Source 2 is upon us, it seems.
Quite what this means, it's impossible to say at the moment, although plenty of people are confidently stating exactly what it means. What we do know is that the latest update for Dota 2 appears to be packing a little more than mod tools. Digging into the files like feverish moles, the excitable detectives of the internet have discovered references to Source 2 in file names and routines. Dota 2 appears to have been ported to the new engine, which means the changes in a game that looks and sounds the same as it did yesterday are now today's big news.
To be absolutely clear, I haven't seen any definite evidence that Dota 2 is running on a new engine. It's entirely possible that the modding tools, most notably Hammer, have been updated to support a new engine that is still under lock and key somewhere. Furthermore, even if this is the first public release of Source 2, it doesn't mean that we're going to see a deluge of new releases from Valve, or even details about any Source 2 games that are in development. Dota's transition from one set of tools to another suggests that Source 2, like Source 1.00-1.99, may be an iteration rather than a giant leap forward.
RoyAwesome on the Dota 2 subreddit has been gathering info.
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.
Something has definitely changed, as a cursory look at the updated Dota console and map editor, Hammer, make clear. If Source 2 is going to be the backbone of all Valve's upcoming releases though and its most valuable current release, it seems likely that any release would be as much a test of newly efficient systems rather than a statement of any kind. If you want to see how a million computers handle the skeleton of a new engine, Dota 2 is one of the most useful delivery vehicles any company could have.
You can see the new Hammer in the video below.
Dota 2 still appears to be in the transition process though. RoyAwesome again:
Dota 2 Workshop Tools Alpha is Dota 2 running on the Source 2 engine. When you compile a map and run it, it launches the Source 2 port of Dota 2 to play.
Because of that, Dota 2 is actively being ported to Source 2, and is pretty much working. You can play it, it functions.
The main game is still running Source 1. The files that the workshop tools spit out are compatible with Source 1, and run in the version of Dota 2 that everyone else has.
Changes to file types and structures. It's not an announcement of anything, not even a stealth one, but it certainly seems to be a commitment to Dota 2, user content and iterative engine improvements.
For now, less this:
And more this:
We'll keep an eye peeled for any major developments during the day and if it turns out the Half Life 3 code is hidden in an ARG which is hidden in a file name extension, I'll eat all of your hats.