libflutter_engine.so install location confusion

[Charlie9830]

Just finished running through the instructions to get an App built for an RPi4. Although I now have the app running (via drm backend) I did have some confusion with where to put the built libflutter_engine.so file.

I could only get it to run correctly if I copied libflutter_engine.so to both the cmake build directory as well as /usr/lib on the target device. I'm not sure if this is due to a bug or intended behavior. If it is intended behavior then I feel like the documentation needs some adjustment to reflect that.
Perhaps Step 5 of BUILDING-ENGINE-EMBEDDER.md could be amended to also include installing libflutter_engine.so to /usr/lib on the target device.

It would also be worth amending step 3) of the Install Flutter Engine library section of the readme for those who download the engine from google infra.

[HidenoriMatsubayashi]

I could only get it to run correctly if I copied libflutter_engine.so to both the cmake build directory as well as /usr/lib on the target device.

You need to install libflutter_engine.so to the path which is added ld-path such as /usr/lib. You can also use LD_LIBRARY_PATH.

e.g.

LD_LIBRARY_PATH=./flutter_engine/ FLUTTER_DRM_DEVICE="/dev/dri/card1" ./flutter-drm-backend ./sample/build/linux/x64/profile/bundle

See also: https://github.com/sony/flutter-embedded-linux#supplement

[Charlie9830]

Thanks Hidenori,

I had skipped over the supplement step as I wasn't planning at this stage to have to quickly switch between engine modes.

[HidenoriMatsubayashi]

Closing this issue. If you have any question, please comment and I can re-open.