Stacked sprite visualizer (#3096)

* Add Stack Visualizer

* Add cigarette pack resources

Adds transparent layers for visualizing cigarettes

* Add Bag Open/Close Visualizer

So storage opened in inventory can have different icons when opened
or closed.

* Create a component that only enumerates single item

Used for creating stuff like matchbox, or cigarettes. As a bonus.
It will only update stack visualizer for that particullar item.

* Refactoring stuff

* Fix other usage of stack in Resources

* Add docs

* Apply suggestions from code review

Apply metalgearsloth suggestions

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Applied suggestions from metalgearsloth

* Changed SingleItemStorageComponent to StorageCounterComponent

Difference. New component doesn't spawn items, merely counts them.

* Refactored StackVisualizer

* Fix breakage with master

* Update Resources/Prototypes/Entities/Objects/Consumable/fancy.yml

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

* Update with MGS suggestions

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>

Content.Shared/GameObjects/Components/SharedBagOpenVisuals.cs

@@ -0,0 +1,19 @@
+#nullable enable
+using System;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components
+{
+    [Serializable, NetSerializable]
+    public enum SharedBagOpenVisuals : byte
+    {
+        BagState,
+    }
+    
+    [Serializable, NetSerializable]
+    public enum SharedBagState : byte
+    {
+        Open,
+        Close,
+    }
+}

Content.Shared/GameObjects/Components/StackVisuals.cs

@@ -0,0 +1,21 @@
+#nullable enable
+using System;
+using Robust.Shared.Serialization;
+
+namespace Content.Shared.GameObjects.Components
+{
+    [Serializable, NetSerializable]
+    public enum StackVisuals : byte
+    {
+        /// <summary>
+        /// The amount of elements in the stack
+        /// </summary>
+        Actual,
+        /// <summary>
+        /// The total amount of elements in the stack. If unspecified, the visualizer assumes
+        /// its 
+        /// </summary>
+        MaxCount,
+        Hide
+    }
+}

Content.Shared/Utility/ContentHelpers.cs

@@ -25,14 +25,17 @@ namespace Content.Shared.Utility
             {
                 throw new ArgumentException("Levels must be greater than 0.", nameof(levels));
             }
+
             if (actual >= max)
             {
                 return levels - 1;
             }
+
             if (actual <= 0)
             {
                 return 0;
             }
+
             var toOne = actual / max;
             double threshold;
             if (levels % 2 == 0)
@@ -49,11 +52,11 @@ namespace Content.Shared.Utility
             var preround = toOne * (levels - 1);
             if (toOne <= threshold || levels <= 2)
             {
-                return (int)Math.Ceiling(preround);
+                return (int) Math.Ceiling(preround);
             }
             else
             {
-                return (int)Math.Floor(preround);
+                return (int) Math.Floor(preround);
             }
         }
 
@@ -81,28 +84,18 @@ namespace Content.Shared.Utility
             {
                 throw new ArgumentException("Levels must be greater than 1.", nameof(levels));
             }
+
             if (actual >= max)
             {
                 return levels;
             }
+
             if (actual <= 0)
             {
                 return 0;
             }
-            double step = max / levels;
 
-            int nearest = 0;
-            double nearestDiff = actual;
-            for (var i = 1; i <= levels; i++)
-            {
-                var diff = Math.Abs(actual - i * step);
-                if (diff < nearestDiff)
-                {
-                    nearestDiff = diff;
-                    nearest = i;
-                }
-            }
-            return nearest;
+            return (int) Math.Round(actual / max * levels, MidpointRounding.AwayFromZero);
         }
     }
 }