Microsoft has bought SyntaxTree, the developers of the UnityVS plug-in for Visual Studio, for an undisclosed price.

UnityVS enables developers using the cross platform game engine, Unity, to write and debug their Unity programs directly within Visual Studio, and judging by the logos on its homepage, the plug-in is popular in the gaming industry, with Microsoft, EA, Ubisoft, Blizzard, Valve, and many others listed.

The plug-in, formerly costing $99 for small teams, $249 for larger ones, will soon be made freely available from Microsoft.

What's notable here isn't the purchase per se, but what Microsoft is doing with Visual Studio. Since last year, Redmond has been cross-promoting Xamarin, the development environment that lets developers write apps for Android, iOS, OS X, Windows Store, Windows Phone, and Windows Desktop. The company is also directly integrating Cordova support into Visual Studio, to allow developers to write HTML5-based applications that target iOS, Android, Windows Store, and Windows Phone.

Unity has support for Windows, Windows Phone, Windows Store, iOS, Android, OS X, Linux, BlackBerry, and even the Web with a plugin. It also supports consoles, with Xbox 360, Xbox One, PlayStation 3, PlayStation 4, Wii and Wii U all supported.

With these purchases, integrations, and collaborations, Microsoft is making Visual Studio the development platform for mobile and multi-platform developers. It's simultaneously trying to make Azure the cloud platform for mobile and multi-platform developers, with toolkits and integrations for any platform.

Microsoft wants developers using its tools and on its platforms, and if that means supporting cross-platform development and deployment, that's a price the company is willing to pay. One wonders how far the company will take it: will we see gcc or LLVM support next?