Guys, stop pissing your pants, this is not the Source engine. It's just a damn SDK for modders. Lots of comments seem to imply the former, which is not the case.
You can't do anything with this code without Source.
To expand, this SDK mostly only builds a few DLLs which allow mods to override various parts of the game logic. It doesn't include the source for the main hl2.exe, for example.
This is how all mods have been built for Valve games dating back to the original Half-Life.
The actual problem is that the license they are using is neither a valid free software license nor a valid open source license. The GPL would honestly be their best option if they wished to build a bigger community around Source engine modding, but I doubt that will ever happen.
No, it would not be, as the GPL would eliminate the core sentence of their current license:
> You may, free of charge, download and use the SDK to develop a modified Valve game running on the Source engine. You may distribute your modified Valve game in source and object code form, but only for free.
This would be prohibited by the GPL, as it eliminates fundamental freedoms (the right to sell the product).
This sentence is (obviously) very important to Valves ecosystem.
I'm pretty sure this is their previously released SDK (though a new release for 2013) which is already available through Steam. What's new here is that they've put it up on GitHub.
1. Free Redistribution
The license shall not restrict any party from selling or giving away the
software as a component of an aggregate software distribution containing
programs from several different sources. The license shall not require a
royalty or other fee for such sale.
From the source SDK license
You may distribute your modified Valve game in source and object code
form, but only for free.
It's not the game code. It's just a mod development kit which has been available forever. This is just the latest version uploaded on GitHub. Not much of interest here.
Do you want a truly open game company?
Take a look at iD. THAT is Open. Many FLOSS games would be nothing without iD. John Carmack is the man. He releases actual engine code (not SDKs) and under GPL license!
And that guy truly revolutionized 3d graphics (though iD's latest games are not very appealing to me) and instead of keeping the techniques as industrial secrets he releases his knowledge[1].
Carmack releases the code _after_ the game engine is well out of the licensing period and not used anymore. Source is an ongoing effort and can still be licensed.
Anything that is "in production" at ID software is as closed as with Valve.
It is true that GoldSrc is not released and Valve is (technology-wise) not an "open company" at all and I don't oppose that. Also, I wrote that the (ID) engines are closed while still sold for licensing - that has nothing to do with whether the old games are still available. The assets and levels are not free after all, so this just gives you the ability to buy those.
I want to oppose the view that ID is an "truly open" company.
A "truly open" company would release the code while it is still in active use. It is a great feat that ID does this and it certainly puts them ahead of Valve in that regard, but this doesn't mean that they are "truly open". All their "active" games are very much released in the same fashion as Valve does it: closed source, open SDK.
Anyways, ID is still way ahead, not only of Valve but of all game companies (AFAIK). Game engines are not as easy to license free as other software since you cannot monetize support, and often the code carries industrial secrets (which is their edge over other free game engines). I guess ID's stance is the best compromise one could achieve.
I keep my point: Carmack deserves credit for what he does and his respect to software development as a whole.
I agree on that. It is just that in my opionion, strong wording with regards to software freedom should be reserved to those that practice it.
In context of the industry, ID is unusually open and releasing their old engines is a valuable service to our community.
It just doesn't really map to what the software linked represents, because thats a scheme that ID uses as well. Also, they were widely applauded for that as well, just for providing the tools to manipulate their games that deeply.
Also, credit where credit is due: Valve is generally very relaxed stance on using their assets for anything non-commercial, e.g. in their Moviemaker (and even allow youtube ad revenue). This is codified:
Oh, the many degrees of freedom :). I don't understand the amount of mischief Valve is getting for providing something nice, even if it can be improved.
It's certainly nice that you can study this code freely, but that isn't a good reason for anyone to use it. The restriction stating that "you can only use this to make mods of valve games" seems particularly ridiculous. For indie developers, there are plenty of free (as in freedom) replacements that are probably better to use.
This code is not a "game engine", let alone a properly free one. It's an SDK specifically to make mods for the Source engine. It only has the code to build mod DLLs, not the main engine source code.
> We have released an update to the Source SDK, bringing support for Mac OS X and Linux to mod developers and exposing the ability for virtual reality support in your mod.
Looks like some of the SSE work in the mathlib directory is unimplemented or unverified in POSIX environments, or else implemented only in C. Not sure how crucial or not that would be in the big picture of things though.
I'm sure it'd be fun to play with, but the license makes it a non-starter for any serious work.
This new release seems to have support for Linux and OS X, which is a new addition to the Source SDK. Previously you've only been able to use mods on Windows. This might be enough to get me back into modding for a bit.
Yah, it is so terrible that valve would release something for free to those who could not pay, but would not supply the ingredients for a commercial effort without some consideration. What scumbags.
This is great. Now we are free to help remove dependencies, improve this engine and in the long run hopefully help Valve take further steps into being a more Open Company , I hope that Valve change the license once they are in a position to do so. They are in a staggeringly odd turn of events starting to 'Open Up ' and working within the view of the outside public on a number of high profile software projects. They are making good moves, I for one intend to encourage them to make more by helping! Pull requests to help them will make them realize they will gain more if the engine is even more open, its a matter of time.
This is just an SDK. It's for their own convenience! You make mods for their closed source Source engine (see what I did there?) and they earn tons of money and Steam users.
What's Open about that? How are you going to remove the Source dependency?
Game companies have been releasing SDKs since what feels like forever.
I love Valve's games, but you have to give credit where it's due.
You can't do anything with this code without Source.