Ambient sound system (#4552)

* Ambient sound system

Client-side system that plays audio from nearby objects that are randomly sampled.

* Decent

* Tweaks

* Tweaks

* Comment this out for now

* reduce VM sound

* Fix rolloff

* Fixes

* Volume tweak

Content.Shared/Audio/AmbientSoundComponent.cs

@@ -0,0 +1,46 @@
+using System;
+using Content.Shared.Sound;
+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+using Robust.Shared.Serialization;
+using Robust.Shared.Serialization.Manager.Attributes;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.Audio
+{
+    [RegisterComponent]
+    [NetworkedComponent]
+    public sealed class AmbientSoundComponent : Component
+    {
+        public override string Name => "AmbientSound";
+
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("enabled")]
+        public bool Enabled { get; set; } = true;
+
+        [DataField("sound")]
+        public SoundSpecifier Sound = default!;
+
+        /// <summary>
+        /// How far away this ambient sound can potentially be heard.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("range")]
+        public float Range = 2f;
+
+        /// <summary>
+        /// Applies this volume to the sound being played.
+        /// </summary>
+        [ViewVariables(VVAccess.ReadWrite)]
+        [DataField("volume")]
+        public float Volume = -10f;
+    }
+
+    [Serializable, NetSerializable]
+    public sealed class AmbientSoundComponentState : ComponentState
+    {
+        public bool Enabled { get; init; }
+        public float Range { get; init; }
+        public float Volume { get; init; }
+    }
+}

Content.Shared/Audio/SharedAmbientSoundSystem.cs

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+using Robust.Shared.GameObjects;
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Audio
+{
+    public abstract class SharedAmbientSoundSystem : EntitySystem
+    {
+        public override void Initialize()
+        {
+            base.Initialize();
+            SubscribeLocalEvent<AmbientSoundComponent, ComponentGetState>(GetCompState);
+            SubscribeLocalEvent<AmbientSoundComponent, ComponentHandleState>(HandleCompState);
+        }
+
+        public void SetAmbience(EntityUid uid, bool value)
+        {
+            // Reason I didn't make this eventbus for the callers is because it seemed a bit silly
+            // trying to account for damageable + powered + toggle, plus we can't just check if it's powered.
+            // So we'll just call it directly for whatever.
+            if (!ComponentManager.TryGetComponent<AmbientSoundComponent>(uid, out var ambience) ||
+                ambience.Enabled == value) return;
+
+            ambience.Enabled = value;
+            ambience.Dirty();
+        }
+
+        private void HandleCompState(EntityUid uid, AmbientSoundComponent component, ref ComponentHandleState args)
+        {
+            if (args.Current is not AmbientSoundComponentState state) return;
+            component.Enabled = state.Enabled;
+            component.Range = state.Range;
+            component.Volume = state.Volume;
+        }
+
+        private void GetCompState(EntityUid uid, AmbientSoundComponent component, ref ComponentGetState args)
+        {
+            args.State = new AmbientSoundComponentState
+            {
+                Enabled = component.Enabled,
+                Range = component.Range,
+                Volume = component.Volume,
+            };
+        }
+    }
+}