Game Dev Best Practices

Q: Biggest beginner mistake?

Putting physics in Update with variable delta - move to FixedUpdate immediately.

Q: Testing?

Unit test pure functions; integration test schedules with App::update() and minimal plugins.

Scalable, performant, testable game code in Rust and Bevy.

How to Use This List

Apply A-B at project start when scaffolding schedules and folders.
Walk C-D before milestone demos and publisher builds.
Revisit E after perf regressions or content scale-up.

A - ECS Design

Keep components small and data-only. Behavior stays in systems, not methods on god structs.
Use marker components for query filters. With<Enemy> beats string tags.
Order systems explicitly when sharing mutable access. Scheduler conflicts serialize unexpectedly otherwise.
Despawn hierarchies on scene exit. Leaked entities cause ghost collisions and memory creep.
Prefer Commands for spawns/despawns. Structural changes batch safely in schedule.

B - Timing and Simulation

Run physics in FixedUpdate only. Variable delta_secs in physics causes jitter and tunneling.
Interpolate render transforms between fixed states. High FPS displays need smooth visuals.
Cap fixed catch-up steps after hitches. Prevent spiral of death freezing gameplay.
Sample input in Update, consume in fixed step via buffer if needed. Consistent control feel.
Pause with virtual time, not busy loops. Menus should not advance simulation accidentally.

C - Assets and Content

Consistent lowercase asset paths for Linux builds. Case mismatch passes on macOS, fails in CI.
Wait for LoadState::Loaded before spawning gameplay. Placeholder pink textures signal missing gate.
Compress audio and textures appropriately. OGG and GPU-compressed formats reduce load and VRAM.
Version scene files with game releases. Old scenes with removed components need migration.
Organize assets/ by domain (sprites, audio, scenes). Content creators navigate faster.

D - Performance and Shipping

Profile Tracy/Puffin on min-spec hardware. Steam Deck and integrated GPU tell truth.
Avoid per-frame allocations in hot systems. Reuse buffers in resources.
Use diagnostics plugins in dev, not spam in release. println! in Update kills FPS.
Release build with LTO for shipping. Debug builds misrepresent performance utterly.
Test headless or minimal plugins in CI for logic. Not every test needs GPU window.

E - Team and Maintenance

Pin Bevy to exact minor version. Read migration guide before bumping.
Document control bindings and gamepad deadzones. QA reproduces bugs faster.
Feature-flag debug overlays (collider draw, FPS). Ship clean player builds.
Separate game crate from engine crate if scope grows. Reuse engine across titles.
Record known Bevy/plugin version pairs in README. Onboarding avoids dependency hell.

FAQs

Biggest beginner mistake?

Putting physics in Update with variable delta - move to FixedUpdate immediately.

When to leave Bevy abstractions?

When render doc shows material batching limit and you need custom wgpu pass - not day one.

Networking?

Plan tick rate and state sync early; retrofitting multiplayer is expensive - outside this list but plan architecture.

Testing?

Unit test pure functions; integration test schedules with App::update() and minimal plugins.

ECS vs OOP?

ECS wins on cache and parallelism for many entities; accept learning curve on queries.

Audio polish?

Event-driven one-shots; loop music on separate entity; cap polyphony - see physics/audio page.

Scope control?

Vertical slice one mechanic with assets loaded, physics, audio, menu before content explosion.

Modding?

Data-driven RON/TOML for stats; keep code modding advanced stretch goal.

Accessibility?

Remappable keys, colorblind palettes, UI scale - plan in Input & Events.

Learn loop?

Game Dev Basics then Bevy Engine.

Bevy Engine - core patterns
Game Loops & Timing - fixed step
Performance for Games - profiling
Game Dev Basics - orientation

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+.

Game Dev Best Practices

Scalable, performant, testable game code in Rust and Bevy.

How to Use This List

Apply A-B at project start when scaffolding schedules and folders.
Walk C-D before milestone demos and publisher builds.
Revisit E after perf regressions or content scale-up.

A - ECS Design

Keep components small and data-only. Behavior stays in systems, not methods on god structs.
Use marker components for query filters. With<Enemy> beats string tags.
Order systems explicitly when sharing mutable access. Scheduler conflicts serialize unexpectedly otherwise.
Despawn hierarchies on scene exit. Leaked entities cause ghost collisions and memory creep.
Prefer Commands for spawns/despawns. Structural changes batch safely in schedule.

B - Timing and Simulation

Run physics in FixedUpdate only. Variable delta_secs in physics causes jitter and tunneling.
Interpolate render transforms between fixed states. High FPS displays need smooth visuals.
Cap fixed catch-up steps after hitches. Prevent spiral of death freezing gameplay.
Sample input in Update, consume in fixed step via buffer if needed. Consistent control feel.
Pause with virtual time, not busy loops. Menus should not advance simulation accidentally.

C - Assets and Content

Consistent lowercase asset paths for Linux builds. Case mismatch passes on macOS, fails in CI.
Wait for LoadState::Loaded before spawning gameplay. Placeholder pink textures signal missing gate.
Compress audio and textures appropriately. OGG and GPU-compressed formats reduce load and VRAM.
Version scene files with game releases. Old scenes with removed components need migration.
Organize assets/ by domain (sprites, audio, scenes). Content creators navigate faster.

D - Performance and Shipping

Profile Tracy/Puffin on min-spec hardware. Steam Deck and integrated GPU tell truth.
Avoid per-frame allocations in hot systems. Reuse buffers in resources.
Use diagnostics plugins in dev, not spam in release. println! in Update kills FPS.
Release build with LTO for shipping. Debug builds misrepresent performance utterly.
Test headless or minimal plugins in CI for logic. Not every test needs GPU window.

E - Team and Maintenance

Pin Bevy to exact minor version. Read migration guide before bumping.
Document control bindings and gamepad deadzones. QA reproduces bugs faster.
Feature-flag debug overlays (collider draw, FPS). Ship clean player builds.
Separate game crate from engine crate if scope grows. Reuse engine across titles.
Record known Bevy/plugin version pairs in README. Onboarding avoids dependency hell.

FAQs

Biggest beginner mistake?

Putting physics in Update with variable delta - move to FixedUpdate immediately.

When to leave Bevy abstractions?

When render doc shows material batching limit and you need custom wgpu pass - not day one.

Networking?

Plan tick rate and state sync early; retrofitting multiplayer is expensive - outside this list but plan architecture.

Testing?

Unit test pure functions; integration test schedules with App::update() and minimal plugins.

ECS vs OOP?

ECS wins on cache and parallelism for many entities; accept learning curve on queries.

Audio polish?

Event-driven one-shots; loop music on separate entity; cap polyphony - see physics/audio page.

Scope control?

Vertical slice one mechanic with assets loaded, physics, audio, menu before content explosion.

Modding?

Data-driven RON/TOML for stats; keep code modding advanced stretch goal.

Accessibility?

Remappable keys, colorblind palettes, UI scale - plan in Input & Events.

Learn loop?

Game Dev Basics then Bevy Engine.

Bevy Engine - core patterns
Game Loops & Timing - fixed step
Performance for Games - profiling
Game Dev Basics - orientation

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+.

Game Dev Best Practices

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Game Dev Best Practices