/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkAssemblyPath.h

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
// .NAME vtkAssemblyPath - a list of nodes that form an assembly path
// .SECTION Description
// vtkAssemblyPath represents an ordered list of assembly nodes that
// represent a fully evaluated assembly path. This class is used primarily
// for picking. Note that the use of this class is to add one or more
// assembly nodes to form the path. (An assembly node consists of an instance
// of vtkProp and vtkMatrix4x4, the matrix may be NULL.) As each node is
// added, the matrices are concatenated to create a final, evaluated matrix.

// .SECTION See Also
// vtkAssemblyNode vtkAssembly vtkActor vtkMatrix4x4 vtkProp vtkAbstractPicker

#ifndef __vtkAssemblyPath_h
#define __vtkAssemblyPath_h

#include "vtkCollection.h"
#include "vtkAssemblyNode.h" // used for inlines

class vtkMatrix4x4;
class vtkTransform;
class vtkProp;

class VTK_COMMON_EXPORT vtkAssemblyPath : public vtkCollection
{
public:
  vtkTypeRevisionMacro(vtkAssemblyPath,vtkCollection);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Instantiate empty path with identify matrix.
  static vtkAssemblyPath *New();

  // Description:
  // Convenience method adds a prop and matrix together,
  // creating an assembly node transparently. The matrix
  // pointer m may be NULL. Note: that matrix is the one,
  // if any, associated with the prop. 
  void AddNode(vtkProp *p, vtkMatrix4x4 *m);

  // Description:
  // Get the next assembly node in the list. The node returned
  // contains a pointer to a prop and a 4x4 matrix. The matrix
  // is evaluated based on the preceding assembly hierarchy
  // (i.e., the matrix is not necessarily as the same as the
  // one that was added with AddNode() because of the 
  // concatenation of matrices in the assembly hierarchy).
  vtkAssemblyNode *GetNextNode();

  // Description:
  // Get the first assembly node in the list. See the comments for
  // GetNextNode() regarding the contents of the returned node. (Note: This
  // node corresponds to the vtkProp associated with the vtkRenderer.
  vtkAssemblyNode *GetFirstNode();
  
  // Description:
  // Get the last assembly node in the list. See the comments
  // for GetNextNode() regarding the contents of the returned node.
  vtkAssemblyNode *GetLastNode();
  
  // Description:
  // Delete the last assembly node in the list. This is like
  // a stack pop.
  void DeleteLastNode();
  
  // Description:
  // Perform a shallow copy (reference counted) on the
  // incoming path.
  void ShallowCopy(vtkAssemblyPath *path);
  
  // Description:
  // Override the standard GetMTime() to check for the modified times
  // of the nodes in this path.
  virtual unsigned long GetMTime();

  //BTX
  // Description: 
  // Reentrant safe way to get an object in a collection. Just pass the
  // same cookie back and forth. 
  vtkAssemblyNode *GetNextNode(vtkCollectionSimpleIterator &cookie) {
    return static_cast<vtkAssemblyNode *>(this->GetNextItemAsObject(cookie));};
  //ETX

protected:
  vtkAssemblyPath();
  ~vtkAssemblyPath();
  
  void AddNode(vtkAssemblyNode *n); //Internal method adds assembly node
  vtkTransform *Transform; //Used to perform matrix concatentation
  vtkProp *TransformedProp; //A transformed prop used to do the rendering

private:
  // hide the standard AddItem from the user and the compiler.
  void AddItem(vtkObject *o) { this->vtkCollection::AddItem(o); };

private:
  vtkAssemblyPath(const vtkAssemblyPath&);  // Not implemented.
  void operator=(const vtkAssemblyPath&);  // Not implemented.
};

#endif
