Article Share,XNA,How to render light map in XNA(use 3ds Max 2008 and Panda

akira32

I wrote an artcile about rendering light map in XNA in my blog as below:
http://tw.myblog.yahoo.com/akira32-akira32/article?mid=290&prev=-1&next=287


Complete source code and max file in the web: http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/BlogYahoo/XNA/LightMapWindows%7C_.rar



Part1: Create 3D Models and their light map and render them with shader

Step1: (file: Content\step1,original material.max)

Add Box and Cylinder
Assign texture to them


Add directional light (Target Directional and enlarge the Hotspot/Beam)
shadows [V] on
"Ray Traced Shadows" or "Shadow Map"

Directinal Parameter:

use proper Hotspot/Beam



Step2: (file: Content\step2,render t texture.max)

Selected Box and Cylinder

Rendering>Render to Texture


Output Page
Add,LightingMap<=Add Elements
Taregt Map Slot: Self-Illumination

Backed Material Page
Output Into Source[V]

Objects to Bake Page
Mapping Coordinates Block
Object==>Use Automomatic Unwrap
Channel=2

Render<===click

Delete the light



Step3: (file: Content\step3,use shader.max)

Change Mterial to be Direct Shader and "Keep old material as sub-material"

Select the Shader of "Content\LightMapEffect.fx"

Assign the Diffuse Map and its Light Map and Select the "Technique1"

At Last,you can export the model by Panda plugin(http://www.andytather.co.uk/Panda/directxmax.aspx), the second uv coordinate will be wrote into FVFData block in XFile. Remember must enable the "Include .fx file" and "Include .fx parameters".





PS:

If you want to see the light map in 3ds max with Shader,you must use two optional steps as below:

Optional Step:

Materail Editor
Show Hardware Maps in Viewport






Optional Step:

Material
DirectX Manager
[V] Enable Plugin Material==>Light Map

DirectX Shader-LightMap
BasTexture: RedB.jpg [V]
Mapping channel=1

light map: cylinder01lightingmap.tga [V]
Mapping channel=2



Part2: LightMapWindows,

Step1:

Load model and measure its size

Add camera


namespace LightMapWindows
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class LightMap : Microsoft.Xna.Framework.Game
{
  GraphicsDeviceManager graphics;
  SpriteBatch spriteBatch;

  //add
  ContentManager content;
  BasicModel basicModel;
  Camera camera;

  public LightMap()
  {
   graphics = new GraphicsDeviceManager(this);
   Content.RootDirectory = "Content";

   //
   content = new ContentManager(Services);
   content.RootDirectory = "Content";

   IsMouseVisible = true;
  }

  protected override void LoadContent()
  {
   // Create a new SpriteBatch, which can be used to draw textures.
   spriteBatch = new SpriteBatch(GraphicsDevice);

   // TODO: use this.Content to load your game content here
   camera = new Camera(this);
   Components.Add(camera);

   basicModel = new BasicModel();
   basicModel.LoadModel(content, @"pillar");
   basicModel.MeasureModel();

   camera.SetSpeed(basicModel.GetModelRadius() / 100.0f);

   float modelRadius = basicModel.GetModelRadius();
   Vector3 modelCenter = basicModel.GetModelCenter();
   Vector3 eyePosition = modelCenter;

   eyePosition.Z += modelRadius * 2;
   eyePosition.Y += modelRadius;

   float aspectRatio = (float)Window.ClientBounds.Width / (float)Window.ClientBounds.Height;

   float nearClip = modelRadius / 100;
   float farClip = modelRadius * 100;

   camera.SetCamera(eyePosition, modelCenter, Vector3.Up);
   camera.SetFOV(MathHelper.PiOver4, aspectRatio, nearClip, farClip);   
  }






Step2: Render model with its effect instance

  protected override void Draw(GameTime gameTime)
  {
   GraphicsDevice.Clear(Color.CornflowerBlue);

   // TODO: Add your drawing code here

   basicModel.DrawLightMap(camera);
   //basicModel.Draw(camera);//basic effect

   base.Draw(gameTime);
  }





namespace AkBasicModel
{
    class BasicModel
    {

......

  public void DrawLightMap(Camera camera)
  {
   //Set transfroms
   Matrix[] transforms = new Matrix[m_model.Bones.Count];
   m_model.CopyAbsoluteBoneTransformsTo(transforms);

   //Loop through meshes and their effects
   foreach (ModelMesh mesh in m_model.Meshes)
   {
    foreach (Effect effect in mesh.Effects)
    {
     //Set BasicEffect information
     effect.CurrentTechnique = effect.Techniques["Technique1"];
     effect.Begin();
     effect.Parameters["World"].SetValue(GetWorld() * transforms[mesh.ParentBone.Index]);
     effect.Parameters["View"].SetValue(camera.view);
     effect.Parameters[&quotrojection"].SetValue(camera.projection);
     effect.End();
    }
    //Draw
    mesh.Draw();
   }
  }