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

  Program:   Visualization Toolkit
  Module:    vtkFixedPointRayCastImage.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 vtkSmartVolumeMapper - Adaptive volume mapper
// .SECTION Description
// vtkSmartVolumeMapper is a volume mapper that will delegate to a specific
// volume mapper based on rendering parameters and available hardware. Use the
// SetRequestedRenderMode() method to control the behavior of the selection.
// The following options are available:
//
//  vtkSmartVolumeMapper::DefaultRenderMode:
//          Allow the vtkSmartVolumeMapper to select the best mapper based on
//          rendering parameters and hardware support. If GPU ray casting is
//          supported, this mapper will be used for all rendering. If not,
//          then if 3D texture mapping is supported, it will be used for
//          interactive rendering and the vtkFixedPointRayCastMapper will be
//          used for still rendering. If 3D texture mapping is not supported,
//          then the vtkFixedPointRayCastMapper will be used exclusively.
//          This is the default requested render mode, and is generally the
//          best option. When you use this option, your volume will always
//          be rendered, but the method used to render it may vary based
//          on parameters and platform.
//
//  vtkSmartVolumeMapper::RayCastAndTextureRenderMode:
//          Use the vtkVolumeTextureMapper3D for interactive rendering,
//          and the vtkFixedPointVolumeRayCastMapper for still renders.
//          If 3D texture mapping is not supported, then the ray
//          caster will be used exclusively. When you use this option your
//          volume will always be rendered, but the method used for
//          interactive rendering will vary based on parameters and
//          platform. The decision on whether a particular render is
//          interactive or still is based on the adjustable parameter
//          InteractiveUpdateRate. If the DesiredUpdateRate found in the
//          vtkRenderWindow that initiated the Render is at or above
//          the InteractiveUpdateRate value, then the render is considered
//          interactive, otherwise it is considered a still render.
//
//  vtkSmartVolumeMapper::RayCastRenderMode:
//          Use the vtkFixedPointVolumeRayCastMapper for both interactive and
//          still rendering. When you use this option your volume will always
//          be rendered with the vtkFixedPointVolumeRayCastMapper.
//
//  vtkSmartVolumeMapper::TextureRenderMode:
//          Use the vtkVolumeTextureMapper3D, if supported, for both
//          interactive and still rendering. If 3D texture mapping is not
//          supported (either by the hardware, or due to the rendering
//          parameters) then no image will be rendered. Use this option only
//          if you have already checked for support based on the current
//          hardware, number of scalar components, and rendering parameters
//          in the vtkVolumeProperty. Also note that the
//          vtkVolumeTextureMapper3D does not support window / level
//          operations on the final image, so FinalColorWindow must be at
//          the default value of 1.0 and FinalColorLevel must be at the
//          default value of 0.5.
//
//  vtkSmartVolumeMapper::GPURenderMode:
//          Use the vtkGPUVolumeRayCastMapper, if supported, for both
//          interactive and still rendering. If the GPU ray caster is not
//          supported (due to hardware limitations or rendering parameters)
//          then no image will be rendered. Use this option only if you have
//          already checked for supported based on the current hardware,
//          number of scalar components, and rendering parameters in the
//          vtkVolumeProperty.
//
//  You can adjust the contrast and brightness in the rendered image using the
//  FinalColorWindow and FinalColorLevel ivars. By default the
//  FinalColorWindow is set to 1.0, and the FinalColorLevel is set to 0.5,
//  which applies no correction to the computed image. To apply the window /
//  level operation to the computer image color, first a Scale and Bias
//  value are computed:
//
//  scale = 1.0 / this->FinalColorWindow
//  bias  = 0.5 - this->FinalColorLevel / this->FinalColorWindow
//
//  To compute a new color (R', G', B', A') from an existing color (R,G,B,A)
//  for a pixel, the following equation is used:
//
//  R' = R*scale + bias*A
//  G' = G*scale + bias*A
//  B' = B*scale + bias*A
//  A' = A
//
// Note that bias is multiplied by the alpha component before adding because
// the red, green, and blue component of the color are already pre-multiplied
// by alpha. Also note that the window / level operation leaves the alpha
// component unchanged - it only adjusts the RGB values.
//
//-----------------------------------------------------------------------------

#ifndef __vtkSmartVolumeMapper_h
#define __vtkSmartVolumeMapper_h

#include "vtkVolumeMapper.h"
#include "vtkImageReslice.h" // for VTK_RESLICE_NEAREST, VTK_RESLICE_CUBIC

class vtkFixedPointVolumeRayCastMapper;
class vtkGPUVolumeRayCastMapper;
class vtkImageResample;
class vtkRenderWindow;
class vtkVolume;
class vtkVolumeProperty;
class vtkVolumeTextureMapper3D;

class VTK_VOLUMERENDERING_EXPORT vtkSmartVolumeMapper : public vtkVolumeMapper
{
public:
  static vtkSmartVolumeMapper *New();
  vtkTypeMacro(vtkSmartVolumeMapper,vtkVolumeMapper);
  void PrintSelf( ostream& os, vtkIndent indent );

  // Description:
  // Set the final color window. This controls the contrast of
  // the image. The default value is 1.0. The Window can be
  // negative (this causes a "negative" effect on the image)
  // Although Window can be set to 0.0, any value less than
  // 0.00001 and greater than or equal to 0.0 will be set to
  // 0.00001, and any value greater than -0.00001 but less
  // than or equal to 0.0 will be set to -0.00001.
  // Initial value is 1.0.
  vtkSetMacro( FinalColorWindow, float );

  // Description:
  // Get the final color window. Initial value is 1.0.
  vtkGetMacro( FinalColorWindow, float );

  // Description:
  // Set the final color level. The level controls the
  // brightness of the image. The final color window will
  // be centered at the final color level, and together
  // represent a linear remapping of color values. The
  // default value for the level is 0.5.
  vtkSetMacro( FinalColorLevel,  float );

  // Description:
  // Get the final color level.
  vtkGetMacro( FinalColorLevel,  float );

//BTX
// The possible values for the default and current render mode ivars
  enum
  {
    DefaultRenderMode=0,
    RayCastAndTextureRenderMode,
    RayCastRenderMode,
    TextureRenderMode,
    GPURenderMode,
    UndefinedRenderMode,
    InvalidRenderMode
  };
//ETX

  // Description:
  // Set the requested render mode. The default is
  // vtkSmartVolumeMapper::DefaultRenderMode.
  void SetRequestedRenderMode(int mode);

  // Description:
  // Set the requested render mode to vtkSmartVolumeMapper::DefaultRenderMode.
  // This is the best option for an application that must adapt to different
  // data types, harware, and rendering parameters.
  void SetRequestedRenderModeToDefault();

  // Description:
  // Set the requested render mode to
  // vtkSmartVolumeMapper::RayCastAndTextureRenderMode.
  // This is a good option if you want to avoid using advanced OpenGL
  // functionality, but would still like to used 3D texture mapping, if
  // available, for interactive rendering.
  void SetRequestedRenderModeToRayCastAndTexture();

  // Description:
  // Set the requested render mode to vtkSmartVolumeMapper::RayCastRenderMode.
  // This option will use software rendering exclusively. This is a good option
  // if you know there is no hardware acceleration.
  void SetRequestedRenderModeToRayCast();

  // Description:
  // Get the requested render mode.
  vtkGetMacro( RequestedRenderMode, int );

  // Description:
  // Set the rate at or above this render will be considered interactive.
  // If the DesiredUpdateRate of the vtkRenderWindow that caused the Render
  // falls at or above this rate, the render is considered interactive and
  // the mapper may be adjusted (depending on the render mode).
  // Initial value is 1.0e-5.
  vtkSetClampMacro( InteractiveUpdateRate, double, 1.0e-10, 1.0e10 );

  // Description:
  // Get the update rate at or above which this is considered an
  // interactive render.
  // Initial value is 1.0e-5.
  vtkGetMacro( InteractiveUpdateRate, double );

  // Description:
  // This will return the render mode used during the previous call to
  // Render().
  int GetLastUsedRenderMode();

  // Description:
  // Value passed to the GPU mapper. Ignored by other mappers.
  // Maximum size of the 3D texture in GPU memory.
  // Will default to the size computed from the graphics
  // card. Can be adjusted by the user.
  // Useful if the automatic detection is defective or missing.
  vtkSetMacro( MaxMemoryInBytes, vtkIdType );
  vtkGetMacro( MaxMemoryInBytes, vtkIdType );

  // Description:
  // Value passed to the GPU mapper. Ignored by other mappers.
  // Maximum fraction of the MaxMemoryInBytes that should
  // be used to hold the texture. Valid values are 0.1 to
  // 1.0.
  vtkSetClampMacro( MaxMemoryFraction, float, 0.1f, 1.0f );
  vtkGetMacro( MaxMemoryFraction, float );

  // Description:
  // Set interpolation mode for downsampling (lowres GPU)
  // (initial value: cubic).
  vtkSetClampMacro(InterpolationMode, int,
                   VTK_RESLICE_NEAREST, VTK_RESLICE_CUBIC);
  vtkGetMacro(InterpolationMode, int);
  void SetInterpolationModeToNearestNeighbor();
  void SetInterpolationModeToLinear();
  void SetInterpolationModeToCubic();

  // Description:
  // This method can be used to render a representative view of the input data
  // into the supplied image given the supplied blending mode, view direction,
  // and view up vector.
  void CreateCanonicalView( vtkRenderer *ren,
                            vtkVolume *volume,
                            vtkVolume *volume2,
                            vtkImageData *image,
                            int blend_mode,
                            double viewDirection[3],
                            double viewUp[3] );


//BTX
  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Initialize rendering for this volume.
  void Render( vtkRenderer *, vtkVolume * );

  // Description:
  // WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
  // Release any graphics resources that are being consumed by this mapper.
  // The parameter window could be used to determine which graphic
  // resources to release.
  void ReleaseGraphicsResources(vtkWindow *);
//ETX

protected:
  vtkSmartVolumeMapper();
  ~vtkSmartVolumeMapper();

  // Description:
  // Connect input of the vtkSmartVolumeMapper to the input of the
  // internal volume mapper by doing a shallow to avoid memory leaks.
  // \pre m_exists: m!=0
  void ConnectMapperInput(vtkVolumeMapper *m);

  // Description:
  // Connect input of the vtkSmartVolumeMapper to the input of the
  // internal resample filter by doing a shallow to avoid memory leaks.
  // \pre m_exists: f!=0
  void ConnectFilterInput(vtkImageResample *f);

  // Window / level ivars
  float   FinalColorWindow;
  float   FinalColorLevel;

  // GPU mapper-specific memory ivars.
  vtkIdType MaxMemoryInBytes;
  float MaxMemoryFraction;

  // Used for downsampling.
  int InterpolationMode;

  // The requested render mode is used to compute the current render mode. Note
  // that the current render mode can be invalid if the requested mode is not
  // supported.
  int     RequestedRenderMode;
  int     CurrentRenderMode;

  // Initialization variables.
  int          Initialized;
  vtkTimeStamp SupportStatusCheckTime;
  int          TextureSupported;
  int          GPUSupported;
  int          RayCastSupported;
  int          LowResGPUNecessary;

  // This is the resample filter that may be used if we need to
  // create a low resolution version of the volume for GPU rendering
  vtkImageResample *GPUResampleFilter;

  // If the DesiredUpdateRate of the vtkRenderWindow causing the Render is at
  // or above this value, the render is considered interactive. Otherwise it is
  // considered still.
  double InteractiveUpdateRate;

  // The initialize method. Called from ComputeRenderMode whenever something
  // relavent has changed.
  void  Initialize(vtkRenderer *ren,
                   vtkVolume *vol);

  // The method that computes the render mode from the requested render mode
  // based on the support status for each render method.
  void  ComputeRenderMode(vtkRenderer *ren,
                          vtkVolume *vol);

  // The three potential mappers
  vtkGPUVolumeRayCastMapper      *GPULowResMapper;
  vtkGPUVolumeRayCastMapper      *GPUMapper;
  vtkFixedPointVolumeRayCastMapper  *RayCastMapper;
  vtkVolumeTextureMapper3D          *TextureMapper;


  // We need to keep track of the blend mode we had when we initialized
  // because we need to reinitialize (and recheck hardware support) if
  // it changes
  int  InitializedBlendMode;

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

#endif
