DistanceToCamera

VTKExamples/Java/Visualization/DistanceToCamera


Description

This example produces two arrows whose scale stays fixed with respect to the distance from the camera (i.e. as you zoom in and out). Standard spheres are drawn for comparison.

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Question

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Code

DistanceToCamera.java

import vtk.vtkActor;
import vtk.vtkNamedColors;
import vtk.vtkNativeLibrary;
import vtk.vtkPolyDataMapper;
import vtk.vtkRenderWindow;
import vtk.vtkRenderWindowInteractor;
import vtk.vtkRenderer;
import vtk.vtkPointSource;
import vtk.vtkDistanceToCamera;
import vtk.vtkArrowSource;
import vtk.vtkGlyph3D;
import vtk.vtkInteractorStyleTrackballCamera;
import vtk.vtkSphereSource;

public class DistanceToCamera 
{
  // -----------------------------------------------------------------
  // Load VTK library and print which library was not properly loaded
  static 
  {
    if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
    {
      for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
      {
        if (!lib.IsLoaded()) 
        {
          System.out.println(lib.GetLibraryName() + " not loaded");
        }
      }
    }
    vtkNativeLibrary.DisableOutputWindow(null);
  }
  // -----------------------------------------------------------------

  public static void main(String args[]) 
  {
    vtkNamedColors colors = new vtkNamedColors();

    //For fixedActor Color
    double fixedActorColor[] = new double[4];
    //For sphereActor Color
    double sphereActorColor[] = new double[4];
    //Renderer Background Color
    double Bgcolor[] = new double[4];

    colors.GetColor("Aqua", fixedActorColor);
    colors.GetColor("Yellow",sphereActorColor);
    colors.GetColor("White", Bgcolor);

    // Draw some arrows that maintain a fixed size during zooming.
    // Create a set of points.
    vtkPointSource fixedPointSource = new vtkPointSource();
    fixedPointSource.SetNumberOfPoints(2);

    // Calculate the distance to the camera of each point.
    vtkDistanceToCamera distanceToCamera = new vtkDistanceToCamera();
    distanceToCamera.SetInputConnection(fixedPointSource.GetOutputPort());
    distanceToCamera.SetScreenSize(100.0);

    // Glyph each point with an arrow.
    vtkArrowSource arrow = new vtkArrowSource();
    vtkGlyph3D fixedGlyph = new vtkGlyph3D();
    fixedGlyph.SetInputConnection(distanceToCamera.GetOutputPort());
    fixedGlyph.SetSourceConnection(arrow.GetOutputPort());

    // Scale each point.
    fixedGlyph.SetScaleModeToScaleByScalar();
    fixedGlyph.SetInputArrayToProcess(0, 0, 0, 0, "DistanceToCamera");

    // Create a mapper.
    vtkPolyDataMapper fixedMapper = new vtkPolyDataMapper();
    fixedMapper.SetInputConnection(fixedGlyph.GetOutputPort());
    fixedMapper.SetScalarVisibility(0);

    // Create an actor.
    vtkActor fixedActor = new vtkActor();
    fixedActor.SetMapper(fixedMapper);
    fixedActor.GetProperty().SetColor(fixedActorColor);

    // Draw some spheres that get bigger when zooming in.
    // Create a set of points.
    vtkPointSource pointSource = new vtkPointSource();
    pointSource.SetNumberOfPoints(4);

    // Glyph each point with a sphere.
    vtkSphereSource sphere = new vtkSphereSource();
    vtkGlyph3D glyph = new vtkGlyph3D();
    glyph.SetInputConnection(pointSource.GetOutputPort());
    glyph.SetSourceConnection(sphere.GetOutputPort());
    glyph.SetScaleFactor(0.1);

    // Create a mapper.
    vtkPolyDataMapper mapper = new vtkPolyDataMapper();
    mapper.SetInputConnection(glyph.GetOutputPort());
    mapper.SetScalarVisibility(0);

    // Create an actor.
    vtkActor actor = new vtkActor();
    actor.SetMapper(mapper);
    actor.GetProperty().SetColor(sphereActorColor);

    // Create the renderer, render window and interactor.
    vtkRenderer ren = new vtkRenderer();
    ren.SetBackground(Bgcolor);

    vtkRenderWindow renWin = new vtkRenderWindow();
    renWin.AddRenderer(ren);

    // Give DistanceToCamera a pointer to the renderer.
    distanceToCamera.SetRenderer(ren);

    // Visualize
    ren.AddActor(fixedActor);
    ren.AddActor(actor);

    vtkRenderWindowInteractor iren = new vtkRenderWindowInteractor();
    iren.SetRenderWindow(renWin);

    vtkInteractorStyleTrackballCamera style = new vtkInteractorStyleTrackballCamera();
    iren.SetInteractorStyle(style);
    iren.SetRenderWindow(renWin);

    renWin.Render();

    iren.Initialize();
    iren.Start();
  }
}