tf2 library for ros2_rust

[DS3a]

Is there a tf2 implementation for ros2_rust? or has it been implemented on a separate package? I'm new to this so I'm not sure if the transform library comes with RCL? If it does. Does it have rust bindings?

[esteve]

@DS3a thanks for your interest in ros2-rust! At the moment, there's no tf2 package for ros2-rust, a straightforward version could just wrap the existing C++ implementation in Rust. Would you like to contribute one? We'd be very happy to help you with it.

[DS3a]

I'd be glad to contribute a tf2 package for ros2-rust... Although I think it might be better to keep most of the code in Rust instead of wrapping it around C++. Especially since the ROS client library does not come with it. Do let me know what you think, and how I should proceed.

[esteve]

It'll be tricky to do a full integration of tf2 and ros2-rust, as the infrastructure is not entirely there yet. For example ros2-rust does not support actions, clocks or timers yet, which are essential for tf2, that's why I suggested wrapping tf2 for now (here's how it was done for rcldotnet https://github.com/IntelligentRoboticsLabs/geometry2/tree/rcldotnet)

If you'd like to implement the full integration, we'd be more than happy to accept contributions for the aforementioned features in ros2-rust 🙂

[DS3a]

Ohh, okay. That makes sense. I'll look into adding support for timers (#121). And hopefully move to the other dependencies and move to the full integration after that.

[Yadunund]

@DS3a did you get around to implementing the Rust wrapper for tf2?

[DS3a]

Nope. Sorry, I got busy with other stuff

[ljburtz]

Hello, any update on tf2 for ros2_rust? already deep into implementation with ros2_rust but now realizing we will also need tf2_msgs and can't find it anywhere! any pointer very appreciated (just need the message definition actually)

[maspe36]

You should be able to vendor tf2_msgs in your workspace just like we do here in the ros2_rust repo for things like std_msgs. Then just make sure you've got tf2_msgs declared in your Cargo.toml and package.xml so we can do the dependency patching in your <colcon ws>/.cargo/config.toml.

Once you vendor tf2_msgs, you'll need to build once with colcon build and then everything should work even when building with only cargo.

[ljburtz]

thank you for the guidance. i could get these tf2_msgs into ros2_rust by:
adding

1. the following to ros2_rust/ros2_rust_humble.repos

ros2/geometry2:
type: git
url: https://github.com/ros2/geometry2.git
version: humble

2. re-importing the repos

vcs import src < src/ros2_rust/ros2_rust_humble.repos
source /opt/ros/humble/setup.sh
colcon build

3. adding tf2_msgs to the dependencies in my Cargo.toml

Would it make sense to open a PR for adding the update to the ros2_rust_humble.repos?

[maspe36]

Awesome! Glad you got it working. No I don't think this needs to go up to ros2_rust.

Really the crux of this is that in the source of your colcon workspace, you needed a copy of tf2_msgs so that our rust message generation would run. Anywhere in <your ws>/src would suffice. That repos file you're mentioning is specifically for ros2 messages that ros2_rust needs for our build.

Hope this helps 👍