demos

title	Demo Crates
document_id	demo-crates-readme-2026-02-04
status	draft
created	2026-02-04T00:00:00Z
last_updated	2026-02-23T00:00:00Z
version	0.1.2
engine_workspace_version	2023.1.30
wgpu_version	26.0.1
shader_backend_default	naga
winit_version	0.29.10
repo_commit	23b883f8e8509a8fa6343ee55abafb10c4f7a86a
owners	lambda-sh
reviewers	engine rendering
tags	demos guide

Demos

Overview

This directory contains runnable demo crates that showcase lambda-rs.

Demo crates are included in the workspace members but excluded from default-members. This keeps cargo build fast while keeping demos available via the -p <package> flag.

Minimal reference examples remain in crates/lambda-rs/examples/ for documentation and rustdoc usage.

Layout (Target)

demos/
  audio/    # Audio-focused demos (output device, decoding)
  minimal/  # Smallest window + render context demo
  physics/  # Physics demos (2D rigid bodies, colliders)
  render/   # Rendering demos (validation flags, advanced passes)

Running Demos

Minimal demo:

cargo run -p lambda-demos-minimal --bin minimal

Audio demos (audio support enabled by default):

cargo run -p lambda-demos-audio --bin sine_wave
cargo run -p lambda-demos-audio --bin sound_buffer
cargo run -p lambda-demos-audio --bin play_sound

Physics demos (requires physics-2d, enabled by default in the demo crate):

cargo run -p lambda-demos-physics --bin physics_falling_quad
cargo run -p lambda-demos-physics --bin physics_rigid_bodies_2d
cargo run -p lambda-demos-physics --bin physics_colliders_2d

Render demos:

cargo run -p lambda-demos-render --bin triangle
cargo run -p lambda-demos-render --bin triangles
cargo run -p lambda-demos-render --bin immediates
cargo run -p lambda-demos-render --bin indexed_multi_vertex_buffers
cargo run -p lambda-demos-render --bin instanced_quads
cargo run -p lambda-demos-render --bin textured_quad
cargo run -p lambda-demos-render --bin textured_cube
cargo run -p lambda-demos-render --bin uniform_buffer_triangle
cargo run -p lambda-demos-render --bin offscreen_post
cargo run -p lambda-demos-render --bin reflective_room

Render demos with validation enabled (feature passthrough to lambda-rs):

cargo run -p lambda-demos-render --bin triangle --features validation
cargo run -p lambda-demos-render --bin triangle --features validation-strict
cargo run -p lambda-demos-render --bin triangle --features validation-all

Workspace Behavior

• cargo build at the repository root MUST NOT build demo crates.
• cargo build -p <demo-package> MUST build the selected demo crate.