/**
 * 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 modelNode.cxx
 * @author drose
 * @date 2002-03-16
 */

#include "modelNode.h"

#include "bamReader.h"
#include "datagram.h"
#include "datagramIterator.h"

TypeHandle ModelNode::_type_handle;


/**
 * Returns a newly-allocated Node that is a shallow copy of this one.  It will
 * be a different Node pointer, but its internal data may or may not be shared
 * with that of the original Node.
 */
PandaNode *ModelNode::
make_copy() const {
  return new ModelNode(*this);
}

/**
 * Collapses this PandaNode with the other PandaNode, if possible, and returns
 * a pointer to the combined PandaNode, or NULL if the two PandaNodes cannot
 * safely be combined.
 *
 * The return value may be this, other, or a new PandaNode altogether.
 *
 * This function is called from GraphReducer::flatten(), and need not deal
 * with children; its job is just to decide whether to collapse the two
 * PandaNodes and what the collapsed PandaNode should look like.
 */
PandaNode *ModelNode::
combine_with(PandaNode *other) {
  if (_preserve_transform == PT_drop_node) {
    // If we have PT_drop_node set, we always yield to the other node.
    return other;
  }

  return PandaNode::combine_with(other);
}

/**
 * Returns true if it is generally safe to flatten out this particular kind of
 * Node by duplicating instances, false otherwise (for instance, a Camera
 * cannot be safely flattened, because the Camera pointer itself is
 * meaningful).
 */
bool ModelNode::
safe_to_flatten() const {
  return _preserve_transform == PT_drop_node;
}

/**
 * Returns true if a flatten operation may safely continue past this node, or
 * false if nodes below this node may not be molested.
 */
bool ModelNode::
safe_to_flatten_below() const {
  return _preserve_transform != PT_no_touch;
}

/**
 * Returns true if it is generally safe to transform this particular kind of
 * Node by calling the xform() method, false otherwise.  For instance, it's
 * usually a bad idea to attempt to xform a Character.
 */
bool ModelNode::
safe_to_transform() const {
  return _preserve_transform == PT_none || _preserve_transform == PT_drop_node;
}

/**
 * Returns true if it is safe to automatically adjust the transform on this
 * kind of node.  Usually, this is only a bad idea if the user expects to find
 * a particular transform on the node.
 *
 * ModelNodes with the preserve_transform flag set are presently the only
 * kinds of nodes that should not have their transform even adjusted.
 */
bool ModelNode::
safe_to_modify_transform() const {
  return _preserve_transform != PT_local && _preserve_transform != PT_no_touch;
}

/**
 * Returns true if it is generally safe to combine this particular kind of
 * PandaNode with other kinds of PandaNodes of compatible type, adding
 * children or whatever.  For instance, an LODNode should not be combined with
 * any other PandaNode, because its set of children is meaningful.
 */
bool ModelNode::
safe_to_combine() const {
  return _preserve_transform == PT_drop_node;
}

/**
 * Returns true if the node's name has extrinsic meaning and must be preserved
 * across a flatten operation, false otherwise.
 */
bool ModelNode::
preserve_name() const {
  return _preserve_transform != PT_drop_node && _preserve_transform != PT_no_touch;
}

/**
 * Returns the union of all attributes from SceneGraphReducer::AttribTypes
 * that may not safely be applied to the vertices of this node.  If this is
 * nonzero, these attributes must be dropped at this node as a state change.
 *
 * This is a generalization of safe_to_transform().
 */
int ModelNode::
get_unsafe_to_apply_attribs() const {
  return _preserve_attributes;
}

/**
 * Tells the BamReader how to create objects of type ModelNode.
 */
void ModelNode::
register_with_read_factory() {
  BamReader::get_factory()->register_factory(get_class_type(), make_from_bam);
}

/**
 * This tests the transform to make sure it's within the specified limits.
 * It's done so we can assert to see when an invalid transform is being
 * applied.
 */
void ModelNode::
test_transform(const TransformState *ts) const {
  LPoint3 pos(ts->get_pos());
  nassertv(pos[0] < _transform_limit);
  nassertv(pos[0] > -_transform_limit);
  nassertv(pos[1] < _transform_limit);
  nassertv(pos[1] > -_transform_limit);
  nassertv(pos[2] < _transform_limit);
  nassertv(pos[2] > -_transform_limit);
}

/**
 * node hook.  This function handles outside (non-physics) actions on the
 * actor and updates the internal representation of the node.  i.e.  copy from
 * PandaNode to PhysicsObject
 */
void ModelNode::
transform_changed() {
  PandaNode::transform_changed();
  // get the transform
  CPT(TransformState) transform = get_transform();

  if (_transform_limit > 0.0) {
    test_transform(transform);
  }
}


/**
 * Writes the contents of this object to the datagram for shipping out to a
 * Bam file.
 */
void ModelNode::
write_datagram(BamWriter *manager, Datagram &dg) {
  PandaNode::write_datagram(manager, dg);
  dg.add_uint8((int)_preserve_transform);
  dg.add_uint16(_preserve_attributes);
}

/**
 * This function is called by the BamReader's factory when a new object of
 * type ModelNode is encountered in the Bam file.  It should create the
 * ModelNode and extract its information from the file.
 */
TypedWritable *ModelNode::
make_from_bam(const FactoryParams &params) {
  ModelNode *node = new ModelNode("");
  DatagramIterator scan;
  BamReader *manager;

  parse_params(params, scan, manager);
  node->fillin(scan, manager);

  return node;
}

/**
 * This internal function is called by make_from_bam to read in all of the
 * relevant data from the BamFile for the new ModelNode.
 */
void ModelNode::
fillin(DatagramIterator &scan, BamReader *manager) {
  PandaNode::fillin(scan, manager);

  _preserve_transform = (PreserveTransform)scan.get_uint8();
  _preserve_attributes = scan.get_uint16();
}