/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file fltTransformRotateScale.cxx
 * @author drose
 * @date 2000-08-30
 */

#include "fltTransformRotateScale.h"
#include "fltRecordReader.h"
#include "fltRecordWriter.h"

#include "mathNumbers.h"
#include "look_at.h"

TypeHandle FltTransformRotateScale::_type_handle;

/**
 *
 */
FltTransformRotateScale::
FltTransformRotateScale(FltHeader *header) : FltTransformRecord(header) {
  _center.set(0.0, 0.0, 0.0);
  _reference_point.set(0.0, 0.0, 0.0);
  _to_point.set(0.0, 0.0, 0.0);
  _overall_scale = 1.0;
  _axis_scale = 1.0;
  _angle = 0.0;
}

/**
 * Defines the transform explicitly.  The angle of rotation is determined by
 * the angle between the reference point and the to point (relative to the
 * center), and the scale factor is determined by the distance between the
 * reference point and the center point.  If axis_scale is true, the scale is
 * along reference point axis only; otherwise, it is a uniform scale.
 */
void FltTransformRotateScale::
set(const LPoint3d &center, const LPoint3d &reference_point,
    const LPoint3d &to_point, bool axis_scale) {
  _center = center;
  _reference_point = reference_point;
  _to_point = to_point;

  LVector3d v1 = _reference_point - _center;
  LVector3d v2 = _to_point - _center;

  _angle =
    acos(dot(normalize(v1), normalize(v2))) * 180.0 / MathNumbers::pi;

  if (axis_scale) {
    _axis_scale = length(v1);
    _overall_scale = 1.0;
  } else {
    _overall_scale = length(v1);
    _axis_scale = 1.0;
  }

  recompute_matrix();
}

/**
 *
 */
const LPoint3d &FltTransformRotateScale::
get_center() const {
  return _center;
}

/**
 *
 */
const LPoint3d &FltTransformRotateScale::
get_reference_point() const {
  return _reference_point;
}

/**
 *
 */
const LPoint3d &FltTransformRotateScale::
get_to_point() const {
  return _to_point;
}

/**
 * Returns the overall scale factor.
 */
PN_stdfloat FltTransformRotateScale::
get_overall_scale() const {
  return _overall_scale;
}

/**
 * Returns the scale factor in the direction of the axis.
 */
PN_stdfloat FltTransformRotateScale::
get_axis_scale() const {
  return _axis_scale;
}

/**
 * Returns the angle of rotation in degrees.
 */
PN_stdfloat FltTransformRotateScale::
get_angle() const {
  return _angle;
}

/**
 *
 */
void FltTransformRotateScale::
recompute_matrix() {
  LVector3d v1 = _reference_point - _center;
  LVector3d v2 = _to_point - _center;
  LVector3d rotate_axis = normalize(cross(v1, v2));

  // To scale along an axis, we have to do a bit of work.  First determine the
  // matrices to rotate and unrotate the rotate axis to the y-forward axis.
  LMatrix4d r1;
  look_at(r1, v1, rotate_axis, CS_zup_right);

  _matrix =
    LMatrix4d::translate_mat(-_center) *
    r1 *
    LMatrix4d::scale_mat(1.0, _axis_scale, 1.0) *
    LMatrix4d::scale_mat(_overall_scale) *
    invert(r1) *
    LMatrix4d::rotate_mat(_angle, rotate_axis, CS_zup_right) *
    LMatrix4d::translate_mat(_center);
}

/**
 * Fills in the information in this record based on the information given in
 * the indicated datagram, whose opcode has already been read.  Returns true
 * on success, false if the datagram is invalid.
 */
bool FltTransformRotateScale::
extract_record(FltRecordReader &reader) {
  if (!FltTransformRecord::extract_record(reader)) {
    return false;
  }

  nassertr(reader.get_opcode() == FO_rotate_and_scale, false);
  DatagramIterator &iterator = reader.get_iterator();

  iterator.skip_bytes(4);   // Undocumented additional padding.

  _center[0] = iterator.get_be_float64();
  _center[1] = iterator.get_be_float64();
  _center[2] = iterator.get_be_float64();
  _reference_point[0] = iterator.get_be_float64();
  _reference_point[1] = iterator.get_be_float64();
  _reference_point[2] = iterator.get_be_float64();
  _to_point[0] = iterator.get_be_float64();
  _to_point[1] = iterator.get_be_float64();
  _to_point[2] = iterator.get_be_float64();
  _overall_scale = iterator.get_be_float32();
  _axis_scale = iterator.get_be_float32();
  _angle = iterator.get_be_float32();

  iterator.skip_bytes(4);   // Undocumented additional padding.

  recompute_matrix();

  check_remaining_size(iterator);
  return true;
}

/**
 * Fills up the current record on the FltRecordWriter with data for this
 * record, but does not advance the writer.  Returns true on success, false if
 * there is some error.
 */
bool FltTransformRotateScale::
build_record(FltRecordWriter &writer) const {
  if (!FltTransformRecord::build_record(writer)) {
    return false;
  }

  writer.set_opcode(FO_put);
  Datagram &datagram = writer.update_datagram();

  datagram.pad_bytes(4);   // Undocumented additional padding.

  datagram.add_be_float64(_center[0]);
  datagram.add_be_float64(_center[1]);
  datagram.add_be_float64(_center[2]);
  datagram.add_be_float64(_reference_point[0]);
  datagram.add_be_float64(_reference_point[1]);
  datagram.add_be_float64(_reference_point[2]);
  datagram.add_be_float64(_to_point[0]);
  datagram.add_be_float64(_to_point[1]);
  datagram.add_be_float64(_to_point[2]);
  datagram.add_be_float32(_overall_scale);
  datagram.add_be_float32(_axis_scale);
  datagram.add_be_float32(_angle);

  datagram.pad_bytes(4);   // Undocumented additional padding.

  return true;
}