// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause

/**
 * @class   vtkUnstructuredGridVolumeRayCastMapper
 * @brief   A software mapper for unstructured volumes
 *
 * This is a software ray caster for rendering volumes in vtkUnstructuredGrid.
 *
 * @sa
 * vtkVolumeMapper
 */

#ifndef vtkUnstructuredGridVolumeRayCastMapper_h
#define vtkUnstructuredGridVolumeRayCastMapper_h

#include "vtkRenderingVolumeModule.h" // For export macro
#include "vtkUnstructuredGridVolumeMapper.h"

VTK_ABI_NAMESPACE_BEGIN
class vtkDoubleArray;
class vtkIdList;
class vtkMultiThreader;
class vtkRayCastImageDisplayHelper;
class vtkRenderer;
class vtkTimerLog;
class vtkUnstructuredGridVolumeRayCastFunction;
class vtkUnstructuredGridVolumeRayCastIterator;
class vtkUnstructuredGridVolumeRayIntegrator;
class vtkVolume;

class VTKRENDERINGVOLUME_EXPORT vtkUnstructuredGridVolumeRayCastMapper
  : public vtkUnstructuredGridVolumeMapper
{
public:
  static vtkUnstructuredGridVolumeRayCastMapper* New();
  vtkTypeMacro(vtkUnstructuredGridVolumeRayCastMapper, vtkUnstructuredGridVolumeMapper);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  ///@{
  /**
   * Sampling distance in the XY image dimensions. Default value of 1 meaning
   * 1 ray cast per pixel. If set to 0.5, 4 rays will be cast per pixel. If
   * set to 2.0, 1 ray will be cast for every 4 (2 by 2) pixels.
   */
  vtkSetClampMacro(ImageSampleDistance, float, 0.1f, 100.0f);
  vtkGetMacro(ImageSampleDistance, float);
  ///@}

  ///@{
  /**
   * This is the minimum image sample distance allow when the image
   * sample distance is being automatically adjusted
   */
  vtkSetClampMacro(MinimumImageSampleDistance, float, 0.1f, 100.0f);
  vtkGetMacro(MinimumImageSampleDistance, float);
  ///@}

  ///@{
  /**
   * This is the maximum image sample distance allow when the image
   * sample distance is being automatically adjusted
   */
  vtkSetClampMacro(MaximumImageSampleDistance, float, 0.1f, 100.0f);
  vtkGetMacro(MaximumImageSampleDistance, float);
  ///@}

  ///@{
  /**
   * If AutoAdjustSampleDistances is on, the ImageSampleDistance
   * will be varied to achieve the allocated render time of this
   * prop (controlled by the desired update rate and any culling in
   * use).
   */
  vtkSetClampMacro(AutoAdjustSampleDistances, vtkTypeBool, 0, 1);
  vtkGetMacro(AutoAdjustSampleDistances, vtkTypeBool);
  vtkBooleanMacro(AutoAdjustSampleDistances, vtkTypeBool);
  ///@}

  ///@{
  /**
   * Set/Get the number of threads to use. This by default is equal to
   * the number of available processors detected.
   */
  vtkSetMacro(NumberOfThreads, int);
  vtkGetMacro(NumberOfThreads, int);
  ///@}

  ///@{
  /**
   * If IntermixIntersectingGeometry is turned on, the zbuffer will be
   * captured and used to limit the traversal of the rays.
   */
  vtkSetClampMacro(IntermixIntersectingGeometry, vtkTypeBool, 0, 1);
  vtkGetMacro(IntermixIntersectingGeometry, vtkTypeBool);
  vtkBooleanMacro(IntermixIntersectingGeometry, vtkTypeBool);
  ///@}

  ///@{
  /**
   * Set/Get the helper class for casting rays.
   */
  virtual void SetRayCastFunction(vtkUnstructuredGridVolumeRayCastFunction* f);
  vtkGetObjectMacro(RayCastFunction, vtkUnstructuredGridVolumeRayCastFunction);
  ///@}

  ///@{
  /**
   * Set/Get the helper class for integrating rays.  If set to NULL, a
   * default integrator will be assigned.
   */
  virtual void SetRayIntegrator(vtkUnstructuredGridVolumeRayIntegrator* ri);
  vtkGetObjectMacro(RayIntegrator, vtkUnstructuredGridVolumeRayIntegrator);
  ///@}

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

  /**
   * 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*) override;

  vtkGetVectorMacro(ImageInUseSize, int, 2);
  vtkGetVectorMacro(ImageOrigin, int, 2);
  vtkGetVectorMacro(ImageViewportSize, int, 2);

  void CastRays(int threadID, int threadCount);

protected:
  vtkUnstructuredGridVolumeRayCastMapper();
  ~vtkUnstructuredGridVolumeRayCastMapper() override;

  float ImageSampleDistance;
  float MinimumImageSampleDistance;
  float MaximumImageSampleDistance;
  vtkTypeBool AutoAdjustSampleDistances;

  vtkMultiThreader* Threader;
  int NumberOfThreads;

  vtkRayCastImageDisplayHelper* ImageDisplayHelper;

  // This is how big the image would be if it covered the entire viewport
  int ImageViewportSize[2];

  // This is how big the allocated memory for image is. This may be bigger
  // or smaller than ImageFullSize - it will be bigger if necessary to
  // ensure a power of 2, it will be smaller if the volume only covers a
  // small region of the viewport
  int ImageMemorySize[2];

  // This is the size of subregion in ImageSize image that we are using for
  // the current image. Since ImageSize is a power of 2, there is likely
  // wasted space in it. This number will be used for things such as clearing
  // the image if necessary.
  int ImageInUseSize[2];

  // This is the location in ImageFullSize image where our ImageSize image
  // is located.
  int ImageOrigin[2];

  // This is the allocated image
  unsigned char* Image;

  float* RenderTimeTable;
  vtkVolume** RenderVolumeTable;
  vtkRenderer** RenderRendererTable;
  int RenderTableSize;
  int RenderTableEntries;

  void StoreRenderTime(vtkRenderer* ren, vtkVolume* vol, float t);
  float RetrieveRenderTime(vtkRenderer* ren, vtkVolume* vol);

  vtkTypeBool IntermixIntersectingGeometry;

  float* ZBuffer;
  int ZBufferSize[2];
  int ZBufferOrigin[2];

  // Get the ZBuffer value corresponding to location (x,y) where (x,y)
  // are indexing into the ImageInUse image. This must be converted to
  // the zbuffer image coordinates. Nearest neighbor value is returned.
  double GetZBufferValue(int x, int y);

  double GetMinimumBoundsDepth(vtkRenderer* ren, vtkVolume* vol);

  vtkUnstructuredGridVolumeRayCastFunction* RayCastFunction;
  vtkUnstructuredGridVolumeRayCastIterator** RayCastIterators;
  vtkUnstructuredGridVolumeRayIntegrator* RayIntegrator;
  vtkUnstructuredGridVolumeRayIntegrator* RealRayIntegrator;

  vtkIdList** IntersectedCellsBuffer;
  vtkDoubleArray** IntersectionLengthsBuffer;
  vtkDataArray** NearIntersectionsBuffer;
  vtkDataArray** FarIntersectionsBuffer;

  vtkVolume* CurrentVolume;
  vtkRenderer* CurrentRenderer;

  vtkDataArray* Scalars;
  int CellScalars;

private:
  vtkUnstructuredGridVolumeRayCastMapper(const vtkUnstructuredGridVolumeRayCastMapper&) = delete;
  void operator=(const vtkUnstructuredGridVolumeRayCastMapper&) = delete;
};

VTK_ABI_NAMESPACE_END
#endif