/*=========================================================================
  
  Program:   Visualization Toolkit
  Module:    vtkLODActor.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$
  
Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
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=========================================================================*/
// .NAME vtkLODActor - an actor that supports multiple levels of detail
// .SECTION Description
// vtkLODActor is an actor that stores multiple levels of detail (LOD) and
// can automatically switch between them. It selects which level of detail to
// use based on how much time it has been allocated to render.  Currently a
// very simple method of TotalTime/NumberOfActors is used.  (In the future
// this should be modified to dynamically allocate the rendering time between
// different actors based on their needs.)
//
// There are three levels of detail by default. The top level is just the
// normal data.  The lowest level of detail is a simple bounding box outline
// of the actor. The middle level of detail is a point cloud of a fixed
// number of points that have been randomly sampled from the mapper's input
// data.  Point attributes are copied over to the point cloud.  These two
// lower levels of detail are accomplished by creating instances of a
// vtkOutlineFilter (low-res) and vtkMaskPoints (medium-res). Additional
// levels of detail can be add using the AddLODMapper() method.
//
// To control the frame rate, you typically set the vtkRenderWindowInteractor
// DesiredUpdateRate and StillUpdateRate. This then will cause vtkLODActor
// to adjust its LOD to fulfill the requested update rate.
//
// For greater control on levels of detail, see also vtkLODProp3D. That
// class allows arbitrary definition of each LOD.

// .SECTION see also
// vtkActor vtkRenderer vtkLODProp3D

#ifndef __vtkLODActor_h
#define __vtkLODActor_h

#include "vtkActor.h"
#include "vtkMaskPoints.h"
#include "vtkOutlineFilter.h"
#include "vtkPolyDataMapper.h"
#include "vtkMapperCollection.h"

class VTK_EXPORT vtkLODActor : public vtkActor
{
public:
  vtkTypeMacro(vtkLODActor,vtkActor);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Creates a vtkLODActor with the following defaults: origin(0,0,0) 
  // position=(0,0,0) scale=(1,1,1) visibility=1 pickable=1 dragable=1
  // orientation=(0,0,0). NumberOfCloudPoints is set to 150.
  static vtkLODActor *New();

  // Description:
  // This causes the actor to be rendered. It, in turn, will render the actor's
  // property and then mapper.  
  virtual void Render(vtkRenderer *, vtkMapper *);

  // Description:
  // This method is used internally by the rendering process.
  // We overide the superclass method to properly set the estimated render time.
  int RenderOpaqueGeometry(vtkViewport *viewport);

  // Description:
  // Release any graphics resources that are being consumed by this actor.
  // The parameter window could be used to determine which graphic
  // resources to release.
  void ReleaseGraphicsResources(vtkWindow *);

  // Description:
  // Add another level of detail.  They do not have to be in any order
  // of complexity.
  void AddLODMapper(vtkMapper *mapper);

  // Description:
  // Set/Get the number of random points for the point cloud.
  vtkGetMacro(NumberOfCloudPoints,int);
  vtkSetMacro(NumberOfCloudPoints,int);

  // Description:
  // All the mappers for different LODs are stored here.
  // The order is not important.
  vtkGetObjectMacro(LODMappers, vtkMapperCollection);

  // Description:
  // When this objects gets modified, this method also modifies the object.
  void Modified();
  
  // Description:
  // Shallow copy of an LOD actor. Overloads the virtual vtkProp method.
  void ShallowCopy(vtkProp *prop);

protected:
  vtkLODActor();
  ~vtkLODActor();
  vtkLODActor(const vtkLODActor&) {};
  void operator=(const vtkLODActor&) {};

  vtkActor            *Device;
  vtkMapperCollection *LODMappers;

  // stuff for creating our own LOD mappers
  vtkMaskPoints       *MaskPoints;
  vtkOutlineFilter    *OutlineFilter;
  vtkTimeStamp        BuildTime;
  int                 NumberOfCloudPoints;
  vtkPolyDataMapper   *LowMapper;
  vtkPolyDataMapper   *MediumMapper;

  void CreateOwnLODs();
  void UpdateOwnLODs();
  void DeleteOwnLODs();
};

#endif


