Method ComputeMatrix

Rendering/Core/vtkFollower.cxx:47–144

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//------------------------------------------------------------------------------
void vtkFollower::ComputeMatrix()
{
  // check whether or not need to rebuild the matrix
  if (this->GetMTime() > this->MatrixMTime ||
    (this->Camera && this->Camera->GetMTime() > this->MatrixMTime))
  {
    this->GetOrientation();
    this->Transform->Push();
    this->Transform->Identity();
    this->Transform->PostMultiply();

    this->Transform->Translate(-this->Origin[0], -this->Origin[1], -this->Origin[2]);
    // scale
    this->Transform->Scale(this->Scale[0], this->Scale[1], this->Scale[2]);

    // rotate
    this->Transform->RotateY(this->Orientation[1]);
    this->Transform->RotateX(this->Orientation[0]);
    this->Transform->RotateZ(this->Orientation[2]);

    if (this->Camera)
    {
      double *pos, *vup, distance;
      double Rx[3], Ry[3], Rz[3];

      vtkMatrix4x4* matrix = this->InternalMatrix;
      matrix->Identity();

      // do the rotation
      // first rotate y
      pos = this->Camera->GetPosition();
      vup = this->Camera->GetViewUp();

      if (this->Camera->GetParallelProjection())
      {
        this->Camera->GetDirectionOfProjection(Rz);
        Rz[0] = -Rz[0];
        Rz[1] = -Rz[1];
        Rz[2] = -Rz[2];
      }
      else
      {
        distance = sqrt((pos[0] - this->Position[0]) * (pos[0] - this->Position[0]) +
          (pos[1] - this->Position[1]) * (pos[1] - this->Position[1]) +
          (pos[2] - this->Position[2]) * (pos[2] - this->Position[2]));
        for (int i = 0; i < 3; i++)
        {
          Rz[i] = (pos[i] - this->Position[i]) / distance;
        }
      }

      // We cannot directly use the vup angle since it can be aligned with Rz:
      // vtkMath::Cross(vup,Rz,Rx);
      // vtkMath::Normalize(Rx);
      // vtkMath::Cross(Rz,Rx,Ry);

      // instead use the view right angle:
      double dop[3], vur[3];