void view_turn(view *V, const double *w)
{
#if 0
double M[16], T[16], q[4], a[3], b[3], c[3], t[3];
assert(V);
/* Transform the mark and drag vectors from eye space into the world */
/* space current at the time of the mark. */
state_matrix(M, &V->mark);
mtranspose(T, M);
vnormalize(t, V->a);
vtransform(a, T, t);
vnormalize(t, w);
vtransform(b, T, t);
/* These determine the axis and angle of rotation. Find the quaternion. */
vcrs(t, a, b);
vnormalize(c, t);
qrotate(q, c, acos(vdot(a, b)));
/* Accumulate this quaternion with the view state, rotating the view. */
qmultiply(view_curr(V)->q, V->mark.q, q);
#endif
}
void sph_model::zoom(double *w, const double *v)
{
double d = vdot(v, zoomv);
if (-1 < d && d < 1)
{
double b = scale(zoomk, acos(d) / M_PI) * M_PI;
double y[3];
double x[3];
vcrs(y, v, zoomv);
vnormalize(y, y);
vcrs(x, zoomv, y);
vnormalize(x, x);
vmul(w, zoomv, cos(b));
vmad(w, w, x, sin(b));
}
else vcpy(w, v);
}
