Particle/Vection Fields (#665)

<!-- A new module or something else important -->
## Major features
- New `ParticleFields` module. Add particles to your planet (ex: leaves,
rain, snow, fireflies, and more). Resolves #219

<!-- A new parameter added to a module, or API feature -->
## Minor features
-

<!-- Some improvement that requires no action on the part of add-on
creators i.e., improved star graphics -->
## Improvements
-

<!-- Be sure to reference the existing issue if it exists -->
## Bug fixes
-

NewHorizons/Builder/Atmosphere/EffectsBuilder.cs

@@ -1,4 +1,5 @@
 using NewHorizons.External.Configs;
+using NewHorizons.External.Modules;
 using NewHorizons.Utility;
 using UnityEngine;
 namespace NewHorizons.Builder.Atmosphere
@@ -7,6 +8,21 @@ namespace NewHorizons.Builder.Atmosphere
     {
         private static GameObject _rainEmitterPrefab;
         private static GameObject _snowEmitterPrefab;
+        private static GameObject _snowLightEmitterPrefab;
+        private static GameObject _emberEmitterPrefab;
+        private static GameObject _leafEmitterPrefab;
+        private static GameObject _planktonEmitterPrefab;
+        private static GameObject _bubbleEmitterPrefab;
+        private static GameObject _currentEmitterPrefab;
+        private static GameObject _cloudEmitterPrefab;
+        private static GameObject _crawliesEmitterPrefab;
+        private static GameObject _firefliesEmitterPrefab;
+        private static GameObject _pollenEmitterPrefab;
+        private static GameObject _iceMoteEmitterPrefab;
+        private static GameObject _rockMoteEmitterPrefab;
+        private static GameObject _crystalMoteEmitterPrefab;
+        private static GameObject _sandMoteEmitterPrefab;
+        private static GameObject _fogEmitterPrefab;
 
         private static bool _isInit;
 
@@ -18,9 +34,24 @@ namespace NewHorizons.Builder.Atmosphere
 
             if (_rainEmitterPrefab == null) _rainEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Sector_GDInterior/Effects_GDInterior/Effects_GD_Rain").InstantiateInactive().Rename("Prefab_Effects_Rain").DontDestroyOnLoad();
             if (_snowEmitterPrefab == null) _snowEmitterPrefab = SearchUtilities.Find("BrittleHollow_Body/Sector_BH/Effects_BH/Effects_BH_Snowflakes").InstantiateInactive().Rename("Prefab_Effects_Snowflakes").DontDestroyOnLoad();
+            if (_snowLightEmitterPrefab == null) _snowLightEmitterPrefab = SearchUtilities.Find("TimberHearth_Body/Sector_TH/Effects_TH/Effects_TH_Snowflakes").InstantiateInactive().Rename("Prefab_Effects_SnowflakesLight").DontDestroyOnLoad();
+            if (_emberEmitterPrefab == null) _emberEmitterPrefab = SearchUtilities.Find("VolcanicMoon_Body/Sector_VM/Effects_VM/Effects_VM_Embers").InstantiateInactive().Rename("Prefab_Effects_Embers").DontDestroyOnLoad();
+            if (_leafEmitterPrefab == null) _leafEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Sector_GDInterior/Effects_GDInterior/Effects_GD_Leaves").InstantiateInactive().Rename("Prefab_Effects_Leaves").DontDestroyOnLoad();
+            if (_planktonEmitterPrefab == null) _planktonEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Sector_GDInterior/Effects_GDInterior/Effects_GD_Plankton").InstantiateInactive().Rename("Prefab_Effects_Plankton").DontDestroyOnLoad();
+            if (_bubbleEmitterPrefab == null) _bubbleEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Sector_GDInterior/Effects_GDInterior/Effects_GD_Bubbles").InstantiateInactive().Rename("Prefab_Effects_Bubbles").DontDestroyOnLoad();
+            if (_currentEmitterPrefab == null) _currentEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Sector_GDInterior/Effects_GDInterior/Effects_GD_RadialCurrent").InstantiateInactive().Rename("Prefab_Effects_Current").DontDestroyOnLoad();
+            if (_cloudEmitterPrefab == null) _cloudEmitterPrefab = SearchUtilities.Find("GiantsDeep_Body/Sector_GD/Effects_GD/Effects_GD_Clouds").InstantiateInactive().Rename("Prefab_Effects_Clouds").DontDestroyOnLoad();
+            if (_crawliesEmitterPrefab == null) _crawliesEmitterPrefab = SearchUtilities.Find("DB_EscapePodDimension_Body/Sector_EscapePodDimension/Effects_EscapePodDimension/Effects_DB_Crawlies (1)").InstantiateInactive().Rename("Prefab_Effects_Crawlies").DontDestroyOnLoad();
+            if (_firefliesEmitterPrefab == null) _firefliesEmitterPrefab = SearchUtilities.Find("TimberHearth_Body/Sector_TH/Effects_TH/Effects_TH_Fireflies").InstantiateInactive().Rename("Prefab_Effects_Fireflies").DontDestroyOnLoad();
+            if (_pollenEmitterPrefab == null) _pollenEmitterPrefab = SearchUtilities.Find("TimberHearth_Body/Sector_TH/Effects_TH/Effects_TH_SurfacePollen").InstantiateInactive().Rename("Prefab_Effects_Pollen").DontDestroyOnLoad();
+            if (_iceMoteEmitterPrefab == null) _iceMoteEmitterPrefab = SearchUtilities.Find("DarkBramble_Body/Effects_DB/Effects_DB_IceMotes").InstantiateInactive().Rename("Prefab_Effects_IceMotes").DontDestroyOnLoad();
+            if (_rockMoteEmitterPrefab == null) _rockMoteEmitterPrefab = SearchUtilities.Find("BrittleHollow_Body/Sector_BH/Effects_BH/Effects_BH_RockMotes").InstantiateInactive().Rename("Prefab_Effects_RockMotes").DontDestroyOnLoad();
+            if (_crystalMoteEmitterPrefab == null) _crystalMoteEmitterPrefab = SearchUtilities.Find("BrittleHollow_Body/Sector_BH/Effects_BH/Effects_BH_CrystalMotes").InstantiateInactive().Rename("Prefab_Effects_CrystalMotes").DontDestroyOnLoad();
+            if (_sandMoteEmitterPrefab == null) _sandMoteEmitterPrefab = SearchUtilities.Find("CaveTwin_Body/Sector_CaveTwin/Effects_CaveTwin/Effects_HGT_SandMotes").InstantiateInactive().Rename("Prefab_Effects_SandMotes").DontDestroyOnLoad();
+            if (_fogEmitterPrefab == null) _fogEmitterPrefab = SearchUtilities.Find("DB_EscapePodDimension_Body/Sector_EscapePodDimension/Effects_EscapePodDimension/Effects_DB_Fog (1)").InstantiateInactive().Rename("Prefab_Effects_Fog").DontDestroyOnLoad();
         }
 
-        public static void Make(GameObject planetGO, Sector sector, PlanetConfig config, float surfaceSize)
+        public static void Make(GameObject planetGO, Sector sector, PlanetConfig config)
         {
             InitPrefabs();
 
@@ -36,7 +67,7 @@ namespace NewHorizons.Builder.Atmosphere
             SCG._dynamicCullingBounds = false;
             SCG._waitForStreaming = false;
 
-            var minHeight = surfaceSize;
+            var minHeight = config.Base.surfaceSize;
             if (config.HeightMap?.minHeight != null)
             {
                 if (config.Water?.size >= config.HeightMap.minHeight) minHeight = config.Water.size; // use sea level if its higher
@@ -48,52 +79,56 @@ namespace NewHorizons.Builder.Atmosphere
             var maxHeight = config.Atmosphere.size;
             if (config.Atmosphere.clouds?.outerCloudRadius != null) maxHeight = config.Atmosphere.clouds.outerCloudRadius;
 
-            if (config.Atmosphere.hasRain)
+            foreach (var particleField in config.ParticleFields)
             {
-                var rainGO = Object.Instantiate(_rainEmitterPrefab, effectsGO.transform);
+                var prefab = GetPrefabByType(particleField.type);
-                rainGO.name = "RainEmitter";
+                var emitter = Object.Instantiate(prefab, effectsGO.transform);
-                rainGO.transform.position = planetGO.transform.position;
+                emitter.name = !string.IsNullOrWhiteSpace(particleField.rename) ? particleField.rename : prefab.name.Replace("Prefab_", "");
+                emitter.transform.position = planetGO.transform.position;
 
-                var pvc = rainGO.GetComponent<PlanetaryVectionController>();
+                var vfe = emitter.GetComponent<VectionFieldEmitter>();
-                pvc._densityByHeight = new AnimationCurve(new Keyframe[]
+                var pvc = emitter.GetComponent<PlanetaryVectionController>();
+                pvc._vectionFieldEmitter = vfe;
+                pvc._densityByHeight = particleField.densityByHeightCurve != null ? particleField.densityByHeightCurve.ToAnimationCurve() : new AnimationCurve(new Keyframe[]
                 {
                     new Keyframe(minHeight - 0.5f, 0),
                     new Keyframe(minHeight, 10f),
                     new Keyframe(maxHeight, 0f)
                 });
+                pvc._followTarget = particleField.followTarget == ParticleFieldModule.FollowTarget.Probe ? PlanetaryVectionController.FollowTarget.Probe : PlanetaryVectionController.FollowTarget.Player;
+                pvc._activeInSector = sector;
+                pvc._exclusionSectors = new Sector[] { };
 
-                rainGO.GetComponent<PlanetaryVectionController>()._activeInSector = sector;
+                emitter.SetActive(true);
-                rainGO.GetComponent<PlanetaryVectionController>()._exclusionSectors = new Sector[] { };
-                rainGO.SetActive(true);
-            }
-
-            if (config.Atmosphere.hasSnow)
-            {
-                var snowGO = new GameObject("SnowEffects");
-                snowGO.transform.parent = effectsGO.transform;
-                snowGO.transform.position = planetGO.transform.position;
-                for (int i = 0; i < 5; i++)
-                {
-                    var snowEmitter = Object.Instantiate(_snowEmitterPrefab, snowGO.transform);
-                    snowEmitter.name = "SnowEmitter";
-                    snowEmitter.transform.position = planetGO.transform.position;
-
-                    var pvc = snowEmitter.GetComponent<PlanetaryVectionController>();
-                    pvc._densityByHeight = new AnimationCurve(new Keyframe[]
-                    {
-                        new Keyframe(minHeight - 0.5f, 0),
-                        new Keyframe(minHeight, 10f),
-                        new Keyframe(maxHeight, 0f)
-                    });
-
-                    snowEmitter.GetComponent<PlanetaryVectionController>()._activeInSector = sector;
-                    snowEmitter.GetComponent<PlanetaryVectionController>()._exclusionSectors = new Sector[] { };
-                    snowEmitter.SetActive(true);
-                }
             }
 
             effectsGO.transform.position = planetGO.transform.position;
             effectsGO.SetActive(true);
         }
+
+        public static GameObject GetPrefabByType(ParticleFieldModule.ParticleFieldType type)
+        {
+            return type switch
+            {
+                ParticleFieldModule.ParticleFieldType.Rain => _rainEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.SnowflakesHeavy => _snowEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.SnowflakesLight => _snowLightEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Embers => _emberEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Clouds => _cloudEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Leaves => _leafEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Bubbles => _bubbleEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Fog => _fogEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.CrystalMotes => _crystalMoteEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.RockMotes => _rockMoteEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.IceMotes => _iceMoteEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.SandMotes => _sandMoteEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Crawlies => _crawliesEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Fireflies => _firefliesEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Plankton => _planktonEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Pollen => _pollenEmitterPrefab,
+                ParticleFieldModule.ParticleFieldType.Current => _currentEmitterPrefab,
+                _ => null,
+            };
+        }
     }
 }

NewHorizons/External/Configs/PlanetConfig.cs

@@ -13,6 +13,7 @@ using System.Collections.Generic;
 using System.ComponentModel;
 using System.ComponentModel.DataAnnotations;
 using System.Linq;
+using UnityEngine;
 
 namespace NewHorizons.External.Configs
 {
@@ -167,6 +168,12 @@ namespace NewHorizons.External.Configs
         /// </summary>
         public WaterModule Water;
 
+        /// <summary>
+        /// Add particle effects in a field around the planet.
+        /// Also known as Vection Fields.
+        /// </summary>
+        public ParticleFieldModule[] ParticleFields;
+
         /// <summary>
         /// Add various volumes on this body
         /// </summary>
@@ -341,6 +348,29 @@ namespace NewHorizons.External.Configs
                 // useBasicCloudShader is obsolete
                 if (Atmosphere.clouds != null && Atmosphere.clouds.useBasicCloudShader)
                     Atmosphere.clouds.cloudsPrefab = CloudPrefabType.Basic;
+
+                if (Atmosphere.hasRain)
+                {
+                    if (ParticleFields == null) ParticleFields = new ParticleFieldModule[0];
+                    ParticleFields = ParticleFields.Append(new ParticleFieldModule
+                    {
+                        type = ParticleFieldModule.ParticleFieldType.Rain,
+                        rename = "RainEmitter"
+                    }).ToArray();
+                }
+
+                if (Atmosphere.hasSnow)
+                {
+                    if (ParticleFields == null) ParticleFields = new ParticleFieldModule[0];
+                    for (int i = 0; i < 5; i++)
+                    {
+                        ParticleFields = ParticleFields.Append(new ParticleFieldModule
+                        {
+                            type = ParticleFieldModule.ParticleFieldType.SnowflakesHeavy,
+                            rename = "SnowEmitter"
+                        }).ToArray();
+                    }
+                }
             }
 
             if (Props?.tornados != null)

NewHorizons/External/Modules/AtmosphereModule.cs

@@ -76,14 +76,11 @@ namespace NewHorizons.External.Modules
 
         /// <summary>
         /// Does this planet have rain? 
+        /// This is equivalent to effects of setting a rain particle/vection field, rain audio volume, and visor effect volume, combined for convenience.
+        /// For more control over the rain, use those individual components.
         /// </summary>
         public bool hasRain;
 
-        /// <summary>
-        /// Does this planet have snow?
-        /// </summary>
-        public bool hasSnow;
-
         /// <summary>
         /// Scale height of the atmosphere
         /// </summary>
@@ -174,7 +171,6 @@ namespace NewHorizons.External.Modules
             /// </summary>
             [DefaultValue(0f)] public float rotationSpeed = 0f;
 
-            
             #region Obsolete
 
             /// <summary>
@@ -189,6 +185,8 @@ namespace NewHorizons.External.Modules
 
 
         #region Obsolete
+        [Obsolete("HasSnow is deprecated, please use ParticleFields instead")]
+        public bool hasSnow;
 
         [Obsolete("CloudTint is deprecated, please use CloudInfo instead")]
         public MColor cloudTint;
@@ -208,7 +206,8 @@ namespace NewHorizons.External.Modules
         [Obsolete("UseBasicCloudShader is deprecated, please use CloudInfo instead")]
         public bool useBasicCloudShader;
 
-        [DefaultValue(true)] [Obsolete("ShadowsOnClouds is deprecated, please use CloudInfo instead")]
+        [DefaultValue(true)]
+        [Obsolete("ShadowsOnClouds is deprecated, please use CloudInfo instead")]
         public bool shadowsOnClouds = true;
 
         [Obsolete("HasAtmosphere is deprecated, please use UseAtmosphereShader instead")]

NewHorizons/External/Modules/VectionFieldModule.cs

@@ -0,0 +1,79 @@
+using NewHorizons.External.Modules.VariableSize;
+using NewHorizons.External.SerializableData;
+using NewHorizons.External.SerializableEnums;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using System;
+using System.ComponentModel;
+using System.Runtime.Serialization;
+
+namespace NewHorizons.External.Modules
+{
+    [JsonObject]
+    public class ParticleFieldModule
+    {
+        /// <summary>
+        /// Particle type for this vection field.
+        /// </summary>
+        public ParticleFieldType type;
+
+        /// <summary>
+        /// What the particle field activates based on.
+        /// </summary>
+        [DefaultValue("player")] public FollowTarget followTarget = FollowTarget.Player;
+
+        /// <summary>
+        /// Density by height curve. Determines how many particles are emitted at different heights.
+        /// Defaults to a curve based on minimum and maximum heights of various other modules.
+        /// </summary>
+        public HeightDensityPair[] densityByHeightCurve;
+
+        /// <summary>
+        /// An optional rename of this object
+        /// </summary>
+        public string rename;
+
+        [JsonObject]
+        public class HeightDensityPair
+        {
+            /// <summary>
+            /// A specific radius
+            /// </summary>
+            public float height;
+
+            /// <summary>
+            /// The particle count for this radius.
+            /// </summary>
+            public float density;
+        }
+
+        [JsonConverter(typeof(StringEnumConverter))]
+        public enum ParticleFieldType
+        {
+            [EnumMember(Value = @"rain")] Rain,
+            [EnumMember(Value = @"snowflakesHeavy")] SnowflakesHeavy,
+            [EnumMember(Value = @"snowflakesLight")] SnowflakesLight,
+            [EnumMember(Value = @"embers")] Embers,
+            [EnumMember(Value = @"clouds")] Clouds,
+            [EnumMember(Value = @"leaves")] Leaves,
+            [EnumMember(Value = @"bubbles")] Bubbles,
+            [EnumMember(Value = @"fog")] Fog,
+            [EnumMember(Value = @"crystalMotes")] CrystalMotes,
+            [EnumMember(Value = @"rockMotes")] RockMotes,
+            [EnumMember(Value = @"iceMotes")] IceMotes,
+            [EnumMember(Value = @"sandMotes")] SandMotes,
+            [EnumMember(Value = @"crawlies")] Crawlies,
+            [EnumMember(Value = @"fireflies")] Fireflies,
+            [EnumMember(Value = @"plankton")] Plankton,
+            [EnumMember(Value = @"pollen")] Pollen,
+            [EnumMember(Value = @"current")] Current
+        }
+
+        [JsonConverter(typeof(StringEnumConverter))]
+        public enum FollowTarget
+        {
+            [EnumMember(Value = @"player")] Player,
+            [EnumMember(Value = @"probe")] Probe
+        }
+    }
+}

NewHorizons/Handlers/PlanetCreationHandler.cs

@@ -654,9 +654,6 @@ namespace NewHorizons.Handlers
                     }
                 }
 
-                if (body.Config.Atmosphere.hasRain || body.Config.Atmosphere.hasSnow)
-                    EffectsBuilder.Make(go, sector, body.Config, surfaceSize);
-
                 if (body.Config.Atmosphere.fogSize != 0)
                 {
                     fog = FogBuilder.Make(go, sector, body.Config.Atmosphere, body.Mod);
@@ -665,6 +662,11 @@ namespace NewHorizons.Handlers
                 atmosphere = AtmosphereBuilder.Make(go, sector, body.Config.Atmosphere, surfaceSize).GetComponentInChildren<LODGroup>();
             }
 
+            if (body.Config.ParticleFields != null)
+            {
+                EffectsBuilder.Make(go, sector, body.Config);
+            }
+
             if (body.Config.Props != null)
             {
                 PropBuildManager.Make(go, sector, rb, body);

NewHorizons/Schemas/body_schema.json

@@ -132,6 +132,13 @@
       "description": "Add water to this planet",
       "$ref": "#/definitions/WaterModule"
     },
+    "ParticleFields": {
+      "type": "array",
+      "description": "Add particle effects in a field around the planet.\nAlso known as Vection Fields.",
+      "items": {
+        "$ref": "#/definitions/ParticleFieldModule"
+      }
+    },
     "Volumes": {
       "description": "Add various volumes on this body",
       "$ref": "#/definitions/VolumesModule"
@@ -371,11 +378,7 @@
         },
         "hasRain": {
           "type": "boolean",
-          "description": "Does this planet have rain?"
+          "description": "Does this planet have rain? \nThis is equivalent to effects of setting a rain particle/vection field, rain audio volume, and visor effect volume, combined for convenience.\nFor more control over the rain, use those individual components."
-        },
-        "hasSnow": {
-          "type": "boolean",
-          "description": "Does this planet have snow?"
         },
         "size": {
           "type": "number",
@@ -3583,6 +3586,102 @@
         }
       }
     },
+    "ParticleFieldModule": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "type": {
+          "description": "Particle type for this vection field.",
+          "$ref": "#/definitions/ParticleFieldType"
+        },
+        "followTarget": {
+          "description": "What the particle field activates based on.",
+          "default": "player",
+          "$ref": "#/definitions/FollowTarget"
+        },
+        "densityByHeightCurve": {
+          "type": "array",
+          "description": "Density by height curve. Determines how many particles are emitted at different heights.\nDefaults to a curve based on minimum and maximum heights of various other modules.",
+          "items": {
+            "$ref": "#/definitions/HeightDensityPair"
+          }
+        },
+        "rename": {
+          "type": "string",
+          "description": "An optional rename of this object"
+        }
+      }
+    },
+    "ParticleFieldType": {
+      "type": "string",
+      "description": "",
+      "x-enumNames": [
+        "Rain",
+        "SnowflakesHeavy",
+        "SnowflakesLight",
+        "Embers",
+        "Clouds",
+        "Leaves",
+        "Bubbles",
+        "Fog",
+        "CrystalMotes",
+        "RockMotes",
+        "IceMotes",
+        "SandMotes",
+        "Crawlies",
+        "Fireflies",
+        "Plankton",
+        "Pollen",
+        "Current"
+      ],
+      "enum": [
+        "rain",
+        "snowflakesHeavy",
+        "snowflakesLight",
+        "embers",
+        "clouds",
+        "leaves",
+        "bubbles",
+        "fog",
+        "crystalMotes",
+        "rockMotes",
+        "iceMotes",
+        "sandMotes",
+        "crawlies",
+        "fireflies",
+        "plankton",
+        "pollen",
+        "current"
+      ]
+    },
+    "FollowTarget": {
+      "type": "string",
+      "description": "",
+      "x-enumNames": [
+        "Player",
+        "Probe"
+      ],
+      "enum": [
+        "player",
+        "probe"
+      ]
+    },
+    "HeightDensityPair": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "height": {
+          "type": "number",
+          "description": "A specific radius",
+          "format": "float"
+        },
+        "density": {
+          "type": "number",
+          "description": "The particle count for this radius.",
+          "format": "float"
+        }
+      }
+    },
     "VolumesModule": {
       "type": "object",
       "additionalProperties": false,

NewHorizons/Utility/NewHorizonExtensions.cs

@@ -1,4 +1,5 @@
 using NewHorizons.External.Configs;
+using NewHorizons.External.Modules.VariableSize;
 using NewHorizons.External.SerializableData;
 using NewHorizons.External.SerializableEnums;
 using NewHorizons.Utility.OWML;
@@ -12,6 +13,7 @@ using System.Reflection;
 using System.Text;
 using System.Text.RegularExpressions;
 using UnityEngine;
+using static NewHorizons.External.Modules.ParticleFieldModule;
 using NomaiCoordinates = NewHorizons.External.Configs.StarSystemConfig.NomaiCoordinates;
 
 namespace NewHorizons.Utility
@@ -277,5 +279,31 @@ namespace NewHorizons.Utility
         {
             go.transform.rotation = Quaternion.FromToRotation(Vector3.forward, direction);
         }
+
+        public static AnimationCurve ToAnimationCurve(this TimeValuePair[] pairs)
+        {
+            var curve = new AnimationCurve();
+            if (pairs != null)
+            {
+                foreach (var pair in pairs)
+                {
+                    curve.AddKey(new Keyframe(pair.time, pair.value));
+                }
+            }
+            return curve;
+        }
+
+        public static AnimationCurve ToAnimationCurve(this HeightDensityPair[] pairs)
+        {
+            var curve = new AnimationCurve();
+            if (pairs != null)
+            {
+                foreach (var pair in pairs)
+                {
+                    curve.AddKey(new Keyframe(pair.height, pair.density));
+                }
+            }
+            return curve;
+        }
     }
 }