meta-flutter

Yocto Layer for Flutter related artifacts.

Recommended development flow starts with making an embedder run on desktop, then target. This approach will save you a good deal of time and aggrevation.

Note: In theory Swift Shader (CPU render) engine builds should work with the right build flags. Be warned it won't work out of the box. Select a SoC with a GPU that supports OpenGL 3.0+ and save yourself the Engineering NRE.

Note: If you get a gray screen running the Gallery app, chances are you don't have LC_ALL set. Check /usr/share/locale/ on your target for available locale, and set LC_ALL appropriately. Example: export LC_ALL=en_GB

Layers dependencies

meta-clang (Sony embedders only)

Overview

Target BSP is expected to have a GPU with OpenGLES v3.0+ support.

This layer includes recipes to build

flutter-engine (channel selection, default is beta)
flutter-sdk (channel selection, default is beta)
fltter-gallery Application (interpreted and AOT - requires master channel override)
flutter-pi (DRM w/VSync)
flutter-wayland (basic POC) / waylandpp/ipugxml
Sony embedders (No VSync except recent naive Wayland Vsync; which is not power friendly)

Notes

Targets flutter-engine is known to work on

AGL QEMU images - x86_64
DragonBoard 410c - aarch64
Intel MinnowBoard Max (BayTrail) - intel-icore7-64
NVIDIA Nano Dev Kit - aarch64
NVIDIA Xavier NX Dev Kit - aarch64
Raspberry Pi 3 / Compute - aarch64 / armv7hf
Raspberry Pi 4 / Compute - aarch64
Renesas R-Car m3ulcb - aarch64
STM32MP157x - cortexa7t2hf
etc, etc

Building for ARM (32-bit) has an outstanding P4 bug on this: https://github.com/flutter/flutter/issues/83765

NVIDIA Xavier/Nano

local.conf changes

TARGET_GCC_VERSION = "8.3.0"
FLUTTER_CHANNEL = "master"
IMAGE_INSTALL_append = " flutter-drm-eglstream-backend"
IMAGE_INSTALL_append = " flutter-gallery"

TARGET_GCC_VERSION = "8.3.0"
FLUTTER_CHANNEL = "master"
CORE_IMAGE_EXTRA_INSTALL += "\
    flutter-drm-eglstream-backend \
    flutter-gallery \
"

Build EGL image

bitbake demo-image-egl

Run Flutter application on target (defaults to AOT)

FLUTTER_DRM_DEVICE=/dev/dri/card0 flutter-drm-eglstream-backend -b /usr/share/flutter-gallery/sony

NXP i.MX 8QuadXPlus MEK

repo init -u https://source.codeaurora.org/external/imx/imx-manifest -b imx-linux-gatesgarth -m imx-5.10.9-1.0.0.xml
repo sync -j20
DISTRO=fslc-wayland MACHINE=imx8qxpmek source setup-environment build
pushd ../sources
git clone -b dunfell https://github.com/jwinarske/meta-flutter.git
popd
bitbake-layers add-layer ../sources/meta-clang ../sources/meta-flutter
echo -e 'TARGET_GCC_VERSION = "10.2.0"' >> conf/local.conf
echo -e 'FLUTTER_CHANNEL = "dev"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-wayland"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-gallery"' >> conf/local.conf
bitbake fsl-image-multimedia
...
Build Configuration:
BB_VERSION           = "1.48.0"
BUILD_SYS            = "x86_64-linux"
NATIVELSBSTRING      = "universal"
TARGET_SYS           = "aarch64-fslc-linux"
MACHINE              = "imx8qxpmek"
DISTRO               = "fslc-wayland"
DISTRO_VERSION       = "3.2-snapshot-20210616"
TUNE_FEATURES        = "aarch64 armv8a crc cortexa35 crypto"
TARGET_FPU           = ""

Raspberry PI 3/4 (aarch64)

export MACHINE=raspberrypi4-64

export MACHINE=raspberrypi3-64

mkdir rpi_yocto && cd rpi_yocto
repo init -u https://github.com/jwinarske/manifests.git -m rpi64.xml -b dunfell
repo sync -j20
source ./setup-environment $MACHINE
bitbake-layers add-layer ../sources/meta-clang ../sources/meta-flutter
echo -e 'FLUTTER_CHANNEL = "dev"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-pi"' >> conf/local.conf
echo -e 'IMAGE_INSTALL_append = " flutter-gallery"' >> conf/local.conf
bitbake core-image-minimal

Note: you may want/need to increase the GPU_MEM value. It's defaulting to 64.

STM32MP157x Discovery Board (doesn't include build hack)

Setup Ubuntu 16.04 for building Yocto images. envsetup.sh will complain if you're missing a package.

mkdir openstlinux-5.10-dunfell-mp1-21-03-31 && cd openstlinux-5.10-dunfell-mp1-21-03-31
repo init -u https://github.com/STMicroelectronics/oe-manifest.git -b refs/tags/openstlinux-5.10-dunfell-mp1-21-03-31
repo sync -j20
DISTRO=openstlinux-eglfs MACHINE=stm32mp1-disco source layers/meta-st/scripts/envsetup.sh
pushd ../layers
git clone -b dunfell https://github.com/jwinarske/meta-flutter.git
git clone -b dunfell https://github.com/kraj/meta-clang.git
popd
bitbake-layers add-layer ../layers/meta-flutter ../layers/meta-clang
echo -e 'MACHINE_FEATURES_remove = "fip"\n' >> conf/local.conf
echo -e 'DISTRO_FEATURES_remove = "wayland"\n' >> conf/local.conf
echo -e 'DISTRO_FEATURES_remove = "x11"\n' >> conf/local.conf
echo -e 'FLUTTER_CHANNEL = "master"\n' >> conf/local.conf
echo -e 'CORE_IMAGE_EXTRA_INSTALL += " \' >> conf/local.conf
echo -e '  flutter-pi \' >> conf/local.conf
echo -e '  flutter-drm-gbm-backend \' >> conf/local.conf
echo -e '  flutter-gallery \' >> conf/local.conf
echo -e '"' >> conf/local.conf
cat conf/local.conf
bitbake st-image-core
...
TARGET_SYS      = "arm-ostl-linux-gnueabi"
MACHINE         = "stm32mp1-disco"
DISTRO          = "openstlinux-eglfs"
DISTRO_VERSION  = "3.1-snapshot-20210602"
TUNE_FEATURES   = "arm vfp cortexa7 neon vfpv4 thumb callconvention-hard"
TARGET_FPU      = "hard"

See release notes regarding "fip": https://wiki.st.com/stm32mpu/wiki/STM32MP15_OpenSTLinux_release_note

Build EGL image

bitbake demo-image-egl

Run Flutter application on target (defaults to AOT)

FLUTTER_DRM_DEVICE=/dev/dri/card0 flutter-drm-eglstream-backend -b /usr/share/flutter-gallery/sony

General Yocto Notes

When building on systems with GCC version > than uninative in Yocto distro add the following to conf/local.conf

INHERIT_remove = "uninative"

Sony notes

not accepting PRs
no real texture solution
preliminary vsync support
weston >= 8 does not work
no multi-engine
no platform view / hybrid composition
not enough debug spew for debug builds
code difficult to follow
too much boiler plate

GitHub

https://github.com/jwinarske/meta-flutter