cirnogodot/Scripts/Components/Actors/MouseAimProvider3D.cs

using Cirno.Scripts.Misc;
using Godot;

namespace Cirno.Scripts.Components.Actors;

public partial class MouseAimProvider3D : Node3D, IMouseAimProvider
{
    private Viewport _viewport;

    public override void _Ready()
    {
        _viewport = GetViewport();
    }
    
    public Vector2 GetMouseAimInput()
    {
        var mouseWorldPos = GetMouseWorldPosition(this.GlobalPosition.Y);
        
        var direction = (mouseWorldPos - this.GlobalPosition).Normalized();
        
        return new Vector2(direction.X, direction.Z);
    }

    public Vector3 GetMouseWorldPosition(float planeHeight = 0)
    {
        var mousePos = _viewport.GetMousePosition();
        var rayOrigin = CameraController3D.Instance.ProjectRayOrigin(mousePos);
        var rayDirection = CameraController3D.Instance.ProjectRayNormal(mousePos);

        var plane = new Plane(Vector3.Up, planeHeight);
        
        var intersection = plane.IntersectsRay(rayOrigin, rayDirection);

        return intersection ?? Vector3.Zero;
    }
}