k] = A[i][k];
		}
		if (k < nrt) {

			/* Compute the k-th row transformation and place the
			 * k-th super-diagonal in e[k].
			 * Compute 2-norm without under/overflow. */
			e[k] = 0;
			for (i = k + 1; i < n; i++) {
				e[k] = hypotf(e[k], e[i]);
			}
			if (e[k] != 0.0f) {
				float invek;
				if (e[k + 1] < 0.0f) {
					e[k] = -e[k];
				}
				invek = 1.0f / e[k];
				for (i = k + 1; i < n; i++) {
					e[i] *= invek;
				}
				e[k + 1] += 1.0f;
			}
			e[k] = -e[k];
			if ((k + 1 < m) & (e[k] != 0.0f)) {
				float invek1;

				/* Apply the transformation. */

				for (i = k + 1; i < m; i++) {
					work[i] = 0.0f;
				}
				for (j = k + 1; j < n; j++) {
					for (i = k + 1; i < m; i++) {
						work[i] += e[j] * A[i][j];
					}
				}
				invek1 = 1.0f / e[k + 1];
				for (j = k + 1; j < n; j++) {
					float t = -e[j] * invek1;
					for (i = k + 1; i < m; i++) {
						A[i][j] += t * work[i];
					}
				}
			}

			/* Place the transformation in V for subsequent
			 * back multiplication. */

			for (i = k + 1; i < n; i++)
				V[i][k] = e[i];
		}
	}

	/* Set up the final bidiagonal matrix or order p. */

	p = min_ii(n, m + 1);
	if (nct < n) {
		s[nct] = A[nct][nct];
	}
	if (m < p) {
		s[p - 1] = 0.0f;
	}
	if (nrt + 1 < p) {
		e[nrt] = A[nrt][p - 1];
	}
	e[p - 1] = 0.0f;

	/* If required, generate U. */

	for (j = nct; j < nu; j++) {
		for (i = 0; i < m; i++) {
			U[i][j] = 0.0f;
		}
		U[j][j] = 1.0f;
	}
	for (k = nct - 1; k >= 0; k--) {
		if (s[k] != 0.0f) {
			for (j = k + 1; j < nu; j++) {
				float t = 0;
				for (i = k; i < m; i++) {
					t += U[i][k] * U[i][j];
				}
				t = -t / U[k][k];
				for (i = k; i < m; i++) {
					U[i][j] += t * U[i][k];
				}
			}
			for (i = k; i < m; i++) {
				U[i][k] = -U[i][k];
			}
			U[k][k] = 1.0f + U[k][k];
			for (i = 0; i < k - 1; i++) {
				U[i][k] = 0.0f;
			}
		}
		else {
			for (i = 0; i < m; i++) {
				U[i][k] = 0.0f;
			}
			U[k][k] = 1.0f;
		}
	}

	/* If required, generate V. */

	for (k = n - 1; k >= 0; k--) {
		if ((k < nrt) & (e[k] != 0.0f)) {
			for (j = k + 1; j < nu; j++) {
				float t = 0;
				for (i = k + 1; i < n; i++) {
					t += V[i][k] * V[i][j];
				}
				t = -t / V[k + 1][k];
				for (i = k + 1; i < n; i++) {
					V[i][j] += t * V[i][k];
				}
			}
		}
		for (i = 0; i < n; i++) {
			V[i][k] = 0.0f;
		}
		V[k][k] = 1.0f;
	}

	/* Main iteration loop for the singular values. */

	pp = p - 1;
	iter = 0;
	eps = powf(2.0f, -52.0f);
	while (p > 0) {
		int kase = 0;

		/* Test for maximum iterations to avoid infinite loop */
		if (maxiter == 0)
			break;
		maxiter--;

		/* This section of the program inspects for
		 * negligible elements in the s and e arrays.  On
		 * completion the variables kase and k are set as follows.
		 *
		 * kase = 1	  if s(p) and e[k - 1] are negligible and k<p
		 * kase = 2	  if s(k) is negligible and k<p
		 * kase = 3	  if e[k - 1] is negligible, k<p, and
		 *               s(k), ..., s(p) are not negligible (qr step).
		 * kase = 4	  if e(p - 1) is negligible (convergence). */

		for (k = p - 2; k >= -1; k--) {
			if (k == -1) {
				break;
			}
			if (fabsf(e[k]) <= eps * (fabsf(s[k]) + fabsf(s[k + 1]))) {
				e[k] = 0.0f;
				break;
			}
		}
		if (k == p - 2) {
			kase = 4;
		}
		else {
			int ks;
			for (ks = p - 1; ks >= k; ks--) {
				float t;
				if (ks == k) {
					break;
				}
				t = (ks != p ? fabsf(e[ks]) : 0.f) +
				    (ks != k + 1 ? fabsf(e[ks - 1]) : 0.0f);
				if (fabsf(s[ks]) <= eps * t) {
					s[ks] = 0.0f;
					break;
				}
			}
			if (ks == k) {
				kase = 3;
			}
			else if (ks == p - 1) {
				kase = 1;
			}
			else {
				kase = 2;
				k = ks;
			}
		}
		k++;

		/* Perform the task indicated by kase. */

		switch (kase) {

			/* Deflate negligible s(p). */

			case 1:
			{
				float f = e[p - 2];
				e[p - 2] = 0.0f;
				for (j = p - 2; j >= k; j--) {
					float t = hypotf(s[j], f);
					float invt = 1.0f / t;
					float cs = s[j] * invt;
					float sn = f * invt;
					s[j] = t;
					if (j != k) {
						f = -sn * e[j - 1];
						e[j - 1] = cs * e[j - 1];
					}

					for (i = 0; i < n; i++) {
						t = cs * V[i][j] + sn * V[i][p - 1];
						V[i][p - 1] = -sn * V[i][j] + cs * V[i][p - 1];
						V[i][j] = t;
					}
				}
				break;
			}

			/* Split at negligible s(k). */

			case 2:
			{
				float f = e[k - 1];
				e[k - 1] = 0.0f;
				for (j = k; j < p; j++) {
					float t = hypotf(s[j], f);
					float invt = 1.0f / t;
					float cs = s[j] * invt;
					float sn = f * invt;
					s[j] = t;
					f = -sn * e[j];
					e[j] = cs * e[j];

					for (i = 0; i < m; i++) {
						t = cs * U[i][j] + sn * U[i][k - 1];
						U[i][k - 1] = -sn * U[i][j] + cs * U[i][k - 1];
						U[i][j] = t;
					}
				}
				break;
			}

			/* Perform one qr step. */

			case 3:
			{

				/* Calculate the shift. */

				float scale = max_ff(max_ff(max_ff(max_ff(
				                   fabsf(s[p - 1]), fabsf(s[p - 2])), fabsf(e[p - 2])),
				                   fabsf(s[k])), fabsf(e[k]));
				float invscale = 1.0f / scale;
				float sp = s[p - 1] * invscale;
				float spm1 = s[p - 2] * invscale;
				float epm1 = e[p - 2] * invscale;
				float sk = s[k] * invscale;
				float ek = e[k] * invscale;
				float b = ((spm1 + sp) * (spm1 - sp) + epm1 * epm1) * 0.5f;
				float c = (sp * epm1) * (sp * epm1);
				float shift = 0.0f;
				float f, g;
				if ((b != 0.0f) || (c != 0.0f)) {
					shift = sqrtf(b * b + c);
					if (b < 0.0f) {
						shift = -shift;
					}
					shift = c / (b + shift);
				}
				f = (sk + sp) * (sk - sp) + shift;
				g = sk * ek;

				/* Chase zeros. */

				for (j = k; j < p - 1; j++) {
					float t = hypotf(f, g);
					/* division by zero checks added to avoid NaN (brecht) */
					float cs = (t == 0.0f) ? 0.0f : f / t;
					float sn = (t == 0.0f) ? 0.0f : g / t;
					if (j != k) {
						e[j - 1] = t;
					}
					f = cs * s[j] + sn * e[j];
					e[j] = cs * e[j] - sn * s[j];
					g = sn * s[j + 1];
					s[j + 1] = cs * s[j + 1];

					for (i = 0; i < n; i++) {
						t = cs * V[i][j] + sn * V[i][j + 1];
						V[i][j + 1] = -sn * V[i][j] + cs * V[i][j + 1];
						V[i][j] = t;
					}

					t = hypotf(f, g);
					/* division by zero checks added to avoid NaN (brecht) */
					cs = (t == 0.0f) ? 0.0f : f / t;
					sn = (t == 0.0f) ? 0.0f : g / t;
					s[j] = t;
					f = cs * e[j] + sn * s[j + 1];
					s[j + 1] = -sn * e[j] + cs * s[j + 1];
					g = sn * e[j + 1];
					e[j + 1] = cs * e[j + 1];
					if (j < m - 1) {
						for (i = 0; i < m; i++) {
							t = cs * U[i][j] + sn * U[i][j + 1];
							U[i][j + 1] = -sn * U[i][j] + cs * U[i][j + 1];
							U[i][j] = t;
						}
					}
				}
				e[p - 2] = f;
				iter = iter + 1;
				break;
			}
			/* Convergence. */

			case 4:
			{

				/* Make the singular values positive. */

				if (s[k] <= 0.0f) {
					s[k] = (s[k] < 0.0f ? -s[k] : 0.0f);

					for (i = 0; i <= pp; i++)
						V[i][k] = -V[i][k];
				}

				/* Order the singular values. */

				while (k < pp) {
					float t;
					if (s[k] >= s[k + 1]) {
						break;
					}
					t = s[k];
					s[k] = s[k + 1];
					s[k + 1] = t;
					if (k < n - 1) {
						for (i = 0; i < n; i++) {
							t = V[i][k + 1];
							V[i][k + 1] = V[i][k];
							V[i][k] = t;
						}
					}
					if (k < m - 1) {
						for (i = 0; i < m; i++) {
							t = U[i][k + 1];
							U[i][k + 1] = U[i][k];
							U[i][k] = t;
						}
					}
					k++;
				}
				iter = 0;
				p--;
				break;
			}
		}
	}
}

void pseudoinverse_m4_m4(float Ainv[4][4], float A[4][4], float epsilon)
{
	/* compute moon-penrose pseudo inverse of matrix, singular values
	 * below epsilon are ignored for stability (truncated SVD) */
	float V[4][4], W[4], Wm[4][4], U[4][4];
	int i;

	transpose_m4(A);
	svd_m4(V, W, U, A);
	transpose_m4(U);
	transpose_m4(V);

	zero_m4(Wm);
	for (i = 0; i < 4; i++)
		Wm[i][i] = (W[i] < epsilon) ? 0.0f : 1.0f / W[i];

	transpose_m4(V);

	mul_m4_series(Ainv, U, Wm, V);
}

void pseudoinverse_m3_m3(float Ainv[3][3], float A[3][3], float epsilon)
{
	/* try regular inverse when possible, otherwise fall back to slow svd */
	if (!invert_m3_m3(Ainv, A)) {
		float tmp[4][4], tmpinv[4][4];

		copy_m4_m3(tmp, A);
		pseudoinverse_m4_m4(tmpinv, tmp, epsilon);
		copy_m3_m4(Ainv, tmpinv);
	}
}

bool has_zero_axis_m4(float matrix[4][4])
{
	return len_squared_v3(matrix[0]) < FLT_EPSILON ||
	       len_squared_v3(matrix[1]) < FLT_EPSILON ||
	       len_squared_v3(matrix[2]) < FLT_EPSILON;
}

void invert_m4_m4_safe(float Ainv[4][4], float A[4][4])
{
	if (!invert_m4_m4(Ainv, A)) {
		float Atemp[4][4];

		copy_m4_m4(Atemp, A);

		/* Matrix is degenerate (e.g. 0 scale on some axis), ideally we should
		 * never be in this situation, but try to invert it anyway with tweak.
		 */
		Atemp[0][0] += 1e-8f;
		Atemp[1][1] += 1e-8f;
		Atemp[2][2] += 1e-8f;

		if (!invert_m4_m4(Ainv, Atemp)) {
			unit_m4(Ainv);
		}
	}
}

/**
 * SpaceTransform struct encapsulates all needed data to convert between two coordinate spaces
 * (where conversion can be represented by a matrix multiplication).
 *
 * A SpaceTransform is initialized using:
 *   BLI_SPACE_TRANSFORM_SETUP(&data,  ob1, ob2)
 *
 * After that the following calls can be used:
 *   BLI_space_transform_apply(&data, co);  // converts a coordinate in ob1 space to the corresponding ob2 space
 *   BLI_space_transform_invert(&data, co);  // converts a coordinate in ob2 space to the corresponding ob1 space
 *
 * Same concept as BLI_space_transform_apply and BLI_space_transform_invert, but no is normalized after conversion
 * (and not translated at all!):
 *   BLI_space_transform_apply_normal(&data, no);
 *   BLI_space_transform_invert_normal(&data, no);
 *
 */

void BLI_space_transform_from_matrices(SpaceTransform *data, float local[4][4], float target[4][4])
{
	float itarget[4][4];
	invert_m4_m4(itarget, target);
	mul_m4_m4m4(data->local2target, itarget, local);
	invert_m4_m4(data->target2local, data->local2target);
}

void BLI_space_transform_apply(const SpaceTransform *data, float co[3])
{
	mul_v3_m4v3(co, ((SpaceTransform *)data)->local2target, co);
}

void BLI_space_transform_invert(const SpaceTransform *data, float co[3])
{
	mul_v3_m4v3(co, ((SpaceTransform *)data)->target2local, co);
}

void BLI_space_transform_apply_normal(const SpaceTransform *data, float no[3])
{
	mul_mat3_m4_v3(((SpaceTransform *)data)->local2target, no);
	normalize_v3(no);
}

void BLI_space_transform_invert_normal(const SpaceTransform *data, float no[3])
{
	mul_mat3_m4_v3(((SpaceTransform *)data)->target2local, no);
	normalize_v3(no);
}
