# ElevationFilter

VTKExamples/CSharp/Meshes/ElevationFilter

### 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
Note: As long as ActiViz.NET is not build with VTK version 6.0 or higher you must define the preprocessor directive VTK_MAJOR_VERSION_5.

### Code

ElevationFilter.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 {
                ElevationFilter();
             }
             catch(Exception ex) {
                MessageBox.Show(ex.Message, "Exception", MessageBoxButtons.OK);
             }
          }

          private void ElevationFilter() {
             // Created a grid of points (heigh/terrian map)
             vtkPoints points = vtkPoints.New();

             uint GridSize = 10;
             for(uint x = 0; x < GridSize; x++) {
                for(uint y = 0; y < GridSize; y++) {
                   points.InsertNextPoint(x, y, ( x + y ) / ( y + 1 ));
                }
             }
             double[] bounds = points.GetBounds();

             // Add the grid points to a polydata object
             vtkPolyData inputPolyData = vtkPolyData.New();
             inputPolyData.SetPoints(points);

             // Triangulate the grid points
             vtkDelaunay2D delaunay = vtkDelaunay2D.New();
    #if VTK_MAJOR_VERSION_5
             delaunay.SetInput(inputPolyData);
    #else
             delaunay.SetInputData(inputPolyData);
    #endif
             delaunay.Update();

             vtkElevationFilter elevationFilter = vtkElevationFilter.New();
             elevationFilter.SetInputConnection(delaunay.GetOutputPort());
             elevationFilter.SetLowPoint(0.0, 0.0, bounds[4]);
             elevationFilter.SetHighPoint(0.0, 0.0, bounds[5]);
             elevationFilter.Update();

             vtkPolyData output = vtkPolyData.New();
             output.ShallowCopy(vtkPolyData.SafeDownCast(elevationFilter.GetOutput()));

             vtkFloatArray elevation =
                vtkFloatArray.SafeDownCast(output.GetPointData().GetArray("Elevation"));

             // Create the color map
             vtkLookupTable colorLookupTable = vtkLookupTable.New();
             colorLookupTable.SetTableRange(bounds[4], bounds[5]);
             colorLookupTable.Build();

             // Generate the colors for each point based on the color map
             vtkUnsignedCharArray colors = vtkUnsignedCharArray.New();
             colors.SetNumberOfComponents(3);
             colors.SetName("Colors");

             for(int i = 0; i < output.GetNumberOfPoints(); i++) {
                double val = elevation.GetValue(i);
                Debug.WriteLine("val: " + val);

                double[] dcolor = colorLookupTable.GetColor(val);
                //Debug.WriteLine("dcolor: "
                //          + dcolor[0] + " "
                //          + dcolor[1] + " "
                //          + dcolor[2]);
                byte[] color = new byte[3];
                for(int j = 0; j < 3; j++) {
                   color[j] = (byte)( 255 * dcolor[j]);
                }
                //Debug.WriteLine("color: "
                //          + color[0] + " "
                //          + color[1] + " "
                //          + color[2]);

                colors.InsertNextTuple3(color[0], color[1], color[2]);
             }

             output.GetPointData().AddArray(colors);

             // Visualize
             vtkPolyDataMapper mapper = vtkPolyDataMapper.New();
    #if VTK_MAJOR_VERSION_5
             mapper.SetInputConnection(output.GetProducerPort());
    #else
             mapper.SetInputData(output);
    #endif

             vtkActor actor = vtkActor.New();
             actor.SetMapper(mapper);

             // 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(actor);
          }
       }
    }