cirnogodot/Scripts/Components/FSM/3DPlayer/ShadowModule.cs

using Godot;

namespace Cirno.Scripts.Components.FSM._3DPlayer;

public partial class ShadowModule : ModuleBase<PlayerState, CharacterBody3D>
{
    [Export] public NodePath ShadowPath;
    [Export] public float MaxShadowScale = 1.2f;
    [Export] public float MinShadowScale = 0.5f;
    [Export] public float MaxShadowHeight = 5f;

    private IStateMachine<PlayerState, CharacterBody3D> _machine;
    private CharacterBody3D MainObject => _machine.MainObject;
    
    [Export] public Node3D Shadow { get; private set; }
    
    [Export(PropertyHint.Layers3DPhysics)] public uint CollisionMask { get; set; }
    
    public override void EnterState(PlayerState state)
    {
        
    }

    public override void ExitState(PlayerState state)
    {
       
    }

    public override void Init(IStateMachine<PlayerState, CharacterBody3D> machine)
    {
        _machine = machine;
    }

    public override void Process(double delta)
    {
        
    }

    public override void PhysicsProcess(double delta)
    {
        if (Shadow == null) return;

        // Raycast down to get ground height
        Vector3 origin = MainObject.GlobalTransform.Origin;
        Vector3 from = origin + Vector3.Up * 0.5f;
        Vector3 to = origin + Vector3.Down * 20f;

        var spaceState = MainObject.GetWorld3D().DirectSpaceState;

        var result = spaceState.IntersectRay(new PhysicsRayQueryParameters3D
        {
            From = from,
            To = to,
            CollideWithBodies = true,
            CollisionMask = CollisionMask,
            Exclude = [MainObject.GetRid()]
        });
        
        if (result.Count > 0)
        {
            Vector3 groundPos = (Vector3)result["position"];
            float height = origin.Y - groundPos.Y;

            // Clamp and scale
            float t = Mathf.Clamp(height / MaxShadowHeight, 0f, 1f);
            float scale = Mathf.Lerp(MaxShadowScale, MinShadowScale, t);

            Shadow.GlobalPosition = new Vector3(origin.X, groundPos.Y + 0.01f, origin.Z);
            Shadow.Scale = new Vector3(scale, 1f, scale);
        }
        else
        {
            Shadow.Visible = false;
        }
    }
}