Support for Opencv4 in ROS2 Foxy [WIP]

[fmrico]

Warning: This is the dirtiest PR I have ever made, but it's the only way that I have found to make it works in Ubuntu 20.04 with OpenCV4

Hi All,

OpenCV 4 makes fail the compilation of darknet_ros for ROS Foxy. This PR makes it work.

Issue referenced in #234 and #200, at least.

If someone finds a better way to compile this, it is wellcome. I hope this could help someone and inspire others for a better solution.

Working on ROS2 Foxy, Ubuntu 20.04 LTS and OpenCV 4.2.0

Signed-off-by: Francisco Martin Rico fmrico@gmail.com

[tomlankhorst]

Thanks, were you able to test on 18.04 too?

[fmrico]

Hi @tomlankhorst

No. The current version in the ros2 branch (without this PR) works in 18.04/Eloquent. This PR tries to fix the significant change to 20.04 (GCC and OpenCV).

Maybe we could have an eloquent branch and a foxy branch, and redirect this PR to foxy. What do you think, @mbjelonic?

[mbjelonic]

@fmrico Yes, we could have a seperate branch for your PR. @tomlankhorst What do you think?

[tomlankhorst]

Let's start with a foxy branch, yes. Might eventually swap foxy for master and master for melodic.
@fmrico, are you able to target this PR to the newly created foxy branch?

[fmrico]

Hi @tomlankhorst

Could you create the foxy branch from the ros2 branch? It seems like it was created from master, and when I change the base branch, there is a lot of conflicts.

[tomasgareau]

Hi @fmrico -- looks like you might have meant @tomlankhorst :)

[fmrico]

Yes, sorry @tomasgareau . Fixing...

[mbjelonic]

@fmrico I created a new branch called foxy and changed the base of this PR.

[mbjelonic]

@fmrico Can you please update the readme and mention that this branch ist running with ROS2 Foxy, Ubuntu 20.04 LTS and OpenCV 4.2.0?

[fmrico]

Hi @mbjelonic

Thanks for creating the branch and changing the base!

I have updated the Readme. I also changed the compilation commands to use colcon.

[mbjelonic]

@fmrico thanks for the work and contributing to daknet_ros! This is great. Can't wait to switch to Ubuntu 20.04. :)

[fmrico]

@mbjelonic Happy to help.

Please, take into account what I wrote in the head of the PR. I am not happy with the final result, but it was a way to make it works. There is duplicated code in some files, and this is very ugly. This is only a starting point ;)

[Paul-Ajay]

@fmrico I was trying to compile it with ros2 foxy and opencv 4.2.0 (output from the command python3 -c "import cv2; print(cv2.__version__)") and still getting /usr/include/opencv4/opencv2/core/cvdef.h:704:4: error: #error "OpenCV 4.x+ requires enabled C++11 support" 704 | # error "OpenCV 4.x+ requires enabled C++11 support"
Any idea what am I missing?

[fmrico]

Hi @ajaypaul2008

I thought that I fixed this with this PR 🤔

In any case, this PR was a horrible patch to make darknet_ros work with the decision of OpenCV. Maybe someone should do a real fix.

[Paul-Ajay]

@fmrico Finally I got it working with opencv4 after I added changes from this PR #202 to foxy branch in my machine

Update : pushed this here https://github.com/ajaypaul2008/darknet_ros/tree/foxy