Background sprites can be set to spawn on the sea floor, particle emitters can be attached to background sprites

Barotrauma/BarotraumaClient/Source/Characters/BackgroundSprite/BackgroundSpritePrefab.cs

@@ -7,20 +7,32 @@ namespace Barotrauma
 {
     class BackgroundSpritePrefab
     {
+        [Flags]
+        public enum SpawnPosType
+        {
+            None = 0,
+            Wall = 1,
+            RuinWall = 2,
+            SeaFloor = 4
+        }
+
         public readonly Sprite Sprite;
 
         public readonly Alignment Alignment;
 
         public readonly Vector2 Scale;
 
-        public bool SpawnOnWalls;
+        public SpawnPosType SpawnPos;
 
         public readonly bool AlignWithSurface;
-
+        
         public readonly Vector2 RandomRotation;
 
         public readonly Vector2 DepthRange;
 
+        public readonly Particles.ParticleEmitter ParticleEmitter;
+        public readonly Vector2 EmitterPosition;
+
         public readonly float SwingAmount;
 
         public readonly int Commonness;
@@ -37,8 +49,16 @@ namespace Barotrauma
             }
 
             Commonness = ToolBox.GetAttributeInt(element, "commonness", 1);
-
-            SpawnOnWalls = ToolBox.GetAttributeBool(element, "spawnonwalls", true);
+            
+            string[] spawnPosStrs = ToolBox.GetAttributeString(element, "spawnpos", "Wall").Split(',');
+            foreach (string spawnPosStr in spawnPosStrs)
+            {
+                SpawnPosType parsedSpawnPos;
+                if (Enum.TryParse(spawnPosStr.Trim(), out parsedSpawnPos))
+                {
+                    SpawnPos |= parsedSpawnPos;
+                }
+            }
 
             Scale.X = ToolBox.GetAttributeFloat(element, "minsize", 1.0f);
             Scale.Y = ToolBox.GetAttributeFloat(element, "maxsize", 1.0f);
@@ -69,7 +89,10 @@ namespace Barotrauma
                             OverrideCommonness.Add(levelType, ToolBox.GetAttributeInt(subElement, "commonness", 1));
                         }
                         break;
-
+                    case "particleemitter":
+                        ParticleEmitter = new Particles.ParticleEmitter(subElement);
+                        EmitterPosition = ToolBox.GetAttributeVector2(subElement, "position", Vector2.Zero);
+                        break;
                 }
             }
         }