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

  Program:   Visualization Toolkit

  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.

=========================================================================*/
#include "vtkSurfaceLICHelper.h"

#include "vtkBoundingBox.h"
#include "vtkCompositeDataIterator.h"
#include "vtkCompositeDataSet.h"
#include "vtkDataSet.h"
#include "vtkImageData.h"
#include "vtkLineIntegralConvolution2D.h"
#include "vtkMath.h"
#include "vtkMatrix4x4.h"
#include "vtkNew.h"
#include "vtkOpenGLActor.h"
#include "vtkOpenGLCamera.h"
#include "vtkOpenGLError.h"
#include "vtkOpenGLFramebufferObject.h"
#include "vtkOpenGLRenderUtilities.h"
#include "vtkOpenGLRenderWindow.h"
#include "vtkPainterCommunicator.h"
#include "vtkPixelBufferObject.h"
#include "vtkRenderer.h"
#include "vtkSurfaceLICComposite.h"
#include "vtkTextureObject.h"
#include "vtk_glew.h"

#include <vector>

#define vtkSurfaceLICHelperDEBUG 0

// Description
// find min/max of unmasked fragments across all regions
// download each search each region individually
void vtkSurfaceLICHelper::StreamingFindMinMax(
  vtkOpenGLFramebufferObject* fbo, std::deque<vtkPixelExtent>& blockExts, float& min, float& max)
{
  size_t nBlocks = blockExts.size();
  // initiate download
  fbo->ActivateReadBuffer(1U);
  vtkStaticCheckFrameBufferStatusMacro(GL_FRAMEBUFFER);
  std::vector<vtkPixelBufferObject*> pbos(nBlocks, nullptr);
  for (size_t e = 0; e < nBlocks; ++e)
  {
    pbos[e] = fbo->Download(blockExts[e].GetData(), VTK_FLOAT, 4, GL_FLOAT, GL_RGBA);
  }
  fbo->RemoveColorAttachment(0U);
  fbo->RemoveColorAttachment(1U);
  fbo->DeactivateDrawBuffers();
  fbo->DeactivateReadBuffer();
  // map search and release each region
  for (size_t e = 0; e < nBlocks; ++e)
  {
    vtkPixelBufferObject*& pbo = pbos[e];
    float* pColors = (float*)pbo->MapPackedBuffer();

    size_t n = blockExts[e].Size();
    for (size_t i = 0; i < n; ++i)
    {
      if (pColors[4 * i + 3] != 0.0f)
      {
        float L = pColors[4 * i + 2];
        min = min > L ? L : min;
        max = max < L ? L : max;
      }
    }
    pbo->UnmapPackedBuffer();
    pbo->Delete();
    pbo = nullptr;
  }
#if vtkSurfaceLICHelperDEBUG >= 1
  cerr << "min=" << min << " max=" << max << endl;
#endif
}

// Description:
// Constructor
vtkSurfaceLICHelper::vtkSurfaceLICHelper()
{
  this->Viewsize[0] = this->Viewsize[1] = 0;

  this->ContextNeedsUpdate = true;
  this->CommunicatorNeedsUpdate = true;

  this->Communicator = new vtkPainterCommunicator;

  this->HasVectors = false;

  this->ColorPass = nullptr;
  this->ColorEnhancePass = nullptr;
  this->CopyPass = nullptr;
}

// Description:
// Destructor
vtkSurfaceLICHelper::~vtkSurfaceLICHelper()
{
  this->ReleaseGraphicsResources(nullptr);

  delete this->ColorPass;
  delete this->ColorEnhancePass;
  delete this->CopyPass;
  this->ColorPass = nullptr;
  this->ColorEnhancePass = nullptr;
  this->CopyPass = nullptr;

  delete this->Communicator;
}

// Description:
// Check for OpenGL support
bool vtkSurfaceLICHelper::IsSupported(vtkOpenGLRenderWindow* context)
{
  if (context == nullptr)
  {
    vtkGenericWarningMacro("OpenGL render window required");
    return false;
  }

  bool lic2d = vtkLineIntegralConvolution2D::IsSupported(context);

  bool floatFormats = vtkTextureObject::IsSupported(context, true, true, false);

  bool support = lic2d && floatFormats;

  if (!support)
  {
    vtkGenericWarningMacro(<< "SurfaceLIC is not supported" << endl
                           << context->GetClassName() << endl
                           << "LIC support = " << lic2d << endl
                           << "floating point texture formats = " << floatFormats);
    return false;
  }
  return true;
}

// Description:
// Free textures and shader programs we're holding a reference to.
void vtkSurfaceLICHelper::ReleaseGraphicsResources(vtkWindow* win)
{
  if (this->ColorEnhancePass)
  {
    this->ColorEnhancePass->ReleaseGraphicsResources(win);
  }
  if (this->ColorPass)
  {
    this->ColorPass->ReleaseGraphicsResources(win);
  }
  if (this->CopyPass)
  {
    this->CopyPass->ReleaseGraphicsResources(win);
  }

  this->ClearTextures();

  this->Compositor = nullptr;
  this->LICer = nullptr;
  this->FBO = nullptr;
}

// Description:
// Free textures we're holding a reference to.
void vtkSurfaceLICHelper::ClearTextures()
{
  this->DepthImage = nullptr;
  this->GeometryImage = nullptr;
  this->VectorImage = nullptr;
  this->MaskVectorImage = nullptr;
  this->CompositeVectorImage = nullptr;
  this->CompositeMaskVectorImage = nullptr;
  this->NoiseImage = nullptr;
  this->LICImage = nullptr;
  this->RGBColorImage = nullptr;
  this->HSLColorImage = nullptr;
}

// Description:
// Allocate textures.
void vtkSurfaceLICHelper::AllocateTextures(vtkOpenGLRenderWindow* context, int* viewsize)
{
  this->AllocateDepthTexture(context, viewsize, this->DepthImage);
  this->AllocateTexture(context, viewsize, this->GeometryImage, vtkTextureObject::Nearest);
  this->AllocateTexture(context, viewsize, this->VectorImage, vtkTextureObject::Linear);
  this->AllocateTexture(context, viewsize, this->MaskVectorImage, vtkTextureObject::Linear);
  this->AllocateTexture(context, viewsize, this->CompositeVectorImage, vtkTextureObject::Linear);
  this->AllocateTexture(
    context, viewsize, this->CompositeMaskVectorImage, vtkTextureObject::Linear);
  this->AllocateTexture(context, viewsize, this->LICImage, vtkTextureObject::Nearest);
  this->AllocateTexture(context, viewsize, this->RGBColorImage, vtkTextureObject::Nearest);
  this->AllocateTexture(context, viewsize, this->HSLColorImage, vtkTextureObject::Nearest);
}

// Description:
// Allocate a size texture, store in the given smart pointer.
void vtkSurfaceLICHelper::AllocateTexture(
  vtkOpenGLRenderWindow* context, int* viewsize, vtkSmartPointer<vtkTextureObject>& tex, int filter)
{
  if (!tex)
  {
    vtkTextureObject* newTex = vtkTextureObject::New();
    newTex->SetContext(context);
    newTex->SetBaseLevel(0);
    newTex->SetMaxLevel(0);
    newTex->SetWrapS(vtkTextureObject::ClampToEdge);
    newTex->SetWrapT(vtkTextureObject::ClampToEdge);
    newTex->SetMinificationFilter(filter);
    newTex->SetMagnificationFilter(filter);
    newTex->SetBorderColor(0.0f, 0.0f, 0.0f, 0.0f);
    newTex->Create2D(viewsize[0], viewsize[1], 4, VTK_FLOAT, false);
    newTex->SetAutoParameters(0);
    tex = newTex;
    newTex->Delete();
  }
}

// Description:
// Allocate a size texture, store in the given smart pointer.
void vtkSurfaceLICHelper::AllocateDepthTexture(
  vtkOpenGLRenderWindow* context, int* viewsize, vtkSmartPointer<vtkTextureObject>& tex)
{
  if (!tex)
  {
    vtkTextureObject* newTex = vtkTextureObject::New();
    newTex->SetContext(context);
    newTex->AllocateDepth(viewsize[0], viewsize[1], vtkTextureObject::Float32);
    newTex->SetAutoParameters(0);
    tex = newTex;
    newTex->Delete();
  }
}

// Description:
// After LIC has been computed reset/clean internal state
void vtkSurfaceLICHelper::Updated()
{
  this->ContextNeedsUpdate = false;
  this->CommunicatorNeedsUpdate = false;
}

// Description:
// Force all stages to re-execute. Necessary if the
// context or communicator changes.
void vtkSurfaceLICHelper::UpdateAll()
{
  this->ContextNeedsUpdate = true;
  this->CommunicatorNeedsUpdate = true;
}

// Description:
// Convert a viewport to a bounding box and it's texture coordinates for a
// screen size texture.
void vtkSurfaceLICHelper::ViewportQuadTextureCoords(
  const vtkPixelExtent& viewExt, const vtkPixelExtent& viewportExt, GLfloat* tcoords)
{
  GLfloat viewsize[2];
  viewExt.Size(viewsize);

  // cell to node
  vtkPixelExtent next(viewportExt);
  next.CellToNode();
  next.GetData(tcoords);

  tcoords[0] = tcoords[0] / viewsize[0];
  tcoords[1] = tcoords[1] / viewsize[0];
  tcoords[2] = tcoords[2] / viewsize[1];
  tcoords[3] = tcoords[3] / viewsize[1];
}

// Description:
// Render a quad (to trigger a shader to run)
void vtkSurfaceLICHelper::RenderQuad(
  const vtkPixelExtent& viewExt, const vtkPixelExtent& viewportExt, vtkOpenGLHelper* cbo)
{
  vtkOpenGLStaticCheckErrorMacro("failed at RenderQuad");

  // cell to node
  vtkPixelExtent next(viewportExt);
  next.CellToNode();

  GLfloat quadPts[4];
  next.GetData(quadPts);

  GLfloat quadTCoords[4];
  this->ViewportQuadTextureCoords(viewExt, viewportExt, quadTCoords);

  float tcoords[] = { quadTCoords[0], quadTCoords[2], quadTCoords[1], quadTCoords[2],
    quadTCoords[1], quadTCoords[3], quadTCoords[0], quadTCoords[3] };

  float verts[] = { quadTCoords[0] * 2.0f - 1.0f, quadTCoords[2] * 2.0f - 1.0f, 0.0f,
    quadTCoords[1] * 2.0f - 1.0f, quadTCoords[2] * 2.0f - 1.0f, 0.0f, quadTCoords[1] * 2.0f - 1.0f,
    quadTCoords[3] * 2.0f - 1.0f, 0.0f, quadTCoords[0] * 2.0f - 1.0f, quadTCoords[3] * 2.0f - 1.0f,
    0.0f };

  vtkOpenGLRenderUtilities::RenderQuad(verts, tcoords, cbo->Program, cbo->VAO);
  vtkOpenGLStaticCheckErrorMacro("failed at RenderQuad");
}

// Description:
// given a axes aligned bounding box in
// normalized device coordinates test for
// view frustum visibility.
// if all points are outside one of the
// view frustum planes then this box
// is not visible. we might have false
// positive where more than one clip
// plane intersects the box.
bool vtkSurfaceLICHelper::VisibilityTest(double ndcBBox[24])
{
  // check all points in the direction d
  // at the same time.
  for (int d = 0; d < 3; ++d)
  {
    if (((ndcBBox[d] < -1.0) && (ndcBBox[3 + d] < -1.0) && (ndcBBox[6 + d] < -1.0) &&
          (ndcBBox[9 + d] < -1.0) && (ndcBBox[12 + d] < -1.0) && (ndcBBox[15 + d] < -1.0) &&
          (ndcBBox[18 + d] < -1.0) && (ndcBBox[21 + d] < -1.0)) ||
      ((ndcBBox[d] > 1.0) && (ndcBBox[3 + d] > 1.0) && (ndcBBox[6 + d] > 1.0) &&
        (ndcBBox[9 + d] > 1.0) && (ndcBBox[12 + d] > 1.0) && (ndcBBox[15 + d] > 1.0) &&
        (ndcBBox[18 + d] > 1.0) && (ndcBBox[21 + d] > 1.0)))
    {
      return false;
    }
  }
  return true;
}

// Description:
// Given world space bounds,
// compute bounding boxes in clip and normalized device
// coordinates and perform view frustum visibility test.
// return true if the bounds are visible. If so the passed
// in extent object is initialized with the corresponding
// screen space extents.
bool vtkSurfaceLICHelper::ProjectBounds(
  double PMV[16], int viewsize[2], double bounds[6], vtkPixelExtent& screenExt)
{
  // this is how to get the 8 corners of a bounding
  // box from the VTK bounds
  int bbIds[24] = { 0, 2, 4, 1, 2, 4, 1, 3, 4, 0, 3, 4, 0, 2, 5, 1, 2, 5, 1, 3, 5, 0, 3, 5 };

  // normalized device coordinate bounding box
  double ndcBBox[24];
  for (int q = 0; q < 8; ++q)
  {
    int qq = 3 * q;
    // bounding box corner
    double wx = bounds[bbIds[qq]];
    double wy = bounds[bbIds[qq + 1]];
    double wz = bounds[bbIds[qq + 2]];
    // to clip coordinates
    ndcBBox[qq] = wx * PMV[idx(0, 0)] + wy * PMV[idx(0, 1)] + wz * PMV[idx(0, 2)] + PMV[idx(0, 3)];
    ndcBBox[qq + 1] =
      wx * PMV[idx(1, 0)] + wy * PMV[idx(1, 1)] + wz * PMV[idx(1, 2)] + PMV[idx(1, 3)];
    ndcBBox[qq + 2] =
      wx * PMV[idx(2, 0)] + wy * PMV[idx(2, 1)] + wz * PMV[idx(2, 2)] + PMV[idx(2, 3)];
    double ndcw = wx * PMV[idx(3, 0)] + wy * PMV[idx(3, 1)] + wz * PMV[idx(3, 2)] + PMV[idx(3, 3)];

    // TODO
    // if the point is past the near clipping plane
    // we need to do something more robust. this ensures
    // the correct result but its inefficient
    if (ndcw < 0.0)
    {
      screenExt = vtkPixelExtent(viewsize[0], viewsize[1]);
      // cerr << "W<0!!!!!!!!!!!!!" << endl;
      return true;
    }

    // to normalized device coordinates
    ndcw = (ndcw == 0.0 ? 1.0 : 1.0 / ndcw);
    ndcBBox[qq] *= ndcw;
    ndcBBox[qq + 1] *= ndcw;
    ndcBBox[qq + 2] *= ndcw;
  }

  // compute screen extent only if the object
  // is inside the view frustum.
  if (VisibilityTest(ndcBBox))
  {
    // these bounds are visible. compute screen
    // space exents
    double vx = viewsize[0] - 1.0;
    double vy = viewsize[1] - 1.0;
    double vx2 = viewsize[0] * 0.5;
    double vy2 = viewsize[1] * 0.5;
    vtkBoundingBox box;
    for (int q = 0; q < 8; ++q)
    {
      int qq = 3 * q;
      double sx = (ndcBBox[qq] + 1.0) * vx2;
      double sy = (ndcBBox[qq + 1] + 1.0) * vy2;
      box.AddPoint(vtkMath::ClampValue(sx, 0.0, vx), vtkMath::ClampValue(sy, 0.0, vy), 0.0);
    }
    // to screen extent
    const double* s0 = box.GetMinPoint();
    const double* s1 = box.GetMaxPoint();
    screenExt[0] = static_cast<int>(s0[0]);
    screenExt[1] = static_cast<int>(s1[0]);
    screenExt[2] = static_cast<int>(s0[1]);
    screenExt[3] = static_cast<int>(s1[1]);
    return true;
  }

  // these bounds aren't visible
  return false;
}

// Description:
// Compute screen space extents for each block in the input
// dataset and for the entire dataset. Only visible blocks
// are used in the computations.
int vtkSurfaceLICHelper::ProjectBounds(vtkRenderer* ren, vtkActor* actor, vtkDataObject* dobj,
  int viewsize[2], vtkPixelExtent& dataExt, std::deque<vtkPixelExtent>& blockExts)
{
  // get the modelview projection matrix
  vtkNew<vtkMatrix4x4> tmpMatrix;

  vtkOpenGLCamera* oglCam = vtkOpenGLCamera::SafeDownCast(ren->GetActiveCamera());
  vtkMatrix4x4* wcdc;
  vtkMatrix4x4* wcvc;
  vtkMatrix3x3* norms;
  vtkMatrix4x4* vcdc;
  oglCam->GetKeyMatrices(ren, wcvc, norms, vcdc, wcdc);

  if (!actor->GetIsIdentity())
  {
    vtkMatrix4x4* mcwc;
    vtkMatrix3x3* anorms;
    ((vtkOpenGLActor*)actor)->GetKeyMatrices(mcwc, anorms);
    vtkMatrix4x4::Multiply4x4(mcwc, wcdc, tmpMatrix);
  }
  else
  {
    tmpMatrix->DeepCopy(wcdc);
  }
  /*
    for ( int c = 0; c < 4; c ++ )
      {
      for ( int r = 0; r < 4; r ++ )
        {
        PMV[c*4+r]
          = P[idx(r,0)] * MV[idx(0,c)]
          + P[idx(r,1)] * MV[idx(1,c)]
          + P[idx(r,2)] * MV[idx(2,c)]
          + P[idx(r,3)] * MV[idx(3,c)];
        }
      }
  */
  // dataset case
  vtkDataSet* ds = dynamic_cast<vtkDataSet*>(dobj);
  if (ds && ds->GetNumberOfCells())
  {
    double bounds[6];
    ds->GetBounds(bounds);
    if (vtkBoundingBox::IsValid(bounds) &&
      this->ProjectBounds(tmpMatrix->Element[0], viewsize, bounds, dataExt))
    {
      // the dataset is visible
      // add its extent
      blockExts.push_back(dataExt);
      return 1;
    }
    // cerr << "ds " << ds << " not visible " << endl;
    return 0;
  }
  // composite dataset case
  vtkCompositeDataSet* cd = dynamic_cast<vtkCompositeDataSet*>(dobj);
  if (cd)
  {
    // process each block's bounds
    vtkBoundingBox bbox;
    vtkCompositeDataIterator* iter = cd->NewIterator();
    for (iter->InitTraversal(); !iter->IsDoneWithTraversal(); iter->GoToNextItem())
    {
      ds = dynamic_cast<vtkDataSet*>(iter->GetCurrentDataObject());
      if (ds && ds->GetNumberOfCells())
      {
        double bounds[6];
        ds->GetBounds(bounds);
        vtkPixelExtent screenExt;
        if (vtkBoundingBox::IsValid(bounds) &&
          this->ProjectBounds(tmpMatrix->Element[0], viewsize, bounds, screenExt))
        {
          // this block is visible
          // save it's screen extent
          // and accumulate its bounds
          blockExts.push_back(screenExt);
          bbox.AddBounds(bounds);
        }
        // else { cerr << "leaf " << ds << " not visible " << endl << endl;}
      }
    }
    iter->Delete();
    // process accumulated dataset bounds
    double bounds[6];
    bbox.GetBounds(bounds);
    if (vtkBoundingBox::IsValid(bounds) &&
      this->ProjectBounds(tmpMatrix->Element[0], viewsize, bounds, dataExt))
    {
      return 1;
    }
    return 0;
  }
  // cerr << "ds " << ds << " no cells " << endl;
  return 0;
}

// Description:
// Shrink an extent to tightly bound non-zero values
void vtkSurfaceLICHelper::GetPixelBounds(float* rgba, int ni, vtkPixelExtent& ext)
{
  vtkPixelExtent text;
  for (int j = ext[2]; j <= ext[3]; ++j)
  {
    for (int i = ext[0]; i <= ext[1]; ++i)
    {
      if (rgba[4 * (j * ni + i) + 3] > 0.0f)
      {
        text[0] = text[0] > i ? i : text[0];
        text[1] = text[1] < i ? i : text[1];
        text[2] = text[2] > j ? j : text[2];
        text[3] = text[3] < j ? j : text[3];
      }
    }
  }
  ext = text;
}

// Description:
// Shrink a set of extents to tightly bound non-zero values
// cull extent if it's empty
void vtkSurfaceLICHelper::GetPixelBounds(float* rgba, int ni, std::deque<vtkPixelExtent>& blockExts)
{
  std::vector<vtkPixelExtent> tmpExts(blockExts.begin(), blockExts.end());
  blockExts.clear();
  size_t nBlocks = tmpExts.size();
  for (size_t b = 0; b < nBlocks; ++b)
  {
    vtkPixelExtent& tmpExt = tmpExts[b];
    GetPixelBounds(rgba, ni, tmpExt);
    if (!tmpExt.Empty())
    {
      blockExts.push_back(tmpExt);
    }
  }
}