New Trait: Light Step (#658)

# Description

**Light Step** is a 1-point Auditory trait that reduces the volume of
your footsteps by roughly 50%, enabling you to be quieter and
stealthier. Inspired by the SS13 trait of the same name.

## TODO

- [x] Locale strings
- [x] ~~Reduce the distance in which Light Step footsteps can be heard~~
- It turns out that whatever I did reduced the delay between footstep
sounds.
- [x] Discuss the balancing values for the trait

## Technical details

In the current implementation, Light Step reduces the volume of
footsteps by 10 dB, resulting in roughly halving the volume.

The fields in `FootstepVolumeModifierComponent` change the volume in
terms of decibels.

## Media


![image](https://github.com/user-attachments/assets/d1e3efee-6f81-4212-a745-ae08687afcc0)

# Changelog

:cl: Skubman
- add: Add the Light Step trait, a 1-point trait that makes your
footsteps quieter.

---------

Signed-off-by: Angelo Fallaria <[email protected]>

Content.Shared/Movement/Systems/SharedMoverController.cs

@@ -12,6 +12,7 @@
 using Content.Shared.Movement.Events;
 using Content.Shared.StepTrigger.Components;
 using Content.Shared.Tag;
+using Content.Shared.Traits.Assorted.Components;
 using Robust.Shared.Audio;
 using Robust.Shared.Audio.Systems;
 using Robust.Shared.Configuration;
@@ -261,9 +262,17 @@ protected void HandleMobMovement(
                     TryGetSound(weightless, uid, mover, mobMover, xform, out var sound, tileDef: tileDef))
                 {
                     var soundModifier = mover.Sprinting ? 3.5f : 1.5f;
+                    var volume = sound.Params.Volume + soundModifier;
+
+                    if (_entities.TryGetComponent(uid, out FootstepVolumeModifierComponent? volumeModifier))
+                    {
+                        volume += mover.Sprinting
+                            ? volumeModifier.SprintVolumeModifier
+                            : volumeModifier.WalkVolumeModifier;
+                    }
 
                     var audioParams = sound.Params
-                        .WithVolume(sound.Params.Volume + soundModifier)
+                        .WithVolume(volume)
                         .WithVariation(sound.Params.Variation ?? FootstepVariation);
 
                     // If we're a relay target then predict the sound for all relays.

Content.Shared/Traits/Assorted/Components/FootstepVolumeModifierComponent.cs

@@ -0,0 +1,22 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.Traits.Assorted.Components;
+
+/// <summary>
+///     This is used for any trait that modifies footstep volumes.
+/// </summary>
+[RegisterComponent, NetworkedComponent, AutoGenerateComponentState]
+public sealed partial class FootstepVolumeModifierComponent : Component
+{
+    /// <summary>
+    ///     What to add to the volume of sprinting, in terms of decibels.
+    /// </summary>
+    [DataField, AutoNetworkedField]
+    public float SprintVolumeModifier;
+
+    /// <summary>
+    ///     What to add to the volume of walking, in terms of decibels.
+    /// </summary>
+    [DataField, AutoNetworkedField]
+    public float WalkVolumeModifier;
+}

Resources/Locale/en-US/traits/traits.ftl

@@ -60,3 +60,7 @@ trait-name-Voracious = Voracious
 trait-description-Voracious =
     Nothing gets between you and your food.
     Your endless consumption of food and drinks is twice as fast.
+
+trait-name-LightStep = Light Step
+trait-description-LightStep =
+    You move with a gentle step, making your footsteps quieter.

Resources/Prototypes/Traits/skills.yml

@@ -40,3 +40,17 @@
     - type: ConsumeDelayModifier
       foodDelayMultiplier: 0.5
       drinkDelayMultiplier: 0.5
+
+- type: trait
+  id: LightStep
+  category: Auditory
+  points: -1
+  components:
+    - type: FootstepVolumeModifier
+      sprintVolumeModifier: -10
+      walkVolumeModifier: -10
+  requirements:
+    - !type:CharacterSpeciesRequirement
+      inverted: true
+      species:
+        - Felinid