blackout/src/sound/volumetric.rs

use bevy::{prelude::*, transform::TransformSystem};
use bevy_rapier2d::{parry::query::ClosestPoints, prelude::*};
use bevy_synthizer::{Listener, Sound};

use crate::{commands::RunIfExistsExt, core::GlobalTransformExt};

#[derive(Component, Clone, Copy, Debug)]
pub struct Volumetric;

fn update(
    listener: Query<(&Collider, &GlobalTransform), With<Listener>>,
    mut sounds: Query<(&Sound, &Parent, &mut Transform), With<Volumetric>>,
    colliders: Query<(&Collider, &GlobalTransform)>,
) {
    if let Ok((listener_collider, listener_global_transform)) = listener.get_single() {
        for (sound, parent, mut sound_transform) in &mut sounds {
            if sound.paused {
                continue;
            }
            if let Ok((sound_collider, sound_global_transform)) = colliders.get(**parent) {
                let closest = listener_global_transform.closest_points(
                    listener_collider,
                    sound_global_transform,
                    sound_collider,
                );
                if let ClosestPoints::WithinMargin(_p1, p2) = closest {
                    let p2 = Vec3::new(p2.x, p2.y, 0.);
                    sound_transform.translation.x = p2.x - sound_global_transform.translation().x;
                    sound_transform.translation.y = p2.y - sound_global_transform.translation().y;
                } else if closest == ClosestPoints::Intersecting {
                    sound_transform.translation.x = listener_global_transform.translation().x
                        - sound_global_transform.translation().x;
                    sound_transform.translation.y = listener_global_transform.translation().y
                        - sound_global_transform.translation().y;
                }
            }
        }
    }
}

fn removed(mut commands: Commands, removed: RemovedComponents<Volumetric>) {
    for entity in removed.iter() {
        commands.run_if_exists(entity, |mut entity| {
            entity.insert_bundle(TransformBundle::default());
        });
    }
}

pub struct VolumetricPlugin;

impl Plugin for VolumetricPlugin {
    fn build(&self, app: &mut App) {
        app.add_system_to_stage(
            CoreStage::PostUpdate,
            update.before(TransformSystem::TransformPropagate),
        )
        .add_system_to_stage(CoreStage::PostUpdate, removed);
    }
}