Chris Brown -- Baby Mama Says He Cheaped Out On Royalty's Birthday

Chris Brown's daughter Royalty got a phone call from her dad on her first birthday ... but a source close to his baby mama says that's it.

Sources close to Royalty's mom, Nia Guzman, tell TMZ ... Brown didn't show up for the 1-year-old's birthday, didn't send a gift and didn't contribute to the cost of the Chuck E. Cheese's shindig. Nia says her boyfriend, King Ba, paid for the whole thing.

Ba -- who's listed on the birth certificate as Royalty's birth father -- seemed to take pleasure in Chris' absence and captioned one pic of Royalty by writing, "Wouldn't Miss This Day For Anything In This World."