void urot_about_axis_f (float m[4][4], /* returned */
float angle, /* input */
float axis[3]) /* input */
#endif
{
gutDouble len, ax[3];
angle *= M_PI/180.0; /* convert to radians */
/* renormalize axis vector, if needed */
len = axis[0]*axis[0] + axis[1]*axis[1] + axis[2]*axis[2];
/* we can save some machine instructions by normalizing only
* if needed. The compiler should be able to schedule in the
* if test "for free". */
if (len != 1.0) {
len = (gutDouble) (1.0 / sqrt ((double) len));
ax[0] = axis[0] * len;
ax[1] = axis[1] * len;
ax[2] = axis[2] * len;
#ifdef __GUTIL_DOUBLE
urot_axis_d (m, angle, ax);
#else
urot_axis_f (m, angle, ax);
#endif
} else {
#ifdef __GUTIL_DOUBLE
urot_axis_d (m, angle, axis);
#else
urot_axis_f (m, angle, axis);
#endif
}
}
void rot_axis_f (float omega, /* input */
float axis[3]) /* input */
{
float m[4][4];
(void) urot_axis_f (m, omega, axis);
MULTMATRIX_F (m);
}
void urot_omega_f (float m[4][4], /* returned */
float axis[3]) /* input */
#endif
{
gutDouble len, ax[3];
/* normalize axis vector */
len = axis[0]*axis[0] + axis[1]*axis[1] + axis[2]*axis[2];
len = (gutDouble) (1.0 / sqrt ((double) len));
ax[0] = axis[0] * len;
ax[1] = axis[1] * len;
ax[2] = axis[2] * len;
/* the amount of rotation is equal to the length, in radians */
#ifdef __GUTIL_DOUBLE
urot_axis_d (m, len, ax);
#else
urot_axis_f (m, len, ax);
#endif
}
