Added texture cache and sprite origins.

AlientAttack.MonoGame/AlienAttackGame.cs

@@ -1,5 +1,6 @@
 using AlienAttack.MonoGame.Audio;
 using AlienAttack.MonoGame.GameLoops;
+using AlienAttack.MonoGame.Textures;
 using AlienAttack.MonoGame.View;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Audio;
@@ -22,6 +23,7 @@ public class AlienAttackGame : Game
     public SpriteBatch SpriteBatch => _spriteBatch;
     public ViewTransform ViewTransform => _viewTransform;
     public AudioManager Audio { get; private set; } = new();
+    public TextureCache Textures { get; } = new();
 
     private const string SDL = "SDL2.dll";
 
@@ -76,6 +78,7 @@ public class AlienAttackGame : Game
 
         // TODO: use this.Content to load your game content here
         Audio.LoadContent(Content);
+        Textures.Initialize(Content);
     }
 
     protected override void Update(GameTime gameTime)