Add MuJoCo to ROS Buildfarm

[peterdavidfagan]

I am starting to develop MuJoCo simulation environments that interface with ROS 2. I have a working example in Python but need to switch to the C API for performance reasons. Currently MuJoCo doesn't appear to be released under the ROS 2 package management ecosystem, I suggest that MuJoCo is added as a package so it can be used more readily by the ROS community.

I guess this is not strictly necessary but it makes handling the MuJoCo dependency a lot cleaner when developing ROS packages. Looks like it may take not insignificant work to add this.

[traversaro]

Note that mujoco is available in recent version of debian, even if the version is relatively old: https://packages.debian.org/source/sid/mujoco, so perhaps if mujoco is added to the buildfarm it could make sense to add it as vendor package.

[peterdavidfagan]

Nice, thanks @traversaro, I wasn't aware of this debian. I have been manually downloading the release to my machine and configuring CMake to point towards shared library files (still in dev as I only just made the switch), agree on it being added as a vendor package.

For now I am going to continue with what I have but I hope in future I'll be able to package my software with MuJoCo in a way that aligns with the ROS ecosystem as I am creating a ROS package.

[peterdavidfagan]

As an update to this thread, for now I add the latest release files to my repository and link them to the project. Not ideal but it gets the job done for my use case: https://github.com/peterdavidfagan/mujoco_ros.

[DavidPL1]

You really should not add the latest release files to your repo. Why don't you reproduce what is done to build Simulate here and/or use a MUJOCO_DIR environment variable to find an unpacked tar of a compatible release in your CMakeLists.txt?

[peterdavidfagan]

I agree I don't think what I have done is best practice, I'll add an issue to migrate to the findorfetch utility.

[githubs-user]

What is the problem with using the latest release file in the repo?
And how we can add the compatible release of MuJoCo to our ROS2 package?

[peterdavidfagan]

What is the problem with using the latest release file in the repo?

Generally you want to handle dependencies with CMake, manually adding a folder for release files is bad practice as it adds unnecessary bloat to the package, imagine having to do this for multiple dependencies.

And how we can add the compatible release of MuJoCo to our ROS2 package?

The link shared by @DavidPL1 demonstrates how to findorfetch MuJoCo, you can add this to your CMakeLists.txt file and appropriately link against MuJoCo to add this dependency.

[peterdavidfagan]

Hi @DavidPL1,

I went with your suggestion and updated my CMakeLists.txt to use FindOrFetch. Thanks for the advice on this.