blackout/src/sound/footstep.rs

use std::collections::HashMap;

use bevy::{prelude::*, transform::TransformSystem};
use bevy_synthizer::{Audio, Buffer, Sound};
use rand::prelude::*;

use crate::core::PointLike;

#[derive(Component, Clone, Debug)]
pub struct Footstep {
    pub audio: Option<Audio>,
    pub step_length: f32,
    pub gain: f64,
    pub pitch: Option<f64>,
    pub pitch_variation: Option<f64>,
}

impl Default for Footstep {
    fn default() -> Self {
        Self {
            audio: default(),
            step_length: 0.8,
            gain: 1.,
            pitch: None,
            pitch_variation: Some(0.15),
        }
    }
}

#[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 {
        if let Some(audio) = &footstep.audio {
            commands.entity(entity).insert(Sound {
                audio: audio.clone(),
                paused: true,
                ..default()
            });
        }
    }
}

fn update(
    mut commands: Commands,
    mut last_step_distance: Local<HashMap<Entity, (f32, GlobalTransform)>>,
    mut query: Query<(
        Entity,
        &Footstep,
        &Parent,
        Option<&mut Sound>,
        Option<&Footsteps>,
    )>,
    transforms_storage: Query<&GlobalTransform>,
) {
    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 {
                            let mut pitch = sound.pitch - pitch_variation / 2.;
                            pitch += random::<f64>() * pitch_variation;
                            sound.pitch = pitch;
                        }
                        sound.paused = false;
                        sound.restart = true;
                    }
                } else if last.1 != *transform {
                    last_step_distance.insert(entity, (distance, *transform));
                }
            } else {
                last_step_distance.insert(entity, (0., *transform));
            }
        }
    }
}

pub struct FootstepPlugin;

impl Plugin for FootstepPlugin {
    fn build(&self, app: &mut App) {
        app.add_system(added.in_base_set(CoreSet::PreUpdate))
            .add_system(
                update
                    .after(TransformSystem::TransformPropagate)
                    .in_base_set(CoreSet::PostUpdate),
            );
    }
}