In a felony offense, are the police officers who arrested you legally required to attend the trial?

The prosecutor calls the witnesses the prosecution wants, and defense counsel calls the witnesses the defense wants. The defense can ask the prosecution to serve subpoenas on witnesses. Police will be there if the prosecutor wants them there, or if you subpoena them. There used to be a "res gestae witness" rule that required the prosecutor to call anyone who qualified as that type of witness, but now the prosecutor only has to list the potential witnesses known to them, and the defense decides which of those witnesses to call.