sneak/Shared/Camera.cs

using Microsoft.Xna.Framework;
using System;

// Good background reading, eventually:
// https://gamasutra.com/blogs/ItayKeren/20150511/243083/Scroll_Back_The_Theory_and_Practice_of_Cameras_in_SideScrollers.php
namespace SemiColinGames {
  class Camera {
    private Rectangle bbox = new Rectangle(0, 0, 1920 / 4, 1080 / 4);

    public int Width { get => bbox.Width; }
    public int Height { get => bbox.Height; }
    public int Left { get => bbox.Left; }

    public void Update(GameTime time, Point player) {
      int diff = player.X - bbox.Center.X;
      // TODO: use the actual center of the player's bbox.
      if (Math.Abs(diff) > 16) {
        bbox.Offset((int) (diff * 0.1), 0);
      }
      if (bbox.Left < 0) {
        bbox.Offset(-bbox.Left, 0);
      }
      Debug.Toast($"p: {player.X}, {player.Y} c: {bbox.Center.X}");
    }
  }
}