Improved background sprite placement logic: orientation of the cell edges determined by their normals instead of their position relative to the cell

Subsurface/Content/BackgroundSprites/BackgroundSpritePrefabs.xml

@@ -1,11 +1,11 @@
 <?xml version="1.0" encoding="utf-8" ?>
 <backgroundsprites>
   <hanging1 alignment="Bottom" minsize="0.5" maxsize="1.5" commonness="5">
-    <Sprite texture="Content/BackgroundSprites/vegetation.png" sourcerect="0,0,242,543" origin="0.5,0.0"/>
+    <Sprite texture="Content/BackgroundSprites/vegetation.png" sourcerect="0,0,242,543" origin="0.5,0.15"/>
   </hanging1>
 
   <hanging2 alignment="Bottom" minsize="0.5" maxsize="1.5" commonness="5">
-    <Sprite texture="Content/BackgroundSprites/vegetation.png" sourcerect="241,0,322,720" origin="0.5,0.0"/>
+    <Sprite texture="Content/BackgroundSprites/vegetation.png" sourcerect="241,0,322,720" origin="0.5,0.15"/>
   </hanging2>
 
   <kelp1 alignment="Top" minsize="0.5" maxsize="1.5" commonness="10">
@@ -35,9 +35,14 @@
 
   <branches2 minsize="0.5" maxsize="2.0" alignwithsurface="true" swingamount="3" randomrotation="-20,20" commonness="4">
     <overridecommonness commonness="10" leveltype="Maze" />
-    <Sprite texture="Content/BackgroundSprites/vegetation2.png" sourcerect="255,0,246,479" origin="0.5,0.9"/>
+    <Sprite texture="Content/BackgroundSprites/vegetation2.png" sourcerect="247,0,278,479" origin="0.2,0.9"/>
   </branches2>
 
+  <branches3 minsize="0.5" maxsize="2.0" alignwithsurface="true" swingamount="3" randomrotation="-20,20" commonness="4">
+    <overridecommonness commonness="10" leveltype="Maze" />
+    <Sprite texture="Content/BackgroundSprites/vegetation2.png" sourcerect="526,0,245,479" origin="0.4,0.9"/>
+  </branches3>
+  
   <fungus minsize="0.5" maxsize="1.5" alignwithsurface="true" swingamount="1" commonness="3">
     <overridecommonness commonness="10" leveltype="Maze" />
     <Sprite texture="Content/BackgroundSprites/vegetation2.png" sourcerect="0,681,442,343" origin="0.5,0.9"/>

Subsurface/Source/Characters/BackgroundSprite/BackgroundSpriteManager.cs

@@ -86,17 +86,15 @@ namespace Barotrauma
             {
                 BackgroundSpritePrefab prefab = GetRandomPrefab(level.GenerationParams.Name);
                 GraphEdge selectedEdge = null;
-                Vector2? pos = FindSpritePosition(level, prefab, out selectedEdge);
+                Vector2 edgeNormal = Vector2.One;
+                Vector2? pos = FindSpritePosition(level, prefab, out selectedEdge, out edgeNormal);
 
                 if (pos == null) continue;
 
                 float rotation = 0.0f;
                 if (prefab.AlignWithSurface)
                 {
-                    Vector2 leftPoint = selectedEdge.point2;
+                    rotation = MathUtils.VectorToAngle(new Vector2(edgeNormal.Y, edgeNormal.X));
-                    Vector2 rightPoint = selectedEdge.point1;
-                    
-                    rotation = -MathUtils.VectorToAngle(rightPoint - leftPoint);
                 }
 
                 rotation += Rand.Range(prefab.RandomRotation.X, prefab.RandomRotation.Y, false);
@@ -105,17 +103,18 @@ namespace Barotrauma
                     (Vector2)pos, Rand.Range(prefab.Scale.X, prefab.Scale.Y, false), rotation);
 
                 int x = (int)Math.Floor(((Vector2)pos).X / GridSize);
-                if (x<0 || x >= sprites.GetLength(0)) continue;
+                if (x < 0 || x >= sprites.GetLength(0)) continue;
                 int y = (int)Math.Floor(((Vector2)pos).Y / GridSize);
-                if (y<0 || y >= sprites.GetLength(1)) continue;
+                if (y < 0 || y >= sprites.GetLength(1)) continue;
 
                 sprites[x,y].Add(newSprite);
             }
         }
 
-        private Vector2? FindSpritePosition(Level level, BackgroundSpritePrefab prefab, out GraphEdge closestEdge)
+        private Vector2? FindSpritePosition(Level level, BackgroundSpritePrefab prefab, out GraphEdge closestEdge, out Vector2 edgeNormal)
         {
             closestEdge = null;
+            edgeNormal = Vector2.One;
 
             Vector2 randomPos = new Vector2(
                 Rand.Range(0.0f, level.Size.X, false), 
@@ -127,43 +126,46 @@ namespace Barotrauma
 
             VoronoiCell cell = cells[Rand.Int(cells.Count, false)];
             List<GraphEdge> edges = new List<GraphEdge>();
+            List<Vector2> normals = new List<Vector2>();
             foreach (GraphEdge edge in cell.edges)
             {
                 if (!edge.isSolid || edge.OutsideLevel) continue;
 
-                if (prefab.Alignment.HasFlag(Alignment.Bottom) &&
+                Vector2 normal = edge.GetNormal(cell);
-                    Math.Abs(edge.point1.X - edge.point2.X) < Math.Abs(edge.point1.Y - edge.point2.Y))
+                
-                {
+                if (prefab.Alignment.HasFlag(Alignment.Bottom) && normal.Y < -0.5f)
-                    if (edge.Center.Y < cell.Center.Y) edges.Add(edge);
-                }
-                else if (prefab.Alignment.HasFlag(Alignment.Top) &&
-                    Math.Abs(edge.point1.X - edge.point2.X) < Math.Abs(edge.point1.Y - edge.point2.Y))
-                {
-                    if (edge.Center.Y > cell.Center.Y) edges.Add(edge);
-                }
-                else if (prefab.Alignment.HasFlag(Alignment.Left))
-                {
-                    if (edge.Center.X < cell.Center.X) edges.Add(edge);
-                }
-                else if (prefab.Alignment.HasFlag(Alignment.Right))
-                {
-                    if (edge.Center.X > cell.Center.X) edges.Add(edge);
-                }
-                else
                 {
                     edges.Add(edge);
                 }
+                else if (prefab.Alignment.HasFlag(Alignment.Top) && normal.Y > 0.5f)
+                {
+                    edges.Add(edge);
+                }
+                else if (prefab.Alignment.HasFlag(Alignment.Left) && normal.X < -0.5f)
+                {
+                    edges.Add(edge);
+                }
+                else if (prefab.Alignment.HasFlag(Alignment.Right) && normal.X > 0.5f)
+                {
+                    edges.Add(edge);
+                }
+                else
+                {
+                    continue;
+                }
+
+                normals.Add(normal);
             }
 
             if (!edges.Any()) return null;
 
-            closestEdge = edges[Rand.Int(edges.Count,false)];
+            int index = Rand.Int(edges.Count,false);
+            closestEdge = edges[index];
+            edgeNormal = normals[index];
 
             float length = Vector2.Distance(closestEdge.point1, closestEdge.point2);
             Vector2 dir = (closestEdge.point1 - closestEdge.point2) / length;
-            Vector2 pos = closestEdge.Center;
+            Vector2 pos = closestEdge.point2 + dir * Rand.Range(prefab.Sprite.size.X / 2.0f, length - prefab.Sprite.size.X / 2.0f, false);
-
-            pos = closestEdge.point2 + dir * Rand.Range(prefab.Sprite.size.X / 2.0f, length - prefab.Sprite.size.X / 2.0f, false);
             
             return pos;
         }

Subsurface/Source/Map/Levels/VoronoiElements.cs

@@ -218,10 +218,25 @@ namespace Voronoi2
             {
                 return cell1;
             }
-            else
+
+            return null;            
+        }
+
+        /// <summary>
+        /// Returns the normal of the edge that points outwards from the specified cell
+        /// </summary>
+        public Vector2 GetNormal(VoronoiCell cell)
+        {
+            Vector2 dir = Vector2.Normalize(point1 - point2);
+
+            Vector2 normal = new Vector2(dir.Y, -dir.X);
+
+            if (cell != null && Vector2.Dot(normal, Vector2.Normalize(Center - cell.Center)) < 0)
             {
-                return null;
+                normal = -normal;
             }
+
+            return normal;
         }
 	}