Rhythm Dungeon: A Blockchain-based Music Roguelike Game Tengfei Wang Shuyi Zhang e Chinese University of Hong Kong, Shenzhen White Matrix Inc. 2001 Longxiang Ave Nanjing, China Shenzhen, China [email protected] [email protected] Xiao Wu Wei Cai∗ White Matrix Inc. e Chinese University of Hong Kong, Shenzhen Nanjing, China 2001 Longxiang Ave [email protected] Shenzhen, China [email protected] ABSTRACT aentions have been aracted to develop a variety of applications Rhythm Dungeon is a rhythm game which leverages the blockchain over blockchain platforms to enjoy the benets of decentraliza- as a shared open database. During the gaming session, the player tion: immutable, transparent and auditable data and functionalities. explores a roguelike dungeon by inpuing specic sequences in Blockchain game [6] is one of the most active categories of dApps 1 time to music rhythm. By integrating smart contract to the game in the market. CrytopKiies , the most popular blockchain game, program, the enemies through the venture are generated from other once dominated the trac in Ethereum network due to its popu- games which share the identical blockchain. On the other hand, the larity. It leverages the benets of immutable virtual asset tokens player may upload their characters at the end of their journey, so and transparent game rules to improve players’ gaming experience. that their own character may appear in other games and make an In fact, blockchain has the potential to redene the relationship inuence. Rhythm Dungeon is designed and implemented to show model between game operators and players: the game data will be the potential of decentralized gaming experience, which utilizes the possessed by the players rather than the game operators. Among blockchain to provide asynchronous interactions among massive the benets blockchain brought to the games, the interoperability players. of game data aracts the most aention. For instance, the Cryp- toCuddles2 allows the players to use their own kiies purchased at CCS CONCEPTS CryptoKitiies to bale. However, the state-of-the-art blockchain games can only reuse the existing tokens available in a single di- •Human-centered computing ! Empirical studies in collabora- rection, which means that the data modication in new games can tive and social computing; •Applied computing ! Media arts; not make eects on the token they inherit. is implies that, the KEYWORDS relationship between the new and the existing games are principal and subordinate, rather than equal interoperability. In this demon- Blockchain, Game, Decentralization, Application, Soware stration3, we design and implement Rhythm Dungeon, a music ACM Reference format: roguelike game to interact with Last Trip and Adam’s Adventure Tengfei Wang, Shuyi Zhang, Xiao Wu, and Wei Cai. 2019. Rhythm Dungeon: (AA), another two blockchain games we developed to demonstrate A Blockchain-based Music Roguelike Game. In Proceedings of e Fourteenth the concept of interoperability [4]. International Conference on the Foundations of Digital Games, San Luis Obispo, CA, USA, August 26–30, 2019 (FDG ’19), 3 pages. 2 SYSTEM FRAMEWORK DOI: 10.1145/3337722.3341836 In order to enable data interoperability, we implement packet Gene- sis4, an open source smart contract package that hosts interoperable arXiv:1907.00042v1 [cs.MM] 28 Jun 2019 1 INTRODUCTION data for multiple games in the blockchain. Due to the length limit, By leveraging the unique features of blockchain technology [8], we would like to skip the implementation details but only introduce decentralized ledger, e.g. BitCoin [7], becomes reality. On this the interfaces for our demo. As illustrated in Figure 1, the Genesis basis, Ethereum [2] further extends the application of blockchain smart contract provides two public functions, ReadCharacter and into the domain of decentralized applications (dApps) [3] by intro- UploadCharacter, to facilitate interoperability. e games devel- ducing the concept of smart contract [1]. Since 2017, tremendous oped with Genesis framework are able to fetch characters from ∗corresponding author Genesis via the ReadCharacter function. Also, aer the function UploadCharacter is called with a character as the parameter, the Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed contract stores the character if it is valid aer checking. Finally, for prot or commercial advantage and that copies bear this notice and the full citation when players play the games that have a connection with Genesis, on the rst page. Copyrights for third-party components of this work must be honored. For all other uses, contact the owner/author(s). 1hps://www.cryptokiies.co/ FDG ’19, San Luis Obispo, CA, USA 2hps://cryptocuddles.com/ © 2019 Copyright held by the owner/author(s). 978-1-4503-7217-6/19/08...$15.00 3Demo video available at: hp://gaim.sse.cuhk.edu.cn/rhythm-dungeon/ DOI: 10.1145/3337722.3341836 4hps://github.com/SFENKSLab/ProjectManis/tree/master/Packages/ProjectGenesis FDG ’19, August 26–30, 2019, San Luis Obispo, CA, USA Tengfei Wang, Shuyi Zhang, Xiao Wu, and Wei Cai player can take one action every two bars. So, it is a kind of turn- based input mechanism, just like the famous PSP game, Patapon. A screenshot of Rhythm Dungeon is illustrated in Figure 2. e role-playing elements of this game are quite straightforward. Player kills enemies to earn experience points to level up. When the player upgrades, he or she collects skill points to increase the character’s strength, armor, luck (related to the chance of a critical hit) and max health. e career of the character is determined by the characteristic of the aributes. Due to the dierent tendency of the aributes, the player can adopt dierent strategies for enemies of dierent careers to kill more enemies. We plan to design more contents for careers, which will be talked about later in the Ongoing Figure 1: System Framework Work section. Regarding the roguelike characteristic of this game, each time the player starts with a new character. e character grows up they can experience the features of the blockchain and contribute when it levels up. e death of the character is permanent, which contents to the contract by playing games. As an open source frame- means there is no chance for the character to come back to life again. work, all players have free access to the content of the contract and However, the player can choose to upload his or her character to can read data that it has stored. the smart contract Genesis deployed on Ethereum. en, although Based on the framework, we have designed and implemented one cannot play that character again, there is a possibility that the two blockchain games: Last Trip and Adam’s Adventure (AA). character is brought back to life when other player plays the game Last Trip is a storybook, in which the players perform dierent or act in other games that fetch this character from the blockchain. actions to improve their characters’ aributes to win the bales. e player can upload his character to the blockchain aer the 4 GAME FEATURES game is over. AA is a multi-player Dungeons and Dragons (D&D) novel-adventure game. In this game, the players will experience 4.1 Asynchronous Interactions among Players three modes: Bale of Adventure, Bale of Dark Lord, and Bale of Players can interact with each other by leing others ght their own Blood Moon. In the Bale of Adventure mode, massive players will characters or challenging characters of others. is is done through create characters to adventure in the Dungeon, conquer demons the uploading and fetching characters to and from the smart con- to empower their characters on their own. All growth in these tract. e uploaded character is checked by the smart contract so characters will eventually be accumulated into Adam, a shared that its aributes do not violate the contract’s pre-dened rules to character stored in the blockchain. In the bale of Dark Lord, regulate the process. With this mechanism, players can interact the player will use the shared Adam and one random character with each other, or even with themselves, in an asynchronous man- summoned from the Last Trip to combat the Dark Lord, the evil ner. Note that, the smart contract is completely accessible to the king created by the system. Each 30 times Dark Lord is defeated public. Everyone can easily see the content of the contract and read in every chain, the bale of Blood Moon can be triggered. e data from it. is transparency of the decentralized process makes player will use the Adam in their corresponding chain to conquer the whole process more reliable than a centralized server handling the Adams in other chains. the whole procedure. e Rhythm Dungeon will interact with the characters uploaded by the games above. erefore, the players in this game may interact 4.2 Interaction with Other Games with past players in Last Trip and Adam’s Adventure. Meanwhile, the newly created characters in Rhythm Dungeon will appear in Rhythm Dungeon, Last Trip and AA are designed to have the equal Last Trip and Adam’s Adventure as well. With this approach, the privilege to access blockchain data through the Genesis smart con- players of the tame will inuence future adventures and contribute tract. ey all have permissions to upload, fetch, and update char- their content to make the stories in these games continuously in- acters. When Rhythm Dungeon fetches a character uploaded by creasing. another game, the player is in combat with a character from a dier- ent game world. Meanwhile, the characters generated by Rhythm 3 GAMEPLAY Dungeon will appear in the other two games as well.