Prerequisite steps for Ubuntu users

You need at least Ubuntu 20.04 for gcc >= 10 and Python 3.9.

Ubuntu >=21.04

sudo apt-get update
sudo apt-get install g++-10 cmake cython3 libeigen3-dev libepoxy-dev libfontconfig1-dev libfreetype6-dev libharfbuzz-dev libogg-dev libopus-dev libopusfile-dev libpng-dev libsdl2-dev libsdl2-image-dev python3-dev python3-jinja2 python3-numpy python3-lz4 python3-pil python3-pip python3-pygments python3-toml qml-module-qtquick-controls qtdeclarative5-dev

You will also need nyan and its dependencies.

Ubuntu 20.04 LTS

On Ubuntu 20.04 you need to install Python 3.9 manually as the default version provided is too old.

sudo apt-get update
sudo apt-get install g++-10 cmake cython3 libeigen3-dev libepoxy-dev libfontconfig1-dev libfreetype6-dev libharfbuzz-dev libogg-dev libopus-dev libopusfile-dev libpng-dev libsdl2-dev libsdl2-image-dev python3.9 python3.9-dev python3.9-jinja2 python3.9-numpy python3.9-lz4 python3.9-pil python3.9-pip python3.9-pygments python3.9-toml qml-module-qtquick-controls qtdeclarative5-dev

You will also need nyan and its dependencies.