TransformOrderDemo

VTKExamples/Cxx/PolyData/TransformOrderDemo

<a href="https://github.com/lorensen/VTKExamples/blob/master/src/Testing/Baseline/Cxx/PolyData/TestTransformOrderDemo.png?raw=true%20target=" _blank"="" style="box-sizing: inherit; -webkit-tap-highlight-color: transparent; color: rgb(63, 81, 181); word-break: break-word; transition: color 0.125s;">

Description¶

This example creates an image. In the left viewport, it translates the image, then translates and rotates the image. In the right viewport, it rotates the image, then rotates and translates the image. One can see that the result is clearly not the same!

Code¶

TransformOrderDemo.cxx

#include
 
 <vtkSmartPointer.h>
#include <vtkTransform.h>
#include <vtkAxesActor.h>
#include <vtkRenderer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkImageMandelbrotSource.h>
#include <vtkImageActor.h>
#include <vtkImageMapper3D.h>
 

#include <vtkImageCast.h>

int main(int, char *[])
{
  // Create an image
  vtkSmartPointer<vtkImageMandelbrotSource> source =
    vtkSmartPointer<vtkImageMandelbrotSource>::New();
  source->Update();

  vtkSmartPointer<vtkImageCast> castFilter =
    vtkSmartPointer<vtkImageCast>::New();
  castFilter->SetInputConnection(source->GetOutputPort());
  castFilter->SetOutputScalarTypeToUnsignedChar();
  castFilter->Update();

  // Create an actor
  vtkSmartPointer<vtkImageActor> actor1a =
    vtkSmartPointer<vtkImageActor>::New();
  actor1a->GetMapper()->SetInputConnection(castFilter->GetOutputPort());
  vtkSmartPointer<vtkImageActor> actor1b =
    vtkSmartPointer<vtkImageActor>::New();
  actor1b->GetMapper()->SetInputConnection(castFilter->GetOutputPort());

  vtkSmartPointer<vtkImageActor> actor2a =
    vtkSmartPointer<vtkImageActor>::New();
  actor2a->GetMapper()->SetInputConnection(castFilter->GetOutputPort());

  vtkSmartPointer<vtkImageActor> actor2b =
    vtkSmartPointer<vtkImageActor>::New();
  actor2b->GetMapper()->SetInputConnection(castFilter->GetOutputPort());

  // Create the transformation
  vtkSmartPointer<vtkTransform> transform1a =
    vtkSmartPointer<vtkTransform>::New();
  transform1a->PostMultiply();
  transform1a->Translate(10.0, 0.0, 0.0);
  actor1a->SetUserTransform(transform1a);

  vtkSmartPointer<vtkTransform> transform1b =
    vtkSmartPointer<vtkTransform>::New();
  transform1b->PostMultiply();
  transform1b->Translate(10.0, 0.0, 0.0);
  transform1b->RotateZ(40.0);
  actor1b->SetUserTransform(transform1b);

  vtkSmartPointer<vtkTransform> transform2a =
    vtkSmartPointer<vtkTransform>::New();
  transform2a->PostMultiply();
  transform2a->RotateZ(40.0);
  actor2a->SetUserTransform(transform2a);

  vtkSmartPointer<vtkTransform> transform2b =
    vtkSmartPointer<vtkTransform>::New();
  transform2b->PostMultiply();
  transform2b->RotateZ(40.0);
  transform2b->Translate(10.0, 0.0, 0.0);
  actor2b->SetUserTransform(transform2b);

  // Define viewport ranges
  // (xmin, ymin, xmax, ymax)
  double leftViewport[4] = {0.0, 0.0, 0.5, 1.0};
  double rightViewport[4] = {0.5, 0.0, 1.0, 1.0};

  // Cetup render window
  vtkSmartPointer<vtkRenderWindow> renderWindow =
    vtkSmartPointer<vtkRenderWindow>::New();

  // Setup both renderers
  vtkSmartPointer<vtkRenderer> leftRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(leftRenderer);
  leftRenderer->SetViewport(leftViewport);
  leftRenderer->SetBackground(.6, .5, .4);

  vtkSmartPointer<vtkRenderer> rightRenderer =
    vtkSmartPointer<vtkRenderer>::New();
  renderWindow->AddRenderer(rightRenderer);
  rightRenderer->SetViewport(rightViewport);
  rightRenderer->SetBackground(.4, .5, .6);  

  // an interactor
  vtkSmartPointer<vtkRenderWindowInteractor> interactor =
    vtkSmartPointer<vtkRenderWindowInteractor>::New();

  interactor->SetRenderWindow(renderWindow);

  vtkSmartPointer<vtkAxesActor> axes =
    vtkSmartPointer<vtkAxesActor>::New();
  axes->AxisLabelsOff();
  axes->SetTotalLength(5,5,5);

  leftRenderer->AddActor(axes);
  leftRenderer->AddActor(actor1a);
  leftRenderer->AddActor(actor1b);

  rightRenderer->AddActor(axes);
  rightRenderer->AddActor(actor2a);
  rightRenderer->AddActor(actor2b);

  leftRenderer->ResetCamera();
  rightRenderer->ResetCamera();

  renderWindow->Render();

  interactor->Start();

  return EXIT_SUCCESS;
}