Show quat.c syntax highlighted
/*
* The 3D Studio File Format Library
* Copyright (C) 1996-2001 by J.E. Hoffmann <je-h@gmx.net>
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id: quat.c,v 1.6 2004/11/20 08:31:31 efalk Exp $
*/
#define LIB3DS_EXPORT
#include <lib3ds/quat.h>
#include <math.h>
/*!
* \defgroup quat Quaternion Mathematics
*
* \author J.E. Hoffmann <je-h@gmx.net>
*/
/*!
* \typedef Lib3dsQuat
* \ingroup quat
*/
/*!
* Clear a quaternion.
* \ingroup quat
*/
void
lib3ds_quat_zero(Lib3dsQuat c)
{
c[0]=c[1]=c[2]=c[3]=0.0f;
}
/*!
* Set a quaternion to Identity
* \ingroup quat
*/
void
lib3ds_quat_identity(Lib3dsQuat c)
{
c[0]=c[1]=c[2]=0.0f;
c[3]=1.0f;
}
/*!
* Copy a quaternion.
* \ingroup quat
*/
void
lib3ds_quat_copy(Lib3dsQuat dest, Lib3dsQuat src)
{
int i;
for (i=0; i<4; ++i) {
dest[i]=src[i];
}
}
/*!
* Compute a quaternion from axis and angle.
*
* \param c Computed quaternion
* \param axis Rotation axis
* \param angle Angle of rotation, radians.
*
* \ingroup quat
*/
void
lib3ds_quat_axis_angle(Lib3dsQuat c, Lib3dsVector axis, Lib3dsFloat angle)
{
Lib3dsDouble omega,s;
Lib3dsDouble l;
l=sqrt(axis[0]*axis[0] + axis[1]*axis[1] + axis[2]*axis[2]);
if (l<LIB3DS_EPSILON) {
c[0]=c[1]=c[2]=0.0f;
c[3]=1.0f;
}
else {
omega=-0.5*angle;
s=sin(omega)/l;
c[0]=(Lib3dsFloat)s*axis[0];
c[1]=(Lib3dsFloat)s*axis[1];
c[2]=(Lib3dsFloat)s*axis[2];
c[3]=(Lib3dsFloat)cos(omega);
}
}
/*!
* Negate a quaternion
*
* \ingroup quat
*/
void
lib3ds_quat_neg(Lib3dsQuat c)
{
int i;
for (i=0; i<4; ++i) {
c[i]=-c[i];
}
}
/*!
* Compute the absolute value of a quaternion
*
* \ingroup quat
*/
void
lib3ds_quat_abs(Lib3dsQuat c)
{
int i;
for (i=0; i<4; ++i) {
c[i]=(Lib3dsFloat)fabs(c[i]);
}
}
/*!
* Compute the conjugate of a quaternion
*
* \ingroup quat
*/
void
lib3ds_quat_cnj(Lib3dsQuat c)
{
int i;
for (i=0; i<3; ++i) {
c[i]=-c[i];
}
}
/*!
* Multiply two quaternions.
*
* \param c Result
* \param a,b Inputs
* \ingroup quat
*/
void
lib3ds_quat_mul(Lib3dsQuat c, Lib3dsQuat a, Lib3dsQuat b)
{
c[0]=a[3]*b[0] + a[0]*b[3] + a[1]*b[2] - a[2]*b[1];
c[1]=a[3]*b[1] + a[1]*b[3] + a[2]*b[0] - a[0]*b[2];
c[2]=a[3]*b[2] + a[2]*b[3] + a[0]*b[1] - a[1]*b[0];
c[3]=a[3]*b[3] - a[0]*b[0] - a[1]*b[1] - a[2]*b[2];
}
/*!
* Multiply a quaternion by a scalar.
*
* \ingroup quat
*/
void
lib3ds_quat_scalar(Lib3dsQuat c, Lib3dsFloat k)
{
int i;
for (i=0; i<4; ++i) {
c[i]*=k;
}
}
/*!
* Normalize a quaternion.
*
* \ingroup quat
*/
void
lib3ds_quat_normalize(Lib3dsQuat c)
{
Lib3dsDouble l,m;
l=sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2] + c[3]*c[3]);
if (fabs(l)<LIB3DS_EPSILON) {
c[0]=c[1]=c[2]=0.0f;
c[3]=1.0f;
}
else {
int i;
m=1.0f/l;
for (i=0; i<4; ++i) {
c[i]=(Lib3dsFloat)(c[i]*m);
}
}
}
/*!
* Compute the inverse of a quaternion.
*
* \ingroup quat
*/
void
lib3ds_quat_inv(Lib3dsQuat c)
{
Lib3dsDouble l,m;
l=sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2] + c[3]*c[3]);
if (fabs(l)<LIB3DS_EPSILON) {
c[0]=c[1]=c[2]=0.0f;
c[3]=1.0f;
}
else {
m=1.0f/l;
c[0]=(Lib3dsFloat)(-c[0]*m);
c[1]=(Lib3dsFloat)(-c[1]*m);
c[2]=(Lib3dsFloat)(-c[2]*m);
c[3]=(Lib3dsFloat)(c[3]*m);
}
}
/*!
* Compute the dot-product of a quaternion.
*
* \ingroup quat
*/
Lib3dsFloat
lib3ds_quat_dot(Lib3dsQuat a, Lib3dsQuat b)
{
return(a[0]*b[0] + a[1]*b[1] + a[2]*b[2] + a[3]*b[3]);
}
/*!
* \ingroup quat
*/
Lib3dsFloat
lib3ds_quat_squared(Lib3dsQuat c)
{
return(c[0]*c[0] + c[1]*c[1] + c[2]*c[2] + c[3]*c[3]);
}
/*!
* \ingroup quat
*/
Lib3dsFloat
lib3ds_quat_length(Lib3dsQuat c)
{
return((Lib3dsFloat)sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2] + c[3]*c[3]));
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_ln(Lib3dsQuat c)
{
Lib3dsDouble om,s,t;
s=sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]);
om=atan2(s,c[3]);
if (fabs(s)<LIB3DS_EPSILON) {
t=0.0f;
}
else {
t=om/s;
}
{
int i;
for (i=0; i<3; ++i) {
c[i]=(Lib3dsFloat)(c[i]*t);
}
c[3]=0.0f;
}
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_ln_dif(Lib3dsQuat c, Lib3dsQuat a, Lib3dsQuat b)
{
Lib3dsQuat invp;
lib3ds_quat_copy(invp, a);
lib3ds_quat_inv(invp);
lib3ds_quat_mul(c, invp, b);
lib3ds_quat_ln(c);
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_exp(Lib3dsQuat c)
{
Lib3dsDouble om,sinom;
om=sqrt(c[0]*c[0] + c[1]*c[1] + c[2]*c[2]);
if (fabs(om)<LIB3DS_EPSILON) {
sinom=1.0f;
}
else {
sinom=sin(om)/om;
}
{
int i;
for (i=0; i<3; ++i) {
c[i]=(Lib3dsFloat)(c[i]*sinom);
}
c[3]=(Lib3dsFloat)cos(om);
}
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_slerp(Lib3dsQuat c, Lib3dsQuat a, Lib3dsQuat b, Lib3dsFloat t)
{
Lib3dsDouble l;
Lib3dsDouble om,sinom;
Lib3dsDouble sp,sq;
Lib3dsQuat q;
l=a[0]*b[0] + a[1]*b[1] + a[2]*b[2] + a[3]*b[3];
if ((1.0+l)>LIB3DS_EPSILON) {
if (fabs(l)>1.0f) l/=fabs(l);
om=acos(l);
sinom=sin(om);
if (fabs(sinom)>LIB3DS_EPSILON) {
sp=sin((1.0f-t)*om)/sinom;
sq=sin(t*om)/sinom;
}
else {
sp=1.0f-t;
sq=t;
}
c[0]=(Lib3dsFloat)(sp*a[0] + sq*b[0]);
c[1]=(Lib3dsFloat)(sp*a[1] + sq*b[1]);
c[2]=(Lib3dsFloat)(sp*a[2] + sq*b[2]);
c[3]=(Lib3dsFloat)(sp*a[3] + sq*b[3]);
}
else {
q[0]=-a[1];
q[1]=a[0];
q[2]=-a[3];
q[3]=a[2];
sp=sin((1.0-t)*LIB3DS_HALFPI);
sq=sin(t*LIB3DS_HALFPI);
c[0]=(Lib3dsFloat)(sp*a[0] + sq*q[0]);
c[1]=(Lib3dsFloat)(sp*a[1] + sq*q[1]);
c[2]=(Lib3dsFloat)(sp*a[2] + sq*q[2]);
c[3]=(Lib3dsFloat)(sp*a[3] + sq*q[3]);
}
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_squad(Lib3dsQuat c, Lib3dsQuat a, Lib3dsQuat p, Lib3dsQuat q,
Lib3dsQuat b, Lib3dsFloat t)
{
Lib3dsQuat ab;
Lib3dsQuat pq;
lib3ds_quat_slerp(ab,a,b,t);
lib3ds_quat_slerp(pq,p,q,t);
lib3ds_quat_slerp(c,ab,pq,2*t*(1-t));
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_tangent(Lib3dsQuat c, Lib3dsQuat p, Lib3dsQuat q, Lib3dsQuat n)
{
Lib3dsQuat dn,dp,x;
int i;
lib3ds_quat_ln_dif(dn, q, n);
lib3ds_quat_ln_dif(dp, q, p);
for (i=0; i<4; i++) {
x[i]=-1.0f/4.0f*(dn[i]+dp[i]);
}
lib3ds_quat_exp(x);
lib3ds_quat_mul(c,q,x);
}
/*!
* \ingroup quat
*/
void
lib3ds_quat_dump(Lib3dsQuat q)
{
printf("%f %f %f %f\n", q[0], q[1], q[2], q[3]);
}
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