LightPlayer

LightPlayer is a work-in-progress application for controlling visual effects on the esp32c6 microcontroller using GLSL shaders.

GLSL shaders are used to define the visual effects, which are just-in-time (JIT) compiled to native RISC-V code on the target device.

The architecture is client-server, designed for headless operation on unattended devices, controlled from a web UI, native app, or by api.

Quick Start

To run the demo project:

# Clone the repo
git clone https://github.com/Yona-Appletree/lp2025.git
cd lp2025

# Initialize your development environment
scripts/dev-init.sh

# Run the demo
just demo

# Run other examples
just demo -- <example-name>

On-device demo (ESP32-C6)

To flash firmware, push the examples/basic project over USB serial, and run it on real hardware:

just demo-esp32c6-host

You need an ESP32-C6 board connected by USB, the RISC-V target installed (the recipe runs install-rv32-target), and espflash on your PATH for flashing.

Wiring (GPIO is hardcoded today): connect a WS2812-class addressable strip (or other device driven the same way) to GPIO 18 as the data line—not the pin field in examples/basic/src/strip.output/node.json, which the firmware does not use yet. The firmware initializes a buffer for 256 LEDs; the basic demo mapping uses 241 pixels, which fits in that limit.

For an empty flash and firmware only (no project push), use just demo-esp32c6-standalone.

Development

To get started with development:

1. Initialize the development environment:

   scripts/dev-init.sh

   This will:

   • Check for required tools (Rust, Cargo, rustup, just, oxipng)
   • Verify Rust version meets minimum requirements (1.90.0+)
   • Install the RISC-V target (riscv32imac-unknown-none-elf) if needed
   • Set up git hooks (pre-commit hook runs just check)

2. Required tools:

   • Rust toolchain (1.90.0 or later) - Install Rust
   • just - Task runner: cargo install just or via package manager
   • oxipng - Lossless PNG optimizer for Studio story image baselines: cargo install oxipng or brew install oxipng

3. Common development commands:

   • just fci - Fix, check, build, and test the whole project. Do this before you submit a PR.
   • just fci-app - Fix, check, build, and test the application.
   • just fci-glsl - Fix, check, build, and test the GLSL compiler.

See just --list for all available commands.

Repository Structure

CLI (lp-cli/)

Developer-facing command-line tools for creating projects, running the dev server, inspecting compiler/runtime behavior, and managing checked-in hardware manifests. lp-cli is intended to run from a LightPlayer source checkout and may assume repository paths such as lp-core/lpc-shared/boards; it is not currently a deployable end-user command-line product.

Hardware manifests can be browsed and edited with:

cargo run -p lp-cli -- hardware manifest

GPIO label calibration is host-driven. Flash the simple calibration firmware, attach a scope to the board label you want to identify, then run the CLI loop:

just fwtest-gpio-calibrate-esp32c6
cargo run -p lp-cli -- hardware calibrate esp32c6 --board seeed/xiao-esp32-c6 --port serial:auto

During calibration, Enter means no/next, y records the visible board label for the active HAL GPIO, p goes back one candidate, and q quits with resume state under target/hardware-calibration.

Firmware (lp-fw/)

• fw-core Core firmware abstractions (serial I/O, transport, logging infrastructure)
• fw-emu Firmware that runs in the RISC-V32 emulator for testing without hardware
• fw-tests Integration tests for firmware (emulator-based testing and USB serial tests)
• fw-esp32 ESP32 firmware

Running Firmware Tests

USB serial integration tests verify firmware behavior with real hardware:

# Run USB serial tests (requires connected ESP32)
cargo test --package fw-tests --features test_usb -- --ignored

# Run with debug output
DEBUG=1 cargo test --package fw-tests --features test_usb -- --ignored

See lp-fw/fw-tests/README.md for more details.

Application Core (lp-core/)

• lp-engine Core rendering engine that executes shaders and manages nodes (fixtures, textures, outputs)
• lp-engine-client Client for lp-engine, handling state sync and local project view
• lp-server Server that manages projects and handles client connections
• lp-client Async client library for communicating with lp-server. Manages filesystem sync and project management.
• lp-model Data models and API definitions for projects, nodes, and server communication
• lp-shared Shared utilities for filesystem, logging, time, and transport

GLSL Compiler (lp-shader/)

Full layout and commands: lp-shader/README.md.

• lps-frontend GLSL → LPIR (via naga)
• lpir LightPlayer IR definitions
• lpvm-native LPIR → custom RV32 machine code (default on-device JIT)
• lpvm-cranelift LPIR → Cranelift → RISC-V machine code (reference backend)
• lpvm-wasm LPIR → WASM (browser / wasm.q32 filetests)
• lps-q32 Fixed-point Q16.16 types: Q32 scalar, Vec2Q32–Vec4Q32, Mat2Q32–Mat4Q32, component-wise math helpers, constant encoding for compiler
• lps-shared Shared type and function-signature shapes for tests / exec helpers
• lps-diagnostics Error codes, spans, GlslError
• lpvm Runtime values and literal parsing (uses glsl parser fork where needed)
• lps-builtin-ids Generated enum of builtin function IDs
• lps-builtins Rust functions used by the generated code: fixed-point math, glsl builtins, lygia-inspired library of native glsl functions
• lps-builtins-emu-app RISC-V guest for running tests linked against builtins
• lps-builtins-gen-app Code generator for builtin function boilerplate
• lps-filetests Collection of tests for GLSL spec compliance and correctness
• lps-filetests-gen-app Generator for repetitive filetests (vector, matrices)
• lps-filetests-app Filetest runner binary
• lpfn-impl-macro Macros for builtin function implementations

RISC-V Tooling (lp-riscv/)

• lp-riscv-emu RISC-V 32-bit emulator used for testing and development
• lp-riscv-emu-shared Shared types between emulator host and guest
• lp-riscv-emu-guest Guest-side runtime for emulated environment
• lp-riscv-emu-guest-test-app Test application for emulator guest
• lp-riscv-inst RISC-V instruction encoding/decoding utilities (no_std)
• lp-riscv-elf ELF file loading and linking utilities (std required)

Other Directories

• examples/ Example LightPlayer projects
• docs/ Documentation, plans, and design notes
• scripts/ Build scripts and development utilities

Acknowledgments

LightPlayer would not be possible without the amazing work of these projects:

• Cranelift - Fast, secure compiler backend (forked to support 32-bit RISC-V and no_std)
• Naga - Shader IR and glsl-in GLSL frontend (used by lps-frontend)
• pp-rs - GLSL preprocessor fork, patched in [patch.crates-io] in the workspace Cargo.toml so naga glsl-in works on no_std targets
• glsl-parser - GLSL parser ( forked for spans)
• Lygia - Shader library (source for lpfn built-in functions)
• DirectXShaderCompiler - HLSL compiler ( compiler architecture inspiration)
• esp-hal - Pure Rust ESP32 bare metal HAL (used for ESP32 firmware)
• GLSL Specification - GLSL language reference
• RISC-V Instruction Set Manual - RISC-V architecture documentation
• RISC-V ELF psABI Specification - RISC-V ABI documentation

... and many more not listed. Thank you to everyone in the open source community for your work.

Special thanks to @SeanConnell for his support and guidance throughout the development of the project.

License

LightPlayer-owned code is licensed under the GNU Affero General Public License version 3 or later (AGPL-3.0-or-later). See LICENSE for the full license text.

Third-party code, vendored forks, and dependencies remain under their own licenses.

Contributions are accepted under the terms in CONTRIBUTING.md.