trackball.cpp File Reference

#include <cmath>
#include <trackball.h>

Go to the source code of this file.

Macros
#define	TRACKBALLSIZE   (0.8f)
#define	RENORMCOUNT   97

Functions
static double	tb_project_to_sphere (double, double, double)
static void	normalize_quat (double[4])
void	vzero (double *v)
void	vset (double *v, double x, double y, double z)
void	vsub (const double *src1, const double *src2, double *dst)
void	vcopy (const double *v1, double *v2)
void	vcross (const double *v1, const double *v2, double *cross)
double	vlength (const double *v)
void	vscale (double *v, double div)
void	vnormal (double *v)
double	vdot (const double *v1, const double *v2)
void	vadd (const double *src1, const double *src2, double *dst)
void	trackball (double q[4], double p1x, double p1y, double p2x, double p2y)
void	axis_to_quat (double a[3], double phi, double q[4])
void	add_quats (double q1[4], double q2[4], double dest[4])
void	build_rotmatrix (float m[4][4], double q[4])

Macro Definition Documentation

RENORMCOUNT

#define RENORMCOUNT   97

Definition at line 247 of file trackball.cpp.

TRACKBALLSIZE

#define TRACKBALLSIZE   (0.8f)

Definition at line 67 of file trackball.cpp.

Function Documentation

add_quats()

void add_quats	(	double	q1[4],
		double	q2[4],
		double	dest[4]
	)

Definition at line 249 of file trackball.cpp.

{
 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 );
 }
}

References normalize_quat(), RENORMCOUNT, vadd(), vcopy(), vcross(), vdot(), and vscale().

axis_to_quat()

void axis_to_quat	(	double	a[3],
		double	phi,
		double	q[4]
	)

Definition at line 205 of file trackball.cpp.

{
 vnormal( a );
 vcopy( a, q );
 vscale( q, (double) sin( phi / 2.0) );
 q[3] = (double) cos( phi / 2.0 );
}

References vcopy(), vnormal(), and vscale().

Referenced by trackball().

build_rotmatrix()

void build_rotmatrix	(	float	m[4][4],
		double	q[4]
	)

Definition at line 306 of file trackball.cpp.

{
 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;
}

Referenced by TRACK_BALL::Drag(), and TRACK_BALL::Interpolate().

normalize_quat()

static void normalize_quat ( double  q[4] )

static

Definition at line 291 of file trackball.cpp.

{
 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;
}

Referenced by add_quats().

tb_project_to_sphere()

static double tb_project_to_sphere ( double  r, double  x, double  y  )

static

Definition at line 217 of file trackball.cpp.

{
 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;
}

Referenced by trackball().

trackball()

void trackball	(	double	q[4],
		double	p1x,
		double	p1y,
		double	p2x,
		double	p2y
	)

Definition at line 155 of file trackball.cpp.

{
 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 );
}

References axis_to_quat(), tb_project_to_sphere(), TRACKBALLSIZE, vcross(), vlength(), vset(), vsub(), and vzero().

Referenced by TRACK_BALL::Drag(), TRACK_BALL::Reset_T1(), and TRACK_BALL::TRACK_BALL().

vadd()

void vadd	(	const double *	src1,
		const double *	src2,
		double *	dst
	)

Definition at line 136 of file trackball.cpp.

{
 dst[0] = src1[0] + src2[0];
 dst[1] = src1[1] + src2[1];
 dst[2] = src1[2] + src2[2];
}

Referenced by add_quats().

vcopy()

void vcopy	(	const double *	v1,
		double *	v2
	)

Definition at line 96 of file trackball.cpp.

{
 int i;
 
 for( i = 0 ; i < 3 ; i++ )
 v2[i] = v1[i];
}

References v1, and v2.

Referenced by add_quats(), axis_to_quat(), and vcross().

vcross()

void vcross	(	const double *	v1,
		const double *	v2,
		double *	cross
	)

Definition at line 104 of file trackball.cpp.

{
 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);
}

References v1, v2, and vcopy().

Referenced by add_quats(), and trackball().

vdot()

double vdot	(	const double *	v1,
		const double *	v2
	)

Definition at line 131 of file trackball.cpp.

{
 return v1[0]*v2[0] + v1[1]*v2[1] + v1[2]*v2[2];
}

References v1, and v2.

Referenced by add_quats().

vlength()

double vlength

(

const double *

v

)

Definition at line 114 of file trackball.cpp.

{
 return (double) sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
}

Referenced by trackball(), and vnormal().

vnormal()

void vnormal

(

double *

v

)

Definition at line 126 of file trackball.cpp.

{
 vscale( v, 1.0f / vlength( v ) );
}

References vlength(), and vscale().

Referenced by axis_to_quat().

vscale()

void vscale	(	double *	v,
		double	div
	)

Definition at line 119 of file trackball.cpp.

{
 v[0] *= div;
 v[1] *= div;
 v[2] *= div;
}

Referenced by add_quats(), axis_to_quat(), and vnormal().

vset()

void vset	(	double *	v,
		double	x,
		double	y,
		double	z
	)

Definition at line 82 of file trackball.cpp.

{
 v[0] = x;
 v[1] = y;
 v[2] = z;
}

Referenced by trackball().

vsub()

void vsub	(	const double *	src1,
		const double *	src2,
		double *	dst
	)

Definition at line 89 of file trackball.cpp.

{
 dst[0] = src1[0] - src2[0];
 dst[1] = src1[1] - src2[1];
 dst[2] = src1[2] - src2[2];
}

Referenced by trackball().

vzero()

void vzero

(

double *

v

)

Definition at line 75 of file trackball.cpp.

{
 v[0] = 0.0;
 v[1] = 0.0;
 v[2] = 0.0;
}

Referenced by trackball().