# WeightedTransformFilter

VTKExamples/CSharp/PolyData/WeightedTransformFilter

### Description

A tutorial on how to setup a Windows Forms Application utilizing ActiViz.NET can be found here: Setup a Windows Forms Application to use ActiViz.NET

### Code

WeightedTransformFilter.cs

    using System;
    using System.Collections.Generic;
    using System.ComponentModel;
    using System.Windows.Forms;
    using System.Diagnostics;

    using Kitware.VTK;

    namespace ActiViz.Examples {
       public partial class Form1 : Form {
          public Form1() {
             InitializeComponent();
          }

          private void renderWindowControl1_Load(object sender, EventArgs e) {
             try {
                WeightedTransformFilter();
             }
             catch(Exception ex) {
                MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK);
             }
          }

          private void WeightedTransformFilter() {
             // Use a sphere as a basis of the shape
             vtkSphereSource sphere = vtkSphereSource.New();
             sphere.SetPhiResolution(40);
             sphere.SetThetaResolution(40);
             sphere.Update();

             vtkPolyData sphereData = sphere.GetOutput();

             // Create a data array to hold the weighting coefficients
             vtkFloatArray tfarray = vtkFloatArray.New();
             int npoints = sphereData.GetNumberOfPoints();
             tfarray.SetNumberOfComponents(2);
             tfarray.SetNumberOfTuples(npoints);

             // Parameterize the sphere along the z axis, and fill the weights
             // with (1.0-a, a) to linearly interpolate across the shape
             IntPtr pPoint = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(double)) * 3);
             double[] point = new double[3];
             for(int i = 0; i < npoints; i++) {
                sphereData.GetPoint(i, pPoint);
                Marshal.Copy(pPoint, point, 0, 3);
                double x = point[0];
                double y = point[1];
                double z = point[2];

                double zn = z + 0.5;
                double zn1 = 1.0 - zn;
                if(zn > 1.0)
                   zn = 1.0;
                if(zn1 < 0.0)
                   zn1 = 0.0;

                tfarray.SetComponent(i, 0, zn1);
                tfarray.SetComponent(i, 1, zn);
             }
             Marshal.FreeHGlobal(pPoint);

             // Create field data to hold the array, and bind it to the sphere
             vtkFieldData fd = vtkFieldData.New();
             tfarray.SetName("weights");
             sphereData.GetPointData().AddArray(tfarray);

             // Use an ordinary transform to stretch the shape
             vtkTransform stretch = vtkTransform.New();
             stretch.Scale(1, 1, 3.2);

             vtkTransformFilter stretchFilter = vtkTransformFilter.New();
             stretchFilter.SetInputConnection(sphereData.GetProducerPort());
             stretchFilter.SetTransform(stretch);

             // Now, for the weighted transform stuff
             vtkWeightedTransformFilter weightedTrans = vtkWeightedTransformFilter.New();

             // Create two transforms to interpolate between
             vtkTransform identity = vtkTransform.New();
             identity.Identity();

             vtkTransform rotated = vtkTransform.New();
             double rotatedAngle = 45;
             rotated.RotateX(rotatedAngle);

             weightedTrans.SetNumberOfTransforms(2);
             weightedTrans.SetTransform(identity, 0);
             weightedTrans.SetTransform(rotated, 1);
             // which data array should the filter use ?
             weightedTrans.SetWeightArray("weights");

             weightedTrans.SetInputConnection(stretchFilter.GetOutputPort());

             vtkPolyDataMapper weightedTransMapper = vtkPolyDataMapper.New();
             weightedTransMapper.SetInputConnection(weightedTrans.GetOutputPort());
             vtkActor weightedTransActor = vtkActor.New();
             weightedTransActor.SetMapper(weightedTransMapper);
             weightedTransActor.GetProperty().SetDiffuseColor(0.8, 0.8, 0.1);
             weightedTransActor.GetProperty().SetRepresentationToSurface();

             // get a reference to the renderwindow of our renderWindowControl1
             vtkRenderWindow renderWindow = renderWindowControl1.RenderWindow;
             // renderer
             vtkRenderer renderer = renderWindow.GetRenderers().GetFirstRenderer();
             // set background color
             renderer.SetBackground(0.2, 0.3, 0.4);
             // add our actor to the renderer
             renderer.AddActor(weightedTransActor);

             renderer.ResetCamera();
             renderer.GetActiveCamera().Azimuth(90);
             renderer.GetActiveCamera().Dolly(1);
          }
       }
    }