Physics & Audio

Integrate physics simulation and audio in Bevy - colliders, rigid bodies, and sound triggers.

Recipe

// Physics (conceptual Avian/Rapier-style):
// commands.spawn((
//     RigidBody::Dynamic,
//     Collider::sphere(0.5),
//     Transform::default(),
// ));
 
// Audio:
fn play_jump(asset_server: Res<AssetServer>, mut commands: Commands) {
    commands.spawn((
        AudioPlayer::new(asset_server.load("audio/jump.ogg")),
        PlaybackSettings::DESPAWN,
    ));
}

When to reach for this:

Platformers and 3D games needing collision
Puzzles with realistic stacking or triggers
Action games with responsive SFX and music layers
VR/desktop titles with spatial audio cues

Working Example

Event-driven audio on jump:

use bevy::prelude::*;
 
#[derive(Event)]
struct JumpEvent;
 
fn play_jump_sfx(
    mut events: EventReader<JumpEvent>,
    asset_server: Res<AssetServer>,
    mut commands: Commands,
) {
    for _ in events.read() {
        commands.spawn((
            AudioPlayer::new(asset_server.load("audio/jump.ogg")),
            PlaybackSettings::DESPAWN,
        ));
    }
}

What this demonstrates:

One-shot audio entity despawns after playback
Decoupled jump logic fires event; audio system listens
Asset path consistent with assets/audio/ folder

Deep Dive

How It Works

Physics plugin steps simulation in FixedUpdate schedule.
Colliders generate contact events for gameplay (damage, footstep).
Audio mixes streams; AudioPlayer starts playback on spawn.
Listener component on camera affects 3D pan/volume.

Integration Points

System	Schedule
Physics step	`FixedUpdate`
SFX spawn	`Update` on events
Music loop	Persistent entity with `PlaybackSettings::LOOP`

Gotchas

Physics in variable Update - tunneling at high speed. Fix: only integrate in FixedUpdate.
Collider mesh mismatch with sprite - unfair hits. Fix: debug draw colliders in dev builds.
Too many simultaneous voices - mixer clipping. Fix: pool SFX channels; priority system.
Large uncompressed WAV - load stutter. Fix: OGG/Vorbis compressed assets.
Forgetting listener entity - 3D audio flat. Fix: attach AudioListener to active camera.

Alternatives

Alternative	Use When	Don't Use When
Custom AABB collision	Simple tile game	Many dynamic bodies
FMOD/Wwise via FFI	AAA audio tooling	Small indie scope
2D grid collision manual	Retro grid movement	Physics realism needed
No audio	Silent prototype	Ship to players

FAQs

Which physics crate?

avian (Bevy 0.14+ ecosystem) or bevy_rapier3d/2d - pick one per project and pin version to Bevy release.

Kinematic vs dynamic?

Kinematic for player-controlled that pushes physics; dynamic for crates and ragdolls.

Collision layers?

Collision groups/masks filter what interacts - define in plugin config to reduce work.

Music crossfade?

Two AudioPlayer entities; tween volumes over 1-2 seconds on state change.

Pause audio?

Global volume resource or pause all players when GameState::Paused.

Physics events?

CollisionStarted/Ended events from plugin map to damage or footstep sounds.

Determinism?

Fixed timestep helps; full network determinism needs fixed-point and controlled ordering.

Performance?

Sleeping bodies, simplified colliders, broadphase tuning - see performance page.

Timing?

Game Loops & Timing for FixedUpdate wiring.

Assets?

Assets & Scenes for audio file organization.

Game Loops & Timing - fixed step
Input & Events - trigger events
Bevy Engine - schedules
Assets & Scenes - load audio

Stack versions: This page was written for Rust 1.97.0 (edition 2024), Tokio 1.x, Axum 0.8, serde 1.0, sqlx 0.8, clap 4, and Polars 0.46+.

Physics & Audio

Integrate physics simulation and audio in Bevy - colliders, rigid bodies, and sound triggers.

Recipe

// Physics (conceptual Avian/Rapier-style):
// commands.spawn((
//     RigidBody::Dynamic,
//     Collider::sphere(0.5),
//     Transform::default(),
// ));
 
// Audio:
fn play_jump(asset_server: Res<AssetServer>, mut commands: Commands) {
    commands.spawn((
        AudioPlayer::new(asset_server.load("audio/jump.ogg")),
        PlaybackSettings::DESPAWN,
    ));
}

When to reach for this:

Platformers and 3D games needing collision
Puzzles with realistic stacking or triggers
Action games with responsive SFX and music layers
VR/desktop titles with spatial audio cues

Working Example

Event-driven audio on jump:

use bevy::prelude::*;
 
#[derive(Event)]
struct JumpEvent;
 
fn play_jump_sfx(
    mut events: EventReader<JumpEvent>,
    asset_server: Res<AssetServer>,
    mut commands: Commands,
) {
    for _ in events.read() {
        commands.spawn((
            AudioPlayer::new(asset_server.load("audio/jump.ogg")),
            PlaybackSettings::DESPAWN,
        ));
    }
}

What this demonstrates:

One-shot audio entity despawns after playback
Decoupled jump logic fires event; audio system listens
Asset path consistent with assets/audio/ folder

Deep Dive

How It Works

Physics plugin steps simulation in FixedUpdate schedule.
Colliders generate contact events for gameplay (damage, footstep).
Audio mixes streams; AudioPlayer starts playback on spawn.
Listener component on camera affects 3D pan/volume.

Integration Points

System	Schedule
Physics step	`FixedUpdate`
SFX spawn	`Update` on events
Music loop	Persistent entity with `PlaybackSettings::LOOP`

Gotchas

Physics in variable Update - tunneling at high speed. Fix: only integrate in FixedUpdate.
Collider mesh mismatch with sprite - unfair hits. Fix: debug draw colliders in dev builds.
Too many simultaneous voices - mixer clipping. Fix: pool SFX channels; priority system.
Large uncompressed WAV - load stutter. Fix: OGG/Vorbis compressed assets.
Forgetting listener entity - 3D audio flat. Fix: attach AudioListener to active camera.

Alternatives

Alternative	Use When	Don't Use When
Custom AABB collision	Simple tile game	Many dynamic bodies
FMOD/Wwise via FFI	AAA audio tooling	Small indie scope
2D grid collision manual	Retro grid movement	Physics realism needed
No audio	Silent prototype	Ship to players

FAQs

Which physics crate?

avian (Bevy 0.14+ ecosystem) or bevy_rapier3d/2d - pick one per project and pin version to Bevy release.

Kinematic vs dynamic?

Kinematic for player-controlled that pushes physics; dynamic for crates and ragdolls.

Collision layers?

Collision groups/masks filter what interacts - define in plugin config to reduce work.

Music crossfade?

Two AudioPlayer entities; tween volumes over 1-2 seconds on state change.

Pause audio?

Global volume resource or pause all players when GameState::Paused.

Physics events?

CollisionStarted/Ended events from plugin map to damage or footstep sounds.

Determinism?

Fixed timestep helps; full network determinism needs fixed-point and controlled ordering.

Performance?

Sleeping bodies, simplified colliders, broadphase tuning - see performance page.

Timing?

Game Loops & Timing for FixedUpdate wiring.

Assets?

Assets & Scenes for audio file organization.

Game Loops & Timing - fixed step
Input & Events - trigger events
Bevy Engine - schedules
Assets & Scenes - load audio

Stack versions: This page was written for Rust 1.97.0 (edition 2024), Tokio 1.x, Axum 0.8, serde 1.0, sqlx 0.8, clap 4, and Polars 0.46+.

Physics & Audio

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Physics & Audio