thirdroom VS rend3

Not sure if Mozilla Hubs federates, but as already said, ThirdRoom is Matrix VRchat thing.

you can calculate 2D CSS transforms which match the equivalent transforms of your WebGL scene in WebXR - as an efficient but hacky way to (for instance) do live video overlays in 3D without having to mess around importing the video texture into WebGL (assuming you don’t need occlusion or environmental effects etc).

we’re toying with this as an approach for video overlays in https://thirdroom.io, especially for underpowered devices.

by “matrix chat 3d like things” do you mean https://thirdroom.io?

It would be super easy to build something like this on Third Room - and then get e2ee and decentralisation etc for free :)

oh, wow. we have 3D Tile support in https://thirdroom.io but had only ever found NASA’s Mars dataset as a good set of tiles to point it at. This could effectively turn Third Room into a FOSS, decentralised, E2EE multiplayer Google Earth running over Matrix!

AT proto has some significant similarities to Matrix:

* Both are work by self-authenticating git-style replication of Merkle trees/DAGs

* Both define strict data schemas for extensible sets of events (Matrix uses JSON schema - https://github.com/matrix-org/matrix-spec/tree/main/data/eve... and OpenAPI; AT uses Lexicons)

* Both use HTTPS for client-server and server-server traffic by default.

* Both are focused on decentralised composable reputation - e.g. https://matrix.org/blog/2020/10/19/combating-abuse-in-matrix... on the Matrix side, or https://paulfrazee.medium.com/the-anti-parler-principles-for... on the bluesky side, etc.

* Both are designed as big-world communication networks. You don't have the server balkanisation that affects ActivityPub.

* Both eschew cryptocurrency systems and incentives.

There are some significant differences too:

* Matrix aspires to be the secure communication layer for the open web.

* AT aspires (i think) to be an open decentralised social networking protocol for the internet.

* AT has portable identity by default. We've been working on this on Matrix (e.g. MSC1228 - https://github.com/matrix-org/matrix-spec-proposals/pull/122... and MSC2787 - https://github.com/matrix-org/matrix-spec-proposals/blob/nei...) and have a new MSC (and implementation on Dendrite) in progress right now which combines the best bits of MSC1228 & MSC2787 into something concrete, at last. In fact the proto-MSC is due to emerge today.

* AT is proposing a asymmetrical federation architecture where user data is stored on Personal Data Servers (PDS), but indexing/fan-out/etc is done by Big Graph Servers (BGS). Matrix is symmetrical and by default federates full-mesh between all servers participating in a conversation, which on one hand is arguably better from a self-sovereignty and resilience perspective - but empirically has created headaches where an underpowered server joins some massive public chatroom and then melts. Matrix has improved this by steady optimisation of both protocol and implementation (i.e. adding lazy loading everywhere - e.g. https://matrix-org.github.io/synapse/latest/development/syna...), but formalising an asymmetrical architecture is an interesting different approach :)

* AT is (today) focused on for public conversations (e.g. prioritising big-world search and indexing etc), whereas Matrix focuses both on private and public communication - whether that's public chatrooms with 100K users over 10K servers, or private encrypted group conversations. For instance, one of Matrix's big novelties is decentralised access control without finality (https://matrix.org/blog/2020/06/16/matrix-decomposition-an-i...) in order to enforce access control for private conversations.

* Matrix also provides end-to-end encryption for private conversations by default, today via Double Ratchet (Olm/Megolm) and in the nearish future MLS (https://arewemlsyet.com). We're also starting to work on post quantum crypto.

* Matrix is obviously ~7 years older, and has many more use cases fleshed out - whether that's native VoIP/Video a la Element Call (https://element.io/blog/introducing-native-matrix-voip-with-...) or virtual worlds like Third Room (https://thirdroom.io) or shared whiteboarding (https://github.com/toger5/TheBoard) etc.

* AT's lexicon approach looks to be a more modular to extend the protocol than Matrix's extensible event schemas - in that AT lexicons include both RPC definitions as well as the schemas for the underlying datatypes, whereas in Matrix the OpenAPI evolves separately to the message schemas.

* AT uses IPLD; Matrix uses Canonical JSON (for now)

* Matrix is perhaps more sophisticated on auth, in that we're switching to OpenID Connect for all authentication (and so get things like passkeys and MFA for free): https://areweoidcyet.com

* Matrix has an open governance model with >50% of spec proposals coming from the wider community these days: https://spec.matrix.org/proposals

* AT has done a much better job of getting mainstream uptake so far, perhaps thanks to building a flagship app from day one (before even finishing or opening up the protocol) - whereas Element coming relatively late to the picture has meant that Element development has been constantly slowed by dealing with existing protocol considerations (and even then we've had constant complaints about Element being too influential in driving Matrix development).

* AT backs up all your personal data on your client (space allowing), to aid portability, whereas Matrix is typically thin-client.

* Architecturally, Matrix is increasingly experimenting with a hybrid P2P model (https://arewep2pyet.com) as our long-term solution - which effectively would end up with all your data being synced to your client. I'd assume bluesky is consciously avoiding P2P having been overextended on previous adventures with DAT/hypercore: https://github.com/beakerbrowser/beaker/blob/master/archive-.... Whereas we're playing the long game to slowly converge on P2P, even if that means building our own overlay networks etc: https://github.com/matrix-org/pinecone

I'm sure there are a bunch of other differences, but these are the ones which pop to the top of my head, plus I'm far from an expert in AT protocol.

It's worth noting that in the early days of bluesky, the Matrix team built out Cerulean (https://matrix.org/blog/2020/12/18/introducing-cerulean) as a demonstration to the bluesky team of how you could build big-world microblogging on top of Matrix, and that Matrix is not just for chat. We demoed it to Jack and Parag, but they opted to fund something entirely new in the form of AT proto. I'm guessing that the factors that went into this were: a) wanting to be able to optimise the architecture purely for social networking (although it's ironic that ATproto has ended up pretty generic too, similar to Matrix), b) wanting to be able to control the strategy and not have to follow Matrix's open governance model, c) wanting to create something new :)

From the Matrix side; we keep in touch with the bluesky team and wish them the best, and it's super depressing to see folks from ActivityPub and Nostr throwing their toys in this manner. It reminds me of the unpleasant behaviour we see from certain XMPP folks who resent the existence of Matrix (e.g. https://news.ycombinator.com/item?id=35874291). The reality is that the 'enemy' here, if anyone, are the centralised communication/social platforms - not other decentralisation projects. And even the centralised platforms have the option of seeing the light and becoming decentralised one day if we play our parts well.

What would be really cool, from my perspective, would be if Matrix ended up being able to help out with the private communication use cases for AT proto - as we obviously have a tonne of prior art now for efficient & audited E2EE private comms and decentralised access control. Moreover, I /think/ the lexicon approach in AT proto could let Matrix itself be expressed as an AT proto lexicon - providing interop with existing Matrix rooms (at least semantically), and supporting existing Matrix clients/SDKs, while using AT proto's ID model and storing data in PDSes etc. Coincidentally, this matches work we've been doing on the Matrix side as part of the MIMI IETF working group to figure out how to layer Matrix on top of other existing protocols: e.g. https://datatracker.ietf.org/doc/draft-ralston-mimi-matrix-t... and https://datatracker.ietf.org/doc/draft-ralston-mimi-matrix-m... - and if I had infinite time right now I'd certainly be trying to map Matrix's CS & SS APIs onto an AT proto lexicon to see what it looks like.

TL;DR: I think AT proto is cool, and I wish that open projects saw each other as fellow travellers rather than competitors.

You could take a look to this project: https://github.com/matrix-org/thirdroom As part of the project they are implementing a web Game engine, uses ThreeJS for graphics, and includes multiplayer using the Matrix protocol. Could be a good starting point.

Have you looked into what thirdroom or ambient have done in the space?

Have you lot made any friends over at Third Room yet? ;)

If you wanted to be serious about it, you could try to make something based on https://thirdroom.io

The WGPU people are still working through lock conflicts in that area. The idea with Vulkan land is that you should be able to load content while rendering is in progress. For that to be useful, all the layers above Vulkan also have to have their locking problems hammered out. Most open source game engines don't do that yet. Unreal Engine and Unity do, which is why you pay for them for your AAA title.

[1] https://raw.githubusercontent.com/BVE-Reborn/rend3/trunk/exa...

[2] https://github.com/BVE-Reborn/rend3/blob/trunk/examples/scen...

[3] https://video.hardlimit.com/w/sFPkECUxRUSxbKXRkCmjJK

The big problem I have with bevy here is that they seem to be very much against bevy being reusable across the ecosystem. Every feature has to be bevyfied into an ECS thing. There's no way one can use bevy_input for input handling outside of bevy, or bevy_audio for audio, or bevy_render to get a 3d renderer like https://rend3.rs/. The Rust ecosystem would've been so much better off if bevy wasn't creating a walled garden and draining insane amounts of effort just for itself, but say instead used rend3 for its rendering, so that other efforts in rust gamedev didn't have to reimplement everything from scratch.

We have our own engine. There aren't really full engines available in the Rust ecosystem. Bevy attempts to fill this, but it's far from being feature complete. There's also https://fyrox.rs/, but that's also work in progress. There's also https://rend3.rs/ which is just a 3d renderer, so you'll need to build the rest of the engine yourself.

That's been fixed. It was one of those things where a complicated workaround for Rust's ownership rules, one that required maintaining internal consistency between multiple tables, was inconsistent.

Rend3 crashes The library's internal memory allocator for GPU objects is losing objects and panicking. This seems to be a race condition that comes up once you get past displaying static scenes and start having moving objects. Rend3 has one overworked main developer. If you're qualified to work on GPU-level stuff, which I am not, that project could use help.

I personally use Rend3, ability to use WGPU to make my own render effects, but I still get to build my own engine around it, although I'm waiting for the vertex-pulling branch to be merged before I really get going