Carla from Source

Introduction

In this article, we will install carla from source with the help of docker and the PHA Project. What we will do is install Carla and Unreal Engine in the SSI. In the last article Carla 0.9.15 Consumption we looked at how the PHA Project can be used for flexible installation of any ROS based package. In this article we will look at how other softwares can be installed with docker. This example will be using make for installations.

Patching Carla for Ubuntu 22.04

To make carla work with Ubuntu 22.04, thre are two changes that are necessary. First, the LLVM version would have to be upgraded to LLVM-12.0 as documented in Carla Under Ubuntu 22.04. Further as Ubuntu 22.04 does not include python2, the python version must also be upgraded to python3.

LLVM-12.0 Update

Change carla/Util/BuildTools/Setup.sh:73 to:

LLVM_BASENAME=llvm-12.0

if this does not exist then change to line 54:

CXX_TAG=c12

Python3 Update

This project uses Python 3.10.

Change carla/Util/BuildTools/BuildCarlaUE4.sh:134 and carla/Util/BuildTools/BuildCarlaUE4.sh:137 to

python3

Alternatively they may be in carla/Util/BuildTools/BuildCarlaUE4.sh:163 and carla/Util/BuildTools/BuildCarlaUE4.sh:166.

If you want to spawn walkers with python 3.9, you should change carla/PythonAPI/carla/source/libcarla/World.cpp Line 305 (or Line 314 in 8854804) from

.def("get_random_location_from_navigation", CALL_RETURNING_OPTIONAL_WITHOUT_GIL(cc::World, GetRandomLocationFromNavigation))`

.def("get_random_location_from_navigation", CALL_RETURNING_OPTIONAL(cc::World, GetRandomLocationFromNavigation))

This is documented in Generate Traffic 3.10.

Then, delete in carla/PythonAPI/carla/source/libcarla/Client.cpp Line 25 (or 28 in 8854804)

carla::PythonUtil::ReleaseGIL unlock;

will solve this problem.

Further, change carla/PythonAPI/examples/requirements.txt and carla/PythonAPI/carla/requirements.txt from

numpy; python_version < '3.0'
numpy==1.18.4; python_version >= '3.0'

numpy; python_version >= '3.0'

Available Patch

The patch is available in Carla Ubuntu 22 Patch.

Pre-Installations

We will start by installing the dependencies required for Carla.

Unity Permissions

Before starting with the installations, be aware that to download the Carla fork of Unreal Engine, you need to have a GitHub account linked to Unreal Engine’s account. If you don’t have this set up, please follow this guide UE on Github before going any further. The commit is 8d08ab7fe891737b7badebdc77333c24b8348ca1

Install Dependencies

Dependencies for Unreal Engine and Carla are available in a neatly packed script install_carla_deps.sh. The content of the scripts are as follows:

#!/bin/bash

# source install_carla_unreal.sh /home/${USER}/docker_share/git_pkgs/simulators

# Variables
IN_CARLA_UNREAL_FOLDER=$1
IN_CARLA_VERSION=$2
IN_CARLA_UNREAL_FOLDER="${IN_CARLA_UNREAL_FOLDER:=/home/${USER}/docker_share/git_pkgs/simulators}"
IN_CARLA_VERSION="${IN_CARLA_VERSION:=0.9.15}"
IN_CARLA_ROOT=${IN_CARLA_UNREAL_FOLDER}/carla
IN_UE4_ROOT=${IN_CARLA_UNREAL_FOLDER}/UnrealEngine_4.26
source /home/${USER}/.bashrc
cd ${IN_CARLA_UNREAL_FOLDER}

# Downloads
git clone --depth 1 -b carla https://github.com/CarlaUnreal/UnrealEngine.git UnrealEngine_4.26
git clone https://github.com/pradhanshrijal/carla -b feature/u22-${IN_CARLA_VERSION}

# Install Unity
cd UnrealEngine_4.26
./Setup.sh && ./GenerateProjectFiles.sh && make

echo -e "\n# Unreal | Carla"
echo "export UE4_ROOT=${IN_UE4_ROOT}" >> /home/${USER}/.bashrc
echo "export CARLA_ROOT=${IN_CARLA_ROOT}" >> /home/${USER}/.bashrc
echo "export PYTHONPATH=\$PYTHONPATH:${IN_CARLA_ROOT}/PythonAPI/carla/dist/carla-${IN_CARLA_VERSION}-py3.10-linux-x86_64.egg:${IN_CARLA_ROOT}/PythonAPI/carla" >> /home/${USER}/.bashrc
source /home/${USER}/.bashrc

# Install Carla
cd ..
cd carla
./Update.sh

These changes are all available in a neatly packed docker image PHA 22 Carla Mini.

Primary Installations

We can now connect everything together. For setting up the SSI we will use PHA Docker.

Folder Setup

First we setup the project as documented in [SSI Space].

cd /home/${USER}
mkdir schreibtisch
cd schreibtisch
git clone https://github.com/pradhanshrijal/pha_docker_files
cd pha_docker_files

Start the Container

./run.sh -c pha-22-carla-sample -i phaenvs/pha-22 \
      -s /home/${USER}/schreibtisch/pha_docker_files/docker_share \
      -t carla-mini 

Enter the Container

./docker_scripts/exec-cont.sh -c pha-22-carla-sample

Install Unreal Engine and Carla

The installations are neatly packed into the script install_carla_unreal.sh.

source docker_share/scripts/install_carla_unreal.sh

WARNING: If the UID an GID of the docker user and host user does not match [1000] then it will be problems.

The content of the scripts are as follows:

#!/bin/bash

# source install_carla_unreal.sh /home/${USER}/docker_share/git_pkgs/simulators

# Variables
IN_CARLA_UNREAL_FOLDER=$1
IN_CARLA_VERSION=$2
IN_CARLA_UNREAL_FOLDER="${IN_CARLA_UNREAL_FOLDER:=/home/${USER}/docker_share/git_pkgs/simulators}"
IN_CARLA_VERSION="${IN_CARLA_VERSION:=0.9.15}"
IN_CARLA_ROOT=${IN_CARLA_UNREAL_FOLDER}/carla
IN_UE4_ROOT=${IN_CARLA_UNREAL_FOLDER}/UnrealEngine_4.26
source /home/${USER}/.bashrc
cd ${IN_CARLA_UNREAL_FOLDER}

# Downloads
git clone --depth 1 -b carla https://github.com/CarlaUnreal/UnrealEngine.git UnrealEngine_4.26
git clone https://github.com/pradhanshrijal/carla -b feature/u22-${IN_CARLA_VERSION}

# Install Unity
cd UnrealEngine_4.26
./Setup.sh && ./GenerateProjectFiles.sh && make

echo -e "\n# Unreal | Carla"
echo "export UE4_ROOT=${IN_UE4_ROOT}" >> /home/${USER}/.bashrc
echo "export CARLA_ROOT=${IN_CARLA_ROOT}" >> /home/${USER}/.bashrc
echo "export PYTHONPATH=\$PYTHONPATH:${IN_CARLA_ROOT}/PythonAPI/carla/dist/carla-${IN_CARLA_VERSION}-py3.10-linux-x86_64.egg:${IN_CARLA_ROOT}/PythonAPI/carla" >> /home/${USER}/.bashrc
source /home/${USER}/.bashrc

# Install Carla
cd ..
cd carla
./Update.sh

Keep in mind that this script also automates the root path export of Unreal Engine and Carla via the .bashrc.

Build and Launch Carla

Navigate to the carla folder:

cd $CARLA_ROOT

Build and launch carla, this has to be done everytime the system is started.

make PythonAPI
make launch -opengl

Known Issues

Here are some known issues with this method, and some solutions

Using Vulkan to launch Carla

The normal way to launch Carla is with vulkan. With this installation method, the system crashes when running this way. This is the reason the launch method uses the -opengl flag. See Can’t Launch Carla.

Visualization of Client running at very low FPS Rate

Set the UE Editor to run on high rate, even when idle. Go to Edit -> Editor preferences -> Performance in the Unreal Engine editor and disable Use less CPU when in background. See Carla FPS Rate.

Changing Map

When changing map there are several issues with Carla. The CPU load explodes, no reason for this has been analyzed. However, there is a possible solution. As PHA is a very scripts based project, the solution is in the form of two scripts; carla_map_update.sh and pha_carla_vars.sh.

pha_carla_vars.sh registers the current map and [carla_map_udpate.sh] updates the map. Very simple, this assigns the default map so the scripts have to be run before the carla system is started. Make sure $CARLA_ROOT/Unreal/CarlaUE4/Config/DefaultEngine.ini and pha_carla_vars.sh have the same starting value for the map.

source /home/${USER}/docker_share/scripts/functions/carla_map_update.sh 01

Size of the Installations

The main reason that this installation makes sense to be done this way is that the Unreal and Carla Source packages are very bulky. In total they are about 90 GB large. If we make a docker container out of it then it becomes too bloated. With this method the install can be associated with the host storage. It can be very easy to install the packages into an external SSD device.

Conclusion

This article provides an alternative simulation installation for the PHA Project using Unreal Engine 4 and Carla with Ubuntu 22.04. This also serves as an example to install packages with docker without bloating the size of the container itself.