Question

I got some problem with texture transparency, I hope ya can help.

Details:

• XNA 4.0

• Texture source is BMP, what I make transparent by code:

  public void Feketealapú(string Azonosító)
  {
    //textúra megállapítása
    Texture2D Textúra = Textúrák[TextúraSzáma(Azonosító)];
  
    //adatok lekérése
    Color[] buffer = new Color[Textúra.Width * Textúra.Height];
    Textúra.GetData<Color>(buffer);
  
    //adatok módosítása
    for (int i = 0; i < buffer.Length; i++)
    {
      Color szín = buffer[i];
      szín.A = ((byte)((szín.R + szín.B + szín.G) / 3));
      buffer[i] = szín;
    }
  
    //adatok visszaírása
    Textúra.SetData<Color>(buffer);
  }
  

• I use the following before I start drawing 3d stuff:

  public void Rajzolj()
  {
    GStatic.Játék.GrafikaiCsatorna.BlendState = BlendState.AlphaBlend;
    GStatic.Játék.GrafikaiCsatorna.DepthStencilState = DepthStencilState.Default;
    GStatic.Játék.GrafikaiCsatorna.RasterizerState = RasterizerState.CullCounterClockwise;
    GStatic.Játék.GrafikaiCsatorna.SamplerStates[0] = SamplerState.LinearWrap;
  

  ..etc.

• If I use BlendState.Opaque I get no transparent textures.

• I get into the following trouble: http://youtu.be/ZiPzyk7AWu8

• Edit: Bit more detail about the problem is: the problem is with the transparent texture, what simulates a fire effect. The fire is from several rectangles with these transparent textures. If I see the fire from an angle, I should see another fire effect’s rectangle through the transparent texture, what is also transparent. The problem is that instead of this, I see the floor’s texture behind the model instead.

So could someone help me out a bit?

Thanks in advance:
Péter

Answer 1

Never mind I don’t think the transparency is the issue. I think that whats happening is the first thing in the Z-Buffer is being draw and nothing else behind it.

http://blogs.msdn.com/b/shawnhar/archive/2009/02/18/depth-sorting-alpha-blended-objects.aspx

The most import part being the where he specifies how best to order your scene and manipulate the DepthBuffer.

1. Set DepthBufferEnable and DepthBufferWriteEnable to true
2. Draw all opaque geometry
3. Leave DepthBufferEnable set to true, but change DepthBufferWriteEnable to false
4. Sort alpha blended objects by distance from the camera, then draw them in order from back to front