TileHitbox.cs

using System;
using System.Linq;
using Microsoft.Xna.Framework;
using OriMod.Utilities;
using Terraria;

namespace OriMod;

/// <summary>
/// Primarily used for <see cref="Abilities.Burrow"/>, stores an array of points as a template, and retrieves tiles of that template when updated.
/// </summary>
public class TileHitbox {
  /// <summary>
  /// Instantiate a <see cref="TileHitbox"/> with local-space <paramref name="template"/>.
  /// </summary>
  /// <param name="template"><see cref="Template"/>. Must have at least 1 item.</param>
  public TileHitbox(params Point[] template) {
    ArgumentNullException.ThrowIfNull(template);
    if (template.Length == 0) {
      throw new ArgumentException("Template must have at least one item.", nameof(template));
    }

    Template = template;
    Points = new Point[Template.Length];
    UpdateHitbox(Point.Zero);
  }

  public TileHitbox(params (int x, int y)[] template) : this(template?.Select(tuple => new Point(tuple.x, tuple.y)).ToArray()) { }

  /// <summary>
  /// Current world position of points in the hitbox, in tile coordinates.
  /// </summary>
  public Point[] Points { get; }

  /// <summary>
  /// Local position of points in the hitbox, in tile coordinates.
  /// </summary>
  public Point[] Template { get; }

  /// <summary>
  /// Updates the position of the hitbox based on the given world position.
  /// </summary>
  /// <param name="origin">World-space position to use.</param>
  public void UpdateHitbox(Vector2 origin) => UpdateHitbox(origin.ToTileCoordinates());

  /// <summary>
  /// Updates the world position of the hitbox based on the given tile position.
  /// </summary>
  /// <param name="origin">Tile-space position to use.</param>
  public void UpdateHitbox(Point origin) {
    for (int i = 0; i < Points.Length; i++) {
      Points[i] = Template[i].Add(origin);
    }
  }
}