State of the Protocol Squad

Welcome to the State of the Protocol Squad document. This document is updated periodically with the status and plan of each implementation and documentation.

The current team members are:

• @leanmendoza - Godot implementation leader
• @robtfm - Bevy implementation leader
• @kuruk-mm - Staff engineer
• @sdilauro - Jr. Scene and Godot Developer

Members that participated:

• @menduz - Babylon implementation leader, technical coordination
• @slezica - Documentation & technical writing

The Protocol Squad has two objectives:

• Publish an extensive and detailed documentation of the Decentraland protocol
• Create alternative implementations of the World Explorer

There are currently three implementations being developed, each implementation has their own different objectives and tints in development.

Current objective: 🔛 Render interactive scenes.

Next objective: 🔜 Connect the explorers together and see eachother in-world.

The team also focuses on documenting the protocol in the shape of Architecture Decision Records (ADR) and as contributions to the Official Documentation

Babylon.js + Typescript

Repository: https://github.com/decentraland/hammurabi

Objective: It is the educational implementation of Decentraland. Its main objective is to provide a clear standard/reference implementation that implements the Decentraland protocol in the most readable and correct way possible. Even though it contains many performance optimizations, complex optimizations are left for other explorers to optimize this one for readability. The test coverage of this implementation should be the highest and its objective is to be the "reference implementation" when implementing new explorers from scratch.

Current state: Not maintained 🟠, the Babylon accomplished his objective, and it's suitable for educating the people to implement an Explorer

Bevy + Rust

Repository: https://github.com/decentraland/bevy-explorer

Objective: Rust may be the greatest language for the coming decades, and its open source nature is very aligned with Decentraland's mission. The same happens with Bevy (the engine). Internally, Bevy is already implemented using an ECS, at the moment of writing this document, creating a Decentraland Explorer in this technology seems to be the best decision long term.

Current state: Completed 🟢

Godot 4 + GDScript + Rust

Repository: https://github.com/decentraland/godot-explorer

Objective: Its objective is to be a production ready (or ready-to-fork) Decentraland Explorer. Godot (fully open source) has been gaining traction in the industry and more and more titles are being published and developed on Godot as time passes.

Current state: Completed 🟢

Unity + C# (Unity Alpha)

Repository: https://github.com/decentraland/unity-explorer

Objective: Its objective is to be a production-ready Decentraland Explorer. Developed by the Decentraland Foundation.

Current state: ON TRACK 🟢

Unity + C# (#1)

Repository: https://github.com/decentraland/unity-renderer

Objective: First unity client developed by the Decentraland Foundation

Implementation, part 1. Render interactive scenes

At this stage, the implementations will focus on loading and unloading scenes, render their content in the world and oferring basic interactivity.

Feature	Specification	Bevy	Babylon	Godot
CI Tests	Continous automated testing in commits and pull requests	✅	✅	✅
Continous release	Continous release of testable artifacts	✅	✅	✅
Load and unload scenes	PENDING	✅	✅	✅
Scene Runtime	ADR-133 (Living)	✅	✅	✅
CRDT protocol	ADR-117 (Living)	✅	✅	✅
Scene Tick	ADR-148 (Living)	✅	✅	✅
Load static realm/world	ADR-110 ADR-111 (Living)	✅	✅	✅
Resolve realm base URL	ADR-144 (Review)	✅	✅	✅
Static entitites for SDK	ADR-219 (Draft)	✅	✅	✅
Player Locomotion	PENDING	✅	✅	✅
├── Colliders	MeshCollider & GltfContainer	✅	1/2	✅
└── First Person Camera	PENDING	✅	✅	✅

SDK Component	Specification	Bevy	Babylon	Godot	SDK
Transform	ADR-153 (Living)	✅	✅	✅	✅
MeshRenderer	PENDING	✅	Partially	✅	✅
MeshCollider	PENDING	✅	Partially	✅	✅
Billboard	ADR-198 (Living)	✅	✅	✅	✅
Raycast	ADR-200 (Draft)	✅	✅	✅	✅
PointerEvents	ADR-214 (Draft)	✅	✅	✅	✅
GltfContainer	ADR-215 (Draft)	✅	✅	✅	✅
GltfContainerLoadingState	ADR-215 (Draft)	✅	✅	✅	✅
Animator	ADR-216 (PENDING)	✅	✅	✅	✅
EngineInfo	ADR-148 (Living)	✅	✅	✅	✅

Implementation, part 2: Seeing other people

Feature	Specification	Bevy	Babylon	Godot
Load a global scene (AvatarsScene)	PENDING	✅	✅	✅
Create ephemeral identity	PENDING	✅	✅	✅
Connect to WebSocket transport	PENDING	✅	✅	✅
├──Transport implementation	ADR-105	✅	✅	✅
└──Expose transport to SDK	PENDING

SDK Component	Specification	Bevy	Babylon	Godot	SDK
AvatarShape	PENDING Render avatars with custom wearables and emotes	✅	✅	✅	✅

Implementation, part 3: Full SDK implementation

Feature	Specification	Bevy	Babylon	Godot
Player Locomotion	PENDING	✅	✅	✅
├── Moving platforms	PENDING	✅		✅
├── Third person camera	PENDING	✅	✅	✅
└── Jump	PENDING	✅	✅	✅
Traversal city loading	PENDING	✅		✅
Scene boundaries checker	PENDING	✅

Runtime API	Specification	Bevy	Babylon	Godot	Unity #1
fetch	ADR-133 addition	✅	✅	✅	✅
WebSocket	ADR-133 addition	✅	✅	✅	✅
PortableExperiences		✅		✅	✅
RestrictedActions		✅		✅	✅
Runtime		✅		✅	✅
SignedFetch		✅		✅	✅
CommsApi		✅		✅	✅

SDK Component	Specification	Bevy	Babylon	Godot	Unity #1
CameraMode	PENDING	✅		✅	✅
CameraModeArea	PENDING	✅		✅
Material	PENDING	✅	✅	✅	✅
AvatarAttach	PENDING	✅		✅	✅
TextShape	PENDING	✅		✅	✅
Visibility	PENDING	✅		✅	✅
AudioSource	PENDING	✅		✅	✅
AudioStream	PENDING	✅		✅	✅
VideoPlayer	PENDING	✅		✅
UiTransform	ADR-124	✅		✅	✅
UiCanvasInformation	ADR-124	✅		✅
UiLabel	ADR-125	✅		✅	✅
UiText	ADR-125	✅		✅	✅
UiInput & UiInputResult	ADR-125	✅		✅	✅
UiDropdown & UiDropdownResult	ADR-125	✅		✅	✅

Comms Support

Feature	Bevy	Babylon	Godot
WebSocket Room	✅	✅	✅
SignedLogin	✅	✅	✅
LiveKit	✅	PR	✅
├──VoiceChat	✅	PR	✅
Archipelago	✅		✅

Runtime 6 support (aka SDK6)

Feature	Bevy	Babylon	Godot	Unity #1
Native support	❌	❌	❌	✅
Proxy support	✅		✅

Proposal #2: implementation part 1

SDK Components

SDK Component	Bevy	Godot
PointerLock	✅	✅
AvatarModifierArea	✅	✅
NftShape	✅	✅
VideoEvent	✅	✅
Tween	✅	✅
TweenSequence	✅	✅
TweenState	✅	✅

Explorer functionality Components

Web3 - Sign-in	Bevy	Godot
External wallet	✅	✅
Browser wallet	✅	✅
Web2 method	✅	✅

Future Ideas

Feature	Description
ReferenceMaterial SDK Component	Reuse materials and reference an entity to use its material while reducing hundreds of CRDT messages
CinematicCamera SDK Component	Ability to attach the camera to a specific entity while standing on a scene. Enables cinematic cameras and new game modes.
GameServers	Enables scenes to run inside a specialized server. The server connects to comms and is considered an authority. The scene can trust messages from the server and automatic entity synchronization can be configured.
Enable actors for comms	A novel communications architecture to enable third party actors to join the communications network of Decentraland. Unblocks game servers
Raycast from global scenes

Links

Governance proposal: https://governance.decentraland.org/proposal/?id=9303c5e0-7cbb-11ed-b135-498029192bca