/**
 *  \file  Cylinder3D.cpp
 *  \brief stores a cylinder
 *
 *  Copyright 2007-2013 IMP Inventors. All rights reserved.
 */
#include <IMP/algebra/Cylinder3D.h>

IMPALGEBRA_BEGIN_NAMESPACE
Cylinder3D::Cylinder3D(const Segment3D &s,
                       double radius)
  :s_(s),radius_(radius){
}

/** Returns a point on the surface of the cylinder,
    specified by its location relative to the cylinder axis
    and its rotation angle about the axis

    @param relative_height a number in the range [0..1] that specifies
                           the point location relative to the cylinder axis
                           such that 0 specifies the cylinder bottom and
                           1 specifies its top
    @param angle angle in radians about the cylinder axis, with 0 set to an
                 arbitrary but consistent direction
*/
const Vector3D
Cylinder3D::get_surface_point_at
(double relative_height, double angle)
{
  double relative_radius = 1.0; // surface
  return get_inner_point_at
    (relative_height, relative_radius, angle);
}

/** Returns a point inside the cylinder,
    specified by its location relative to the cylinder axis,
    its relative radius and  its rotation angle about the axis

    @param relative_height a number in the range [0..1] that specifies
                           the point location relative to the cylinder axis
                           such that 0 specifies the cylinder bottom and
                           1 specifies its top
    @param relative_radius a number in the range [0..1] that specifies
                           the distance of the point from the cylinder axis
                           relative to the cylinder radius, 0 being on the
                           axis itself, and 1 being on the cylinder surface
    @param angle angle in radians about the cylinder axis, with 0 set to
                 an arbitrary but consistent direction
  */
const Vector3D
Cylinder3D::get_inner_point_at
(double relative_height,
 double relative_radius,
 double angle) const
{
  // compute the point relative to cylinder of equivalent dimensions,
  // but whose main axis segment is z-aligned and lying at the origin
  Vector3D scaling(get_radius() * relative_radius,
                   get_radius() * relative_radius,
                   get_segment().get_length());
  Vector3D pt(scaling[0]*sin(angle),
              scaling[1]*cos(angle),
              scaling[2]*relative_height);
  // transform the cylinder axis from the origin to the correct location
  Rotation3D rot
    = get_rotation_taking_first_to_second
    (Vector3D(0,0,1),
     get_segment().get_point(1) - get_segment().get_point(0));
  Transformation3D tr(rot, get_segment().get_point(0));
  return tr.get_transformed(pt);

}



IMPALGEBRA_END_NAMESPACE