[Penumbra] Mark light dirty when ignored hull collection changed

Source/Graphics/Renderers/ShadowRenderer.cs

@@ -160,7 +160,7 @@ public void Dispose()
                     continue;
                 }
 
-                Polygon points = hull.WorldPoints;                
+                Polygon points = hull.WorldPoints;
 
                 Vector2 prevPoint = points[points.Count - 1];
 

Source/Light.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 using Penumbra.Geometry;
@@ -20,9 +21,18 @@ public abstract class Light
     {
         private const float Epsilon = 1e-5f;
 
+        private readonly ObservableCollection<Hull> _ignoredHulls = new ObservableCollection<Hull>();
         // Used privately to determine when to calculate world transform and bounds.
         private bool _worldDirty = true;
 
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Light"/> class.
+        /// </summary>
+        protected Light()
+        {
+            _ignoredHulls.CollectionChanged += (s, e) => Dirty = true;
+        }
+
         /// <summary>
         /// Gets or sets if the light is enabled and should be rendered.
         /// </summary>
@@ -124,7 +134,7 @@ public Vector2 Scale
                 }
             }
         }
-        
+
         private Color _nonPremultipliedColor = Color.White;
         private Vector3 _color = Vector3.One;
         /// <summary>
@@ -140,7 +150,7 @@ public Color Color
                 Calculate.FromNonPremultiplied(value, out _color);
             }
         }
-                
+
         private float _intensity = 1.0f;
         /// <summary>
         /// Gets or sets the intensity of the color applied to the final scene.
@@ -180,8 +190,8 @@ public float Radius
                     Dirty = true;
                 }
             }
-        }                
-        
+        }
+
         /// <summary>
         /// Gets or sets how the shadow <see cref="Hull"/>s are shadowed. See
         /// <see cref="ShadowType"/> for more information.
@@ -191,14 +201,14 @@ public float Radius
         /// <summary>
         /// Gets a list of hulls not participating in the light's shadow casting process.
         /// </summary>
-        public List<Hull> IgnoredHulls { get; } = new List<Hull>();
+        public IList<Hull> IgnoredHulls => _ignoredHulls;
 
-        // Cleared by the engine. Used by other systems to know if the light's world transform has changed.
+        // Cleared by the engine. Used by other systems to know when to regenerate shadows for the light.
         internal bool Dirty;
 
         internal BoundingRectangle Bounds;
 
-        internal Matrix LocalToWorld;              
+        internal Matrix LocalToWorld;
 
         internal virtual EffectTechnique ApplyEffectParams(LightRenderer renderer)
         {
@@ -232,18 +242,18 @@ private void CalculateBounds()
                 Vector2.Multiply(ref _origin, ref _scale, out min);
                 Vector2.Subtract(ref _position, ref min, out min);
 
-                Vector2 max;                
+                Vector2 max;
                 Vector2.Add(ref min, ref _scale, out max);
 
                 Bounds = new BoundingRectangle(min, max);
             }
             else
-            {                
+            {
                 var bounds = new BoundingRectangle(Vector2.Zero, Vector2.One);
                 BoundingRectangle.Transform(ref bounds, ref LocalToWorld, out Bounds);
             }
         }
-    }  
+    }
 
     /// <summary>
     /// Determines how the shadows cast by the light affect shadow <see cref="Hull"/>s.
@@ -257,7 +267,7 @@ public enum ShadowType
         /// <summary>
         /// Shadow hulls are not lit by the light.
         /// </summary>
-        Solid,        
+        Solid,
         /// <summary>
         /// Occluded shadow hulls (hulls behind other hulls) are not lit.
         /// </summary>