void GLViewController::set_view_param(const Vec3f& e, const Vec3f& c, const Vec3f& u)
{
// native viewing direction is the negative z-axis
// while right is the x-axis and up is the y-axis
Vec3f view = c - e;
float eye_dist = length(view);
view /= eye_dist;
Vec3f right = normalize(cross(view, u));
Vec3f up = cross(right, view);
Mat3x3f rot(right, up, -view);
rot = transpose(rot); // since matrix is row-major
// convert the change-of-basis matrix to a quaternion
Quatf qrot;
qrot.make_rot(rot);
set_rotation(qrot);
set_centre(c);
set_eye_dist(eye_dist);
}
