Valve has finally taken the wraps off their brand new game engine, Source 2, at GDC 2015. As a successor to the original Source engine that launched alongside Counter-Strike: Source in 2004 (pictured above), it'll be Valve's first new game engine in 11 years.
In a press release announcing Source 2, Valve's Jay Stelly said that "with Source 2, our focus is increasing creator productivity. Given how important user generated content is becoming, Source 2 is designed not for just the professional developer, but enabling gamers themselves to participate in the creation and development of their favorite games". As such, the game engine will be available for free to content developers, just like the latest versions of the Unreal Engine and Unity.
Not much is known about the Source 2 at this stage, though Valve did mention that they will be releasing a special Vulkan-compatible version of the engine for developers that want to harness the low-overhead API.
Valve didn't mention when Source 2 will become available to developers either, or whether the company has any games in development that use it. It's fair to assume that Valve has Source 2 projects in the works, though they weren't ready to share further details.