RaspberryPi2EGLFS: Difference between revisions

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7. Get qtbase (note that Qt 5.6 is not yed released and is work in progress) and configure Qt. The target directory is /usr/local/qt5pi on the Pi, the host tools like qmake will go to ~/raspi/qt5, while make install will target ~/raspi/qt5pi (this is what we will sync to the device).
7. Get qtbase (note that Qt 5.6 is not yet released and is work in progress) and configure Qt. The target directory is /usr/local/qt5pi on the Pi, the host tools like qmake will go to ~/raspi/qt5, while make install will target ~/raspi/qt5pi (this is what we will sync to the device).


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Revision as of 20:32, 7 November 2015

A modern guide for cross-compiling Qt 5.6 for HW accelerated OpenGL with eglfs on Raspbian Jessie.

Note that this is not intended for running desktop-style, windowed Qt apps under X11, but rather for the real embedded/device creation use case where the Qt app runs fullscreen on top of dispmanx/EGL using the Broadcom drivers.

1. Get the latest image from https://downloads.raspberrypi.org/raspbian_latest

2. Unzip and write it to a memory card. Replace ... with the SD card device (check dmesg).

sudo dd if=2015-09-24-raspbian-jessie.img of=... bs=4M

3. Boot it up, run raspi-config, change it to boot to the console instead of X, change the GPU memory to 256 MB, install a bunch of development files (for simplicity we use build-dep, not everything is really needed, but it is easier this way), and prepare our target directory:

sudo raspi-config
sudo nano /etc/apt/sources.list

and uncomment the deb-src line.

sudo apt-get update
sudo apt-get build-dep qt4-x11
sudo apt-get build-dep libqt5gui5
sudo apt-get install libudev-dev libinput-dev libts-dev

sudo mkdir /usr/local/qt5pi
sudo chown pi:pi /usr/local/qt5pi

4. Back on the host PC, create our working directory and get a toolchain:

mkdir ~/raspi
cd ~/raspi
git clone https://github.com/raspberrypi/tools

5. Create a sysroot. Using rsync we can properly keep things synchronized in the future as well. Replace IP with the address of the Pi.

mkdir sysroot sysroot/usr sysroot/opt
rsync -avz pi@IP:/lib sysroot
rsync -avz pi@IP:/usr/include sysroot/usr
rsync -avz pi@IP:/usr/lib sysroot/usr
rsync -avz pi@IP:/opt/vc sysroot/opt

6. Adjust symlinks to be relative. Instead of the old fixQualifiedLibraryPaths get a script that works:

wget https://raw.githubusercontent.com/riscv/riscv-poky/master/scripts/sysroot-relativelinks.py
chmod +x sysroot-relativelinks.py
./sysroot-relativelinks.py sysroot

7. Get qtbase (note that Qt 5.6 is not yet released and is work in progress) and configure Qt. The target directory is /usr/local/qt5pi on the Pi, the host tools like qmake will go to ~/raspi/qt5, while make install will target ~/raspi/qt5pi (this is what we will sync to the device).

git clone git://code.qt.io/qt/qtbase.git -b 5.6
cd qtbase
./configure -release -opengl es2 -device linux-rasp-pi2-g++ -device-option CROSS_COMPILE=~/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf- -sysroot ~/raspi/sysroot -opensource -confirm-license -make libs -prefix /usr/local/qt5pi -extprefix ~/raspi/qt5pi -hostprefix ~/raspi/qt5 -v
make
make install

8. Deploy to the device. We simply sync everything from ~/raspi/qt5pi to the prefix we configured above.

rsync -avz qt5pi pi@IP:/usr/local

9. Build an example:

cd qtbase/examples/opengl/qopenglwidget
~/raspi/qt5/bin/qmake
make
scp qopenglwidget pi@IP:/home/pi

10. On the device, let the linker find the Qt libs:

echo /usr/local/qt5pi/lib | sudo tee /etc/ld.so.conf.d/qt5pi.conf
sudo ldconfig

11. Still on the device, fix the EGL/GLES library nonsense:

The device may have the Mesa version of libEGL and libGLESv2 in /usr/lib/arm-linux-gnueabihf, resulting Qt apps picking these instead of the real thing from /opt/vc/lib. This may be fine for X11 desktop apps not caring about OpenGL performance but is totally useless for windowing system-less, fullscreen embedded apps.

sudo rm /usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0 /usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0
sudo ln -s /opt/vc/lib/libEGL.so /usr/lib/arm-linux-gnueabihf/libEGL.so.1.0.0
sudo ln -s /opt/vc/lib/libGLESv2.so /usr/lib/arm-linux-gnueabihf/libGLESv2.so.2.0.0

You may want to save the originals somewhere, just in case.

12. Run qopenglwidget we deployed to /home/pi. At this point it should just work at fullscreen with 60 FPS and mouse and keyboard support.

13. Build other Qt modules as desired, the steps are the same always:

~/raspi/qt5/bin/qmake -r
make
make install

then deploy the new files by running

rsync -avz qt5pi pi@IP:/usr/local

in ~/raspi