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Course 3D_MDX: 3D-Graphics with Managed DirectX 9.0
Chapter C2: Cylinder with Directional Light

Copyright © by V. Miszalok, last update: 26-04-2007

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  Projekt lights1
  Form1, OnResize, OnTimer

Project lights1

This chapter is a summary of a Direct3D-Tutorial from Microsoft: Tutorial4. You find the tutorial here: C:\DXSDK\Samples\Managed\Direct3D\Tutorials.

Main Menu after starting VS 2008: File → New Project... → Visual Studio installed templates: Windows Forms Application
Name: lights1 → Location: C:\temp → Create directory for solution:
switch it off → OK
Delete the files Program.cs and Form1.Designer.cs and the content of Form1.cs, as described in the chapters 2DCisC1 to 2DCisC4.

If You find no Solution Explorer-window, open it via the main menu: View → Solution Explorer.
Inside the Solution Explorer-window click the plus-sign in front of lights1. A tree opens. Look for the branch "References". Right-click References and left-click Add Reference.... An Add Reference dialog box opens. Scroll down to the component name: Microsoft.DirectX Version 1.0.2902.0.
Highlight this reference by a left-click and (holding the Strg-key pressed) the reference Microsoft.DirectX.Direct3D Version 1.0.2902.0 somewhere below. Quit the Add Reference dialog box with OK.
Check if both references Microsoft.DirectX and Microsoft.DirectX.Direct3D are now visible inside the Solution Explorer window underneath lights1 → References.

If You use Visual Studio 2008 Professional You should switch off the vexatious automatic format- and indent- mechanism of the code editor before You copy the following code to Form1.cs (otherwise all the code will be reformatted into chaos):
1. Main menu of Visual Studio 2008 Professional: click menu "Tools".
2. A DropDown-menu appears. Click "Options...".
3. An Options dialog box appears.
4. Click the branch "Projects and Solutions". Click "General". Redirect all three paths to C:\temp.
5. Click the branch "Text Editor", then click "C#".
6. A sub-tree appears with the branches "General, Tabs, Advanced, Formatting, IntelliSense".
7. Click "Tabs". Change "Indenting" to None, "Tab size" and "Indent size" to 1 and switch on the option "Insert spaces".
8. Inside the sub-tree "C#" click the plus-sign in front of "Formatting" and change all "Formatting"-branches as follows:
"General": switch off all CheckBoxes, "Indentation": switch off all CheckBoxes, "New Lines": switch off all CheckBoxes, "Spacing": switch off all CheckBoxes, "Wrapping": switch on both CheckBoxes.
9. Leave the dialog box with button "OK".


Form1, OnResize, OnTimer

Write the following code to Form1.cs:

using System;
using System.Drawing;
using System.Windows.Forms;
using Microsoft.DirectX;
using Microsoft.DirectX.Direct3D;

public class Form1 : Form
{ [STAThread] static void Main() { Application.Run( new Form1() ); }
  static Device device = null;
  static float fAngle;
  VertexBuffer vertexBuffer;
  const int N = 100; //N must be an even no. 6, 8, 10, etc
  CustomVertex.PositionNormal[] vv = new CustomVertex.PositionNormal[N];
  Timer myTimer = new Timer();
  public Form1()
  { Text = "D3DLights";
    //TriangleStrip forming a cylinder
    //radius = 1; axis = Z-axis; top = 1; bottom = -1; => height = 2;
    //in order to see the vertices, replace the TriangleStrip by a LineStrip in OnTimer(...)
    float arcus_increment = (float)( 2 * Math.PI / (N-2) );
    Vector3 v = new Vector3();
    for (int i = 0; i < N; i++) //Fill up coordinates and normal vectors
    { float arcus = i * arcus_increment;
      v.X = (float)Math.Cos( arcus );
      v.Y = (float)Math.Sin( arcus );
      if ( i%2 == 0 ) v.Z =  1f;
      else            v.Z = -1f; //zigzag between top and bottom
      vv[ i ].Position = v; //vertex = (cos,sin,+1) or (cos,sin,-1)
      v.Z =  0;             //cylinder normals are parallel to the xy-plane
      vv[ i ].Normal   = v; //normal = (cos,sin,0)
    //set up the timer
    myTimer.Tick += new EventHandler( OnTimer );
    myTimer.Interval = 1;
    ClientSize = new Size( 400, 300 ); //Calls OnResize( ... )

  protected override void OnResize( System.EventArgs e )
  //Whenever the window changes we have to initialize Direct3D from scratch
  { myTimer.Stop();// stop the timer during initialization
    { //get information from the operating system about its current graphics properties
      PresentParameters presentParams = new PresentParameters();
      //we have to set two flags
      presentParams.Windowed = true;                 //no full screen display
      presentParams.SwapEffect = SwapEffect.Discard; //no swap buffer
      presentParams.EnableAutoDepthStencil = true;   //with depth buffer
      presentParams.AutoDepthStencilFormat = DepthFormat.D16; //16 bit depth
      //Create a new D3D-device that serves as canvas.
      if ( device != null ) device.Dispose(); //free the old canvas if any
      device = new Device( 0, DeviceType.Hardware, this,
                           CreateFlags.SoftwareVertexProcessing, presentParams );
      //Create a white material.
      Material mtrl = new Material();
      mtrl.Diffuse = mtrl.Ambient = Color.White;
      device.Material = mtrl;
      //Create a single, white, directional, diffuse light source and a gray ambient light.
      //Many lights may be active at a time. (Notice: Each one slows down the render process.)
      device.Lights[0].Type = LightType.Directional;
      device.Lights[0].Diffuse = System.Drawing.Color.DarkTurquoise;
      device.Lights[0].Direction = new Vector3( 1, 1, 5 );
      device.Lights[0].Enabled = true;//turn it on
      //Finally, turn on some ambient light that scatters and lights the object evenly
      device.RenderState.Ambient = System.Drawing.Color.FromArgb( 0x202020 );
      //set up the transformation of world coordinates into camera or view space
      device.Transform.View = Matrix.LookAtLH(
        new Vector3( 0f, 0f,-4f ),   //eye point 4.0 in front of the canvas
        new Vector3( 0f, 0f, 0f ),   //camera looks at point 0,0,0
        new Vector3( 0f, 1f, 0f ) ); //world's up direction is the y-axis
      //set up the projection transformation using 4 parameters:
      //1.: field of view = 45 degrees; 2.: aspect ratio = width / height = 1 = square window;
      //3.: near clipping distance = 1; 4.: far clipping distance = 10;
      device.Transform.Projection = Matrix.PerspectiveFovLH( (float)Math.PI/4, 1f, 1f, 10f );
      device.RenderState.CullMode = Cull.None;
      device.RenderState.Lighting = true;
      device.VertexFormat = CustomVertex.PositionNormal.Format;
      //create a new vertex buffer and connect it to the device
      if ( vertexBuffer != null ) vertexBuffer.Dispose();//free the old vertexBuffer if any
      vertexBuffer = new VertexBuffer( typeof(CustomVertex.PositionNormal), N,
                                       device, 0, CustomVertex.PositionNormal.Format,
                                       Pool.Default );
      //copy the coordinates and colors of "vv" into the vertex buffer
      vertexBuffer.SetData( vv, 0, LockFlags.None );
      device.SetStreamSource( 0, vertexBuffer, 0 );
      myTimer.Start();//start the timer again
    catch (DirectXException) { MessageBox.Show("Could not initialize Direct3D."); return; }

  protected static void OnTimer( Object myObject, EventArgs myEventArgs )
  { if (device == null) return;
    //throw the old image away
    device.Clear( ClearFlags.Target | ClearFlags.ZBuffer, Color.Blue, 1f, 0 );
    //rotate with an angular velocity = 5.7o/timer event
    fAngle += 0.1f;
    device.Transform.World = Matrix.RotationAxis( new Vector3(1, 1, 1), fAngle );
    //draw on the canvas
      device.DrawPrimitives( PrimitiveType.TriangleStrip, 0, N-2 );
      //Experiment: Replace the TriangleStrip by a LineStrip as follows:
      //device.DrawPrimitives( PrimitiveType.LineStrip, 0, N-2 );
    device.Present(); //show the canvas

Click DebugStart Without Debugging Ctrl F5. Try to drag all window borders.



1. In the 5th next to the last line of protected static void OnTimer( Object myObject, EventArgs myEventArgs ) replace TriangleStrip by LineStrip and try out how the vertex framework changes when You vary the constant N (in the 5th line of the class declaration of Form1) from 6 to 8, to 12, to 48 etc. to 100.
2. Slow the animation down by increasing myTimer.Interval = 100; inside the constructor.
3. Accelerate the animation by increasing fAngle += 0.5f; in OnTimer.
4. Rotate the cylinder around other axes as (1,1,1) in OnTimer.
5. Light the cylinder with another diffuse color.
6. Light the cylinder with another ambient color.
7. Vary the position of the light source: from top only, from bottom only, from left only etc.
8. Step back with the eye point from ( 0f, 0f,-4f ) to ( 0f, 0f,-100f ) and get closer with ( 0f, 0f,-2f ).
9. Read the comments C3DCisC2_Comment.htm and try to understand the sense of the code lines.
10. You can find more explanations and comments about this chapter here: http://msdn.microsoft.com/en-us/library/default.aspx.
Caution: Mozilla Firefox doesn't correctly display the tree on the left side. Use the Internet Explorer here !
Click trough the tree on the left side:
Win32 and COM Development → Graphics and Multimedia DirectX SDK Documentation DirectX SDK Managed DirectX SDK Introducing DirectX 9.0 Direct3D Graphics Getting Started with Direct3D Direct3D Tutorials Tutorial 4: Using Materials and Lights.

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