// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright 2003 Sandia Corporation
// SPDX-License-Identifier: LicenseRef-BSD-3-Clause-Sandia-USGov
/**
 * @class   vtkParallelRenderManager
 * @brief   An object to control parallel rendering.
 *
 *
 * vtkParallelRenderManager operates in multiple processes.  It provides
 * proper renderers and render windows for performing the parallel
 * rendering correctly.  It can also attach itself to render windows and
 * propagate rendering events and camera views.
 *
 * @attention
 * Many parallel rendering schemes do not correctly handle transparency.
 * Unless otherwise documented, assume a sub class does not.
 *
 * @todo
 * Synchronization/barrier primitives.
 *
 * @todo
 * Query ranges of scalar values of objects in addition to the boundary in
 * three-space
 *
 */

#ifndef vtkParallelRenderManager_h
#define vtkParallelRenderManager_h

#include "vtkObject.h"
#include "vtkRenderingParallelModule.h" // For export macro

VTK_ABI_NAMESPACE_BEGIN
class vtkDoubleArray;
class vtkMultiProcessController;
class vtkMultiProcessStream;
class vtkRenderer;
class vtkRendererCollection;
class vtkRenderWindow;
class vtkTimerLog;
class vtkUnsignedCharArray;

class VTKRENDERINGPARALLEL_EXPORT vtkParallelRenderManager : public vtkObject
{
public:
  vtkTypeMacro(vtkParallelRenderManager, vtkObject);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  /**
   * Builds a vtkRenderWindow compatible with this render manager.  The
   * user program is responsible for registering the render window with the
   * SetRenderWindow method and calling Delete.  It is not advisable to use
   * a parallel render manager with a render window that was not built with
   * this method.
   */
  virtual vtkRenderWindow* MakeRenderWindow();

  /**
   * Builds a vtkRenderer compatible with this render manager.  (Should we
   * also register it?)  The user program is responsible for calling
   * Delete.  It is not advisable to use a parallel render manager with a
   * renderer that was not built with this method.
   */
  virtual vtkRenderer* MakeRenderer();

  ///@{
  /**
   * Set/Get the RenderWindow to use for compositing.
   * We add a start and end observer to the window.
   */
  vtkGetObjectMacro(RenderWindow, vtkRenderWindow);
  virtual void SetRenderWindow(vtkRenderWindow* renWin);
  ///@}

  ///@{
  /**
   * Set/Get the vtkMultiProcessController which will handle communications
   * for the parallel rendering.
   */
  vtkGetObjectMacro(Controller, vtkMultiProcessController);
  virtual void SetController(vtkMultiProcessController* controller);
  ///@}

  /**
   * This method sets the piece and number of pieces for each
   * actor with a polydata mapper.
   */
  virtual void InitializePieces();

  /**
   * Make all rendering windows not viewable set as off screen rendering.
   * To make all renderwindows on screen rendering again, call
   * OffScreenRenderingOff on all the render windows.  This class assumes
   * the window on root node is the only one viewable.  Subclasses should
   * change this as necessary.
   */
  virtual void InitializeOffScreen();

  /**
   * Initializes the RMIs and then, if on root node, starts the interactor
   * on the attached render window.  Otherwise, starts processing RMIs.
   * When the interactor returns, it breaks the RMI listening on all other
   * processors.
   */
  virtual void StartInteractor();

  /**
   * If on node other than root, starts serving RMI requests for parallel
   * renders.
   */
  virtual void StartServices();

  /**
   * If on root node, stops the RMI processing on all service nodes.
   */
  virtual void StopServices();

  ///@{
  /**
   * Callbacks that initialize and finish rendering and other tasks.
   */
  virtual void StartRender();
  virtual void EndRender();
  virtual void SatelliteStartRender();
  virtual void SatelliteEndRender();
  virtual void RenderRMI();
  virtual void ResetCamera(vtkRenderer* ren);
  virtual void ResetCameraClippingRange(vtkRenderer* ren);
  virtual void ComputeVisiblePropBoundsRMI(int renderId);
  ///@}

  virtual void InitializeRMIs();

  /**
   * Resets the camera of each renderer contained in the RenderWindow.
   * Should only be called in the "root" process, and all remote processes
   * must be processing RMIs for this method to complete.
   */
  virtual void ResetAllCameras();

  /**
   * Calculates the bounds by gathering information from all processes.
   */
  virtual void ComputeVisiblePropBounds(vtkRenderer* ren, double bounds[6]);

  ///@{
  /**
   * Turns on/off parallel rendering.  When on (the default) the object
   * responds to render events of the attached window, propagates the
   * render event to other processors, and otherwise enables the parallel
   * rendering process.
   */
  vtkSetMacro(ParallelRendering, int);
  vtkGetMacro(ParallelRendering, int);
  vtkBooleanMacro(ParallelRendering, int);
  ///@}

  ///@{
  /**
   * Turns on/off render event propagation.  When on (the default) and
   * ParallelRendering is on, process 0 will send an RMI call to all remote
   * processes to perform a synchronized render.  When off, render must be
   * manually called on each process.
   */
  vtkSetMacro(RenderEventPropagation, int);
  vtkGetMacro(RenderEventPropagation, int);
  vtkBooleanMacro(RenderEventPropagation, int);
  ///@}

  /**
   * Get/Set the default value used for RenderEventPropagation when a new
   * instance of vtkParallelRenderManager is created.
   * Set to true by default.
   */
  static void SetDefaultRenderEventPropagation(bool val)
  {
    vtkParallelRenderManager::DefaultRenderEventPropagation = val;
  }
  static bool GetDefaultRenderEventPropagation()
  {
    return vtkParallelRenderManager::DefaultRenderEventPropagation;
  }

  ///@{
  /**
   * This is used for tiled display rendering.  When data has been
   * duplicated on all processes, then we do not need to compositing.
   * Cameras and renders are still propagated though.
   */
  vtkSetMacro(UseCompositing, int);
  vtkGetMacro(UseCompositing, int);
  vtkBooleanMacro(UseCompositing, int);
  ///@}

  ///@{
  /**
   * Set/Get the reduction factor (for sort-last based parallel renderers).
   * The size of rendered image is divided by the reduction factor and then
   * is blown up to the size of the current vtkRenderWindow.  Setting
   * higher reduction factors enables shorter image transfer times (which
   * is often the bottleneck) but will greatly reduce image quality.  A
   * reduction factor of 2 or greater should only be used for intermediate
   * images in interactive applications.  A reduction factor of 1 (or less)
   * will result in no change in image quality.  A parallel render manager
   * may ignore the image reduction factor if it will result in little or
   * no performance enhancements (eg. it does not do image space
   * manipulations).
   */
  virtual void SetImageReductionFactor(double factor);
  vtkGetMacro(ImageReductionFactor, double);
  ///@}

  vtkSetMacro(MaxImageReductionFactor, double);
  vtkGetMacro(MaxImageReductionFactor, double);

  /**
   * Sets the ReductionFactor based on the given desired update rate and
   * the rendering metrics taken from the last time UpdateServerInfo was
   * called.  Note that if AutoReductionFactor is on, this function is called
   * with the desired update rate of the render window automatically.
   */
  virtual void SetImageReductionFactorForUpdateRate(double DesiredUpdateRate);

  ///@{
  /**
   * If on, the ReductionFactor is automatically adjusted to best meet the
   * the DesiredUpdateRate in the current RenderWindow based on metrics
   * from the last render.
   */
  vtkSetMacro(AutoImageReductionFactor, int);
  vtkGetMacro(AutoImageReductionFactor, int);
  vtkBooleanMacro(AutoImageReductionFactor, int);
  ///@}

  ///@{
  /**
   * Get rendering metrics.
   */
  vtkGetMacro(RenderTime, double);
  vtkGetMacro(ImageProcessingTime, double);
  ///@}

  ///@{
  /**
   * By default, the state of all renderers in the root's render window is
   * propagated to the rest of the processes.  In order for this to work, all
   * render windows must have the same renderers in the same order.  If this is
   * not the case, you can turn off the SyncRenderWindowRenderers.  When this
   * flag is off, the list of renderers held by this parallel render manager
   * (initially empty) is synced.  You can modify the list of renderers with the
   * AddRenderer, RemoveRenderer, and RemoveAllRenderers methods.
   */
  vtkGetMacro(SyncRenderWindowRenderers, int);
  vtkSetMacro(SyncRenderWindowRenderers, int);
  vtkBooleanMacro(SyncRenderWindowRenderers, int);
  virtual void AddRenderer(vtkRenderer*);
  virtual void RemoveRenderer(vtkRenderer*);
  virtual void RemoveAllRenderers();
  ///@}

  ///@{
  /**
   * If on (the default), the result of any image space manipulations are
   * written back to the render window frame buffer.  If off, the image
   * stored in the frame buffer may not be correct.  Either way, the
   * correct frame buffer images may be read with
   * vtkParallelRenderManager::GetPixelData.  Turning WriteBackImages off
   * may result in a speedup if the render window is not visible to the user
   * and images are read back for further processing or transit.
   */
  vtkSetMacro(WriteBackImages, int);
  vtkGetMacro(WriteBackImages, int);
  vtkBooleanMacro(WriteBackImages, int);
  ///@}

  ///@{
  /**
   * If on (the default), when the ImageReductionFactor is greater than 1
   * and WriteBackImages is on, the image will be magnified to fill the
   * entire render window.
   */
  vtkSetMacro(MagnifyImages, int);
  vtkGetMacro(MagnifyImages, int);
  vtkBooleanMacro(MagnifyImages, int);
  ///@}

  enum
  {
    NEAREST,
    LINEAR
  };

  ///@{
  /**
   * Sets the method used to magnify images.  Nearest simply replicates
   * each pixel enough times to fill the image.  Linear performs linear
   * interpolation between the pixels.
   */
  virtual void SetMagnifyImageMethod(int method);
  vtkGetMacro(MagnifyImageMethod, int);
  void SetMagnifyImageMethodToNearest() { this->SetMagnifyImageMethod(NEAREST); }
  void SetMagnifyImageMethodToLinear() { this->SetMagnifyImageMethod(LINEAR); }
  ///@}

  ///@{
  /**
   * Convenience functions for magnifying images.
   */
  virtual void MagnifyImage(vtkUnsignedCharArray* fullImage, const int fullImageSize[2],
    vtkUnsignedCharArray* reducedImage, const int reducedImageSize[2],
    const int fullImageViewport[4] = nullptr, const int reducedImageViewport[4] = nullptr);
  static void MagnifyImageNearest(vtkUnsignedCharArray* fullImage, const int fullImageSize[2],
    vtkUnsignedCharArray* reducedImage, const int reducedImageSize[2],
    const int fullImageViewport[4] = nullptr, const int reducedImageViewport[4] = nullptr);
  static void MagnifyImageLinear(vtkUnsignedCharArray* fullImage, const int fullImageSize[2],
    vtkUnsignedCharArray* reducedImage, const int reducedImageSize[2],
    const int fullImageViewport[4] = nullptr, const int reducedImageViewport[4] = nullptr);
  ///@}

  ///@{
  /**
   * The most appropriate way to retrieve full size image data after a
   * render.  Will work regardless of whether WriteBackImages or
   * MagnifyImage is on or off.  The data returned may be a shallow copy of
   * an internal array.  Therefore, the data may be invalid after the next
   * render or if the ParallelRenderManager is destroyed.
   */
  virtual void GetPixelData(vtkUnsignedCharArray* data);
  virtual void GetPixelData(int x1, int y1, int x2, int y2, vtkUnsignedCharArray* data);
  ///@}

  ///@{
  /**
   * The most appropriate way to retrieve reduced size image data after a
   * render.  Will work regardless of whether WriteBackImages or
   * MagnifyImage is on or off.  The data returned may be a shallow copy of
   * an internal array.  Therefore, the data may be invalid after the next
   * render or if the ParallelRenderManager is destroyed.
   */
  virtual void GetReducedPixelData(vtkUnsignedCharArray* data);
  virtual void GetReducedPixelData(int x1, int y1, int x2, int y2, vtkUnsignedCharArray* data);
  ///@}

  ///@{
  /**
   * Returns the full image size calculated at the last render.
   */
  vtkGetVector2Macro(FullImageSize, int);
  ///@}
  ///@{
  /**
   * Returns the reduced image size calculated at the last render.
   */
  vtkGetVector2Macro(ReducedImageSize, int);
  ///@}

  /**
   * Given the x and y size of the render windows, reposition them
   * in a tile of n columns.
   */
  void TileWindows(int xsize, int ysize, int nColumns);

  ///@{
  /**
   * Get/Set if all Images must use RGBA instead of RGB. By default,
   * this flag is on.
   */
  vtkSetMacro(UseRGBA, int);
  vtkGetMacro(UseRGBA, int);
  ///@}

  ///@{
  /**
   * If ForceRenderWindowSize is set to true, the render manager will use
   * the RenderWindowSize ivar instead of getting the size from the render window.
   */
  vtkSetMacro(ForceRenderWindowSize, int);
  vtkGetMacro(ForceRenderWindowSize, int);
  ///@}

  ///@{
  /**
   * If ForceRenderWindowSize is set to true, the render manager will use
   * the Size ivar instead of getting the size from the render window.
   */
  vtkSetVector2Macro(ForcedRenderWindowSize, int);
  vtkGetVector2Macro(ForcedRenderWindowSize, int);
  ///@}

  enum Tags
  {
    RENDER_RMI_TAG = 34532,
    COMPUTE_VISIBLE_PROP_BOUNDS_RMI_TAG = 54636,
    WIN_INFO_TAG = 87834,
    REN_INFO_TAG = 87836,
    LIGHT_INFO_TAG = 87838,
    REN_ID_TAG = 58794,
    BOUNDS_TAG = 23543
  };

  virtual void CheckForAbortRender() {}
  virtual int CheckForAbortComposite() { return 0; }

  ///@{
  /**
   * The default is to allow the use of the back buffer for compositing.
   * If set to false, this will prevent to manager from swapping buffers.
   * This allows something else (for instance VisibleCellSelection) to
   * control front/back buffer swapping.
   */
  vtkSetMacro(UseBackBuffer, int);
  vtkGetMacro(UseBackBuffer, int);
  vtkBooleanMacro(UseBackBuffer, int);
  ///@}

  ///@{
  /**
   * When set the render manager will synchronize the TileViewport and TileScale
   * properties. This may not be desirable in cases where there's some other
   * mechanism to set the tile dimensions eg. Tile displays.
   */
  vtkSetMacro(SynchronizeTileProperties, int);
  vtkGetMacro(SynchronizeTileProperties, int);
  vtkBooleanMacro(SynchronizeTileProperties, int);
  ///@}

  ///@{
  /**
   * INTERNAL METHODS (DON NOT USE).
   * There are internal methods made public so that they can be called from
   * callback functions.
   */
  virtual void GenericStartRenderCallback();
  virtual void GenericEndRenderCallback();
  ///@}

protected:
  vtkParallelRenderManager();
  ~vtkParallelRenderManager() override;

  ///@{
  /**
   * Add/Remove event handlers for the render window.
   */
  void AddRenderWindowEventHandlers();
  void RemoveRenderWindowEventHandlers();
  ///@}

  vtkRenderWindow* RenderWindow;
  vtkMultiProcessController* Controller;
  vtkRendererCollection* Renderers;

  virtual vtkRendererCollection* GetRenderers();

  int ForceRenderWindowSize;
  int ForcedRenderWindowSize[2];

  /**
   * The "root" node's process id.  This is the node which is listening for
   * and propagating new render events from the RenderWindow.  All
   * processes on the controller must have the same value.  This value must
   * be set before SetRenderWindow method is called.  In the constructor or
   * the SetController methods are good places.  By default this is set to
   * 0.
   */
  int RootProcessId;

  int ObservingRenderWindow;
  int ObservingAbort;

  unsigned long StartRenderTag;
  unsigned long EndRenderTag;
  unsigned long ResetCameraTag;
  unsigned long ResetCameraClippingRangeTag;
  unsigned long AbortRenderCheckTag;

  double ImageReductionFactor;
  double MaxImageReductionFactor;
  int AutoImageReductionFactor;

  int WriteBackImages;
  int MagnifyImages;
  int MagnifyImageMethod;

  int UseRGBA;
  int SynchronizeTileProperties;
  int FullImageSize[2];
  int ReducedImageSize[2];

  vtkUnsignedCharArray* FullImage;
  vtkUnsignedCharArray* ReducedImage;

  int FullImageUpToDate;
  int ReducedImageUpToDate;
  int RenderWindowImageUpToDate;

  vtkDoubleArray* Viewports;

  int Lock;
  int ParallelRendering;
  int RenderEventPropagation;
  int UseCompositing;
  int SyncRenderWindowRenderers;

  vtkTimerLog* Timer;

  double RenderTime;
  double ImageProcessingTime;

  /**
   * Used by SetImageReductionFactorForUpdateRate to smooth transitions
   * transitions between image reduction factors.
   */
  double AverageTimePerPixel;

  /**
   * Used to synchronize rendering information per frame.
   * These are old methods provided for backward compatibility. One should look
   * at using CollectWindowInformation(), ProcessWindowInformation() etc. for
   * buffered sending of information over.
   */
  virtual void SendWindowInformation() {}
  virtual void ReceiveWindowInformation() {}
  virtual void SendRendererInformation(vtkRenderer*) {}
  virtual void ReceiveRendererInformation(vtkRenderer*) {}

  /**
   * Subclass should override these methods (instead of
   * SendWindowInformation/ReceiveWindowInformation or
   * SendRendererInformation/ReceiveRendererInformation) to collect or process
   * meta-data to synchronize rendering information per frame.
   * Subclass should not use the Controller directly to send receive messages
   * in any of these methods otherwise deadlocks may ensue.
   */
  virtual void CollectWindowInformation(vtkMultiProcessStream&) {}
  virtual bool ProcessWindowInformation(vtkMultiProcessStream&) { return true; }
  virtual void CollectRendererInformation(vtkRenderer*, vtkMultiProcessStream&) {}
  virtual bool ProcessRendererInformation(vtkRenderer*, vtkMultiProcessStream&) { return true; }

  ///@{
  /**
   * Here is a good place to handle processing of data before and after
   * render.
   */
  virtual void PreRenderProcessing() = 0;
  virtual void PostRenderProcessing() = 0;
  ///@}

  /**
   * Called in satellites to set the render window size to the current
   * FullImageSize and ReducedImageSize (or vice versa).
   */
  virtual void SetRenderWindowSize();

  /**
   * Called by ComputeVisiblePropBoundsRMI to get the bounds of a local
   * renderer.  Override this method if the true bounds are different than
   * those reported by the renderer.
   */
  virtual void LocalComputeVisiblePropBounds(vtkRenderer* ren, double bounds[6]);

  /**
   * When called, fills FullImage.
   */
  virtual void MagnifyReducedImage();

  /**
   * Write the full image back to the RenderWindow.
   */
  virtual void WriteFullImage();

  /**
   * Reads in the reduced image from the RenderWindow.
   */
  virtual void ReadReducedImage();

  /**
   * Returns 1 if the RenderWindow's last image is in the front buffer, 0
   * if it is in the back.
   */
  virtual int LastRenderInFrontBuffer();

  /**
   * Select buffer to read from / render into.
   */
  virtual int ChooseBuffer();

  /**
   * Sets the current render window's pixel data.
   */
  virtual void SetRenderWindowPixelData(vtkUnsignedCharArray* pixels, const int pixelDimensions[2]);

  /**
   * Returns true if the image for the given renderer should be rendered at a
   * reduced size to be magnified later.  This method always returns true, but
   * subclasses may render some renderers at a reduced size, magnify them, and
   * then render the other renderers at full resolution.
   */
  virtual int ImageReduceRenderer(vtkRenderer*) { return 1; }

  struct RenderWindowInfo
  {
    int FullSize[2];
    int ReducedSize[2];
    int NumberOfRenderers;
    int UseCompositing;
    int TileScale[2];
    double ImageReductionFactor;
    double DesiredUpdateRate;
    double TileViewport[4];

    // Initialize members
    RenderWindowInfo() = default;

    // Save/restore the struct to/from a stream.
    void Save(vtkMultiProcessStream& stream);
    bool Restore(vtkMultiProcessStream& stream);
  };

  struct RendererInfo
  {
    int Draw = 0;
    int NumberOfLights = 0;
    double Viewport[4] = { 0., 0., 0., 0. };
    double CameraPosition[3] = { 0., 0., 0. };
    double CameraFocalPoint[3] = { 0., 0., 0. };
    double CameraViewUp[3] = { 0., 0., 0. };
    double WindowCenter[2] = { 0., 0. };
    double CameraClippingRange[2] = { 0., 0. };
    double CameraViewAngle = 0.;
    double Background[3] = { 0., 0., 0. };
    double Background2[3] = { 0., 0., 0. };
    bool GradientBackground = false;

    double ParallelScale = 0.;

    // Initialize members
    RendererInfo() = default;

    // Save/restore the struct to/from a stream.
    void Save(vtkMultiProcessStream& stream);
    bool Restore(vtkMultiProcessStream& stream);
  };

  struct LightInfo
  {
    double Position[3];
    double FocalPoint[3];
    double Type;

    // Initialize members
    LightInfo() = default;

    // Save/restore the struct to/from a stream.
    void Save(vtkMultiProcessStream& stream);
    bool Restore(vtkMultiProcessStream& stream);
  };

  int AddedRMIs;
  unsigned long RenderRMIId;
  unsigned long BoundsRMIId;
  int UseBackBuffer;

  static bool DefaultRenderEventPropagation;

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

VTK_ABI_NAMESPACE_END
#endif // vtkParalleRenderManager_h