quaternion.cpp
上传用户:gb3593
上传日期:2022-01-07
资源大小:3028k
文件大小:6k
- /***********************************************************************
- quaternion.cpp - A quaternion class
- -------------------------------------------------------------------
- GLUI User Interface Toolkit (LGPL)
- Copyright (c) 1998 Paul Rademacher
- WWW: http://sourceforge.net/projects/glui/
- Forums: http://sourceforge.net/forum/?group_id=92496
- This library 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 library 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 library; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- ************************************************************************
- Feb 1998, Paul Rademacher (rademach@cs.unc.edu)
- Oct 2003, Nigel Stewart - GLUI Code Cleaning
-
- ************************************************************************/
- #include "quaternion.h"
- #include <cmath>
- #include "glui_internal.h"
- /******************************************* constructors **************/
- quat::quat()
- {
- *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(const vec3 &_v, const float _s)
- {
- set( _v, _s );
- }
- quat::quat(const float _s, const 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] = (float) d[0];
- v[1] = (float) d[1];
- v[2] = (float) d[2];
- s = (float) d[3];
- }
- quat::quat(const quat &q)
- {
- v = q.v;
- s = q.s;
- }
- void quat::set(const vec3 &_v, const 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() const
- {
- float xs, ys, zs, wx, wy, wz, xx, xy, xz, yy, yz, zz;
- float t = 2.0f / (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(
- 1.0f-(yy+zz), xy+wz, xz-wy, 0.0f,
- xy-wz, 1.0f-(xx+zz), yz+wx, 0.0f,
- xz+wy, yz-wx, 1.0f-(xx+yy), 0.0f,
- 0.0f, 0.0f, 0.0f, 1.0f );
- return matrix;
- }
- /************************************************* quat_identity() *****/
- /* Returns quaternion identity element */
- quat quat_identity()
- {
- return quat( vec3( 0.0, 0.0, 0.0 ), 1.0 );
- }
- /************************************************ quat_slerp() ********/
- /* Quaternion spherical interpolation */
- quat quat_slerp(const quat &from, const quat &to, float t)
- {
- quat to1;
- float 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 = (float) acos( cosom );
- sinom = (float) sin( omega );
- scale0 = (float) sin((1.0 - t) * omega) / sinom;
- scale1 = (float) sin(t * omega) / sinom;
- }
- else
- {
- /* 'from' and 'to' are very close - just do linear interpolation */
- scale0 = 1.0f - 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 = (float) cos( DEG2RAD( f ) / 2.0 );
- v = axis * (float) 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() const
- {
- return (float) RAD2DEG( 2.0 * acos( s ) );
- }
- /********************************************* get_axis() **************/
- vec3 quat::get_axis() const
- {
- float scale = (float) 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, const char *name) const
- {
- fprintf( dest, "%s: v:<%3.2f %3.2f %3.2f> s:%3.2fn",
- name, v[0], v[1], v[2], s );
- }