It seems that sbt-android is ignoring the presence of the RenderScript files and is not generating the ScriptC_xxx java classes that are normally generated by gradle builds/Android Studio [UPDATE: this is false, se the update note below]. Because of this issue, the sbt-android build is failing because to use the scripts we need to reference the generated ScriptC_xxx classes, which gives the following error when building:
[error] apackage/YYYClass.java:55: cannot find symbol
[error] symbol: class ScriptC_xxx
[error] location: class apackage.YYYClass
[error] ScriptC_xxx xxxScript = new ScriptC_xxx(rs);
The generated .sbt file from the existing project (which compiles normally by gradle) has the apparent necessary configuration for RenderScript, generated from the build.gradle file:
rsTargetApi in Android := "18",
rsSupportMode in Android := rsSupportMode.value || true
What I am missing to be able to compile renderscript-containing android projects with sbt-android ?
UPDATE: I realized that the java classes for the scripts are being generated correctly, but somehow the classes that use those generated classes cannot find them, so maybe I have a classpath configuration problem.
This is the current file structure:
./asubmodule/src/main/rs/xxx.rs
(using package declaration #pragma rs java_package_name(apackage.scripts))
./asubmodle/src/main/java/apackage/YYYClass.java
./asubmodule/target/android/generated/source/android/support/v7/appcompat/R.java
./asubmodule/target/android/generated/source/apackage/scripts/ScriptC_xxx.java
Unfortunately, it seems com.android.builder.core.AndroidBuilder no longer generates .d files for processed renderscript sources. Bypassing AndroidBuilder to use com.android.sdklib.build.RenderScriptProcessor in sbt-android could restore the .d files that are required to determine the generated files. But that would be a solution for a future version of sbt-android.
To work around your problem for now, you can add the following into your build.sbt:
sourceGenerators in Compile += Def.task {
implicit output = outputLayout.value
val layout = projectLayout.value
(layout.generatedSrc ** "ScriptC_*.java").get ++ (layout.generatedSrc ** "*BitCode.java").get
}.taskValue
Since it sounds like you're using sbt-android-gradle you can just create a new file build.sbt and throw the above in (do not edit the 00-gradle-generated.sbt)
Update: this will be fixed in the next version of sbt-android https://github.com/scala-android/sbt-android/commit/ec09a55233aabd50e7df0085b10c567e38b616d3