Separate ParticleEmitter & ParticleEmitterPrefab classes - the emission timer (and maybe some other values in the future) can't be in the prefab class because multiple objects may use the same prefab.

Barotrauma/BarotraumaClient/Source/Characters/Attack.cs

@@ -8,7 +8,7 @@ namespace Barotrauma
     {
         private Sound sound;
 
-        private ParticleEmitter particleEmitterPrefab;
+        private ParticleEmitter particleEmitter;
 
         partial void InitProjSpecific(XElement element)
         {
@@ -23,7 +23,7 @@ namespace Barotrauma
                 switch (subElement.Name.ToString().ToLowerInvariant())
                 {
                     case "particleemitter":
-                        particleEmitterPrefab = new ParticleEmitter(subElement);
+                        particleEmitter = new ParticleEmitter(subElement);
                         break;
                 }
 
@@ -32,9 +32,9 @@ namespace Barotrauma
 
         partial void DamageParticles(float deltaTime, Vector2 worldPosition)
         {
-            if (particleEmitterPrefab != null)
+            if (particleEmitter != null)
             {
-                particleEmitterPrefab.Emit(deltaTime, worldPosition);
+                particleEmitter.Emit(deltaTime, worldPosition);
             }
 
             if (sound != null)

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

@@ -1,4 +1,5 @@
-using Microsoft.Xna.Framework;
+using Barotrauma.Particles;
+using Microsoft.Xna.Framework;
 using Microsoft.Xna.Framework.Graphics;
 using System;
 using System.Collections.Generic;
@@ -16,6 +17,8 @@ namespace Barotrauma
         public float Scale;
 
         public float Rotation;
+
+        public Particles.ParticleEmitter ParticleEmitter;
         
         //public Vector2[] spriteCorners;
 
@@ -27,6 +30,8 @@ namespace Barotrauma
             this.Scale = scale;
 
             this.Rotation = rotation;
+
+            this.ParticleEmitter = new ParticleEmitter(prefab.ParticleEmitterPrefab);
         }
     }
 
@@ -240,7 +245,7 @@ namespace Barotrauma
 
             foreach (BackgroundSprite s in visibleSprites)
             {
-                if (s.Prefab.ParticleEmitter != null)
+                if (s.Prefab.ParticleEmitterPrefab != null)
                 {
                     Vector2 emitterPos = new Vector2(s.Prefab.EmitterPosition.X, s.Prefab.EmitterPosition.Y);
 
@@ -254,7 +259,7 @@ namespace Barotrauma
                             -sa * emitterPos.X + ca * emitterPos.Y);
                     }
 
-                    s.Prefab.ParticleEmitter.Emit(deltaTime, new Vector2(s.Position.X, s.Position.Y) + emitterPos);
+                    s.ParticleEmitter.Emit(deltaTime, new Vector2(s.Position.X, s.Position.Y) + emitterPos);
                 }
             }
             

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

@@ -30,7 +30,7 @@ namespace Barotrauma
 
         public readonly Vector2 DepthRange;
 
-        public readonly Particles.ParticleEmitter ParticleEmitter;
+        public readonly Particles.ParticleEmitterPrefab ParticleEmitterPrefab;
         public readonly Vector2 EmitterPosition;
 
         public readonly float SwingAmount;
@@ -90,7 +90,7 @@ namespace Barotrauma
                         }
                         break;
                     case "particleemitter":
-                        ParticleEmitter = new Particles.ParticleEmitter(subElement);
+                        ParticleEmitterPrefab = new Particles.ParticleEmitterPrefab(subElement);
                         EmitterPosition = ToolBox.GetAttributeVector2(subElement, "position", Vector2.Zero);
                         break;
                 }

Barotrauma/BarotraumaClient/Source/Particles/ParticleEmitter.cs

@@ -5,10 +5,60 @@ using System.Xml.Linq;
 namespace Barotrauma.Particles
 {
     class ParticleEmitter
+    {
+        private float emitTimer;
+
+        public readonly ParticleEmitterPrefab Prefab;
+
+        public ParticleEmitter(XElement element)
+        {
+            Prefab = new ParticleEmitterPrefab(element);
+        }
+
+        public ParticleEmitter(ParticleEmitterPrefab prefab)
+        {
+            Prefab = prefab;
+        }
+
+        public void Emit(float deltaTime, Vector2 position, Hull hullGuess = null)
+        {
+            emitTimer += deltaTime;
+
+            if (Prefab.ParticlesPerSecond > 0)
+            {
+                float emitInterval = 1.0f / Prefab.ParticlesPerSecond;
+                while (emitTimer > emitInterval)
+                {
+                    Emit(position, hullGuess);
+                    emitTimer -= emitInterval;
+                }
+            }
+
+            for (int i = 0; i < Prefab.ParticleAmount; i++)
+            {
+                Emit(position, hullGuess);
+            }
+        }
+
+        private void Emit(Vector2 position, Hull hullGuess = null)
+        {
+            float angle = Rand.Range(Prefab.AngleMin, Prefab.AngleMax);
+            Vector2 velocity = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle)) * Rand.Range(Prefab.VelocityMin, Prefab.VelocityMax);
+
+            var particle = GameMain.ParticleManager.CreateParticle(Prefab.ParticlePrefab, position, velocity, 0.0f, hullGuess);
+
+            if (particle != null)
+            {
+                particle.Size *= Rand.Range(Prefab.ScaleMin, Prefab.ScaleMax);
+            }
+        }
+    }
+
+    class ParticleEmitterPrefab
     {        
         public readonly string Name;
 
-        public readonly ParticlePrefab particlePrefab;
+        public readonly ParticlePrefab ParticlePrefab;
 
         public readonly float AngleMin, AngleMax;
 
@@ -17,16 +67,13 @@ namespace Barotrauma.Particles
         public readonly float ScaleMin, ScaleMax;
         
         public readonly int ParticleAmount;
+        public readonly float ParticlesPerSecond;        
 
-        public readonly float ParticlesPerSecond;
-        
-        private float emitTimer;
-
-        public ParticleEmitter(XElement element)
+        public ParticleEmitterPrefab(XElement element)
         {
             Name = element.Name.ToString();
 
-            particlePrefab = GameMain.ParticleManager.FindPrefab(ToolBox.GetAttributeString(element, "particle", ""));
+            ParticlePrefab = GameMain.ParticleManager.FindPrefab(ToolBox.GetAttributeString(element, "particle", ""));
 
             if (element.Attribute("startrotation") == null)
             {
@@ -67,38 +114,5 @@ namespace Barotrauma.Particles
             ParticlesPerSecond = ToolBox.GetAttributeInt(element, "particlespersecond", 0);
             ParticleAmount = ToolBox.GetAttributeInt(element, "particleamount", 0);
         }
-
-        public void Emit(float deltaTime, Vector2 position, Hull hullGuess = null)
-        {
-            emitTimer += deltaTime;
-            
-            if (ParticlesPerSecond > 0)
-            {
-                float emitInterval = 1.0f / ParticlesPerSecond;
-                while (emitTimer > emitInterval)
-                {
-                    Emit(position, hullGuess);
-                    emitTimer -= emitInterval;
-                }
-            }
-
-            for (int i = 0; i<ParticleAmount; i++)
-            {
-                Emit(position, hullGuess);
-            }
-        }
-
-        private void Emit(Vector2 position, Hull hullGuess = null)
-        {
-            float angle = Rand.Range(AngleMin, AngleMax);
-            Vector2 velocity = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle)) * Rand.Range(VelocityMin, VelocityMax);
-
-            var particle = GameMain.ParticleManager.CreateParticle(particlePrefab, position, velocity, 0.0f, hullGuess);
-
-            if (particle != null)
-            {
-                particle.Size *= Rand.Range(ScaleMin, ScaleMax);
-            }
-        }
     }
 }