GodotComponentTest/scenes/HexTile3D.cs

using Godot;

public class HexTile3D : Spatial
{
    public enum TileType
    {
        Sand,
        Grass,
        DeepGrass
    }
    static public TileType[] ValidTileTypes = { TileType.Sand, TileType.Grass, TileType.DeepGrass };

    // scene nodes
    private MeshInstance _mesh;
    private Area _area;
    
    // signals
    [Signal]
    delegate void TileSelected(HexTile3D tile3d);

    // other member variables
    private SpatialMaterial _sandMaterial;
    private SpatialMaterial _grassMaterial;
    private SpatialMaterial _deepGrassMaterial;
    private SpatialMaterial _previousMaterial;

    public HexCell Cell = new HexCell();
    public bool IsMouseOver = false;

    private TileType _type;
    public TileType Type
    {
        get
        {
            return _type;
        }

        set
        {
            _type = value;

            switch (_type)
            {
                case TileType.Sand: _mesh.SetSurfaceMaterial(0, _sandMaterial);
                    break;
                case TileType.Grass: _mesh.SetSurfaceMaterial(0, _grassMaterial);
                    break;
                case TileType.DeepGrass: _mesh.SetSurfaceMaterial(0, _deepGrassMaterial);
                    break;
                default:
                    GD.Print("Invalid tile type: " + value.ToString());
                    break;
            }
        }
    }

    // Called when the node enters the scene tree for the first time.
    public override void _Ready()
    {
        _mesh = GetNode<MeshInstance>("Mesh");
        _area = GetNode<Area>("Mesh/Area");

        _area.Connect("input_event", this, nameof(OnAreaInputEvent));
        _area.Connect("mouse_entered", this, nameof(OnAreaMouseEntered));
        _area.Connect("mouse_exited", this, nameof(OnAreaMouseExited));

        _sandMaterial = GD.Load<SpatialMaterial>("res://materials/SandTile.tres");
        _grassMaterial = GD.Load<SpatialMaterial>("res://materials/GrassTile.tres");
        _deepGrassMaterial = GD.Load<SpatialMaterial>("res://materials/DeepGrassTile.tres");

        this.Type = TileType.Grass;
    }

    
    public void OnAreaInputEvent(Node camera, InputEvent inputEvent, Vector3 position, Vector3 normal, int shapeIndex)
    {
        if (IsMouseOver && inputEvent is InputEventMouseButton)
        {
            InputEventMouseButton mouseButtonEvent = (InputEventMouseButton)inputEvent;
            if (mouseButtonEvent.ButtonIndex == 1 && mouseButtonEvent.Pressed)
            {
                EmitSignal("tile_selected", this);
            }
        }
    }

    public void OnAreaMouseEntered()
    {
        IsMouseOver = true;
        _previousMaterial = (SpatialMaterial)_mesh.MaterialOverride;

        SpatialMaterial clonedMaterial = (SpatialMaterial)_mesh.GetSurfaceMaterial(0).Duplicate();
        clonedMaterial.AlbedoColor = new Color(1, 0, 0);
        _mesh.MaterialOverride = clonedMaterial;
    }

    public void OnAreaMouseExited()
    {
        IsMouseOver = false;
        _mesh.MaterialOverride = _previousMaterial;
    }
    
//  // Called every frame. 'delta' is the elapsed time since the previous frame.
//  public override void _Process(float delta)
//  {
//      
//  }
}