Cross-platform play

In video games, cross-platform play or cross-play is a term used to describe the ability of a video game with an online gaming component that allows 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.

The term is related to but distinct from the notion of cross-platform development, which use software languages and tools to enable deployment of software on multiple platforms. Cross-platform play is also a distinct concept from the ability to allow a player to play a game on different hardware platforms and retaining their progress in the game through the use of cloud storage or similar techniques.

Background

Video games are frequently developed as cross-platform software products, using standard software libraries, game engines, and scripting languages that isolate platform-specific details from the specific elements for the game itself. Such tools enable games to be released simultaneously for many 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. The different types of inputs between computer and consoles also can create certain advantages for players on specific types of hardware, commonly when comparing keyboard and mouse controls on personal computers to that of analog controllers for consoles in games requiring precision aiming like first person shooters. In 2010, Rahul Sood, the president of Voodoo PC, stated that Microsoft had terminated cross-platform play between Xbox 360 and PC players for an upcoming game claiming that even skilled console players "got destroyed every time" in matches against PC players of mediocre skill due to the different between controller and keyboard-and-mouse controls, and thus would be seen as an embarrassment to the Xbox 360. Microsoft's Senior Director of PC 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.

Providing cross-platform play is a see 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 PC platform is considered to be very open due to this. Though digital online services that operate on the PC 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 Corporation's online game service, Steam was initially built for Windows computers, but in 2010 expanded to OS X systems, and in 2013 to Linux (including Valve's customized SteamOS). 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.

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. In 2002, Sony introduced online play between the PlayStation 2 and personal computers for Final Fantasy 11.

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. Though 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 PC 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.

It is also suggested that cross-platform play has been restricted by console makers as to assure players remain with their platform for future games. Kyle Orland for Ars Technica notes that if a player wants to continue playing new games with friends, the lack of cross-platform play requires them to continue to purchase the new games for that console platform, creating "powerful network effects".

Microsoft has looking into cross-platform play between their Xbox consoles and players on Windows machines. Microsoft developed the Games for Windows – Live interface in part to work with the Xbox Live services so that cross-platform play could be released, with the first such title released being Shadowrun (2007). With the Xbox One and introduction of Windows 10, Microsoft has expressed more interest in providing cross-play capabilities, though issues related to the different control schemes remain a limiting factor.

In April 2011, Valve worked with Sony to create a version of Steam to operate on the PlayStation 3 that enabled cross-platform play for its games, including Portal 2, with computer users.

In March 2016, Microsoft announced a new initiative to open up the Xbox One to cross-platform play to Windows users, initially starting with the game Rocket League in May 2016, and inviting other online networks to participate as well. Sony responded by saying they are open to having discussions for cross-platform play in light of this invitation. Yoshiaa noted that while connecting the PlayStation networks to the PC is straightforward given the openness of the computer's platform, connection to the Xbox platform requires them to think about the nature of connecting two closed systems. Yoshida considered that the primary challenge would be policy- and business-related rather than any technical challenge, but are open to working out cross-platform play on a per-game basis.

Relating to mobile devices

In general, games on mobile devices, though using iOS, Android, or Windows Mobile operating systems, do not have cross-platform play support. Mobile games are developed with recognition of connection speed limitations of cellular networks, and thus most multiplayer games are often turn-based strategy games rather than real-time action games. Many multiplayer games for mobile devices are asynchronous, where players individually complete turns or actions, these actions sent to central services and pushed out to the other players that may be impacted by those actions.

There are mobile games that do feature synchronous cross-platform play, typically using centralized services to normalize out platform choices. A common example is Hearthstone: Heroes of Warcraft which enables mobile players to challenge players on any other platform that the game has been released on, including PC.

Other hardware

CCP Games have announced they plan to enable cross-platform play for their virtual reality (VR) title, Eve: Valkyrie, between the three major VR systems: the Oculus Rift, the HTC Vive, and the PlayStation VR.