// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/**
 * @class   vtkFrustumCoverageCuller
 * @brief   cull props based on frustum coverage
 *
 * vtkFrustumCoverageCuller will cull props based on the coverage in
 * the view frustum. The coverage is computed by enclosing the prop in
 * a bounding sphere, projecting that to the viewing coordinate system, then
 * taking a slice through the view frustum at the center of the sphere. This
 * results in a circle on the plane slice through the view frustum. This
 * circle is enclosed in a squared, and the fraction of the plane slice that
 * this square covers is the coverage. This is a number between 0 and 1.
 * If the number is less than the MinimumCoverage, the allocated render time
 * for that prop is set to zero. If it is greater than the MaximumCoverage,
 * the allocated render time is set to 1.0. In between, a linear ramp is used
 * to convert coverage into allocated render time.
 *
 * @sa
 * vtkCuller
 */

#ifndef vtkFrustumCoverageCuller_h
#define vtkFrustumCoverageCuller_h

#include "vtkCuller.h"
#include "vtkRenderingCoreModule.h" // For export macro

#define VTK_CULLER_SORT_NONE 0
#define VTK_CULLER_SORT_FRONT_TO_BACK 1
#define VTK_CULLER_SORT_BACK_TO_FRONT 2

VTK_ABI_NAMESPACE_BEGIN
class vtkProp;
class vtkRenderer;

class VTKRENDERINGCORE_EXPORT vtkFrustumCoverageCuller : public vtkCuller
{
public:
  static vtkFrustumCoverageCuller* New();
  vtkTypeMacro(vtkFrustumCoverageCuller, vtkCuller);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  ///@{
  /**
   * Set/Get the minimum coverage - props with less coverage than this
   * are given no time to render (they are culled)
   */
  vtkSetMacro(MinimumCoverage, double);
  vtkGetMacro(MinimumCoverage, double);
  ///@}

  ///@{
  /**
   * Set/Get the maximum coverage - props with more coverage than this are
   * given an allocated render time of 1.0 (the maximum)
   */
  vtkSetMacro(MaximumCoverage, double);
  vtkGetMacro(MaximumCoverage, double);
  ///@}

  ///@{
  /**
   * Set the sorting style - none, front-to-back or back-to-front
   * The default is none
   */
  vtkSetClampMacro(SortingStyle, int, VTK_CULLER_SORT_NONE, VTK_CULLER_SORT_BACK_TO_FRONT);
  vtkGetMacro(SortingStyle, int);
  void SetSortingStyleToNone() { this->SetSortingStyle(VTK_CULLER_SORT_NONE); }
  void SetSortingStyleToBackToFront() { this->SetSortingStyle(VTK_CULLER_SORT_BACK_TO_FRONT); }
  void SetSortingStyleToFrontToBack() { this->SetSortingStyle(VTK_CULLER_SORT_FRONT_TO_BACK); }
  const char* GetSortingStyleAsString();
  ///@}

  /**
   * WARNING: INTERNAL METHOD - NOT INTENDED FOR GENERAL USE
   * DO NOT USE THESE METHODS OUTSIDE OF THE RENDERING PROCESS
   * Perform the cull operation
   * This method should only be called by vtkRenderer as part of
   * the render process
   */
  double Cull(vtkRenderer* ren, vtkProp** propList, int& listLength, int& initialized) override;

protected:
  vtkFrustumCoverageCuller();
  ~vtkFrustumCoverageCuller() override = default;

  double MinimumCoverage;
  double MaximumCoverage;
  int SortingStyle;

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

VTK_ABI_NAMESPACE_END
#endif
