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

  Program:   Visualization Toolkit
  Module:    vtkRayCaster.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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   from this software without specific prior written permission.

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=========================================================================*/
// .NAME vtkRayCaster - A helper object for renderer that controls ray casting

// .SECTION Description
// vtkRayCaster is an automatically created object within vtkRenderer. It is
// used for ray casting operations. It stores variables such as the view
// rays, and information on multiresolution image rendering which are queried
// by the specific ray casters.

// .SECTION see also
// vtkRenderer vtkViewRays

#ifndef __vtkRayCaster_h
#define __vtkRayCaster_h

#include "vtkRenderer.h"
#include "vtkVolume.h"
#include "vtkViewRays.h"
#include "vtkVolumeMapper.h"
#include "vtkMultiThreader.h"

#define VTK_MAX_VIEW_RAYS_LEVEL 4

class VTK_EXPORT vtkRayCaster : public vtkObject
{
public:
  static vtkRayCaster *New();
  vtkTypeMacro(vtkRayCaster,vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Method for a vtkVolumeMapper to retrieve the view rays 
  // for a perspective projection
  float *GetPerspectiveViewRays();

  // Description:
  // Get the size in pixels of the view rays for the selected scale index
  void GetViewRaysSize( int size[2] );


  // Description:
  // For a parallel projection, get the starting position of a ray in
  // the lower left hand corder of the viewport.
  float *GetParallelStartPosition( void );

  // Description:
  // For a parallel projection, get the (x,y,z) world increments to move one
  // pixel along the image plane x and the image plane y axes.
  float *GetParallelIncrements( void );

  
  // Description:
  // Set/Get the scale factor for a given level. This is used during multi-
  // resolution interactive rendering
  void SetImageScale(int level, float scale); 
  float GetImageScale(int level); 

  // Description:
  // Get the number of levels of resolution.
  int GetImageScaleCount( void ) { return VTK_MAX_VIEW_RAYS_LEVEL; };

  // Description:
  // During multi-resolution rendering, this indicated the selected level
  // of resolution
  vtkSetClampMacro(SelectedImageScaleIndex, int, 0, VTK_MAX_VIEW_RAYS_LEVEL-1);
  vtkGetMacro( SelectedImageScaleIndex, int );

  // Description:
  // For each level of resolution, set the step size associated with that
  // level. This may be used by the vtkVolumeMapper.
  void SetViewRaysStepSize(int level, float scale); 
  float GetViewRaysStepSize(int level); 

  // Description:
  // Get the value of AutomaticScaleAdjustment. 0 = off, 1 = on
  vtkGetMacro( AutomaticScaleAdjustment, int );
  
  // Description:
  // Turn the automatic scale adjustment on
  void AutomaticScaleAdjustmentOn( void );

  // Description:
  // Turn the automatic scale adjustment off
  void AutomaticScaleAdjustmentOff( void );

  // Description:
  // Set / Get the lower limit for scaling an image. This will define the
  // worst resolution allowed during multiresolution rendering. The default
  // value is 0.15.
  vtkSetClampMacro( AutomaticScaleLowerLimit, float, 0.0, 1.0 );
  vtkGetMacro( AutomaticScaleLowerLimit, float );

  // Description:
  // Set/Get the value of bilinear image zooming.
  vtkSetMacro( BilinearImageZoom, int );
  vtkGetMacro( BilinearImageZoom, int );
  vtkBooleanMacro( BilinearImageZoom, int );

  // Description:
  // Get the total time required for ray casting.
  vtkGetMacro( TotalRenderTime, float );
 
  // Description:
  // Set / Get the number of threads used during ray casting
  vtkSetMacro( NumberOfThreads, int );
  vtkGetMacro( NumberOfThreads, int );

  // Description:
  // Get the number of samples taken during the last image rendered.
  // This is the number of samples for ray casted images only - any
  // samples taken from other types of mapper will be reported in that
  // mapper directly
  int GetNumberOfSamplesTaken();

  int **RowBounds;
  int *RowBoundsSize;
  
  vtkProp **SoftwareProps;
  vtkProp **RayCastProps;

//BTX

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // This method allows the ray caster to know about the renderer with which 
  // it is associated
  vtkSetObjectMacro(Renderer,vtkRenderer);
  vtkGetObjectMacro(Renderer,vtkRenderer);

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // DO NOT USE THIS METHOD OUTSIDE OF THE RENDERING PROCESS
  // Render all prop that require ray casting or that render into
  // an image buffer. Merge the results with the image generated from
  // updating the geometry, and place it on the screen. 
  void Render(vtkRenderer *, int, vtkProp **, int, vtkProp **);

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // DO NOT USE THIS METHOD OUTSIDE OF THE RENDERING PROCESS
  // This method returns the scale that should be applied to the viewport
  // for geometric rendering, and for the image in volume rendering. It 
  // is either explicitly set (if AutomaticScaleAdjustment is off) or
  // is adjusted automatically to get the desired frame rate.
  //
  // Note: IMPORTANT!!!! This should only be called once per render!!!
  //
  float GetViewportScaleFactor( vtkRenderer *ren );

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // DO NOT USE THIS METHOD OUTSIDE OF THE RENDERING PROCESS
  // Get the step size that should be used 
  float GetViewportStepSize( );
  

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // DO NOT USE THIS METHOD OUTSIDE OF THE RENDERING PROCESS
  float *GetCurrentZBuffer()
  {
    if ( this->FirstBlend )
      {
      return NULL;
      }
    else
      {
      return this->ZImage;
      }
  };

//ETX

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

  // Description:
  // Zoom the small image up the full size using nearest neighbor 
  // interpolation
  void NearestNeighborZoom(float *smallImage, float *largeImage,
			   int smallDims[2], int largeDims[2] );

  // Description:
  // Zoom the small image up the full size using bilinear interpolation
  void BilinearZoom(float *smallImage, float *largeImage,
			   int smallDims[2], int largeDims[2] );


  // Description:
  // Rescale the image from the small size to the full size using one of
  // the two interpolation methods above - NearestNeighborZoom or
  // BilinearZoom.
  void RescaleImage( );

  void RenderFrameBufferVolumes( vtkRenderer *ren );
  void InitializeRenderBuffers( vtkRenderer *ren );
  void InitializeRayCasting( vtkRenderer *ren );

//BTX
  void ComputeRowBounds( vtkRenderer *ren, vtkProp *prop, int index );
//ETX

  friend VTK_THREAD_RETURN_TYPE RayCast_RenderImage( void *arg );

  vtkMultiThreader *Threader;

  int              NumberOfThreads;

  int              NumberOfSamplesTaken[VTK_MAX_THREADS];

  vtkRenderer   *Renderer;

  // These are the variables necessary for adjusting the image
  // size during ray casting to achieve a desired update rate
  vtkViewRays   *ViewRays[VTK_MAX_VIEW_RAYS_LEVEL+1];
  float         *SelectedViewRays;
  float         ImageScale[VTK_MAX_VIEW_RAYS_LEVEL+1];
  int           ImageSize[2];
  int           FullImageSize[2];
  int		BilinearImageZoom;
  int           SelectedImageScaleIndex;
  int           StableImageScaleCounter;
  float         PreviousAllocatedTime;
  int           AutomaticScaleAdjustment;
  float         AutomaticScaleLowerLimit;
  float         ImageRenderTime[2];
  float         ViewRaysStepSize[VTK_MAX_VIEW_RAYS_LEVEL];
  float         TotalRenderTime;

  // The working color and depth image
  float         *RGBAImage;
  float         *ZImage;


  // Hang on to a pointer to each volume with a ray cast mapper.
  // We'll also need some information for each of these volumes
  vtkVolume     **RayCastVolumes;
  //BTX
  struct VolumeRayCastVolumeInfoStruct *VolumeInfo;
  //ETX
  int           RayCastPropCount;
  int           SoftwareBufferPropCount;
  vtkTransform  *ViewToWorldTransform;
  float         CameraClippingRange[2];
  float         ViewToWorldMatrix[4][4];
  int           FirstBlend;
  float         CameraInverse22;
  float         CameraInverse23;
  float         CameraInverse32;
  float         CameraInverse33;
  float         CameraPosition[3];
  float         *ParallelStartPosition;
  float         *ParallelIncrements;
  int           ParallelProjection;
  int           NeedBackgroundBlend;
  float         Background[3];
};

#endif


