add a little screen-shake

Shared/Camera.cs

@@ -13,11 +13,14 @@ namespace SemiColinGames {
     public int Top { get => bbox.Top; }
     public Point HalfSize { get => new Point(Width / 2, Height / 2); }
 
+    private float shakeTime = 0.0f;
+    private Random random = new Random();
+
     public Matrix Projection {
       get => Matrix.CreateOrthographicOffCenter(Left, Left + Width, Height, 0, -1, 1);
     }
 
-    public void Update(Point player, int worldWidth) {
+    public void Update(float modelTime, Point player, int worldWidth) {
       int diff = player.X - bbox.Center.X;
       if (Math.Abs(diff) > 16) {
         bbox.Offset((int) (diff * 0.1), 0);
@@ -28,7 +31,16 @@ namespace SemiColinGames {
       if (bbox.Right > worldWidth) {
         bbox.Offset(worldWidth - bbox.Right, 0);
       }
+      if (shakeTime > 0) {
+        shakeTime -= modelTime;
+        int x = random.Next(-4, 5);
+        bbox.Offset(x, 0);
+      }
       Debug.AddToast($"p: {player.X}, {player.Y} c: {bbox.Center.X}");
     }
+
+    public void Shake() {
+      shakeTime = 0.5f;
+    }
   }
 }

Shared/Player.cs

@@ -150,6 +150,7 @@ namespace SemiColinGames {
       }
 
       if (harmedByCollision && invincibilityTime <= 0) {
+        world.ScreenShake();
         Health -= 1;
         invincibilityTime = 0.6f;
       }

Shared/World.cs

@@ -164,7 +164,11 @@ namespace SemiColinGames {
         Reset();
       }
       LinesOfSight.Update(npcs, CollisionTargets);
-      Camera.Update(Player.Position, Width);
+      Camera.Update(modelTime, Player.Position, Width);
+    }
+
+    public void ScreenShake() {
+      Camera.Shake();
     }
 
     // Draws everything that's behind the player, from back to front.