3dpcp/3rdparty/glui/quaternion.cpp

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/***********************************************************************
quaternion.cpp
A quaternion class
-------------------------------------------------------------------
Feb 1998, Paul Rademacher (rademach@cs.unc.edu)
************************************************************************/
#include "quaternion.h"
#include <math.h>
#include "stdinc.h"
/******************************************* constructors **************/
quat::quat( void )
{
*this = quat_identity();
}
quat::quat(const float x, const float y, const float z, const float w)
{
v.set( x, y, z );
s = w;
}
quat::quat( vec3 _v, float _s )
{
set( _v, _s );
}
quat::quat( float _s, vec3 _v )
{
set( _v, _s );
}
quat::quat( const float *d )
{
v[0] = d[0];
v[1] = d[1];
v[2] = d[2];
s = d[3];
}
quat::quat( const double *d )
{
v[0] = d[0];
v[1] = d[1];
v[2] = d[2];
s = d[3];
}
quat::quat( const quat &q )
{
v = q.v;
s = q.s;
}
void quat::set( vec3 _v, float _s )
{
v = _v;
s = _s;
}
quat& quat::operator = (const quat& q)
{
v = q.v; s = q.s; return *this;
}
/* ... */
/******** quat friends ************/
quat operator + (const quat &a, const quat &b)
{
return quat( a.s+b.s, a.v+b.v );
}
quat operator - (const quat &a, const quat &b)
{
return quat( a.s-b.s, a.v-b.v );
}
quat operator - (const quat &a )
{
return quat( -a.s, -a.v );
}
quat operator * ( const quat &a, const quat &b)
{
return quat( a.s*b.s - a.v*b.v, a.s*b.v + b.s*a.v + ((a.v)^(b.v)) );
}
quat operator * ( const quat &a, const float t)
{
return quat( a.v * t, a.s * t );
}
quat operator * ( const float t, const quat &a )
{
return quat( a.v * t, a.s * t );
}
mat4 quat::to_mat4( void )
{
float t, xs, ys, zs, wx, wy, wz, xx, xy, xz, yy, yz, zz;
t = 2.0 / (v*v + s*s);
xs = v[VX]*t; ys = v[VY]*t; zs = v[VZ]*t;
wx = s*xs; wy = s*ys; wz = s*zs;
xx = v[VX]*xs; xy = v[VX]*ys; xz = v[VX]*zs;
yy = v[VY]*ys; yz = v[VY]*zs; zz = v[VZ]*zs;
mat4 matrix( 1.0-(yy+zz), xy+wz, xz-wy, 0.0,
xy-wz, 1.0-(xx+zz), yz+wx, 0.0,
xz+wy, yz-wx, 1.0-(xx+yy), 0.0,
0.0, 0.0, 0.0, 1.0 );
return matrix;
}
/************************************************* quat_identity() *****/
/* Returns quaternion identity element */
quat quat_identity( void )
{
return quat( vec3( 0.0, 0.0, 0.0 ), 1.0 );
}
/************************************************ quat_slerp() ********/
/* Quaternion spherical interpolation */
quat quat_slerp( quat from, quat to, float t )
{
quat to1;
double omega, cosom, sinom, scale0, scale1;
/* calculate cosine */
cosom = from.v * to.v + from.s + to.s;
/* Adjust signs (if necessary) */
if ( cosom < 0.0 ) {
cosom = -cosom;
to1 = -to;
}
else
{
to1 = to;
}
/* Calculate coefficients */
if ((1.0 - cosom) > FUDGE ) {
/* standard case (slerp) */
omega = acos( cosom );
sinom = sin( omega );
scale0 = sin((1.0 - t) * omega) / sinom;
scale1 = sin(t * omega) / sinom;
}
else {
/* 'from' and 'to' are very close - just do linear interpolation */
scale0 = 1.0 - t;
scale1 = t;
}
return scale0 * from + scale1 * to1;
}
/********************************************** set_angle() ************/
/* set rot angle (degrees) */
void quat::set_angle( float f )
{
vec3 axis = get_axis();
s = cos( DEG2RAD( f ) / 2.0 );
v = axis * sin(DEG2RAD(f) / 2.0);
}
/********************************************** scale_angle() ************/
/* scale rot angle (degrees) */
void quat::scale_angle( float f )
{
set_angle( f * get_angle() );
}
/********************************************** get_angle() ************/
/* get rot angle (degrees). Assumes s is between -1 and 1 */
float quat::get_angle( void )
{
return RAD2DEG( 2.0 * acos( s ) );
}
/********************************************* get_axis() **************/
vec3 quat::get_axis( void )
{
float scale;
scale = sin( acos( s ) );
if ( scale < FUDGE AND scale > -FUDGE )
return vec3( 0.0, 0.0, 0.0 );
else
return v / scale;
}
/******************************************* quat::print() ************/
void quat::print( FILE *dest, char *name )
{
fprintf( dest, "%s: v:<%3.2f %3.2f %3.2f> s:%3.2f\n", name,
v[0], v[1], v[2], s );
}