Function Init

Rendering/Volume/vtkUnstructuredGridVolumeZSweepMapper.cxx:254–694

Initialize the edge by the vertices v0 and v2 (ordered in y) `onRight' is true if the edge in on the right side of the triangle.

  // Initialize the edge by the vertices v0 and v2 (ordered in y)
  // `onRight' is true if the edge in on the right side of the triangle.
  void Init(vtkVertexEntry* v0, vtkVertexEntry* v2, int dx20, int dy20, int onRight)
  {
    double z0 = v0->GetZview();
    double z2 = v2->GetZview();

    double invW0 = v0->GetInvW();
    double invW2 = v2->GetInvW();

    double pv0[VTK_VALUES_SIZE];
    double pv2[VTK_VALUES_SIZE];
    int i = 0;
    while (i < VTK_VALUES_SIZE)
    {
      pv0[i] = v0->GetValues()[i] * invW0;
      this->PValues[i] = pv0[i];
      pv2[i] = v2->GetValues()[i] * invW2;
      ++i;
    }

    this->InvW = invW0;
    this->Zview = z0;

    int x0 = v0->GetScreenX();
    int x2 = v2->GetScreenX();

    this->X0 = x0;
    this->X2 = x2;

    this->V2 = v2;

    this->X = x0;

    if (dx20 == 0)
    {
      this->Case = VTK_CASE_VERTICAL;
      double invDy20 = 1.0 / dy20;
      i = 0;
      while (i < VTK_VALUES_SIZE)
      {
        this->Dpv[i] = (pv2[i] - pv0[i]) * invDy20;
        ++i;
      }
      this->DinvW = (invW2 - invW0) * invDy20;
      this->Dz = (z2 - z0) * invDy20;
    }
    else
    {
      if (dx20 > 0)
      {
        this->IncX = 1;
        if (dx20 > dy20)
        {
          // Mostly horizontal
#ifdef HORI_EDGE_EQUATION
          if (onRight)
          {
            this->Case = VTK_CASE_HORIZONTAL_IN_TO_OUT;
          }