RaspberryPi4EGLFS

A modern guide for cross-compiling Qt (with QtWebEngine) for HW accelerated OpenGL with EGLFS on Raspbian

Tested configuration:

• Raspberry Pi 4 4GB version;
• Raspbian Buster February 2020 version;
• Qt 5.14.2;
• Host system: Manjaro Kyria 19.0.2.

Step by step

• Prepare the image:
  • download raspbian;
  • unzip and write to the microSD card.
• Boot up the Raspberry Pi.

[on RPI]:

• in raspi-config set the GPU memory to at least 256 MB and enable SSH;
• prepare destination folder for cross-compiled Qt:

sudo mkdir /opt/qt5
sudo chown `whoami` /opt/qt5

• uncomment debian repository in /etc/apt/sources.list
• update the system:

sudo apt update; sudo apt dist-upgrade -y

• install the necessary libraries:

sudo apt install -y \
freetds-dev \
gstreamer1.0-omx \
libasound2-dev \
libavcodec-dev \
libcap-dev \
libdbus-1-dev \
libegl1-mesa-dev \
libevent-dev \
libfontconfig1-dev \
libfreetype6-dev \
libgbm-dev \
libgconf2-dev \
libgcrypt20-dev \
libgl1-mesa-dev \
libgles2-mesa-dev \
libglew-dev \
libgnome-keyring-dev \
libgstreamer-plugins-base1.0-dev \
libgstreamer1.0-dev \
libgtk-3-dev \
libicu-dev \
libinput-dev \
libjpeg-dev \
libjsoncpp-dev \
libkrb5-dev \
liblcms2-dev \
libminizip-dev \
libnss3 \
libnss3-dev \
libopus-dev \
libpci-dev \
libperl-dev \
libpng-dev \
libpoppler-cpp-dev \
libprotobuf-dev \
libpulse-dev \
libre2-dev \
libsnappy-dev \
libsqlite3-dev \
libssl-dev \
libts-dev \
libudev-dev \
libvpx-dev \
libvulkan-dev \
libwebp-dev \
libx11-dev \
libx11-xcb-dev \
libxcb-glx0-dev \
libxcb-icccm4-dev \
libxcb-image0-dev \
libxcb-keysyms1-dev \
libxcb-randr0-dev \
libxcb-render-util0-dev \
libxcb-shape0-dev \
libxcb-shm0-dev \
libxcb-sync-dev \
libxcb-xfixes0-dev \
libxcb-xinerama0 \
libxcb-xinerama0-dev \
libxcb-xinput-dev \
libxcb1-dev \
libxext-dev \
libxfixes-dev \
libxi-dev \
libxkbcommon-x11-dev \
libxml2-dev \
libxrender-dev \
libxslt1-dev \
libxss-dev \
libxtst-dev \
libzstd-dev \
mesa-common-dev \
sqlite \
symlinks \
upower \
zstd

[on HOST]:

• create a working directory:

mkdir ~/raspi

• set pi_ip to your RPi address and prepare sysroot:

cd ~/raspi; \
pi_ip=192.168.0.200; \
rsync -avzz pi@${pi_ip}:/lib sysroot; \
rsync -avzz pi@${pi_ip}:/usr/include sysroot/usr; \
rsync -avzz pi@${pi_ip}:/usr/lib sysroot/usr; \
rsync -avzz pi@${pi_ip}:/usr/share/pkgconfig sysroot/usr/share; \
rsync -avzz pi@${pi_ip}:/opt/vc sysroot/opt

• fix relative links:

wget https://raw.githubusercontent.com/Kukkimonsuta/rpi-buildqt/master/scripts/utils/sysroot-relativelinks.py
chmod +x sysroot-relativelinks.py
./sysroot-relativelinks.py sysroot

• install necessary libraries:

For Ubuntu:

sudo apt install -y lib32z1 lib32ncurses5 lib32stdc++6 build-essential
sudo apt install -y libgl1-mesa-dev libgles2-mesa-dev mesa-common-dev
sudo apt install -y g++-multilib python pkg-config gperf bison flex re2c cmake ninja-build libnss3 libnss3-dev libjsoncpp-dev libre2-dev

For Manjaro:

sudo pacman -S pkgconf cmake ninja flex re2c re2 bison jsoncpp nss

• create toolchain with build_toolchain.sh script;
• create folder for qt sources:

mkdir qt-src

• if you need several Qt modules you can edit the script build_qt_modules.sh and it will download and build them automatically. If you need all Qt libraries then download the sources manually. Then run the configure script:

workdir=~/raspi; \
device=linux-rasp-pi4-v3d-g++; \
./configure -release -opensource -confirm-license -v \
-device ${device} \
-device-option CROSS_COMPILE=${workdir}/toolchain/bin/arm-linux-gnueabihf- \
-prefix /opt/qt5 \
-extprefix ${workdir}/qt5pi \
-hostprefix ${workdir}/qt5 \
-sysroot ${workdir}/sysroot \
-opengl es2 \
-eglfs \
-xcb \
-no-pch \
-nomake examples \
-nomake tests \
-no-use-gold-linker

• compile Qt:

make -j $(nproc); make install

• install libraries on RPi:

pi_ip=192.168.0.200; \
rsync -avzz qt5pi/* pi@${pi_ip}:/opt/qt5

[on RPI]:

• for desktop usage (platform xcb) you need to set the environment variable before starting your app:

export LD_LIBRARY_PATH=/opt/qt5/lib

• for EGLFS:
  • switch from graphical to console login via raspi-config;
  • add the user to the render group:

sudo gpasswd -a `whoami` render

• start your application in EGLFS mode:

-platform eglfs

• for application with QtWebEngine you can also enable GPU rasterization by adding the appropriate parameters to the comand line:

--enable-gpu-rasterization