https://www.youtube.com/watch?v=FsA8imG7Nbw
Final: https://www.youtube.com/watch?v=QRiiZZAc1VI
Reference source:
Indie Programmer: https://www.youtube.com/channel/UC0MHs87ehhLOtPQf_bAWDEA
Series Java Game Programming: https://www.youtube.com/watch?v=rfR09erJu7U&list=PLFUqwj4q1Zr8GHs6bO4d6gxMGUh_2pcNg