While there were plenty of rumors regarding possible Half Life 3 announcement from Valve during GDC 2015, the company has just announced its Source 2 engine.
Successor to the original Source engine which launched back in 2004, which we know from Counter-Strike: Source, Half Life 2, Left 4 Dead and more, the new Source 2 engine will allow Valve to increase creator productivity and has been designed not only for the professional developer but also gamers themselves.
While it did not shed much details regarding the engine, its release date or any projects that might be based on the new Source 2 engine in near future, Valve did note that it will be available for free to content developers, which puts it in line with Epic Games' recent announcement regarding Unreal Engine 4 and the Unity's Unity 5 engine.
Valve also announced that Source 2 engine will support Vulkan, a low-overhead API from Khronos Group, previously known as glNext or a new version of OpenGL.
Hopefully, Valve will soon reveal more details regarding its Source 2 engine.
Source:
IGN.com.