Particle additions:

- Support for subemitters (= particles can emit particles).
- Option to set a different velocity change value for particles in water (can be used to simulate buouancy).
- Fixed drag vector & timer not being reset when initializing a particle.

Barotrauma/BarotraumaClient/Source/GameMain.cs

@@ -293,6 +293,7 @@ namespace Barotrauma
         yield return CoroutineStatus.Running;
 
             ParticleManager = new ParticleManager("Content/Particles/ParticlePrefabs.xml", GameScreen.Cam);
+            ParticleManager.LoadPrefabs();
             DecalManager = new DecalManager("Content/Particles/DecalPrefabs.xml");
         yield return CoroutineStatus.Running;
 

Barotrauma/BarotraumaClient/Source/Particles/Particle.cs

@@ -38,6 +38,7 @@ namespace Barotrauma.Particles
         private float lifeTime;
 
         private Vector2 velocityChange;
+        private Vector2 velocityChangeWater;
 
         private Vector2 drawPosition;
         private float drawRotation;
@@ -46,6 +47,8 @@ namespace Barotrauma.Particles
 
         private List<Gap> hullGaps;
 
+        private List<ParticleEmitter> subEmitters = new List<ParticleEmitter>();
+
         private float animState;
         private int animFrame;
         
@@ -71,6 +74,12 @@ namespace Barotrauma.Particles
             set { velocityChange = value; }
         }
 
+        public Vector2 VelocityChangeWater
+        {
+            get { return velocityChangeWater; }
+            set { velocityChangeWater = value; }
+        }
+
         public Vector2 Velocity
         {
             get { return velocity; }
@@ -90,6 +99,8 @@ namespace Barotrauma.Particles
 
             animState = 0;
             animFrame = 0;
+            dragWait = 0;
+            dragVec = Vector2.Zero;
 
             currentHull = Hull.FindHull(position, hullGuess);
 
@@ -121,9 +132,16 @@ namespace Barotrauma.Particles
             alpha = prefab.StartAlpha;
             
             velocityChange = prefab.VelocityChangeDisplay;
+            velocityChangeWater = prefab.VelocityChangeWaterDisplay;
 
             OnChangeHull = null;
 
+            subEmitters.Clear();
+            foreach (ParticleEmitterPrefab emitterPrefab in prefab.SubEmitters)
+            {
+                subEmitters.Add(new ParticleEmitter(emitterPrefab));
+            }
+
             if (prefab.DeleteOnCollision || prefab.CollidesWithWalls)
             {
                 hullGaps = currentHull == null ? new List<Gap>() : currentHull.ConnectedGaps;
@@ -158,19 +176,26 @@ namespace Barotrauma.Particles
                 rotation += angularVelocity * deltaTime;
             }
 
-            if (prefab.WaterDrag > 0.0f && 
+            bool inWater = (currentHull == null || (currentHull.Submarine != null && position.Y - currentHull.Submarine.DrawPosition.Y < currentHull.Surface));
-                (currentHull == null || (currentHull.Submarine != null && position.Y - currentHull.Submarine.DrawPosition.Y < currentHull.Surface)))
+            if (inWater)
             {
-                ApplyDrag(prefab.WaterDrag, deltaTime);
+                velocity.X += velocityChangeWater.X * deltaTime;
+                velocity.Y += velocityChangeWater.Y * deltaTime;
+                if (prefab.WaterDrag > 0.0f)
+                {
+                    ApplyDrag(prefab.WaterDrag, deltaTime);
+                }
             }
-            else if (prefab.Drag > 0.0f)
+            else
             {
-                ApplyDrag(prefab.Drag, deltaTime);
+                velocity.X += velocityChange.X * deltaTime;
+                velocity.Y += velocityChange.Y * deltaTime; 
+                if (prefab.Drag > 0.0f)
+                {
+                    ApplyDrag(prefab.Drag, deltaTime);
+                }
             }
 
-            velocity.X += velocityChange.X * deltaTime;
-            velocity.Y += velocityChange.Y * deltaTime; 
-
             size.X += sizeChange.X * deltaTime;
             size.Y += sizeChange.Y * deltaTime;  
 
@@ -191,6 +216,11 @@ namespace Barotrauma.Particles
             lifeTime -= deltaTime;
             if (lifeTime <= 0.0f || alpha <= 0.0f || size.X <= 0.0f || size.Y <= 0.0f) return false;
 
+            foreach (ParticleEmitter emitter in subEmitters)
+            {
+                emitter.Emit(deltaTime, position, currentHull);
+            }
+
             if (!prefab.DeleteOnCollision && !prefab.CollidesWithWalls) return true;
             
             if (currentHull == null)
@@ -201,7 +231,6 @@ namespace Barotrauma.Particles
                     if (prefab.DeleteOnCollision) return false;
                     OnWallCollisionOutside(collidedHull);
                 }
-
             }
             else
             {
@@ -281,8 +310,11 @@ namespace Barotrauma.Particles
             }
             if (Math.Abs(velocity.X) < 0.0001f && Math.Abs(velocity.Y) < 0.0001f) return;
             
+            //TODO: some better way to handle particle drag
+            //this doesn't work that well because the drag vector is only updated every 0.5 seconds, allowing the particle to accelerate way more than it should
+            //(e.g. a falling particle can freely accelerate for 0.5 seconds before the drag takes effect)
             dragWait--;
-            if (dragWait<=0)
+            if (dragWait <= 0)
             {
                 dragWait = 30;
 

Barotrauma/BarotraumaClient/Source/Particles/ParticleManager.cs

@@ -32,13 +32,11 @@ namespace Barotrauma.Particles
             this.cam = cam;
 
             particles = new Particle[MaxParticles];
-
-            LoadPrefabs(configFile);
         }
 
-        public void LoadPrefabs(string file)
+        public void LoadPrefabs()
         {
-            XDocument doc = XMLExtensions.TryLoadXml(file);
+            XDocument doc = XMLExtensions.TryLoadXml(ConfigFile);
             if (doc == null || doc.Root == null) return;
 
             prefabs = new Dictionary<string, ParticlePrefab>();
@@ -47,7 +45,7 @@ namespace Barotrauma.Particles
             {
                 if (prefabs.ContainsKey(element.Name.ToString()))
                 {
-                    DebugConsole.ThrowError("Error in " + file + "! Each particle prefab must have a unique name.");
+                    DebugConsole.ThrowError("Error in " + ConfigFile + "! Each particle prefab must have a unique name.");
                     continue;
                 }
                 prefabs.Add(element.Name.ToString(), new ParticlePrefab(element));

Barotrauma/BarotraumaClient/Source/Particles/ParticlePrefab.cs

@@ -101,6 +101,20 @@ namespace Barotrauma.Particles
             }
         }
 
+        private Vector2 velocityChangeWater;
+        public Vector2 VelocityChangeWaterDisplay { get; private set; }
+
+        [Editable(ToolTip = "How much the velocity of the particle changes per second when in water."), Serialize("0.0,0.0", false)]
+        public Vector2 VelocityChangeWater
+        {
+            get { return velocityChangeWater; }
+            private set
+            {
+                velocityChangeWater = value;
+                VelocityChangeWaterDisplay = ConvertUnits.ToDisplayUnits(value);
+            }
+        }
+
         [Editable(0.0f, 10000.0f, ToolTip = "Drag applied to the particle when it's moving through water."), Serialize(0.0f, false)]
         public float CollisionRadius { get; private set; }
 
@@ -164,6 +178,8 @@ namespace Barotrauma.Particles
 
         //----------------------------------------------------
 
+        public readonly List<ParticleEmitterPrefab> SubEmitters = new List<ParticleEmitterPrefab>();
+
         public Dictionary<string, SerializableProperty> SerializableProperties
         {
             get;
@@ -191,9 +207,20 @@ namespace Barotrauma.Particles
                     case "animatedsprite":
                         Sprites.Add(new SpriteSheet(subElement));
                         break;
+                    case "particleemitter":
+                    case "emitter":
+                    case "subemitter":
+                        SubEmitters.Add(new ParticleEmitterPrefab(subElement));
+                        break;
                 }
             }
 
+            //if velocity change in water is not given, it defaults to the normal velocity change
+            if (element.Attribute("velocitychangewater") == null)
+            {
+                VelocityChangeWater = VelocityChange;
+            }
+
             if (element.Attribute("angularvelocity") != null)
             {
                 AngularVelocityMin = element.GetAttributeFloat("angularvelocity", 0.0f);

Barotrauma/BarotraumaClient/Source/Screens/ParticleEditorScreen.cs

@@ -16,7 +16,9 @@ namespace Barotrauma
         {
             public float EmitTimer;
 
-            [Editable(), Serialize("0.0,0.0", false)]
+            public float BurstTimer;
+
+            [Editable(), Serialize("0.0,360.0", false)]
             public Vector2 AngleRange { get; private set; }
 
             [Editable(), Serialize("0.0,0.0", false)]
@@ -26,8 +28,12 @@ namespace Barotrauma
             public Vector2 ScaleRange { get; private set; }
 
             [Editable(), Serialize(0, false)]
-            public int ParticleAmount { get; private set; }
+            public int ParticleBurstAmount { get; private set; }
-            [Editable(), Serialize(0.0f, false)]
+
+            [Editable(), Serialize(1.0f, false)]
+            public float ParticleBurstInterval { get; private set; }
+
+            [Editable(), Serialize(1.0f, false)]
             public float ParticlesPerSecond { get; private set; }
 
             public string Name
@@ -46,6 +52,11 @@ namespace Barotrauma
 
             public Emitter()
             {
+                ScaleRange = Vector2.One;
+                AngleRange = new Vector2(0.0f, 360.0f);
+                ParticleBurstAmount = 1;
+                ParticleBurstInterval = 1.0f;
+
                 SerializableProperties = SerializableProperty.GetProperties(this);
             }
         }
@@ -210,6 +221,8 @@ namespace Barotrauma
             if (selectedPrefab != null)
             {
                 emitter.EmitTimer += (float)deltaTime;
+                emitter.BurstTimer += (float)deltaTime;
+
 
                 if (emitter.ParticlesPerSecond > 0)
                 {
@@ -221,10 +234,15 @@ namespace Barotrauma
                     }
                 }
 
-                for (int i = 0; i < emitter.ParticleAmount; i++)
+                if (emitter.BurstTimer > emitter.ParticleBurstInterval)
                 {
-                    Emit(Vector2.Zero);
+                    for (int i = 0; i < emitter.ParticleBurstAmount; i++)
+                    {
+                        Emit(Vector2.Zero);
+                    }
+                    emitter.BurstTimer = 0.0f;
                 }
+
             }
 
             GameMain.ParticleManager.Update((float)deltaTime);