This repo is intended as a source of information regarding the Retroid Dual Screen Add-on (RDS Add-on) for use on other devices.
The RDS Add-on uses portrait natural orientation. To use the RDS Add-on in landscape orientation, you need to add a function to the surfaceflinger. This is a commit as a reference on how to change the orientation in the RDS Add-on:
Apply orientation based on persist.panel.rds.orientation value
After applying the patch, here's an example for Retroid Pocket 5 using a 270-degree orientation. You can set the RDS Add-on orientation as follows:
setprop persist.panel.rds.orientation 270
To be able to get the benefits of using multi-display, we must use a Launcher that supports multi-display, here are some Launchers that you can try using for multi-display : Launcher3QuickStep.apk
To use it, you can tap and hold the icon of the application you want to run, then select the "Launch Screen" option. After that, select which screen you want to use to launch the application.
The RDS add-on ships with a portrait display orientation and a landscape touchscreen orientation; this is the default configuration used for Retroid Pocket devices.
If you're using it for a device that requires portrait touchscreen orientation, you can change it through a firmware flashing application using Windows.
Here are two updaters you can use depending on your needs.
Landscape touchscreen firmware : RDSTouchUpdater_landscape.exe
Portrait touchscreen firmware : RDSTouchUpdater_portrait.exe