enemy now moves

Shared/ShmupWorld.cs

@@ -82,14 +82,34 @@ namespace SemiColinGames {
       }
     }
 
+    public interface IMoveBehavior {
+      public Vector2 Velocity(float modelTime);
+    }
+
+    public class MoveLeft : IMoveBehavior {
+      public Vector2 Velocity(float modelTime) {
+        return new Vector2(-100, 0);
+      }
+    }
+
     public class Enemy {
       public TextureRef Texture = Textures.Blue1;
       // Center of sprite.
       public Vector2 Position = new Vector2(1920 / 4 - 48, 1080 / 8);
       // TODO: use a bounds rect instead of HalfSize.
       public Vector2 HalfSize = new Vector2(16, 10);
+      public Rectangle Bounds;
+      private IMoveBehavior moveBehavior = new MoveLeft();
 
       public void Update(float modelTime) {
+        Vector2 velocity = moveBehavior.Velocity(modelTime);
+        Position = Vector2.Add(Position, Vector2.Multiply(velocity, modelTime));
+
+        Bounds = new Rectangle(
+            (int) (Position.X - HalfSize.X),
+            (int) (Position.Y - HalfSize.Y),
+            (int) HalfSize.X * 2,
+            (int) HalfSize.Y * 2);
       }
 
       public void Draw(SpriteBatch spriteBatch) {
@@ -142,8 +162,9 @@ namespace SemiColinGames {
       Rectangle paddedBounds = Bounds;
       paddedBounds.Inflate(16, 16);
       Shots.RemoveAll(shot => !paddedBounds.Intersects(shot.Bounds));
+      Enemies.RemoveAll(enemy => !paddedBounds.Intersects(enemy.Bounds));
 
-      Debug.AddToast("shots: " + Shots.Count);
+      Debug.AddToast("shots: " + Shots.Count + " enemies: " + Enemies.Count);
     }
   }
 }