How to manage depth with a lot of layers of Texture2D

Question

Within my game, I have to manage a lot of objects. Every object has Depth value that will be used when calling its draw function.

Every object is created with a layer-system:

Layer1: obj1 - obj2 - obj3 - obj4
Layer2: obj1 - obj2 - obj3 - obj4
Layer3: obj1 - obj2 - obj3 - obj4
Layer4: obj1 - obj2 - obj3 - obj4
ecc.

A Layer is just a list of objects.

My problem is how to manage every Depth of every layer.

From a higher level, Layer1 is on top of Layer2,Layer3,Layer4; Layer2 is bottom of Layer1 but on top of Layer3,Layer4. So, considering that the Depth value in the draw call is a value between 0 and 1, I just assigned to every level a value starting from 0, to 1, step 0.01. In this way I will have max 100 layers.

Now I need to define an order of Depth also within layers, so for every object: Layer1.obj1 is on top of obj2, obj3, obj4, but also on top of Layer2.obj1, Layer2.obj2 ecc.

How can I achieve this?

Answer 1

enum LayerState : byte
{
    One,
    Two,
    Three,
    Four
}
void DrawLayer(LayerState state)
{
    switch (state)
    {
        case One:
          foreach (object obj in Layer1)
            SpriteBatch.Draw(obj);
        break;
        case Two:
          foreach (object obj in Layer2)
            SpriteBatch.Draw(obj);
        break;
        case Three:
          foreach (object obj in Layer3)
            SpriteBatch.Draw(obj);
        break;
        case Four:
          foreach (object obj in Layer4)
            SpriteBatch.Draw(obj);
        break;
     }
}

public override void Draw()
{
   SpriteBatch.Begin();
   DrawLayer(LayerState.Two) // play with states for result
   SpriteBatch.End();
   SpriteBatch.Begin();
   DrawLayer(LayerState.One) // play with states for result
   SpriteBatch.End();
   SpriteBatch.Begin();
   DrawLayer(LayerState.Three) // play with states for result
   SpriteBatch.End();
   SpriteBatch.Begin();
   DrawLayer(LayerState.Four) // play with states for result
   SpriteBatch.End();
}

I'm sorry if it doesn't work. Just suggest. I think void DrawLayer() will manage Layers depth depends of LayerState and sprite batches manage layers' objects.

Answer 2

You could further subdivide your 0.01 increments on your depth.

Alternatively you could simply use the draw order to decide what is drawn on top of other things?