kicad/3d-viewer/3d_rendering/trackball.cpp

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/*
* (c) Copyright 1993, 1994, Silicon Graphics, Inc.
* ALL RIGHTS RESERVED
* Permission to use, copy, modify, and distribute this software for
* any purpose and without fee is hereby granted, provided that the above
* copyright notice appear in all copies and that both the copyright notice
* and this permission notice appear in supporting documentation, and that
* the name of Silicon Graphics, Inc. not be used in advertising
* or publicity pertaining to distribution of the software without specific,
* written prior permission.
*
* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
*
* US Government Users Restricted Rights
* Use, duplication, or disclosure by the Government is subject to
* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
* (c)(1)(ii) of the Rights in Technical Data and Computer Software
* clause at DFARS 252.227-7013 and/or in similar or successor
* clauses in the FAR or the DOD or NASA FAR Supplement.
* Unpublished-- rights reserved under the copyright laws of the
* United States. Contractor/manufacturer is Silicon Graphics,
* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
*
* OpenGL(TM) is a trademark of Silicon Graphics, Inc.
*/
/*
* Trackball code:
*
* Implementation of a virtual trackball.
* Implemented by Gavin Bell, lots of ideas from Thant Tessman and
* the August '88 issue of Siggraph's "Computer Graphics," pp. 121-129.
*
* Vector manip code:
*
* Original code from:
* David M. Ciemiewicz, Mark Grossman, Henry Moreton, and Paul Haeberli
*
* Much mucking with by:
* Gavin Bell
*/
#include <cmath>
#include <trackball.h>
/*
* This size should really be based on the distance from the center of
* rotation to the point on the object underneath the mouse. That
* point would then track the mouse as closely as possible. This is a
* simple example, though, so that is left as an Exercise for the
* Programmer.
*/
#define TRACKBALLSIZE (0.8f)
/*
* Local function prototypes (not defined in trackball.h)
*/
static double tb_project_to_sphere( double, double, double );
static void normalize_quat( double [4] );
void vzero( double *v )
{
v[0] = 0.0;
v[1] = 0.0;
v[2] = 0.0;
}
void vset( double *v, double x, double y, double z )
{
v[0] = x;
v[1] = y;
v[2] = z;
}
void vsub( const double *src1, const double *src2, double *dst )
{
dst[0] = src1[0] - src2[0];
dst[1] = src1[1] - src2[1];
dst[2] = src1[2] - src2[2];
}
void vcopy( const double *v1, double *v2 )
{
register int i;
for( i = 0 ; i < 3 ; i++ )
v2[i] = v1[i];
}
void vcross( const double *v1, const double *v2, double *cross )
{
double temp[3];
temp[0] = (v1[1] * v2[2]) - (v1[2] * v2[1]);
temp[1] = (v1[2] * v2[0]) - (v1[0] * v2[2]);
temp[2] = (v1[0] * v2[1]) - (v1[1] * v2[0]);
vcopy(temp, cross);
}
double vlength( const double *v )
{
return (double) sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
}
void vscale( double *v, double div )
{
v[0] *= div;
v[1] *= div;
v[2] *= div;
}
void vnormal( double *v )
{
vscale( v, 1.0f / vlength( v ) );
}
double vdot( const double *v1, const double *v2 )
{
return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}
void vadd( const double *src1, const double *src2, double *dst )
{
dst[0] = src1[0] + src2[0];
dst[1] = src1[1] + src2[1];
dst[2] = src1[2] + src2[2];
}
/*
* Ok, simulate a track-ball. Project the points onto the virtual
* trackball, then figure out the axis of rotation, which is the cross
* product of P1 P2 and O P1 (O is the center of the ball, 0,0,0)
* Note: This is a deformed trackball-- is a trackball in the center,
* but is deformed into a hyperbolic sheet of rotation away from the
* center. This particular function was chosen after trying out
* several variations.
*
* It is assumed that the arguments to this routine are in the range
* (-1.0 ... 1.0)
*/
void trackball( double q[4], double p1x, double p1y, double p2x, double p2y )
{
double a[3]; /* Axis of rotation */
double phi; /* how much to rotate about axis */
double p1[3], p2[3], d[3];
double t;
if( p1x == p2x && p1y == p2y )
{
/* Zero rotation */
vzero( q );
q[3] = 1.0;
return;
}
/*
* First, figure out z-coordinates for projection of P1 and P2 to
* deformed sphere
*/
vset( p1, p1x, p1y, tb_project_to_sphere( TRACKBALLSIZE, p1x, p1y ) );
vset( p2, p2x, p2y, tb_project_to_sphere( TRACKBALLSIZE, p2x, p2y ) );
/*
* Now, we want the cross product of P1 and P2
*/
vcross(p2,p1,a);
/*
* Figure out how much to rotate around that axis.
*/
vsub( p1, p2, d );
t = vlength( d ) / (2.0f * TRACKBALLSIZE);
/*
* Avoid problems with out-of-control values...
*/
if( t > 1.0 )
t = 1.0;
if( t < -1.0 )
t = -1.0;
phi = 2.0f * (double) asin( t );
axis_to_quat( a, phi, q );
}
/*
* Given an axis and angle, compute quaternion.
*/
void axis_to_quat( double a[3], double phi, double q[4] )
{
vnormal( a );
vcopy( a, q );
vscale( q, (double) sin( phi / 2.0) );
q[3] = (double) cos( phi / 2.0 );
}
/*
* Project an x,y pair onto a sphere of radius r OR a hyperbolic sheet
* if we are away from the center of the sphere.
*/
static double tb_project_to_sphere( double r, double x, double y )
{
double d, z;
d = (double) sqrt( x*x + y*y );
if( d < r * 0.70710678118654752440 )
{ /* Inside sphere */
z = (double) sqrt( r*r - d*d );
}
else
{ /* On hyperbola */
const double t = r / 1.41421356237309504880f;
z = t*t / d;
}
return z;
}
/*
* Given two rotations, e1 and e2, expressed as quaternion rotations,
* figure out the equivalent single rotation and stuff it into dest.
*
* This routine also normalizes the result every RENORMCOUNT times it is
* called, to keep error from creeping in.
*
* NOTE: This routine is written so that q1 or q2 may be the same
* as dest (or each other).
*/
#define RENORMCOUNT 97
void add_quats( double q1[4], double q2[4], double dest[4] )
{
static int count=0;
double t1[4], t2[4], t3[4];
double tf[4];
vcopy( q1, t1 );
vscale( t1, q2[3] );
vcopy( q2, t2 );
vscale( t2, q1[3] );
vcross( q2, q1, t3 );
vadd( t1, t2, tf );
vadd( t3, tf, tf );
tf[3] = q1[3] * q2[3] - vdot( q1, q2 );
dest[0] = tf[0];
dest[1] = tf[1];
dest[2] = tf[2];
dest[3] = tf[3];
if( ++count > RENORMCOUNT )
{
count = 0;
normalize_quat( dest );
}
}
/*
* Quaternions always obey: a^2 + b^2 + c^2 + d^2 = 1.0
* If they don't add up to 1.0, dividing by their magnitued will
* renormalize them.
*
* Note: See the following for more information on quaternions:
*
* - Shoemake, K., Animating rotation with quaternion curves, Computer
* Graphics 19, No 3 (Proc. SIGGRAPH'85), 245-254, 1985.
* - Pletinckx, D., Quaternion calculus as a basic tool in computer
* graphics, The Visual Computer 5, 2-13, 1989.
*/
static void normalize_quat( double q[4] )
{
int i;
double mag;
mag = (q[0]*q[0] + q[1]*q[1] + q[2]*q[2] + q[3]*q[3]);
for( i = 0; i < 4; i++ )
q[i] /= mag;
}
/*
* Build a rotation matrix, given a quaternion rotation.
*
*/
void build_rotmatrix( float m[4][4], double q[4] )
{
m[0][0] = (float)(1.0 - 2.0 * (q[1] * q[1] + q[2] * q[2]));
m[0][1] = (float)(2.0 * (q[0] * q[1] - q[2] * q[3]));
m[0][2] = (float)(2.0 * (q[2] * q[0] + q[1] * q[3]));
m[0][3] = 0.0f;
m[1][0] = (float)(2.0 * (q[0] * q[1] + q[2] * q[3]));
m[1][1] = (float)(1.0 - 2.0f * (q[2] * q[2] + q[0] * q[0]));
m[1][2] = (float)(2.0 * (q[1] * q[2] - q[0] * q[3]));
m[1][3] = 0.0f;
m[2][0] = (float)(2.0 * (q[2] * q[0] - q[1] * q[3]));
m[2][1] = (float)(2.0 * (q[1] * q[2] + q[0] * q[3]));
m[2][2] = (float)(1.0 - 2.0 * (q[1] * q[1] + q[0] * q[0]));
m[2][3] = 0.0f;
m[3][0] = 0.0f;
m[3][1] = 0.0f;
m[3][2] = 0.0f;
m[3][3] = 1.0f;
}