source: orxonox.OLD/trunk/src/lib/coord/p_node.cc @ 5769

/*
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Patrick Boenzli
   co-programmer: Benjamin Grauer
*/

#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_PNODE

#include "p_node.h"
#include "null_parent.h"

#include "load_param.h"
#include "class_list.h"

#include "stdincl.h"
#include "compiler.h"
#include "error.h"
#include "debug.h"
#include "list.h"
#include "vector.h"

#include "color.h"

using namespace std;


/**
 *  standard constructor
 */
PNode::PNode ()
{
  init(NULL);

  NullParent::getInstance()->addChild(this);
}

/**
 * @param root the load-Element for the PNode
 */
PNode::PNode(const TiXmlElement* root)
{
  this->init(NULL);
  this->loadParams(root);

  if (this->parent == NULL)
    NullParent::getInstance()->addChild(this);
}

/**
 *  constructor with coodinates
 * @param absCoordinate the Absolute coordinate of the Object
 * @param parent The parent-node of this node.
 */
PNode::PNode (const Vector& absCoor, PNode* parent )
{
  this->init(parent);

  if (likely(parent != NULL))
    parent->addChild (this);

  this->setAbsCoor(absCoor);
}

/**
 * standard deconstructor
 *
 * There are two general ways to delete a PNode
 * 1. delete instance;
 *   -> result
 *    delete this Node and all its children and children's children...
 *    (danger if you still need the children's instance somewhere else!!)
 *
 * 2. instance->remove2D(); delete instance;
 *   -> result:
 *    moves its children to the NullParent
 *    then deletes the Element.
 */
PNode::~PNode ()
{
  // remove the Node, delete it's children.
  tIterator<PNode>* iterator = this->children->getIterator();
  PNode* child = iterator->firstElement();

  while( child != NULL)
  {
    delete child;
    child = iterator->nextElement();
  }
  delete iterator;

  if (this->parent != NULL)
  {
    this->parent->children->remove(this);
    this->parent = NULL;
  }
  delete this->children;

  // remove all other allocated memory.
  if (this->toCoordinate != NULL)
    delete this->toCoordinate;
  if (this->toDirection != NULL)
    delete this->toDirection;
}


/**
 *  initializes a PNode
 * @param parent the parent for this PNode
 */
void PNode::init(PNode* parent)
{
  this->setClassID(CL_PARENT_NODE, "PNode");

  this->children = new tList<PNode>();
  this->bRelCoorChanged = true;
  this->bRelDirChanged = true;
  this->parent = parent;
  this->parentMode = PNODE_PARENT_MODE_DEFAULT;

  // iterators
  this->toCoordinate = NULL;
  this->toDirection = NULL;
  this->bias = 1.0;
}

/**
 *  loads parameters of the PNode
 * @param root the XML-element to load the properties of
 */
void PNode::loadParams(const TiXmlElement* root)
{
  static_cast<BaseObject*>(this)->loadParams(root);

  LoadParam(root, "rel-coor", this, PNode, setRelCoor)
      .describe("Sets The relative position of the Node to its parent.");

  LoadParam(root, "abs-coor", this, PNode, setAbsCoor)
      .describe("Sets The absolute Position of the Node.");

  LoadParam(root, "rel-dir", this, PNode, setRelDir)
      .describe("Sets The relative rotation of the Node to its parent.");

  LoadParam(root, "abs-dir", this, PNode, setAbsDir)
      .describe("Sets The absolute rotation of the Node.");

  LoadParam(root, "parent", this, PNode, setParent)
      .describe("the Name of the Parent of this PNode");

  LoadParam(root, "parent-mode", this, PNode, setParentMode)
      .describe("the mode to connect this node to its parent ()");

  // cycling properties
  if (root != NULL)
  {
    LOAD_PARAM_START_CYCLE(root, element);
    {
      LoadParam_CYCLE(element, "parent", this, PNode, addChild)
          .describe("adds a new Child to the current Node.");

    }
    LOAD_PARAM_END_CYCLE(element);
  }
}

/**
 *  set relative coordinates
 * @param relCoord relative coordinates to its parent
 *
 *
 * it is very importand, that you use this function, if you want to update the
 * relCoordinates. If you don't use this, the PNode won't recognize, that something
 * has changed and won't update the children Nodes.
 */
void PNode::setRelCoor (const Vector& relCoord)
{
  if (this->toCoordinate!= NULL)
  {
    delete this->toCoordinate;
    this->toCoordinate = NULL;
  }

  this->relCoordinate = relCoord;
  this->bRelCoorChanged = true;
}

/**
 *  set relative coordinates
 * @param x x-relative coordinates to its parent
 * @param y y-relative coordinates to its parent
 * @param z z-relative coordinates to its parent
 * @see  void PNode::setRelCoor (const Vector& relCoord)
 */
void PNode::setRelCoor (float x, float y, float z)
{
  this->setRelCoor(Vector(x, y, z));
}

/**
 * sets a new relative position smoothely
 * @param relCoordSoft the new Position to iterate to
 * @param bias how fast to iterate to this position
 */
void PNode::setRelCoorSoft(const Vector& relCoordSoft, float bias)
{
  if (likely(this->toCoordinate == NULL))
    this->toCoordinate = new Vector();

  *this->toCoordinate = relCoordSoft;
  this->bias = bias;
}


/**
 *  set relative coordinates smoothely
 * @param x x-relative coordinates to its parent
 * @param y y-relative coordinates to its parent
 * @param z z-relative coordinates to its parent
 * @see  void PNode::setRelCoorSoft (const Vector&, float)
 */
void PNode::setRelCoorSoft (float x, float y, float z, float bias)
{
  this->setRelCoorSoft(Vector(x, y, z), bias);
}


/**
 * @param absCoord set absolute coordinate
 */
void PNode::setAbsCoor (const Vector& absCoord)
{
  if (this->toCoordinate!= NULL)
  {
    delete this->toCoordinate;
    this->toCoordinate = NULL;
  }

  if( likely(this->parentMode & PNODE_MOVEMENT))
  {
      /* if you have set the absolute coordinates this overrides all other changes */
    if (likely(this->parent != NULL))
      this->relCoordinate = absCoord - parent->getAbsCoor ();
    else
      this->relCoordinate = absCoord;
  }
  if( this->parentMode & PNODE_ROTATE_MOVEMENT)
  {
    if (likely(this->parent != NULL))
      this->relCoordinate = absCoord - parent->getAbsCoor ();
    else
      this->relCoordinate = absCoord;
  }

  this->bRelCoorChanged = true;
//  this->absCoordinate = absCoord;
}


/**
 * @param x x-coordinate.
 * @param y y-coordinate.
 * @param z z-coordinate.
 * @see void PNode::setAbsCoor (const Vector& absCoord)
 */
void PNode::setAbsCoor(float x, float y, float z)
{
  this->setAbsCoor(Vector(x, y, z));
}

/**
 * @param absCoord set absolute coordinate
 * @todo check off
 */
void PNode::setAbsCoorSoft (const Vector& absCoordSoft, float bias)
{
  if (this->toCoordinate == NULL)
    this->toCoordinate = new Vector;

  if( likely(this->parentMode & PNODE_MOVEMENT))
  {
      /* if you have set the absolute coordinates this overrides all other changes */
    if (likely(this->parent != NULL))
      *this->toCoordinate = absCoordSoft - parent->getAbsCoor ();
    else
      *this->toCoordinate = absCoordSoft;
  }
  if( this->parentMode & PNODE_ROTATE_MOVEMENT)
  {
    if (likely(this->parent != NULL))
      *this->toCoordinate = absCoordSoft - parent->getAbsCoor ();
    else
      *this->toCoordinate = absCoordSoft;
  }
}


/**
 *  shift coordinate relative
 * @param shift shift vector
 *
 * this function shifts the current coordinates about the vector shift. this is
 * usefull because from some place else you can:
 * PNode* someNode = ...;
 * Vector objectMovement = calculateShift();
 * someNode->shiftCoor(objectMovement);
 *
 * this is the internal method of:
 * PNode* someNode = ...;
 * Vector objectMovement = calculateShift();
 * Vector currentCoor = someNode->getRelCoor();
 * Vector newCoor = currentCoor + objectMovement;
 * someNode->setRelCoor(newCoor);
 *
 */
void PNode::shiftCoor (const Vector& shift)
{
  this->relCoordinate += shift;
  this->bRelCoorChanged = true;
}

/**
 *  set relative direction
 * @param relDir to its parent
 */
void PNode::setRelDir (const Quaternion& relDir)
{
  if (this->toDirection!= NULL)
  {
    delete this->toDirection;
    this->toDirection = NULL;
  }
  this->relDirection = relDir;
  this->bRelCoorChanged = true;
}

/**
 * @see void PNode::setRelDir (const Quaternion& relDir)
 * @param x the x direction
 * @param y the y direction
 * @param z the z direction
 *
 * main difference is, that here you give a directional vector, that will be translated into a Quaternion
 */
void PNode::setRelDir (float x, float y, float z)
{
  this->setRelDir(Quaternion(Vector(x,y,z), Vector(0,1,0)));
}


/**
 * sets the Relative Direction of this node to its parent in a Smoothed way
 * @param relDirSoft the direction to iterate to smoothely.
 * @param bias how fast to iterate to the new Direction
 */
void PNode::setRelDirSoft(const Quaternion& relDirSoft, float bias)
{
  if (likely(this->toDirection == NULL))
    this->toDirection = new Quaternion();

  *this->toDirection = relDirSoft;
  this->bias = bias;
}

/**
 * @see void PNode::setRelDirSoft (const Quaternion& relDir)
 * @param x the x direction
 * @param y the y direction
 * @param z the z direction
 *
 * main difference is, that here you give a directional vector, that will be translated into a Quaternion
 */
void PNode::setRelDirSoft(float x, float y, float z, float bias)
{
  this->setRelDirSoft(Quaternion(Vector(x,y,z), Vector(0,1,0)), bias);
}

/**
 *  sets the absolute direction
 * @param absDir absolute coordinates
 */
void PNode::setAbsDir (const Quaternion& absDir)
{
  if (this->toDirection!= NULL)
  {
    delete this->toDirection;
    this->toDirection = NULL;
  }

  if (likely(this->parent != NULL))
    this->relDirection = absDir / this->parent->getAbsDir();
  else
   this->relDirection = absDir;

  this->bRelDirChanged = true;
}

/**
 * @see void PNode::setAbsDir (const Quaternion& relDir)
 * @param x the x direction
 * @param y the y direction
 * @param z the z direction
 *
 * main difference is, that here you give a directional vector, that will be translated into a Quaternion
 */
void PNode::setAbsDir (float x, float y, float z)
{
  this->setAbsDir(Quaternion(Vector(x,y,z), Vector(0,1,0)));
}

/**
 * sets the absolute direction
 * @param absDir absolute coordinates
 */
void PNode::setAbsDirSoft (const Quaternion& absDirSoft, float bias)
{
  if (this->toDirection == NULL)
    this->toDirection = new Quaternion();

  if (likely(this->parent != NULL))
    *this->toDirection = absDirSoft / this->parent->getAbsDir();
  else
   *this->toDirection = absDirSoft;

  this->bias = bias;
}

/**
 * @see void PNode::setAbsDir (const Quaternion& relDir)
 * @param x the x direction
 * @param y the y direction
 * @param z the z direction
 *
 * main difference is, that here you give a directional vector, that will be translated into a Quaternion
 */
void PNode::setAbsDirSoft (float x, float y, float z, float bias)
{
  this->setAbsDirSoft(Quaternion(Vector(x,y,z), Vector(0,1,0)), bias);
}


/**
 * shift Direction
 * @param shift the direction around which to shift.
 */
void PNode::shiftDir (const Quaternion& shift)
{
  this->relDirection = this->relDirection * shift;
  this->bRelDirChanged = true;
}

/**
 *  adds a child and makes this node to a parent
 * @param child child reference
 * use this to add a child to this node.
 */
void PNode::addChild (PNode* child)
{
  if( likely(child->parent != NULL))
    {
      PRINTF(5)("PNode::addChild() - reparenting node: removing it and adding it again\n");
      child->parent->children->remove(child);
    }
  child->parent = this;
  if (unlikely(this != NULL))
    this->children->add(child);
  child->parentCoorChanged();
}

/**
 * @see PNode::addChild(PNode* child);
 * @param childName the name of the child to add to this PNode
 */
void PNode::addChild (const char* childName)
{
  PNode* childNode = dynamic_cast<PNode*>(ClassList::getObject(childName, CL_PARENT_NODE));
  if (childNode != NULL)
    this->addChild(childNode);
}

/**
 *  removes a child from the node
 * @param child the child to remove from this pNode.
 *
 * Children from pNode will not be lost, they are referenced to NullPointer
 */
void PNode::removeChild (PNode* child)
{
  if (child != NULL)
  {
   child->removeNode();
//   this->children->remove(child);
//   child->parent = NULL;
  }
}

/**
 *  remove this pnode from the tree and adds all following to NullParent
 *
 * this can be the case, if an entity in the world is being destroyed.
 */
void PNode::removeNode()
{
  tIterator<PNode>* iterator = this->children->getIterator();
  PNode* pn = iterator->firstElement();

  while( pn != NULL)
  {
      NullParent::getInstance()->addChild(pn);
      pn = iterator->nextElement();
    }
  delete iterator;
  if (this->parent != NULL)
    this->parent->children->remove(this);
}

/**
 * sets the parent of this PNode
 * @param parent the Parent to set
 */
void PNode::setParent (PNode* parent)
{
  parent->addChild(this);
}

/**
 * @see PNode::setParent(PNode* parent);
 * @param parentName the name of the Parent to set to this PNode
 */
void PNode::setParent (const char* parentName)
{
  PNode* parentNode = dynamic_cast<PNode*>(ClassList::getObject(parentName, CL_PARENT_NODE));
  if (parentNode != NULL)
    parentNode->addChild(this);
}

/**
 * does the reparenting in a very smooth way
 * @param parentNode the new Node to connect this node to.
 * @param bias the speed to iterate to this new Positions
 */
void PNode::setParentSoft(PNode* parentNode, float bias)
{
  // return if the new parent and the old one match
  if (this->parent == parentNode)
    return;

  // store the Valures to iterate to.
  if (likely(this->toCoordinate == NULL))
  {
    this->toCoordinate = new Vector();
    *this->toCoordinate = this->getRelCoor();
  }
  if (likely(this->toDirection == NULL))
  {
    this->toDirection = new Quaternion();
    *this->toDirection = this->getRelDir();
  }
  this->bias = bias;


  Vector tmpV = this->getAbsCoor();
  Quaternion tmpQ = this->getAbsDir();

  parentNode->addChild(this);

 if (this->parentMode & PNODE_ROTATE_MOVEMENT && this->parent != NULL)
   this->relCoordinate = this->parent->getAbsDir().inverse().apply(tmpV - this->parent->getAbsCoor());
 else
   this->relCoordinate = tmpV - parentNode->getAbsCoor();

 this->relDirection = tmpQ / parentNode->getAbsDir();
}

/**
 * does the reparenting in a very smooth way
 * @param parentName the name of the Parent to reconnect to
 * @param bias the speed to iterate to this new Positions
 */
void PNode::setParentSoft(const char* parentName, float bias)
{
  PNode* parentNode = dynamic_cast<PNode*>(ClassList::getObject(parentName, CL_PARENT_NODE));
  if (parentNode != NULL)
    this->setParentSoft(parentNode, bias);
}

/**
 *  sets the mode of this parent manually
 * @param parentMode a String representing this parentingMode
 */
void PNode::setParentMode (const char* parentingMode)
{
  this->setParentMode(PNode::charToParentingMode(parentingMode));
}

/**
 *  updates the absCoordinate/absDirection
 * @param dt The time passed since the last update
 *
 * this is used to go through the parent-tree to update all the absolute coordinates
 * and directions. this update should be done by the engine, so you don't have to
 * worry, normaly...
 */
void PNode::updateNode (float dt)
{
  if( likely(this->parent != NULL))
    {
      // movement for nodes with smoothMove enabled
      if (unlikely(this->toCoordinate != NULL))
      {
        Vector moveVect = (*this->toCoordinate - this->relCoordinate) *fabsf(dt)*bias;
        if (likely(moveVect.len() >= PNODE_ITERATION_DELTA))
        {
          this->shiftCoor(moveVect);
        }
        else
        {
          delete this->toCoordinate;
          this->toCoordinate = NULL;
          PRINTF(5)("SmoothMove of %s finished\n", this->getName());
        }
      }
      if (unlikely(this->toDirection != NULL))
      {
        Quaternion rotQuat = Quaternion::quatSlerp(this->relDirection,*this->toDirection, fabsf(dt)*this->bias);
        if (this->relDirection.distance(rotQuat) >PNODE_ITERATION_DELTA)
        {
          this->relDirection = rotQuat;
          this->bRelDirChanged;
        }
        else
        {
          delete this->toDirection;
          this->toDirection = NULL;
          PRINTF(5)("SmoothRotate of %s finished\n", this->getName());
        }
      }

      // MAIN UPDATE /////////////////////////////////////
      this->lastAbsCoordinate = this->absCoordinate;

      PRINTF(5)("PNode::update - %s - (%f, %f, %f)\n", this->getName(), this->absCoordinate.x, this->absCoordinate.y, this->absCoordinate.z);


      if( this->parentMode & PNODE_LOCAL_ROTATE && this->bRelDirChanged)
      {
        /* update the current absDirection - remember * means rotation around sth.*/
        this->prevRelCoordinate = this->relCoordinate;
        this->absDirection = this->relDirection * parent->getAbsDir();;
      }

      if(likely(this->parentMode & PNODE_MOVEMENT && this->bRelCoorChanged))
      {
        /* update the current absCoordinate */
        this->prevRelCoordinate = this->relCoordinate;
        this->absCoordinate = this->parent->getAbsCoor() + this->relCoordinate;
      }
      else if( this->parentMode & PNODE_ROTATE_MOVEMENT && this->bRelCoorChanged)
      {
        /* update the current absCoordinate */
        this->prevRelCoordinate = this->relCoordinate;
        this->absCoordinate = this->parent->getAbsCoor() + parent->getAbsDir().apply(this->relCoordinate);
      }
      /////////////////////////////////////////////////
   }
  else
    {
      PRINTF(4)("NullParent::update - (%f, %f, %f)\n", this->absCoordinate.x, this->absCoordinate.y, this->absCoordinate.z);
      if (this->bRelCoorChanged)
      {
        this->prevRelCoordinate = this->relCoordinate;
        this->absCoordinate = this->relCoordinate;
      }
      if (this->bRelDirChanged)
      {
        this->prevRelDirection = this->relDirection;
        this->absDirection = this->getAbsDir () * this->relDirection;
      }
    }

    if(this->children->getSize() > 0)
    {
      tIterator<PNode>* iterator = this->children->getIterator();
      PNode* pn = iterator->firstElement();
      while( pn != NULL)
      {
        /* if this node has changed, make sure, that all children are updated also */
        if( likely(this->bRelCoorChanged))
          pn->parentCoorChanged ();
        if( likely(this->bRelDirChanged))
          pn->parentDirChanged ();

        pn->updateNode(dt);
        pn = iterator->nextElement();
      }
      delete iterator;
    }
    this->velocity = (this->absCoordinate - this->lastAbsCoordinate) / dt;
    this->bRelCoorChanged = false;
    this->bRelDirChanged = false;
}


void PNode::countChildNodes(int& nodes) const
{
  nodes++;
  tIterator<PNode>* it = this->children->getIterator();
  PNode* node = it->firstElement();
  while(node != NULL)
  {
    node->countChildNodes(nodes);
    node = it->nextElement();
  }

}


/**
 *  displays some information about this pNode
 * @param depth The deph into which to debug the children of this PNode to.
 * (0: all children will be debugged, 1: only this PNode, 2: this and direct children, ...)
 * @param level !! INTERNAL !! The n-th level of the Node we draw (this is internal and only for nice output).
 */
void PNode::debugNode(unsigned int depth, unsigned int level) const
{
  for (unsigned int i = 0; i < level; i++)
    PRINT(0)(" |");
  if (this->children->getSize() > 0)
    PRINT(0)(" +");
  else
    PRINT(0)(" -");

  int childNodeCount = 0;
  this->countChildNodes(childNodeCount);

  PRINT(0)("PNode(%s::%s) - absCoord: (%0.2f, %0.2f, %0.2f), relCoord(%0.2f, %0.2f, %0.2f), direction(%0.2f, %0.2f, %0.2f) - %s - %d childs\n",
           this->getClassName(),
           this->getName(),
           this->absCoordinate.x,
           this->absCoordinate.y,
           this->absCoordinate.z,
           this->relCoordinate.x,
           this->relCoordinate.y,
           this->relCoordinate.z,
           this->getAbsDirV().x,
           this->getAbsDirV().y,
           this->getAbsDirV().z,
           this->parentingModeToChar(parentMode),
           childNodeCount);
  if (depth >= 2 || depth == 0)
  {
    tIterator<PNode>* iterator = this->children->getIterator();
      //PNode* pn = this->children->enumerate ();
    PNode* pn = iterator->firstElement();
    while( pn != NULL)
    {
      if (depth == 0)
        pn->debugNode(0, level + 1);
      else
        pn->debugNode(depth - 1, level +1);
      pn = iterator->nextElement();
    }
    delete iterator;
  }
}

/**
 * displays the PNode at its position with its rotation as a cube.
 * @param  depth The deph into which to debug the children of this PNode to.
 * (0: all children will be displayed, 1: only this PNode, 2: this and direct children, ...)
 * @param size the Size of the Box to draw.
 * @param color the color of the Box to display.
 * @param level !! INTERNAL !! The n-th level of the Node we draw (this is internal and only for nice output).
 */
void PNode::debugDraw(unsigned int depth, float size, const Vector& color, unsigned int level) const
{
  // if this is the first Element we draw
  if (level == 0)
  {
    glPushAttrib(GL_ENABLE_BIT); // save the Enable-attributes
    glMatrixMode(GL_MODELVIEW);  // goto the ModelView Matrix

    glDisable(GL_LIGHTING);      // disable lighting (we do not need them for just lighting)
    glDisable(GL_BLEND);         // ''
    glDisable(GL_TEXTURE_2D);    // ''
    glDisable(GL_DEPTH_TEST);    // ''
  }

  glPushMatrix();                // repush the Matrix-stack
  /* translate */
  glTranslatef (this->getAbsCoor ().x,
                this->getAbsCoor ().y,
                this->getAbsCoor ().z);
//  this->getAbsDir ().matrix (matrix);

  /* rotate */
  Vector tmpRot = this->getAbsDir().getSpacialAxis();
  glRotatef (this->getAbsDir().getSpacialAxisAngle(), tmpRot.x, tmpRot.y, tmpRot.z );
  /* set the new Color */
  glColor3f(color.x, color.y, color.z);
  { /* draw a cube of size size */
    glBegin(GL_LINE_STRIP);
    glVertex3f(-.5*size, -.5*size,  -.5*size);
    glVertex3f(+.5*size, -.5*size,  -.5*size);
    glVertex3f(+.5*size, -.5*size,  +.5*size);
    glVertex3f(-.5*size, -.5*size,  +.5*size);
    glVertex3f(-.5*size, -.5*size,  -.5*size);
    glEnd();
    glBegin(GL_LINE_STRIP);
    glVertex3f(-.5*size, +.5*size,  -.5*size);
    glVertex3f(+.5*size, +.5*size,  -.5*size);
    glVertex3f(+.5*size, +.5*size,  +.5*size);
    glVertex3f(-.5*size, +.5*size,  +.5*size);
    glVertex3f(-.5*size, +.5*size,  -.5*size);
    glEnd();

    glBegin(GL_LINES);
    glVertex3f(-.5*size, -.5*size,  -.5*size);
    glVertex3f(-.5*size, +.5*size,  -.5*size);
    glVertex3f(+.5*size, -.5*size,  -.5*size);
    glVertex3f(+.5*size, +.5*size,  -.5*size);
    glVertex3f(+.5*size, -.5*size,  +.5*size);
    glVertex3f(+.5*size, +.5*size,  +.5*size);
    glVertex3f(-.5*size, -.5*size,  +.5*size);
    glVertex3f(-.5*size, +.5*size,  +.5*size);
    glEnd();
  }

  glPopMatrix();
  if (depth >= 2 || depth == 0)
  {
    /* rotate the current color in HSV space around 20 degree */
    Vector childColor =  Color::HSVtoRGB(Color::RGBtoHSV(color)+Vector(20,0,.0));
    tIterator<PNode>* iterator = this->children->getIterator();
    PNode* pn = iterator->firstElement();
    while( pn != NULL)
    {
      // drawing the Dependency graph
     if (this != NullParent::getInstance())
      {
       glBegin(GL_LINES);
       glColor3f(color.x, color.y, color.z);
       glVertex3f(this->getAbsCoor ().x,
                  this->getAbsCoor ().y,
                  this->getAbsCoor ().z);
        glColor3f(childColor.x, childColor.y, childColor.z);
        glVertex3f(pn->getAbsCoor ().x,
                   pn->getAbsCoor ().y,
                   pn->getAbsCoor ().z);
        glEnd();
      }
      /* if we want to draw the children too */
      if (depth == 0) /* -> all of them */
        pn->debugDraw(0, size, childColor, level+1);
      else            /* -> only the Next one */
        pn->debugDraw(depth - 1, size, childColor, level +1);
      pn = iterator->nextElement();
    }
    delete iterator;
  }
  if (level == 0)
    glPopAttrib(); /* pop the saved attributes back out */
}



/////////////////////
// HELPER_FUCTIONS //
/////////////////////

/**
 * converts a parentingMode into a string that is the name of it
 * @param parentingMode the ParentingMode to convert
 * @return the converted string
 */
const char* PNode::parentingModeToChar(int parentingMode)
{
  if (parentingMode == PNODE_LOCAL_ROTATE)
    return "local-rotate";
  else if (parentingMode == PNODE_ROTATE_MOVEMENT)
    return "rotate-movement";
  else if (parentingMode == PNODE_MOVEMENT)
    return "movement";
  else if (parentingMode == PNODE_ALL)
    return "all";
  else if (parentingMode == PNODE_ROTATE_AND_MOVE)
    return "rotate-and-move";
}

/**
 * converts a parenting-mode-string into a int
 * @param parentingMode the string naming the parentingMode
 * @return the int corresponding to the named parentingMode
 */
PARENT_MODE PNode::charToParentingMode(const char* parentingMode)
{
  if (!strcmp(parentingMode, "local-rotate"))
    return (PNODE_LOCAL_ROTATE);
  else  if (!strcmp(parentingMode, "rotate-movement"))
    return (PNODE_ROTATE_MOVEMENT);
  else  if (!strcmp(parentingMode, "movement"))
    return (PNODE_MOVEMENT);
  else  if (!strcmp(parentingMode, "all"))
    return (PNODE_ALL);
  else  if (!strcmp(parentingMode, "rotate-and-move"))
    return (PNODE_ROTATE_AND_MOVE);
}