Support randomized footsteps.

src/sound/footstep.rs

@@ -1,14 +1,14 @@
 use std::collections::HashMap;
 
 use bevy::{prelude::*, transform::TransformSystem};
-use bevy_synthizer::{Audio, Sound};
-use rand::random;
+use bevy_synthizer::{Audio, Buffer, Sound};
+use rand::prelude::*;
 
 use crate::core::PointLike;
 
 #[derive(Component, Clone, Debug)]
 pub struct Footstep {
-    pub audio: Audio,
+    pub audio: Option<Audio>,
     pub step_length: f32,
     pub gain: f64,
     pub pitch: Option<f64>,
@@ -27,28 +27,82 @@ impl Default for Footstep {
     }
 }
 
+#[derive(Component, Clone, Default, Deref, DerefMut, Debug)]
+pub struct Footsteps(pub Vec<Audio>);
+
+impl Footsteps {
+    pub fn from_handles(handles: Vec<Handle<Buffer>>) -> Self {
+        Self(
+            handles
+                .iter()
+                .cloned()
+                .map(|v| v.into())
+                .collect::<Vec<Audio>>(),
+        )
+    }
+}
+
 fn added(mut commands: Commands, footsteps: Query<(Entity, &Footstep), Added<Footstep>>) {
     for (entity, footstep) in &footsteps {
-        let buffer = footstep.audio.clone();
+        if let Some(audio) = &footstep.audio {
             commands.entity(entity).insert(Sound {
-            audio: buffer.into(),
+                audio: audio.clone(),
                 paused: true,
                 ..default()
             });
         }
+    }
 }
 
 fn update(
+    mut commands: Commands,
     mut last_step_distance: Local<HashMap<Entity, (f32, GlobalTransform)>>,
-    mut footsteps: Query<(Entity, &Footstep, &Parent, &mut Sound)>,
+    mut query: Query<(
+        Entity,
+        &Footstep,
+        &Parent,
+        Option<&mut Sound>,
+        Option<&Footsteps>,
+    )>,
     transforms_storage: Query<&GlobalTransform>,
 ) {
-    for (entity, footstep, parent, mut sound) in &mut footsteps {
+    for (entity, footstep, parent, sound, footsteps) in &mut query {
         if let Ok(transform) = transforms_storage.get(**parent) {
             if let Some(last) = last_step_distance.get(&entity) {
                 let distance = last.0 + (last.1.distance(transform));
                 if distance >= footstep.step_length {
                     last_step_distance.insert(entity, (0., *transform));
+                    if let Some(footsteps) = footsteps {
+                        let audio = if footsteps.len() == 1 {
+                            Some(footsteps[0].clone())
+                        } else if !footsteps.is_empty() {
+                            let mut footsteps = footsteps.clone();
+                            footsteps.shuffle(&mut thread_rng());
+                            let mut audio = footsteps.first().unwrap().clone();
+                            if let Some(sound) = sound {
+                                while sound.audio == audio {
+                                    footsteps.shuffle(&mut thread_rng());
+                                    audio = footsteps[0].clone();
+                                }
+                            }
+                            Some(audio)
+                        } else {
+                            None
+                        };
+                        if let Some(audio) = audio {
+                            let mut pitch = 1.;
+                            if let Some(pitch_variation) = footstep.pitch_variation {
+                                pitch -= pitch_variation / 2.;
+                                pitch += random::<f64>() * pitch_variation;
+                            }
+                            commands.entity(entity).insert(Sound {
+                                audio,
+                                gain: footstep.gain,
+                                pitch,
+                                ..default()
+                            });
+                        }
+                    } else if let Some(mut sound) = sound {
                         sound.gain = footstep.gain;
                         sound.pitch = footstep.pitch.unwrap_or(1.);
                         if let Some(pitch_variation) = footstep.pitch_variation {
@@ -58,6 +112,7 @@ fn update(
                         }
                         sound.paused = false;
                         sound.restart = true;
+                    }
                 } else if last.1 != *transform {
                     last_step_distance.insert(entity, (distance, *transform));
                 }

src/sound/mod.rs

@@ -5,7 +5,7 @@ pub mod icon;
 pub mod pitch_shift;
 pub mod volumetric;
 
-pub use footstep::Footstep;
+pub use footstep::{Footstep, Footsteps};
 pub use icon::{SoundIcon, SoundIconPlugin};
 pub use pitch_shift::PitchShiftPlugin;
 pub use volumetric::Volumetric;