How to change layer depth according to player location?

Question

I would like to change the layer depth of objects, so that the player can go behind them. Right now it looks like this when the player is behind the object:

The problem is that the layer depth doesn't take into account the players location in relation to the object, so it doesn't look correct when the player is in front of the object:

What would be a good way to accomplish this? Could it be done just by comparing the locations of collision boxes (green boxes in the image) when they overlap? Or should I calculate and change the depth for all objects currently on-screen? How could I do that?

Thanks.

[UPDATE]

Here is the draw call from the base class for game objects:

public virtual void Draw(SpriteBatch spriteBatch) {

        if (texture != null && Active == true) {
            spriteBatch.Draw(texture, position, null, Color, 0f, Vector2.Zero, Scale, SpriteEffects.None, LayerDepth);
        }

        DrawCollision(spriteBatch); // DEBUG

}

It's an overload of the built-in MonoGame SpriteBatch.Draw() function. The thing that determines the draw order is LayerDepth. LayerDepth is a property inside each object. Currently it is just set to a fixed value.

Answer 1

Scale the shifted negated Y value to use as the LayerDepth.

Lower is nearest to screen.

Note: The following equations are not linear and may require adjustments to fit the runtime environment.

---

Define(all are float values):

• GroundY as the Y value in the middle of the green line signifying ground. (Per object)

• MinY the smallest GroundY value, back-most or highest on the screen, GroundY of any non-background object. (Once)

• MaxY the largest GroundY value, front-most or lowest on the screen, GroundY of any non-UI object.(Once)

• RangeY = MaxY - MinY + 100 The added 100(adjust this and the 50, 1/2 of 100 below as needed) pixel offset allows room for background parallax layers and UI layers.(Once, either static or in base object)

Set the LayerDepth value of all ground based objects:

LayerDepth = (GroundY - 50) / RangeY; 
// the 50 evenly divides the 100px/RangeY into:
// Foreground(UI) depth:  (0 to 50)/LayerDepth 
// Background depth: (MaxY to MaxY + 50)/LayerDepth

---

If the GroundY values are discrete, as in several distinct lanes:

Apply rounding to GroundY about (RangeY-100) / (NumberofLanes + 1).

LayerDepth = NumberofLanes * 

Math.Floor(0.48f + (GroundY -50)/ (RangeY-100) / (NumberofLanes + 1));
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