Method RasterizeLine

Rendering/Volume/vtkUnstructuredGridVolumeZSweepMapper.cxx:3803–4058

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//------------------------------------------------------------------------------
void vtkUnstructuredGridVolumeZSweepMapper::RasterizeLine(
  vtkVertexEntry* v0, vtkVertexEntry* v1, bool exitFace)
{
  assert("pre: v0_exists" && v0 != nullptr);
  assert("pre: v1_exists" && v1 != nullptr);
  assert("pre: y_ordered" && v0->GetScreenY() <= v1->GetScreenY());

  int lineCase;
  int xIncrement; // if true increment x, if false increment y
  int dx;
  int dy;
  int xSign;

  // initialization is not useful, it is just to remove compiler warnings
  int dx2 = 0;
  int dy2 = 0;
  int e = 0;

  double values[VTK_VALUES_SIZE];
  double pValues[VTK_VALUES_SIZE];

  double dPv[VTK_VALUES_SIZE];
  double dInvW;
  double dZ;

  double zView;
  double invW;

  int i;

  int x = v0->GetScreenX();
  int y = v0->GetScreenY();

  // 1. Find the case
  dx = v1->GetScreenX() - v0->GetScreenX();
  if (dx < 0)
  {
    dx = -dx;
    xSign = -1;
  }
  else
  {
    xSign = 1;
  }
  dy = v1->GetScreenY() - v0->GetScreenY();
  xIncrement = dx > dy;
  if (xIncrement)
  {
    if (dy == 0)
    {
      lineCase = VTK_LINE_CONSTANT;
    }
    else
    {
      lineCase = VTK_LINE_BRESENHAM;
      dx2 = dx << 1;
      dy2 = dy << 1;
      e = dx;