Yup!  The State Statute says so at least.

ORS  163.465¹   Public indecency

1)  A person commits the crime of public indecency if while in, or in view of, a public place the person performs

(c)  An act of exposing the genitals of the person with the intent of arousing the sexual desire of the person or another person.

His 'intent' can be proven by circumstantial evidence.  Did he 'intend' to sexually arouse himself?  You be the juror.