AndroidStudio and Renderscript's ScriptC error

[rfat99]

AndroidStudio (AS) fails to find the definition of ScriptC_invert when implementing a Renderscript (in another file invert.rs). It is placed in a directory src/main/rs and this is updated in the gradle (AndroidStudio folder). I am using Android SDK 33 which should still support Renderscripts.

I am sure there are no code-wise issues as I am consistent with several examples online, namely, the invert.rs contains:

// File: invert.rs

#pragma version(1)
#pragma rs java_package_name(com.example.sharp)

and the Java code:

ScriptC_invert invert = new ScriptC_invert(rs);

but I get:

error: cannot find symbol ScriptC_invert invert = new ScriptC_invert(rs);

The build.gradle contains:

renderscriptTargetApi 18
renderscriptSupportModeEnabled true

as well as:

sourceSets {
main {
renderscript {
srcDirs 'src/main/rs'
}
}
}

Anyone managed to get this running on current android/AS versions? Thanks!