Cross-platform play
In video games with online gaming functionality, also called cross-compatible play, cross-platform play, crossplay, or cross-play describes the ability of players using different video game hardware to play with each other simultaneously. It is commonly applied to the ability for players using a game on a specific video game console to play alongside a player on a different hardware platform such as another console or a computer. A related concept is cross-save, in which the player's progress in a game is stored in separate servers, and can be continued in the game but on a different hardware platform.
Cross-play is related to but distinct from the notions of cross-platform development, cross-platform releases, cross-buy, and cross-platform save game cloud synchronisation.
Cross-platform play, while technically feasible with today's computer hardware, generally is impeded by two factors. One factor is the difference in control schemes between personal computers and consoles, with the keyboard-and-mouse controls typically giving computer players an advantage that cannot be easily remedied. The second factor relates to the closed online services used on consoles that are designed to provide a safe and consistent environment for its players that require the businesses' cooperation to open up for cross-platform play. Up through September 2018, Sony Interactive Entertainment had restricted PlayStation 4 cross-platform play with other consoles, creating a rift between players of popular games like Rocket League and Fortnite Battle Royale. In September 2018, Sony changed their stance, and had opened up beta-testing for Fortnite cross-platform play. Sony officially stated it will allow any developers to support cross-platform play in October 2019.
Background
Prior to the seventh generation of video game consoles, video games were typically developed for a single console with only a few games receiving cross-platform releases across multiple consoles. This was due to the unique processing architecture of each console, making development for each a closed ecosystem and requiring additional effort to port to other systems. With the seventh generation of consoles, which saw console systems use similar processor hardware as personal computers, cross-platform development for both consoles and personal computers became much easier to achieve using standard software libraries, game engines, and scripting languages that isolate platform-specific details from the specific elements for the game itself. Such tools enabled games to be released simultaneously for multiple platforms.With the availability of the Internet, games have included online multiplayer components, allowing two or more users to play simultaneously on different computer systems. Games released for a platform may be able to take advantage of platform-specific networking libraries to accomplish this, such as the Winsock layer for Microsoft Windows. These games would not be able to be played cross-platform with other versions released on other systems. Instead, most games with online components and developed for multiple platforms generally use standard TCP/IP-type functions for communication between players' clients, or between a client and a game server, nullifying the intrinsic differences between hardware platforms.
There are some practical limitations for cross-platform play. In games where the player's computer or console acts as the server, the hardware capabilities may place limits on the number of players that that server can host, and thus preventing cross-platform play. Hardware also plays an issue in considering how much the player can customize the game on a computer to run at a high framerate, while console versions are fixed to run at the optimal experience on the set hardware configuration.
The most common limitation for supporting cross-platform play from a developer's stance is the difference in control schemes between consoles and computers. Computers with keyboard and mouse controls on personal computers are generally considered to have a significant advantage in games that require aiming, such as first-person shooters, over analog controllers for consoles. Console games are then subsequently developed with features such as aim assist to make up for the lack of precision controls. In 2010, Rahul Sood, the president of Voodoo PC, stated that Microsoft had terminated cross-platform play between Xbox 360 and computer players for an upcoming game claiming that even skilled console players "got destroyed every time" in matches against computer players of mediocre skill due to the difference between controller and keyboard-and-mouse controls, and thus would be seen as an embarrassment to the Xbox 360. Microsoft's Senior Director of Computer and Mobile Gaming Kevin Unangst countered this point, stating that Microsoft's internal testing found that much of the issues related to control scheme difference can be mitigated through a game's design and balance. Blizzard Entertainment implemented cross-platform play in its game Overwatch for all supported consoles and on personal computers, but due to the advantage keyboard-mouse players have over controllers, which greatly affects performance in the fast-paced game, they kept the game's competitive play mode segregated into console and computer player pools. Cliff Bleszinski believed that cross-platform play for his game LawBreakers was a "pipe dream", as he anticipated that by placing tools such as aim assist to help console players match computer players, computer players would be upset at the handicap this introduced, and the player base would react negatively towards this. Following wider adoption of cross-platform play in many mainstream titles starting around 2020, the issues of balancing the game with the use of aim assist in first-person shooters, where the game automatically locks onto targets for those using controllers, became of concern as a game with aggressive aim assist could lead to poor balance between cross-platform players.
Providing cross-platform play is seen as a means to keep a game's player base large even several months out after a game's release.
History
Generally, cross-platform play between personal computers of different operating systems is readily enabled using standard communication protocols, and only requires the game to be appropriately ported to these other systems; the computer platform is considered to be very open due to this. Though digital online services that operate on the computer have become popular since around 2010, these systems typically remain open, providing the developer with tools to take advantage of cross-platform play. For example, Valve's online game service, Steam was initially built for Windows computers, but in 2010 expanded to OS X systems, and in 2013 to Linux. The Steamworks API offered to developers through the service enables cross-platform play to uses on these different operating systems while taking advantage of the friends, communication, and matchmaking features offered by Steam. With the introduction of the Epic Games Store, Epic Games released its own set of backend tools to support networking for games released on the store. Though initially games on both the Epic Games and Steam were not compatible, Epic developed and released a free API for supporting cross-platform play for games released on both storefronts in June 2022, with plans to expand this for mobile and console games.Relating to consoles
Prior to 2006, hardware consoles typically lacked built-in Internet connections, often requiring special hardware to be able to connect to the Internet. This enabled some games to be deployed as cross-platform titles. Early attempts at cross-platform play include the 1998 Sega Dreamcast which included a built-in modem; Microsoft worked with Sega to provide a version of Windows CE to developers to make cross-platform games between Dreamcast and Windows players for games such as 4x4 Evo, Maximum Pool, Quake 3 Arena and Phantasy Star Online. Sony would launch the PlayStation 2 in 2000, which feature support for online play via an external modem. On September 13, 2001, Capcom vs. SNK 2 was released for the Dreamcast and PlayStation 2 in Japan. The Japanese versions of the game allow players from both platforms to compete against each other online via KDDI's Multi-Matching service, making it the first game title to allow cross-play between game consoles from competing manufacturers. Square Enix would introduce online play between PlayStation 2 and Windows users for Final Fantasy XI in 2002.The introduction of Internet-ready game consoles, such as Sony's PlayStation 3 and Microsoft's Xbox, brought online services that aid in securely managing the player's credentials, digital store purchases, friend lists, messaging and other social features, and online matchmaking for multiplayer games. Though providing benefits to the player, these online services also aid the managing company to maintain a consistent and attractive experience for its users, assuring games, updates, and other content meet both desirable quality and content restrictions as to draw new players to these consoles. Historically, cross-platform play with consoles has been very limited as a result of these services, and the ability to have console games with cross-platform play is considered to be a "holy grail" within the video game sector.
One technical challenge that faces console-based cross-platform play is the network communication between platforms, managing the different protocols used by each service. However, the technical limitations can be overcome, with at least three developers stating they could enable cross-platform play within a day once they were allowed to do so. A "configuration issue" briefly allowed computer, PlayStation 4, and Xbox One players to play alongside each other in the online cooperative game Fortnite in mid-September 2017. This had not been an expected feature of the game, as cited by the game's current specifications. While Epic Games corrected the configuration and stated this was a mistake, the brief situations demonstrated that technical barriers to cross-platform play can be met. Later in March 2018, Epic announced plans to take the spinoff title, Fortnite Battle Royale for Windows, PlayStation 4, Xbox One, and mobile devices, with cross-platform play enabled between computer, PlayStation 4 and mobile, and computer, Xbox One, Nintendo Switch, and mobile.
Once these technical challenges can be overcome, the primarily limiting factor for cross-platform play has been the terms of service and acceptable use policy that developers and players must abide by when using the consoles' online services. Sony's Shuhei Yoshida, in discussing the possibility of cross-platform play between PlayStation and Xbox platforms, noted that "the technical aspect could be the easiest" to overcome compared to policy and business-related issues. Some online services have restrictions on age-related content which prevent certain games from using cross-platform play or to disable certain features to allow it; Dave Hagewood, a lead developer for Rocket League, noted that they had to launch their game, which supports cross-platform play between Windows and the PlayStation 4 versions, without the ability for players to communicate across systems due to content regulations Sony has in place; they were able to later patch in filters to allow for this communications under Sony's service. Valve had to drop PlayStation 3 and computer cross-platform play from its 2012 Counter-Strike: Global Offensive just before launch as they wanted the ability to patch the game on a frequent basis, which would be limited by Sony's certification process on the PlayStation system; they had similarly tried to bring Steamworks to the Xbox 360 for this game, but also found Microsoft's certification policies to be too restrictive for frequent updates.
For decades, console manufacturers have worked proactively to protect the exclusivity of a game on their system from other console competitors, to which cross-platform play can be seen as a threat. Some journalists have postulated that cross-platform play had been restricted by console makers as to assure players remain with their platform for future games. Kyle Orland for Ars Technica said that if a player wants to continue playing new games with friends, the lack of cross-platform play required them to continue to purchase the new games for that console platform, creating "powerful network effects". Alex Perry of Mic similarly noted that lack of cross-platform play can lead a player to try to push and influence their friends to buy the same console so they can play together, boosting sales for that console manufacturer.