blender-archive/source/blender/blenlib/intern/arithb.c

/* arithb.c
 *
 * simple math for blender code
 *
 * sort of cleaned up mar-01 nzc
 *
 * Functions here get counterparts with MTC prefixes. Basically, we phase
 * out the calls here in favour of fully prototyped versions.
 *
 * $Id$
 *
 * ***** BEGIN GPL/BL DUAL 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. The Blender
 * Foundation also sells licenses for use in proprietary software under
 * the Blender License.  See http://www.blender.org/BL/ for information
 * about this.
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL/BL DUAL LICENSE BLOCK *****
 */

/* ************************ FUNKTIES **************************** */

#include <math.h>
#include <sys/types.h>
#include <string.h> 
#include <float.h>

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef __sun__
#include <strings.h>
#endif

#if !defined(__sgi) && !defined(WIN32)
#include <sys/time.h>
#include <unistd.h>
#endif

#include <stdio.h>
#include "BLI_arithb.h"

/* A few small defines. Keep'em local! */
#define SMALL_NUMBER	1.e-8
#define ABS(x)	((x) < 0 ? -(x) : (x))
#define SWAP(type, a, b)	{ type sw_ap; sw_ap=(a); (a)=(b); (b)=sw_ap; }


#if defined(WIN32) || defined(__APPLE__)
#include <stdlib.h>
#define M_PI 3.14159265358979323846
#define M_SQRT2 1.41421356237309504880   

#endif /* defined(WIN32) || defined(__APPLE__) */


float saacos(float fac)
{
	if(fac<= -1.0f) return (float)M_PI;
	else if(fac>=1.0f) return 0.0;
	else return (float)acos(fac);
}

float sasqrt(float fac)
{
	if(fac<=0.0) return 0.0;
	return (float)sqrt(fac);
}

float Normalise(float *n)
{
	float d;
	
	d= n[0]*n[0]+n[1]*n[1]+n[2]*n[2];
	/* FLT_EPSILON is too large! A larger value causes normalise errors in a scaled down utah teapot */
	if(d>0.0000000000001) {
		d= (float)sqrt(d);

		n[0]/=d; 
		n[1]/=d; 
		n[2]/=d;
	} else {
		n[0]=n[1]=n[2]= 0.0;
		d= 0.0;
	}
	return d;
}

void Crossf(float *c, float *a, float *b)
{
	c[0] = a[1] * b[2] - a[2] * b[1];
	c[1] = a[2] * b[0] - a[0] * b[2];
	c[2] = a[0] * b[1] - a[1] * b[0];
}

float Inpf( float *v1, float *v2)
{
	return v1[0]*v2[0]+v1[1]*v2[1]+v1[2]*v2[2];
}

void Mat3Transp(float mat[][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 Mat4Transp(float mat[][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;
}


/*
 * 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
 */

int Mat4Invert(float inverse[][4], float mat[][4])
{
	int i, j, k;
	double temp;
	float tempmat[4][4];
	float max;
	int maxj;

	/* 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 = ABS(tempmat[i][i]);
		maxj = i;
		for(j = i + 1; j < 4; j++) {
			if(ABS(tempmat[j][i]) > max) {
				max = ABS(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)(tempmat[i][k]/temp);
			inverse[i][k] = (float)(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)(tempmat[i][k]*temp);
					inverse[j][k] -= (float)(inverse[i][k]*temp);
				}
			}
		}
	}
	return 1;
}
#ifdef TEST_ACTIVE
void Mat4InvertSimp(float inverse[][4], float mat[][4])
{
	/* only for Matrices that have a rotation */
	/* based at GG IV pag 205 */
	float scale;
	
	scale= mat[0][0]*mat[0][0] + mat[1][0]*mat[1][0] + mat[2][0]*mat[2][0];
	if(scale==0.0) return;
	
	scale= 1.0/scale;
	
	/* transpose and scale */
	inverse[0][0]= scale*mat[0][0];
	inverse[1][0]= scale*mat[0][1];
	inverse[2][0]= scale*mat[0][2];
	inverse[0][1]= scale*mat[1][0];
	inverse[1][1]= scale*mat[1][1];
	inverse[2][1]= scale*mat[1][2];
	inverse[0][2]= scale*mat[2][0];
	inverse[1][2]= scale*mat[2][1];
	inverse[2][2]= scale*mat[2][2];

	inverse[3][0]= -(inverse[0][0]*mat[3][0] + inverse[1][0]*mat[3][1] + inverse[2][0]*mat[3][2]);
	inverse[3][1]= -(inverse[0][1]*mat[3][0] + inverse[1][1]*mat[3][1] + inverse[2][1]*mat[3][2]);
	inverse[3][2]= -(inverse[0][2]*mat[3][0] + inverse[1][2]*mat[3][1] + inverse[2][2]*mat[3][2]);
	
	inverse[0][3]= inverse[1][3]= inverse[2][3]= 0.0;
	inverse[3][3]= 1.0;
}
#endif
/*  struct Matrix4; */

#ifdef TEST_ACTIVE
/* this seems to be unused.. */

void Mat4Inv(float *m1, float *m2)
{

/* This gets me into trouble:  */
	float mat1[3][3], mat2[3][3]; 
	
/*  	void Mat3Inv(); */
/*  	void Mat3CpyMat4(); */
/*  	void Mat4CpyMat3(); */

	Mat3CpyMat4((float*)mat2,m2);
	Mat3Inv((float*)mat1, (float*) mat2);
	Mat4CpyMat3(m1, mat1);

}
#endif


float Det2x2(float a,float b,float c,float d)
{

	return a*d - b*c;
}



float Det3x3(float a1, float a2, float a3,
			 float b1, float b2, float b3,
			 float c1, float c2, float c3 )
{
	float ans;

	ans = a1 * Det2x2( b2, b3, c2, c3 )
	    - b1 * Det2x2( a2, a3, c2, c3 )
	    + c1 * Det2x2( a2, a3, b2, b3 );

	return ans;
}

float Det4x4(float m[][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 * Det3x3( b2, b3, b4, c2, c3, c4, d2, d3, d4)
	    - b1 * Det3x3( a2, a3, a4, c2, c3, c4, d2, d3, d4)
	    + c1 * Det3x3( a2, a3, a4, b2, b3, b4, d2, d3, d4)
	    - d1 * Det3x3( a2, a3, a4, b2, b3, b4, c2, c3, c4);

	return ans;
}


void Mat4Adj(float out[][4], float in[][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]  =   Det3x3( b2, b3, b4, c2, c3, c4, d2, d3, d4);
	out[1][0]  = - Det3x3( a2, a3, a4, c2, c3, c4, d2, d3, d4);
	out[2][0]  =   Det3x3( a2, a3, a4, b2, b3, b4, d2, d3, d4);
	out[3][0]  = - Det3x3( a2, a3, a4, b2, b3, b4, c2, c3, c4);

	out[0][1]  = - Det3x3( b1, b3, b4, c1, c3, c4, d1, d3, d4);
	out[1][1]  =   Det3x3( a1, a3, a4, c1, c3, c4, d1, d3, d4);
	out[2][1]  = - Det3x3( a1, a3, a4, b1, b3, b4, d1, d3, d4);
	out[3][1]  =   Det3x3( a1, a3, a4, b1, b3, b4, c1, c3, c4);

	out[0][2]  =   Det3x3( b1, b2, b4, c1, c2, c4, d1, d2, d4);
	out[1][2]  = - Det3x3( a1, a2, a4, c1, c2, c4, d1, d2, d4);
	out[2][2]  =   Det3x3( a1, a2, a4, b1, b2, b4, d1, d2, d4);
	out[3][2]  = - Det3x3( a1, a2, a4, b1, b2, b4, c1, c2, c4);

	out[0][3]  = - Det3x3( b1, b2, b3, c1, c2, c3, d1, d2, d3);
	out[1][3]  =   Det3x3( a1, a2, a3, c1, c2, c3, d1, d2, d3);
	out[2][3]  = - Det3x3( a1, a2, a3, b1, b2, b3, d1, d2, d3);
	out[3][3]  =   Det3x3( a1, a2, a3, b1, b2, b3, c1, c2, c3);
}

void Mat4InvGG(float out[][4], float in[][4])	/* from Graphic Gems I, out= INV(in)  */
{
	int i, j;
	float det;

	/* calculate the adjoint matrix */

	Mat4Adj(out,in);

	det = Det4x4(out);

	if ( fabs( det ) < SMALL_NUMBER) {
		return;
	}

	/* scale the adjoint matrix to get the inverse */

	for (i=0; i<4; i++)
		for(j=0; j<4; j++)
			out[i][j] = out[i][j] / det;

	/* the last factor is not always 1. For that reason an extra division should be implemented? */
}


void Mat3Inv(float m1[][3], float m2[][3])
{
	short a,b;
	float det;

	/* calc adjoint */
	Mat3Adj(m1,m2);

	/* then determinant old matrix! */
	det= m2[0][0]* (m2[1][1]*m2[2][2] - m2[1][2]*m2[2][1])
	    -m2[1][0]* (m2[0][1]*m2[2][2] - m2[0][2]*m2[2][1])
	    +m2[2][0]* (m2[0][1]*m2[1][2] - m2[0][2]*m2[1][1]);

	if(det==0) det=1;
	det= 1/det;
	for(a=0;a<3;a++) {
		for(b=0;b<3;b++) {
			m1[a][b]*=det;
		}
	}
}

void Mat3Adj(float m1[][3], float m[][3])
{
	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 Mat4MulMat4(float m1[][4], float m2[][4], float m3[][4])
{
  /* 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];

}
#ifdef TEST_ACTIVE
void subMat4MulMat4(float *m1, float *m2, float *m3)
{

	m1[0]= m2[0]*m3[0] + m2[1]*m3[4] + m2[2]*m3[8];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[5] + m2[2]*m3[9];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[6] + m2[2]*m3[10];
	m1[3]= m2[0]*m3[3] + m2[1]*m3[7] + m2[2]*m3[11] + m2[3];
	m1+=4;
	m2+=4;
	m1[0]= m2[0]*m3[0] + m2[1]*m3[4] + m2[2]*m3[8];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[5] + m2[2]*m3[9];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[6] + m2[2]*m3[10];
	m1[3]= m2[0]*m3[3] + m2[1]*m3[7] + m2[2]*m3[11] + m2[3];
	m1+=4;
	m2+=4;
	m1[0]= m2[0]*m3[0] + m2[1]*m3[4] + m2[2]*m3[8];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[5] + m2[2]*m3[9];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[6] + m2[2]*m3[10];
	m1[3]= m2[0]*m3[3] + m2[1]*m3[7] + m2[2]*m3[11] + m2[3];
}
#endif

#ifndef TEST_ACTIVE
void Mat3MulMat3(float m1[][3], float m3[][3], float m2[][3])
#else
void Mat3MulMat3(float *m1, float *m3, float *m2)
#endif
{
   /*  m1[i][j] = m2[i][k]*m3[k][j], args are flipped!  */
#ifndef TEST_ACTIVE
  	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]; 
#else
	m1[0]= m2[0]*m3[0] + m2[1]*m3[3] + m2[2]*m3[6];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[4] + m2[2]*m3[7];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[5] + m2[2]*m3[8];
	m1+=3;
	m2+=3;
	m1[0]= m2[0]*m3[0] + m2[1]*m3[3] + m2[2]*m3[6];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[4] + m2[2]*m3[7];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[5] + m2[2]*m3[8];
	m1+=3;
	m2+=3;
	m1[0]= m2[0]*m3[0] + m2[1]*m3[3] + m2[2]*m3[6];
	m1[1]= m2[0]*m3[1] + m2[1]*m3[4] + m2[2]*m3[7];
	m1[2]= m2[0]*m3[2] + m2[1]*m3[5] + m2[2]*m3[8];
#endif
} /* end of void Mat3MulMat3(float m1[][3], float m3[][3], float m2[][3]) */

void Mat4MulMat43(float (*m1)[4], float (*m3)[4], float (*m2)[3])
{
	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 Mat3IsMat3MulMat4(float m1[][3], float m2[][3], float m3[][4])
{
    /* 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 Mat4MulMat34(float (*m1)[4], float (*m3)[3], float (*m2)[4])
{
	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 Mat4CpyMat4(float m1[][4], float m2[][4]) 
{
	memcpy(m1, m2, 4*4*sizeof(float));
}

void Mat4SwapMat4(float *m1, float *m2)
{
	float t;
	int i;

	for(i=0;i<16;i++) {
		t= *m1;
		*m1= *m2;
		*m2= t;
		m1++; 
		m2++;
	}
}

typedef float Mat3Row[3];
typedef float Mat4Row[4];

#ifdef TEST_ACTIVE
void Mat3CpyMat4(float *m1p, float *m2p)
#else
void Mat3CpyMat4(float m1[][3], float m2[][4])
#endif
{
#ifdef TEST_ACTIVE
	int i, j;
  	Mat3Row *m1= (Mat3Row *)m1p; 
  	Mat4Row *m2= (Mat4Row *)m2p; 
	for ( i = 0; i++; i < 3) {
		for (j = 0; j++; j < 3) {
			m1p[3*i + j] = m2p[4*i + j];
		}
	}	 		
#endif
	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];
}

/* Butched. See .h for comment */
/*  void Mat4CpyMat3(float m1[][4], float m2[][3]) */
#ifdef TEST_ACTIVE
void Mat4CpyMat3(float* m1, float *m2)
{
	int i;
	for (i = 0; i < 3; i++) {
		m1[(4*i)]    = m2[(3*i)];
		m1[(4*i) + 1]= m2[(3*i) + 1];
		m1[(4*i) + 2]= m2[(3*i) + 2];
		m1[(4*i) + 3]= 0.0;
		i++;
	}

	m1[12]=m1[13]= m1[14]= 0.0;
	m1[15]= 1.0;
}
#else

void Mat4CpyMat3(float m1[][4], float m2[][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;


}
#endif

void Mat3CpyMat3(float m1[][3], float m2[][3]) 
{	
	/* destination comes first: */
	memcpy(&m1[0], &m2[0], 9*sizeof(float));
}

void Mat3MulSerie(float answ[][3],
				   float m1[][3], float m2[][3], float m3[][3],
				   float m4[][3], float m5[][3], float m6[][3],
				   float m7[][3], float m8[][3])
{
	float temp[3][3];
	
	if(m1==0 || m2==0) return;

	
	Mat3MulMat3(answ, m2, m1);
	if(m3) {
		Mat3MulMat3(temp, m3, answ);
		if(m4) {
			Mat3MulMat3(answ, m4, temp);
			if(m5) {
				Mat3MulMat3(temp, m5, answ);
				if(m6) {
					Mat3MulMat3(answ, m6, temp);
					if(m7) {
						Mat3MulMat3(temp, m7, answ);
						if(m8) {
							Mat3MulMat3(answ, m8, temp);
						}
						else Mat3CpyMat3(answ, temp);
					}
				}
				else Mat3CpyMat3(answ, temp);
			}
		}
		else Mat3CpyMat3(answ, temp);
	}
}

void Mat4MulSerie(float answ[][4], float m1[][4],
				float m2[][4], float m3[][4], float m4[][4],
				float m5[][4], float m6[][4], float m7[][4],
				float m8[][4])
{
	float temp[4][4];
	
	if(m1==0 || m2==0) return;
	
	Mat4MulMat4(answ, m2, m1);
	if(m3) {
		Mat4MulMat4(temp, m3, answ);
		if(m4) {
			Mat4MulMat4(answ, m4, temp);
			if(m5) {
				Mat4MulMat4(temp, m5, answ);
				if(m6) {
					Mat4MulMat4(answ, m6, temp);
					if(m7) {
						Mat4MulMat4(temp, m7, answ);
						if(m8) {
							Mat4MulMat4(answ, m8, temp);
						}
						else Mat4CpyMat4(answ, temp);
					}
				}
				else Mat4CpyMat4(answ, temp);
			}
		}
		else Mat4CpyMat4(answ, temp);
	}
}



void Mat4Clr(float *m)
{
	memset(m, 0, 4*4*sizeof(float));
}

void Mat3Clr(float *m)
{
	memset(m, 0, 3*3*sizeof(float));
}

void Mat4One(float m[][4])
{

	m[0][0]= m[1][1]= m[2][2]= 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 Mat3One(float m[][3])
{

	m[0][0]= m[1][1]= m[2][2]= 1.0;
	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 Mat4MulVec( float mat[][4], int *vec)
{
	int x,y;

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

void Mat4MulVecfl( float mat[][4], float *vec)
{
	float x,y;

	x=vec[0]; 
	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 VecMat4MulVecfl(float *in, float mat[][4], float *vec)
{
	float x,y;

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

void Mat4Mul3Vecfl( float mat[][4], float *vec)
{
	float x,y;

	x= vec[0]; 
	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 Mat4MulVec4fl( float mat[][4], float *vec)
{
	float x,y,z;

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

void Mat3MulVec( float mat[][3], int *vec)
{
	int x,y;

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

void Mat3MulVecfl( float mat[][3], float *vec)
{
	float x,y;

	x=vec[0]; 
	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 Mat3MulVecd( float mat[][3], double *vec)
{
	double x,y;

	x=vec[0]; 
	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 Mat3TransMulVecfl( float mat[][3], float *vec)
{
	float x,y;

	x=vec[0]; 
	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 Mat3MulFloat(float *m, float f)
{
	int i;

	for(i=0;i<9;i++) m[i]*=f;
}

void Mat4MulFloat(float *m, float f)
{
	int i;

	for(i=0;i<12;i++) m[i]*=f;	/* count to 12: without vector component */
}


void Mat4MulFloat3(float *m, float f)		/* only scale component */
{
	int i,j;

	for(i=0; i<3; i++) {
		for(j=0; j<3; j++) {
			
			m[4*i+j] *= f;
		}
	}
}

void VecStar(float mat[][3], float *vec)
{

	mat[0][0]= mat[1][1]= mat[2][2]= 0.0;
	mat[0][1]= -vec[2];	
	mat[0][2]= vec[1];
	mat[1][0]= vec[2];	
	mat[1][2]= -vec[0];
	mat[2][0]= -vec[1];	
	mat[2][1]= vec[0];
	
}
#ifdef TEST_ACTIVE
short EenheidsMat(float mat[][3])
{

	if(mat[0][0]==1.0 && mat[0][1]==0.0 && mat[0][2]==0.0)
		if(mat[1][0]==0.0 && mat[1][1]==1.0 && mat[1][2]==0.0)
			if(mat[2][0]==0.0 && mat[2][1]==0.0 && mat[2][2]==1.0)
				return 1;
	return 0;
}
#endif

int FloatCompare( float *v1,  float *v2, float limit)
{

	if( fabs(v1[0]-v2[0])<limit ) {
		if( fabs(v1[1]-v2[1])<limit ) {
			if( fabs(v1[2]-v2[2])<limit ) return 1;
		}
	}
	return 0;
}

void printmatrix4( char *str,  float m[][4])
{
	printf("%s\n", str);
	printf("%f %f %f %f\n",m[0][0],m[0][1],m[0][2],m[0][3]);
	printf("%f %f %f %f\n",m[1][0],m[1][1],m[1][2],m[1][3]);
	printf("%f %f %f %f\n",m[2][0],m[2][1],m[2][2],m[2][3]);
	printf("%f %f %f %f\n",m[3][0],m[3][1],m[3][2],m[3][3]);
	printf("\n");

}

void printmatrix3( char *str,  float m[][3])
{
	printf("%s\n", str);
	printf("%f %f %f\n",m[0][0],m[0][1],m[0][2]);
	printf("%f %f %f\n",m[1][0],m[1][1],m[1][2]);
	printf("%f %f %f\n",m[2][0],m[2][1],m[2][2]);
	printf("\n");

}

/* **************** QUATERNIONS ********** */


void QuatMul(float *q, float *q1, float *q2)
{
	float t0,t1,t2;

	t0=   q1[0]*q2[0]-q1[1]*q2[1]-q1[2]*q2[2]-q1[3]*q2[3];
	t1=   q1[0]*q2[1]+q1[1]*q2[0]+q1[2]*q2[3]-q1[3]*q2[2];
	t2=   q1[0]*q2[2]+q1[2]*q2[0]+q1[3]*q2[1]-q1[1]*q2[3];
	q[3]= q1[0]*q2[3]+q1[3]*q2[0]+q1[1]*q2[2]-q1[2]*q2[1];
	q[0]=t0; 
	q[1]=t1; 
	q[2]=t2;
}

void QuatSub(float *q, float *q1, float *q2)
{
	q2[0]= -q2[0];
	QuatMul(q, q1, q2);
	q2[0]= -q2[0];
}


void QuatToMat3( float *q, float m[][3])
{
	double q0, q1, q2, q3, qda,qdb,qdc,qaa,qab,qac,qbb,qbc,qcc;

	q0= M_SQRT2 * q[0];
	q1= M_SQRT2 * q[1];
	q2= M_SQRT2 * q[2];
	q3= M_SQRT2 * q[3];

	qda= q0*q1;
	qdb= q0*q2;
	qdc= q0*q3;
	qaa= q1*q1;
	qab= q1*q2;
	qac= q1*q3;
	qbb= q2*q2;
	qbc= q2*q3;
	qcc= q3*q3;

	m[0][0]= (float)(1.0-qbb-qcc);
	m[0][1]= (float)(qdc+qab);
	m[0][2]= (float)(-qdb+qac);

	m[1][0]= (float)(-qdc+qab);
	m[1][1]= (float)(1.0-qaa-qcc);
	m[1][2]= (float)(qda+qbc);

	m[2][0]= (float)(qdb+qac);
	m[2][1]= (float)(-qda+qbc);
	m[2][2]= (float)(1.0-qaa-qbb);
}


void QuatToMat4( float *q, float m[][4])
{
	double q0, q1, q2, q3, qda,qdb,qdc,qaa,qab,qac,qbb,qbc,qcc;

	q0= M_SQRT2 * q[0];
	q1= M_SQRT2 * q[1];
	q2= M_SQRT2 * q[2];
	q3= M_SQRT2 * q[3];

	qda= q0*q1;
	qdb= q0*q2;
	qdc= q0*q3;
	qaa= q1*q1;
	qab= q1*q2;
	qac= q1*q3;
	qbb= q2*q2;
	qbc= q2*q3;
	qcc= q3*q3;

	m[0][0]= (float)(1.0-qbb-qcc);
	m[0][1]= (float)(qdc+qab);
	m[0][2]= (float)(-qdb+qac);
	m[0][3]= 0.0f;

	m[1][0]= (float)(-qdc+qab);
	m[1][1]= (float)(1.0-qaa-qcc);
	m[1][2]= (float)(qda+qbc);
	m[1][3]= 0.0f;

	m[2][0]= (float)(qdb+qac);
	m[2][1]= (float)(-qda+qbc);
	m[2][2]= (float)(1.0-qaa-qbb);
	m[2][3]= 0.0f;
	
	m[3][0]= m[3][1]= m[3][2]= 0.0f;
	m[3][3]= 1.0f;
}

void Mat3ToQuat( float wmat[][3], float *q)		/* from Sig.Proc.85 pag 253 */
{
	double tr, s;
	float mat[3][3];

	/* work on a copy */
	Mat3CpyMat3(mat, wmat);
	Mat3Ortho(mat);			/* this is needed AND a NormalQuat in the end */
	
	tr= 0.25*(1.0+mat[0][0]+mat[1][1]+mat[2][2]);
	
	if(tr>FLT_EPSILON) {
		s= sqrt( tr);
		q[0]= (float)s;
		s*= 4.0;
		q[1]= (float)((mat[1][2]-mat[2][1])/s);
		q[2]= (float)((mat[2][0]-mat[0][2])/s);
		q[3]= (float)((mat[0][1]-mat[1][0])/s);
	}
	else {
		q[0]= 0.0f;
		s= -0.5*(mat[1][1]+mat[2][2]);
		
		if(s>FLT_EPSILON) {
			s= sqrt(s);
			q[1]= (float)s;
			q[2]= (float)(mat[0][1]/(2*s));
			q[3]= (float)(mat[0][2]/(2*s));
		}
		else {
			q[1]= 0.0f;
			s= 0.5*(1.0-mat[2][2]);
			
			if(s>FLT_EPSILON) {
				s= sqrt(s);
				q[2]= (float)s;
				q[3]= (float)(mat[1][2]/(2*s));
			}
			else {
				q[2]= 0.0f;
				q[3]= 1.0f;
			}
		}
	}
	NormalQuat(q);
}

void Mat3ToQuat_is_ok( float wmat[][3], float *q)
{
	float mat[3][3], matr[3][3], matn[3][3], q1[4], q2[4], hoek, si, co, nor[3];

	/* work on a copy */
	Mat3CpyMat3(mat, wmat);
	Mat3Ortho(mat);
	
	/* rotate z-axis of matrix to z-axis */

	nor[0] = mat[2][1];		/* cross product with (0,0,1) */
	nor[1] =  -mat[2][0];
	nor[2] = 0.0;
	Normalise(nor);
	
	co= mat[2][2];
	hoek= 0.5f*saacos(co);
	
	co= (float)cos(hoek);
	si= (float)sin(hoek);
	q1[0]= co;
	q1[1]= -nor[0]*si;		/* negative here, but why? */
	q1[2]= -nor[1]*si;
	q1[3]= -nor[2]*si;

	/* rotate back x-axis from mat, using inverse q1 */
	QuatToMat3(q1, matr);
	Mat3Inv(matn, matr);
	Mat3MulVecfl(matn, mat[0]);
	
	/* and align x-axes */
	hoek= (float)(0.5*atan2(mat[0][1], mat[0][0]));
	
	co= (float)cos(hoek);
	si= (float)sin(hoek);
	q2[0]= co;
	q2[1]= 0.0f;
	q2[2]= 0.0f;
	q2[3]= si;
	
	QuatMul(q, q1, q2);
}


void Mat4ToQuat( float m[][4], float *q)
{
	float mat[3][3];
	
	Mat3CpyMat4(mat, m);
	Mat3ToQuat(mat, q);
	
}

void QuatOne(float *q)
{
	q[0]= q[2]= q[3]= 0.0;
	q[1]= 1.0;
}

void NormalQuat(float *q)
{
	float len;
	
	len= (float)sqrt(q[0]*q[0]+q[1]*q[1]+q[2]*q[2]+q[3]*q[3]);
	if(len!=0.0) {
		q[0]/= len;
		q[1]/= len;
		q[2]/= len;
		q[3]/= len;
	} else {
		q[1]= 1.0f;
		q[0]= q[2]= q[3]= 0.0f;			
	}
}

float *vectoquat( float *vec, short axis, short upflag)
{
	static float q1[4];
	float q2[4], nor[3], *fp, mat[3][3], hoek, si, co, x2, y2, z2, len1;
	
	/* first rotate to axis */
	if(axis>2) {	
		x2= vec[0] ; y2= vec[1] ; z2= vec[2];
		axis-= 3;
	}
	else {
		x2= -vec[0] ; y2= -vec[1] ; z2= -vec[2];
	}
	
	q1[0]=1.0; 
	q1[1]=q1[2]=q1[3]= 0.0;

	len1= (float)sqrt(x2*x2+y2*y2+z2*z2);
	if(len1 == 0.0) return(q1);

	/* nasty! I need a good routine for this...
	 * problem is a rotation of an Y axis to the negative Y-axis for example.
	 */

	if(axis==0) {	/* x-axis */
		nor[0]= 0.0;
		nor[1]= -z2;
		nor[2]= y2;

		if( fabs(y2)+fabs(z2)<0.0001 ) {
			nor[1]= 1.0;
		}

		co= x2;
	}
	else if(axis==1) {	/* y-axis */
		nor[0]= z2;
		nor[1]= 0.0;
		nor[2]= -x2;
		
		if( fabs(x2)+fabs(z2)<0.0001 ) {
			nor[2]= 1.0;
		}
		
		co= y2;
	}
	else {			/* z-axis */
		nor[0]= -y2;
		nor[1]= x2;
		nor[2]= 0.0;

		if( fabs(x2)+fabs(y2)<0.0001 ) {
			nor[0]= 1.0;
		}

		co= z2;
	}
	co/= len1;

	Normalise(nor);
	
	hoek= 0.5f*saacos(co);
	si= (float)sin(hoek);
	q1[0]= (float)cos(hoek);
	q1[1]= nor[0]*si;
	q1[2]= nor[1]*si;
	q1[3]= nor[2]*si;
	
	if(axis!=upflag) {
		QuatToMat3(q1, mat);

		fp= mat[2];
		if(axis==0) {
			if(upflag==1) hoek= (float)(0.5*atan2(fp[2], fp[1]));
			else hoek= (float)(-0.5*atan2(fp[1], fp[2]));
		}
		else if(axis==1) {
			if(upflag==0) hoek= (float)(-0.5*atan2(fp[2], fp[0]));
			else hoek= (float)(0.5*atan2(fp[0], fp[2]));
		}
		else {
			if(upflag==0) hoek= (float)(0.5*atan2(-fp[1], -fp[0]));
			else hoek= (float)(-0.5*atan2(-fp[0], -fp[1]));
		}
				
		co= (float)cos(hoek);
		si= (float)(sin(hoek)/len1);
		q2[0]= co;
		q2[1]= x2*si;
		q2[2]= y2*si;
		q2[3]= z2*si;
			
		QuatMul(q1,q2,q1);
	}

	return(q1);
}

void VecUpMat3old( float *vec, float mat[][3], short axis)
{
	float inp, up[3];
	short cox = 0, coy = 0, coz = 0;
	
	/* using different up's is not useful, infact there is no real 'up'!
	 */

	up[0]= 0.0;
	up[1]= 0.0;
	up[2]= 1.0;

	if(axis==0) {
		cox= 0; coy= 1; coz= 2;		/* Y up Z tr */
	}
	if(axis==1) {
		cox= 1; coy= 2; coz= 0;		/* Z up X tr */
	}
	if(axis==2) {
		cox= 2; coy= 0; coz= 1;		/* X up Y tr */
	}
	if(axis==3) {
		cox= 0; coy= 2; coz= 1;		/*  */
	}
	if(axis==4) {
		cox= 1; coy= 0; coz= 2;		/*  */
	}
	if(axis==5) {
		cox= 2; coy= 1; coz= 0;		/* Y up X tr */
	}

	mat[coz][0]= vec[0];
	mat[coz][1]= vec[1];
	mat[coz][2]= vec[2];
	Normalise((float *)mat[coz]);
	
	inp= mat[coz][0]*up[0] + mat[coz][1]*up[1] + mat[coz][2]*up[2];
	mat[coy][0]= up[0] - inp*mat[coz][0];
	mat[coy][1]= up[1] - inp*mat[coz][1];
	mat[coy][2]= up[2] - inp*mat[coz][2];

	Normalise((float *)mat[coy]);
	
	Crossf(mat[cox], mat[coy], mat[coz]);
	
}

void VecUpMat3(float *vec, float mat[][3], short axis)
{
	float inp;
	short cox = 0, coy = 0, coz = 0;

	/* using different up's is not useful, infact there is no real 'up'!
	*/

	if(axis==0) {
		cox= 0; coy= 1; coz= 2;		/* Y up Z tr */
	}
	if(axis==1) {
		cox= 1; coy= 2; coz= 0;		/* Z up X tr */
	}
	if(axis==2) {
		cox= 2; coy= 0; coz= 1;		/* X up Y tr */
	}
	if(axis==3) {
		cox= 0; coy= 1; coz= 2;		/* Y op -Z tr */
		vec[0]= -vec[0];
		vec[1]= -vec[1];
		vec[2]= -vec[2];
	}
	if(axis==4) {
		cox= 1; coy= 0; coz= 2;		/*  */
	}
	if(axis==5) {
		cox= 2; coy= 1; coz= 0;		/* Y up X tr */
	}

	mat[coz][0]= vec[0];
	mat[coz][1]= vec[1];
	mat[coz][2]= vec[2];
	Normalise((float *)mat[coz]);
	
	inp= mat[coz][2];
	mat[coy][0]= - inp*mat[coz][0];
	mat[coy][1]= - inp*mat[coz][1];
	mat[coy][2]= 1.0f - inp*mat[coz][2];

	Normalise((float *)mat[coy]);
	
	Crossf(mat[cox], mat[coy], mat[coz]);
	
}


/* **************** VIEW / PROJECTION ********************************  */


void i_ortho(
	float left, float right,
	float bottom, float top,
	float nearClip, float farClip,
	float matrix[][4]
){
    float Xdelta, Ydelta, Zdelta;
 
    Xdelta = right - left;
    Ydelta = top - bottom;
    Zdelta = farClip - nearClip;
    if (Xdelta == 0.0 || Ydelta == 0.0 || Zdelta == 0.0) {
		return;
    }
    Mat4One(matrix);
    matrix[0][0] = 2.0f/Xdelta;
    matrix[3][0] = -(right + left)/Xdelta;
    matrix[1][1] = 2.0f/Ydelta;
    matrix[3][1] = -(top + bottom)/Ydelta;
    matrix[2][2] = -2.0f/Zdelta;		/* note: negate Z	*/
    matrix[3][2] = -(farClip + nearClip)/Zdelta;
}

void i_window(
	float left, float right,
	float bottom, float top,
	float nearClip, float farClip,
	float mat[][4]
){
	float Xdelta, Ydelta, Zdelta;

	Xdelta = right - left;
	Ydelta = top - bottom;
	Zdelta = farClip - nearClip;

	if (Xdelta == 0.0 || Ydelta == 0.0 || Zdelta == 0.0) {
		return;
	}
	mat[0][0] = nearClip * 2.0f/Xdelta;
	mat[1][1] = nearClip * 2.0f/Ydelta;
	mat[2][0] = (right + left)/Xdelta;		/* note: negate Z	*/
	mat[2][1] = (top + bottom)/Ydelta;
	mat[2][2] = -(farClip + nearClip)/Zdelta;
	mat[2][3] = -1.0f;
	mat[3][2] = (-2.0f * nearClip * farClip)/Zdelta;
	mat[0][1] = mat[0][2] = mat[0][3] =
	    mat[1][0] = mat[1][2] = mat[1][3] =
	    mat[3][0] = mat[3][1] = mat[3][3] = 0.0;

}

void i_translate(float Tx, float Ty, float Tz, float mat[][4])
{
    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 i_multmatrix( float icand[][4], float Vm[][4])
{
    int row, col;
    float temp[4][4];

    for(row=0 ; row<4 ; row++) 
        for(col=0 ; col<4 ; col++)
            temp[row][col] = icand[row][0] * Vm[0][col]
                           + icand[row][1] * Vm[1][col]
                           + icand[row][2] * Vm[2][col]
                           + icand[row][3] * Vm[3][col];
	Mat4CpyMat4(Vm, temp);
}

void i_rotate(float angle, char axis, float mat[][4])
{
	int col;
    float temp[4];
    float cosine, sine;

    for(col=0; col<4 ; col++)	/* init temp to zero matrix */
        temp[col] = 0;

    angle = (float)(angle*(3.1415926535/180.0));
    cosine = (float)cos(angle);
    sine = (float)sin(angle);
    switch(axis){
    case 'x':    
    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':
    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':
    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 i_polarview(float dist, float azimuth, float incidence, float twist, float Vm[][4])
{

	Mat4One(Vm);

    i_translate(0.0, 0.0, -dist, Vm);
    i_rotate(-twist,'z', Vm);	
    i_rotate(-incidence,'x', Vm);
    i_rotate(-azimuth,'z', Vm);
}

void i_lookat(float vx, float vy, float vz, float px, float py, float pz, float twist, float mat[][4])
{
	float sine, cosine, hyp, hyp1, dx, dy, dz;
	float mat1[4][4];
	
	Mat4One(mat);
	Mat4One(mat1);

	i_rotate(-twist,'z', mat);

	dx = px - vx;
	dy = py - vy;
	dz = pz - vz;
	hyp = dx * dx + dz * dz;	/* hyp squared	*/
	hyp1 = (float)sqrt(dy*dy + hyp);
	hyp = (float)sqrt(hyp);		/* the real hyp	*/
	
	if (hyp1 != 0.0) {		/* rotate X	*/
		sine = -dy / hyp1;
		cosine = hyp /hyp1;
	} else {
		sine = 0;
		cosine = 1.0f;
	}
	mat1[1][1] = cosine;
	mat1[1][2] = sine;
	mat1[2][1] = -sine;
	mat1[2][2] = cosine;
	
	i_multmatrix(mat1, mat);

    mat1[1][1] = mat1[2][2] = 1.0f;	/* be careful here to reinit	*/
    mat1[1][2] = mat1[2][1] = 0.0;	/* those modified by the last	*/
	
	/* paragraph	*/
	if (hyp != 0.0f) {			/* rotate Y	*/
		sine = dx / hyp;
		cosine = -dz / hyp;
	} else {
		sine = 0;
		cosine = 1.0f;
	}
	mat1[0][0] = cosine;
	mat1[0][2] = -sine;
	mat1[2][0] = sine;
	mat1[2][2] = cosine;
	
	i_multmatrix(mat1, mat);
	i_translate(-vx,-vy,-vz, mat);	/* translate viewpoint to origin */
}





/* ************************************************  */

void Mat3Ortho(float mat[][3])
{	
	Normalise(mat[0]);
	Normalise(mat[1]);
	Normalise(mat[2]);
}

void Mat4Ortho(float mat[][4])
{
	float len;
	
	len= Normalise(mat[0]);
	if(len!=0.0) mat[0][3]/= len;
	len= Normalise(mat[1]);
	if(len!=0.0) mat[1][3]/= len;
	len= Normalise(mat[2]);
	if(len!=0.0) mat[2][3]/= len;
}

void VecCopyf(float *v1, float *v2)
{

	v1[0]= v2[0];
	v1[1]= v2[1];
	v1[2]= v2[2];
}

int VecLen( int *v1, int *v2)
{
	float x,y,z;

	x=(float)(v1[0]-v2[0]);
	y=(float)(v1[1]-v2[1]);
	z=(float)(v1[2]-v2[2]);
	return (int)floor(sqrt(x*x+y*y+z*z));
}

float VecLenf( float *v1, float *v2)
{
	float x,y,z;

	x=v1[0]-v2[0];
	y=v1[1]-v2[1];
	z=v1[2]-v2[2];
	return (float)sqrt(x*x+y*y+z*z);
}

void VecAddf(float *v, float *v1, float *v2)
{
	v[0]= v1[0]+ v2[0];
	v[1]= v1[1]+ v2[1];
	v[2]= v1[2]+ v2[2];
}

void VecSubf(float *v, float *v1, float *v2)
{
	v[0]= v1[0]- v2[0];
	v[1]= v1[1]- v2[1];
	v[2]= v1[2]- v2[2];
}

void VecMidf(float *v, float *v1, float *v2)
{
	v[0]= 0.5f*(v1[0]+ v2[0]);
	v[1]= 0.5f*(v1[1]+ v2[1]);
	v[2]= 0.5f*(v1[2]+ v2[2]);
}

void VecMulf(float *v1, float f)
{

	v1[0]*= f;
	v1[1]*= f;
	v1[2]*= f;
}

int VecCompare( float *v1, float *v2, float limit)
{
	if( fabs(v1[0]-v2[0])<limit )
		if( fabs(v1[1]-v2[1])<limit )
			if( fabs(v1[2]-v2[2])<limit ) return 1;
	return 0;
}

void CalcNormShort( short *v1, short *v2, short *v3, float *n) /* is also cross product */
{
	float n1[3],n2[3];

	n1[0]= (float)(v1[0]-v2[0]);
	n2[0]= (float)(v2[0]-v3[0]);
	n1[1]= (float)(v1[1]-v2[1]);
	n2[1]= (float)(v2[1]-v3[1]);
	n1[2]= (float)(v1[2]-v2[2]);
	n2[2]= (float)(v2[2]-v3[2]);
	n[0]= n1[1]*n2[2]-n1[2]*n2[1];
	n[1]= n1[2]*n2[0]-n1[0]*n2[2];
	n[2]= n1[0]*n2[1]-n1[1]*n2[0];
	Normalise(n);
}

void CalcNormLong( int* v1, int*v2, int*v3, float *n)
{
	float n1[3],n2[3];

	n1[0]= (float)(v1[0]-v2[0]);
	n2[0]= (float)(v2[0]-v3[0]);
	n1[1]= (float)(v1[1]-v2[1]);
	n2[1]= (float)(v2[1]-v3[1]);
	n1[2]= (float)(v1[2]-v2[2]);
	n2[2]= (float)(v2[2]-v3[2]);
	n[0]= n1[1]*n2[2]-n1[2]*n2[1];
	n[1]= n1[2]*n2[0]-n1[0]*n2[2];
	n[2]= n1[0]*n2[1]-n1[1]*n2[0];
	Normalise(n);
}

float CalcNormFloat( float *v1, float *v2, float *v3, float *n)
{
	float n1[3],n2[3];

	n1[0]= v1[0]-v2[0];
	n2[0]= v2[0]-v3[0];
	n1[1]= v1[1]-v2[1];
	n2[1]= v2[1]-v3[1];
	n1[2]= v1[2]-v2[2];
	n2[2]= v2[2]-v3[2];
	n[0]= n1[1]*n2[2]-n1[2]*n2[1];
	n[1]= n1[2]*n2[0]-n1[0]*n2[2];
	n[2]= n1[0]*n2[1]-n1[1]*n2[0];
	return Normalise(n);
}

float CalcNormFloat4( float *v1, float *v2, float *v3, float *v4, float *n)
{
	/* real cross! */
	float n1[3],n2[3];

	n1[0]= v1[0]-v3[0];
	n1[1]= v1[1]-v3[1];
	n1[2]= v1[2]-v3[2];

	n2[0]= v2[0]-v4[0];
	n2[1]= v2[1]-v4[1];
	n2[2]= v2[2]-v4[2];

	n[0]= n1[1]*n2[2]-n1[2]*n2[1];
	n[1]= n1[2]*n2[0]-n1[0]*n2[2];
	n[2]= n1[0]*n2[1]-n1[1]*n2[0];

	return Normalise(n);
}


void CalcCent3f(float *cent, float *v1, float *v2, float *v3)
{

	cent[0]= 0.33333f*(v1[0]+v2[0]+v3[0]);
	cent[1]= 0.33333f*(v1[1]+v2[1]+v3[1]);
	cent[2]= 0.33333f*(v1[2]+v2[2]+v3[2]);
}

void CalcCent4f(float *cent, float *v1, float *v2, float *v3, float *v4)
{

	cent[0]= 0.25f*(v1[0]+v2[0]+v3[0]+v4[0]);
	cent[1]= 0.25f*(v1[1]+v2[1]+v3[1]+v4[1]);
	cent[2]= 0.25f*(v1[2]+v2[2]+v3[2]+v4[2]);
}

float Sqrt3f(float f)
{
	if(f==0.0) return 0;
	if(f<0) return (float)(-exp(log(-f)/3));
	else return (float)(exp(log(f)/3));
}

double Sqrt3d(double d)
{
	if(d==0.0) return 0;
	if(d<0) return -exp(log(-d)/3);
	else return exp(log(d)/3);
}

/* distance v1 to line v2-v3 */
/* using Hesse formula, NO LINE PIECE! */
float DistVL2Dfl( float *v1, float *v2, float *v3)  {
	float a[2],deler;

	a[0]= v2[1]-v3[1];
	a[1]= v3[0]-v2[0];
	deler= (float)sqrt(a[0]*a[0]+a[1]*a[1]);
	if(deler== 0.0f) return 0;

	return (float)(fabs((v1[0]-v2[0])*a[0]+(v1[1]-v2[1])*a[1])/deler);

}

/* distance v1 to line-piece v2-v3 */
float PdistVL2Dfl( float *v1, float *v2, float *v3) 
{
	float labda, rc[2], pt[2], len;
	
	rc[0]= v3[0]-v2[0];
	rc[1]= v3[1]-v2[1];
	len= rc[0]*rc[0]+ rc[1]*rc[1];
	if(len==0.0) {
		rc[0]= v1[0]-v2[0];
		rc[1]= v1[1]-v2[1];
		return (float)(sqrt(rc[0]*rc[0]+ rc[1]*rc[1]));
	}
	
	labda= ( rc[0]*(v1[0]-v2[0]) + rc[1]*(v1[1]-v2[1]) )/len;
	if(labda<=0.0) {
		pt[0]= v2[0];
		pt[1]= v2[1];
	}
	else if(labda>=1.0) {
		pt[0]= v3[0];
		pt[1]= v3[1];
	}
	else {
		pt[0]= labda*rc[0]+v2[0];
		pt[1]= labda*rc[1]+v2[1];
	}

	rc[0]= pt[0]-v1[0];
	rc[1]= pt[1]-v1[1];
	return (float)sqrt(rc[0]*rc[0]+ rc[1]*rc[1]);
}

float AreaF2Dfl( float *v1, float *v2, float *v3)
{
	return (float)(0.5*fabs( (v1[0]-v2[0])*(v2[1]-v3[1]) + (v1[1]-v2[1])*(v3[0]-v2[0]) ));
}


float AreaQ3Dfl( float *v1, float *v2, float *v3,  float *v4)  /* only convex Quadrilaterals */
{
	float len, vec1[3], vec2[3], n[3];

	VecSubf(vec1, v2, v1);
	VecSubf(vec2, v4, v1);
	Crossf(n, vec1, vec2);
	len= Normalise(n);

	VecSubf(vec1, v4, v3);
	VecSubf(vec2, v2, v3);
	Crossf(n, vec1, vec2);
	len+= Normalise(n);

	return (len/2.0f);
}

float AreaT3Dfl( float *v1, float *v2, float *v3)  /* Triangles */
{
	float len, vec1[3], vec2[3], n[3];

	VecSubf(vec1, v3, v2);
	VecSubf(vec2, v1, v2);
	Crossf(n, vec1, vec2);
	len= Normalise(n);

	return (len/2.0f);
}

#define MAX2(x,y)		( (x)>(y) ? (x) : (y) )
#define MAX3(x,y,z)		MAX2( MAX2((x),(y)) , (z) )


float AreaPoly3Dfl(int nr, float *verts, float *normal)
{
	float x, y, z, area, max;
	float *cur, *prev;
	int a, px=0, py=1;

	/* first: find dominant axis: 0==X, 1==Y, 2==Z */
	x= (float)fabs(normal[0]);
	y= (float)fabs(normal[1]);
	z= (float)fabs(normal[2]);
	max = MAX3(x, y, z);
	if(max==y) py=2;
	else if(max==x) {
		px=1; 
		py= 2;
	}

	/* The Trapezium Area Rule */
	prev= verts+3*(nr-1);
	cur= verts;
	area= 0;
	for(a=0; a<nr; a++) {
		area+= (cur[px]-prev[px])*(cur[py]+prev[py]);
		prev= cur;
		cur+=3;
	}

	return (float)fabs(0.5*area/max);
}

void MinMax3(float *min, float *max, float *vec)
{
	if(min[0]>vec[0]) min[0]= vec[0];
	if(min[1]>vec[1]) min[1]= vec[1];
	if(min[2]>vec[2]) min[2]= vec[2];

	if(max[0]<vec[0]) max[0]= vec[0];
	if(max[1]<vec[1]) max[1]= vec[1];
	if(max[2]<vec[2]) max[2]= vec[2];
}

/* ************ EULER *************** */

void EulToMat3( float *eul, float mat[][3])
{
	double ci, cj, ch, si, sj, sh, cc, cs, sc, ss;
	
	ci = cos(eul[0]); 
	cj = cos(eul[1]); 
	ch = cos(eul[2]);
	si = sin(eul[0]); 
	sj = sin(eul[1]); 
	sh = sin(eul[2]);
	cc = ci*ch; 
	cs = ci*sh; 
	sc = si*ch; 
	ss = si*sh;

	mat[0][0] = (float)(cj*ch); 
	mat[1][0] = (float)(sj*sc-cs); 
	mat[2][0] = (float)(sj*cc+ss);
	mat[0][1] = (float)(cj*sh); 
	mat[1][1] = (float)(sj*ss+cc); 
	mat[2][1] = (float)(sj*cs-sc);
	mat[0][2] = (float)-sj;	 
	mat[1][2] = (float)(cj*si);    
	mat[2][2] = (float)(cj*ci);

}

void EulToMat4( float *eul,float mat[][4])
{
	double ci, cj, ch, si, sj, sh, cc, cs, sc, ss;
	
	ci = cos(eul[0]); 
	cj = cos(eul[1]); 
	ch = cos(eul[2]);
	si = sin(eul[0]); 
	sj = sin(eul[1]); 
	sh = sin(eul[2]);
	cc = ci*ch; 
	cs = ci*sh; 
	sc = si*ch; 
	ss = si*sh;

	mat[0][0] = (float)(cj*ch); 
	mat[1][0] = (float)(sj*sc-cs); 
	mat[2][0] = (float)(sj*cc+ss);
	mat[0][1] = (float)(cj*sh); 
	mat[1][1] = (float)(sj*ss+cc); 
	mat[2][1] = (float)(sj*cs-sc);
	mat[0][2] = (float)-sj;	 
	mat[1][2] = (float)(cj*si);    
	mat[2][2] = (float)(cj*ci);


	mat[3][0]= mat[3][1]= mat[3][2]= mat[0][3]= mat[1][3]= mat[2][3]= 0.0f;
	mat[3][3]= 1.0f;
}


void Mat3ToEul(float tmat[][3], float *eul
){
	float cy, quat[4], mat[3][3];
	
	Mat3ToQuat(tmat, quat);
	QuatToMat3(quat, mat);
	Mat3CpyMat3(mat, tmat);
	Mat3Ortho(mat);
	
	cy = (float)sqrt(mat[0][0]*mat[0][0] + mat[0][1]*mat[0][1]);

	if (cy > 16.0*FLT_EPSILON) {
		eul[0] = (float)atan2(mat[1][2], mat[2][2]);
		eul[1] = (float)atan2(-mat[0][2], cy);
		eul[2] = (float)atan2(mat[0][1], mat[0][0]);
	} else {
		eul[0] = (float)atan2(-mat[2][1], mat[1][1]);
		eul[1] = (float)atan2(-mat[0][2], cy);
		eul[2] = 0.0f;
	}
}

void Mat3ToEuln( float tmat[][3], float *eul)
{
	float sin1, cos1, sin2, cos2, sin3, cos3;
	
	sin1 = -tmat[2][0];
	cos1 = (float)sqrt(1 - sin1*sin1);

	if ( fabs(cos1) > FLT_EPSILON ) {
		sin2 = tmat[2][1] / cos1;
		cos2 = tmat[2][2] / cos1;
		sin3 = tmat[1][0] / cos1;
		cos3 = tmat[0][0] / cos1;
    } 
	else {
		sin2 = -tmat[1][2];
		cos2 = tmat[1][1];
		sin3 = 0.0;
		cos3 = 1.0;
    }
	
	eul[0] = (float)atan2(sin3, cos3);
	eul[1] = (float)atan2(sin1, cos1);
	eul[2] = (float)atan2(sin2, cos2);

} 


void QuatToEul( float *quat, float *eul)
{
	float mat[3][3];
	
	QuatToMat3(quat, mat);
	Mat3ToEul(mat, eul);
}

void QuatToSpher( float *quat, float *sph)
/* Not working 100% yet I don't think... */
{
	float tx, ty, tz;
	float qw, qx, qy, qz;
	float cos_theta;
	float sin_theta;
	
	qx = quat[0];
	qy = quat[1];
	qz = quat[2];
	qw = quat[3];

	cos_theta = qw;
	sin_theta = (float)sqrt(1.0 - cos_theta * cos_theta);

	if (fabs(sin_theta) < 0.0005)
		sin_theta = 1.0;

	tx = qx / sin_theta;
	ty = qy / sin_theta;
	tz = qz / sin_theta;

	/* Lattitude */
	sph[0] = -(float)asin(ty);

	/* Longitude */
	if (tx*tx + tz*tz <0.0005)
		sph[1] = 0.0;
	else
		sph[1] = (float)atan2(tx, tz);

	if (sph[1] < 0.0)
		sph[1] +=(float)(M_PI*2);

	/* Roll */
	sph[2] = (float)(acos(cos_theta) * 2.0) ;
}

void Mat3ToSpher ( float *mat3, float *sph)
{
	float quat[4];

	Mat3ToQuat(mat3, quat);
	QuatToSpher(quat, sph);
}


void EulToQuat( float *eul, float *quat)
{
    float ti, tj, th, ci, cj, ch, si, sj, sh, cc, cs, sc, ss;
 
    ti = eul[0]*0.5f; tj = eul[1]*0.5f; th = eul[2]*0.5f;
    ci = (float)cos(ti);  cj = (float)cos(tj);  ch = (float)cos(th);
    si = (float)sin(ti);  sj = (float)sin(tj);  sh = (float)sin(th);
    cc = ci*ch; cs = ci*sh; sc = si*ch; ss = si*sh;
	
	quat[0] = cj*cc + sj*ss;
	quat[1] = cj*sc - sj*cs;
	quat[2] = cj*ss + sj*cc;
	quat[3] = cj*cs - sj*sc;
}

void VecRotToMat3( float *vec, float phi, float mat[][3])
{
	/* rotation of phi radials around vec */
	float vx, vx2, vy, vy2, vz, vz2, co, si;
	
	vx= vec[0];
	vy= vec[1];
	vz= vec[2];
	vx2= vx*vx;
	vy2= vy*vy;
	vz2= vz*vz;
	co= (float)cos(phi);
	si= (float)sin(phi);
	
	mat[0][0]= vx2+co*(1.0f-vx2);
	mat[0][1]= vx*vy*(1.0f-co)+vz*si;
	mat[0][2]= vz*vx*(1.0f-co)-vy*si;
	mat[1][0]= vx*vy*(1.0f-co)-vz*si;
	mat[1][1]= vy2+co*(1.0f-vy2);
	mat[1][2]= vy*vz*(1.0f-co)+vx*si;
	mat[2][0]= vz*vx*(1.0f-co)+vy*si;
	mat[2][1]= vy*vz*(1.0f-co)-vx*si;
	mat[2][2]= vz2+co*(1.0f-vz2);
	
}

void VecRotToQuat( float *vec, float phi, float *quat)
{
	/* rotation of phi radials around vec */
	float si;

	quat[1]= vec[0];
	quat[2]= vec[1];
	quat[3]= vec[2];
													   
	if( Normalise(quat+1) == 0.0) {
		QuatOne(quat);
	}
	else {
		quat[0]= (float)cos( phi/2.0 );
		si= (float)sin( phi/2.0 );
		quat[1] *= si;
		quat[2] *= si;
		quat[3] *= si;
	}
}

void euler_rot(float *beul, float ang, char axis)
{
	float eul[3], mat1[3][3], mat2[3][3], totmat[3][3];
	
	eul[0]= eul[1]= eul[2]= 0.0;
	if(axis=='x') eul[0]= ang;
	else if(axis=='y') eul[1]= ang;
	else eul[2]= ang;
	
	EulToMat3(eul, mat1);
	EulToMat3(beul, mat2);
	
	Mat3MulMat3(totmat, mat2, mat1);
	
	Mat3ToEul(totmat, beul);
	
}



void SizeToMat3( float *size, float mat[][3])
{
	mat[0][0]= size[0];
	mat[0][1]= 0.0;
	mat[0][2]= 0.0;
	mat[1][1]= size[1];
	mat[1][0]= 0.0;
	mat[1][2]= 0.0;
	mat[2][2]= size[2];
	mat[2][1]= 0.0;
	mat[2][0]= 0.0;
}

void Mat3ToSize( float mat[][3], float *size)
{
	float vec[3];


	VecCopyf(vec, mat[0]);
	size[0]= Normalise(vec);
	VecCopyf(vec, mat[1]);
	size[1]= Normalise(vec);
	VecCopyf(vec, mat[2]);
	size[2]= Normalise(vec);

}

void Mat4ToSize( float mat[][4], float *size)
{
	float vec[3];
	

	VecCopyf(vec, mat[0]);
	size[0]= Normalise(vec);
	VecCopyf(vec, mat[1]);
	size[1]= Normalise(vec);
	VecCopyf(vec, mat[2]);
	size[2]= Normalise(vec);
}

/* ************* SPECIALS ******************* */

void triatoquat( float *v1,  float *v2,  float *v3, float *quat)
{
	/* imaginary x-axis, y-axis triangle is being rotated */
	float vec[3], q1[4], q2[4], n[3], si, co, hoek, mat[3][3], imat[3][3];
	
	/* move z-axis to face-normal */
	CalcNormFloat(v1, v2, v3, vec);

	n[0]= vec[1];
	n[1]= -vec[0];
	n[2]= 0.0;
	Normalise(n);
	
	if(n[0]==0.0 && n[1]==0.0) n[0]= 1.0;
	
	hoek= -0.5f*saacos(vec[2]);
	co= (float)cos(hoek);
	si= (float)sin(hoek);
	q1[0]= co;
	q1[1]= n[0]*si;
	q1[2]= n[1]*si;
	q1[3]= 0.0f;
	
	/* rotate back line v1-v2 */
	QuatToMat3(q1, mat);
	Mat3Inv(imat, mat);
	VecSubf(vec, v2, v1);
	Mat3MulVecfl(imat, vec);

	/* what angle has this line with x-axis? */
	vec[2]= 0.0;
	Normalise(vec);

	hoek= (float)(0.5*atan2(vec[1], vec[0]));
	co= (float)cos(hoek);
	si= (float)sin(hoek);
	q2[0]= co;
	q2[1]= 0.0f;
	q2[2]= 0.0f;
	q2[3]= si;
	
	QuatMul(quat, q1, q2);
}

void MinMaxRGB(short c[])
{
	if(c[0]>255) c[0]=255;
	else if(c[0]<0) c[0]=0;
	if(c[1]>255) c[1]=255;
	else if(c[1]<0) c[1]=0;
	if(c[2]>255) c[2]=255;
	else if(c[2]<0) c[2]=0;
}

void hsv_to_rgb(float h, float s, float v, float *r, float *g, float *b)
{
	int i;
	float f, p, q, t;

	h *= 360.0f;
	
	if(s==0 && 0) {
		*r = v;
		*g = v;
		*b = v;
	}
	else {
		if(h==360) h = 0;
		
		h /= 60;
		i = (int)floor(h);
		f = h - i;
		p = v*(1.0f-s);
		q = v*(1.0f-(s*f));
		t = v*(1.0f-(s*(1.0f-f)));
		
		switch (i) {
		case 0 :
			*r = v;
			*g = t;
			*b = p;
			break;
		case 1 :
			*r = q;
			*g = v;
			*b = p;
			break;
		case 2 :
			*r = p;
			*g = v;
			*b = t;
			break;
		case 3 :
			*r = p;
			*g = q;
			*b = v;
			break;
		case 4 :
			*r = t;
			*g = p;
			*b = v;
			break;
		case 5 :
			*r = v;
			*g = p;
			*b = q;
			break;
		}
	}
}

void rgb_to_hsv(float r, float g, float b, float *lh, float *ls, float *lv)
{
	float h, s, v;
	float cmax, cmin, cdelta;
	float rc, gc, bc;

	cmax = r;
	cmin = r;
	cmax = (g>cmax ? g:cmax);
	cmin = (g<cmin ? g:cmin);
	cmax = (b>cmax ? b:cmax);
	cmin = (b<cmin ? b:cmin);

	v = cmax;		/* value */
	if (cmax!=0.0)
		s = (cmax - cmin)/cmax;
	else {
		s = 0.0;
		h = 0.0;
	}
	if (s == 0.0)
		h = -1.0;
	else {
		cdelta = cmax-cmin;
		rc = (cmax-r)/cdelta;
		gc = (cmax-g)/cdelta;
		bc = (cmax-b)/cdelta;
		if (r==cmax)
			h = bc-gc;
		else
			if (g==cmax)
				h = 2.0f+rc-bc;
			else
				h = 4.0f+gc-rc;
		h = h*60.0f;
		if (h<0.0f)
			h += 360.0f;
	}
	
	*ls = s;
	*lh = h/360.0f;
	if( *lh < 0.0) *lh= 0.0;
	*lv = v;
}


/* we define a 'cpack' here as a (3 byte color code) number that can be expressed like 0xFFAA66 or so.
   for that reason it is sensitive for endianness... with this function it works correctly
*/

unsigned int hsv_to_cpack(float h, float s, float v)
{
	short r, g, b;
	float rf, gf, bf;
	unsigned int col;
	
	hsv_to_rgb(h, s, v, &rf, &gf, &bf);
	
	r= (short)(rf*255.0f);
	g= (short)(gf*255.0f);
	b= (short)(bf*255.0f);
	
	col= ( r + (g*256) + (b*256*256) );
	return col;
}


unsigned int rgb_to_cpack(float r, float g, float b)
{
	int ir, ig, ib;
	
	ir= (int)floor(255.0*r);
	if(ir<0) ir= 0; else if(ir>255) ir= 255;
	ig= (int)floor(255.0*g);
	if(ig<0) ig= 0; else if(ig>255) ig= 255;
	ib= (int)floor(255.0*b);
	if(ib<0) ib= 0; else if(ib>255) ib= 255;
	
	return (ir+ (ig*256) + (ib*256*256));
}

void cpack_to_rgb(unsigned int col, float *r, float *g, float *b)
{
	
	*r= (float)((col)&0xFF);
	*r /= 255.0f;

	*g= (float)(((col)>>8)&0xFF);
	*g /= 255.0f;

	*b= (float)(((col)>>16)&0xFF);
	*b /= 255.0f;
}