// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
// This test covers rendering of translucent image actor with depth peeling.
//
// The command line arguments are:
// -I        => run in interactive mode; unless this is used, the program will
//              not allow interaction and exit

#include "vtkRegressionTestImage.h"
#include "vtkTestUtilities.h"

#include "vtkActor.h"
#include "vtkCamera.h"
#include "vtkImageActor.h"
#include "vtkImageMapper3D.h"
#include "vtkNew.h"
#include "vtkPNGReader.h"
#include "vtkRenderWindow.h"
#include "vtkRenderWindowInteractor.h"
#include "vtkRenderer.h"

#include <iostream>

int TestTranslucentImageActorDepthPeeling(int argc, char* argv[])
{
  vtkNew<vtkRenderWindowInteractor> iren;
  vtkNew<vtkRenderWindow> renWin;
  if (renWin->IsA("vtkWebAssemblyOpenGLRenderWindow"))
  {
    // WebAssembly OpenGL requires additional steps for dual depth peeling. See
    // TestFramebufferPass.cxx for details.
    std::cout << "Skipping test with dual-depth peeling for WebAssembly OpenGL\n";
    return VTK_SKIP_RETURN_CODE;
  }
  iren->SetRenderWindow(renWin);

  renWin->SetMultiSamples(0);
  renWin->SetAlphaBitPlanes(1);

  vtkNew<vtkRenderer> renderer;
  renWin->AddRenderer(renderer);

  renderer->SetUseDepthPeeling(1);
  renderer->SetMaximumNumberOfPeels(200);
  renderer->SetOcclusionRatio(0.1);

  vtkNew<vtkImageActor> ia;
  renderer->AddActor(ia);

  vtkNew<vtkPNGReader> pnmReader;
  ia->GetMapper()->SetInputConnection(pnmReader->GetOutputPort());

  char* fname = vtkTestUtilities::ExpandDataFileName(argc, argv, "Data/alphachannel.png");

  pnmReader->SetFileName(fname);
  delete[] fname;

  renderer->SetBackground(0.1, 0.2, 0.4);
  renWin->SetSize(400, 400);

  renWin->Render();
  if (renderer->GetLastRenderingUsedDepthPeeling())
  {
    std::cout << "depth peeling was used" << std::endl;
  }
  else
  {
    std::cout << "depth peeling was not used (alpha blending instead)" << std::endl;
  }
  int retVal = vtkRegressionTestImage(renWin);
  if (retVal == vtkRegressionTester::DO_INTERACTOR)
  {
    iren->Start();
  }

  return !retVal;
}