Has Source Engine 2 been soft-launched in the latest DOTA 2 update?

Valve, in what would be a quintessentially Valve-like manoeuvre, seems to have slipped a soft-launch of Source Engine 2 into the latest tools update for Dota 2, modders and reverse engineers believe.

A thread on Reddit is speculating that, in an update to DOTA 2's Workshop tools, the enigmatic developer may have also pushed an update to its legendary engine, which has powered games like Half Life, Left For Dead, Portal and Dear Esther in its long history.

Yesterday, Valve announced the update to its workshop tools for the phenomenally popular DOTA 2, but made no mention of what would be an enormously significant move.

"This is the first release of a new set of tools to create, play, and share custom maps and game modes for Dota. This is a developer focused release and currently has high system requirements which means not everyone will be able to run the tools."

Nonetheless, Reddit user RoyAwesome has compiled a list of 'evidence' which he and other Redditors think points to the presence of Source 2 in the Workshop code.

"Everything that would share a name with Source is named '...2'. That's 'engine2.dll', 'vconsole2.exe', 'vphysics2.dll'," he writes.

"When you go to open a map in Hammer, it asks for .vmap files. One of the other options is '.vmf (Source 1.0)' files.

"What we're seeing here could be Source 2, or it could be that a bunch of components from Source 2 have been backported. Either way it's kind of meaningless... If the game looks and plays the same what difference does it make?"

Garry Newman, CEO Facepunch Studios, creator of Garry's Mod

"There is a new Key-Value like format (that i'm gonna call KV2). It is type safe. It looks like this: http://pastebin.com/RVQtkv1j. The engine calls them 'Schema Files', written by CSchemaTextWriter.

"That script also allows for different dlls to load and render different assets (vmaps are rendered by worldrenderer.dll, etc). This is a completely new architecture from Valves previous system. This bit alone would indicate a significant amount of engine work has been done to split these bits out of the engine and into their own libraries. That means the engine is also completely plug-and-play with new engine level components if valve creates them for different games. This is pretty freaking huge."

However, not everyone is convinced. Garry Newman, CEO of Facepunch Studios and creator of Rust and the seminal Garry's Mod - the toolset which introduced millions to the original Source Engine's potential - is exercising caution.

"The Source Engine is pretty modular," he told GamesIndustry.biz. "The components talk to each other through interfaces. It's possible to upgrade certain elements like physics, sound, GUI, renderer, engine without having to upgrade the entire engine.

"What we're seeing here could be Source 2, or it could be that a bunch of components from Source 2 have been backported. Either way it's kind of meaningless... If the game looks and plays the same what difference does it make?"

Of course, as with every possible sliver of activity from Valve, the names of Half Life 3 and Left For Dead 3 are being whispered in increasingly urgent tones across the internet. It makes sense that Valve would want to launch these games on a new engine, and to have big name games to promote the engine when it does launch, but prepare for speculation to reach the point of saturation before anything is confirmed.

Valve has been contacted for confirmation. Don't hold your collective breath.