Valve and The Road to GDC 2015


Content Director
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Aug 27, 2004
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Valve is going to have a large presence at GDC 2015 in March. Not only are they expected to reveal the entire Steam Universe, but several Valve employees will be holding informational sessions. These sessions are:
But don't expect Valve to explicitly talk about Source 2, Left 4 Dead 3, or Half-Life 3 at any of these sessions. The keyword being "explicitly", because sometimes information about new software is sprinkled around in the discussions, but little is put into focus. The big software reveals will probably be left to E3, PAX, and/or Gamescom.

In preparation for GDC, I thought it'd be nice to write a little bit of background for each session. It was hard for me to decide what info to put in and what to leave out, so I hope I covered enough for you all. So, let's just get into it...


Valve will be unveiling the next evolution of OpenGL, known currently as glNext. This session will be presented by Valve's John McDonald and Pierre-Loup Griffais, and they will be accompanied by developers from DICE, Unity, and Oxide.

Why All the Hubbub About glNext?

As told by the Khronos Group, an organization that is today responsible for OpenGL and other important APIs, this chart illustrates a good point...


...OpenGL is the only major graphics library that's supported by all modern GPUs and operating systems. This means that, if a video game developer took advantage of it, it should be easier for them to support a game that spans across multiple platforms, such as Windows, Linux, Mac, and it's even a stepping stone for Mobile support. As a result, developers can reach a wider audience with their games, and consumers won't potentially miss out on playing a particular game due to platform limitations.

There are also a lot of other important notes about glNext that can be taken from the presentation that's linked above:
  • After twenty two years -- need ground up design of API for high-efficiency access to graphics and compute on modern GPUs
  • Incremental change is not enough. GL has a good track record of adaptive evolution... but structural problems can’t be fixed by accretion
  • Who's on board: Valve, Apple, AMD, Intel, Nvidia, and others
  • Fast-paced work on detailed proposals and designs are already underway
  • NOT your father’s multi-year design-by-committee process
  • Goals:
    • Clean, modern architecture
    • Greatly reduced CPU overhead
    • Multi-thread / multicore-friendly
    • Improved reliability and consistency between implementations
    • Unify OpenGL and OpenGL ES
It sounds like Valve wants their games to run with OpenGL. They've said that Source 2 has "multiple rendering back-ends," and that they would like to "drop the Direct3D back-end and go OpenGL-exclusive." So, we could guess that Source 2 will be natively-powered by OpenGL. But, whether or not it will use glNext out of the gate remains to be seen.

Also, since SteamOS is a Linux operating system, Valve probably doesn't want to continue translating DirectX games over to OpenGL with Source 2. It would make development much simpler if they were able to concentrate on one API, and it would be beneficial to use the API that runs the best on the SteamOS.

While developing for and exploring the performance capabilities of OpenGL over the recent years, Valve has become a key player in OpenGL's evolutionary development, and that brings us to...

Valve's Known Roles in the Future of OpenGL

Valve has had a very, very active role over the years in improving the next-iteration of OpenGL. They are, after all, a Contributing Member of the Khronos Group.

Valve has been working closely with hardware and technology vendors such as NVIDIA, AMD, and Intel to improve graphic driver performance on Linux. As a result, they identified driver & multithreading issues and were able to increase Left 4 Dead 2's performance by about 15% on Linux over Windows with OpenGL.

While settling in and learning as they go on with OpenGL and Linux game development, Valve has created some open-source tools.

ToGL: A Direct3D -> OpenGL translation layer. This can make it easier for game developers to port their Direct3D 9.0c games over to OpenGL.
VOGL: An OpenGL debugger first conceived by Rich Gelreich, a former software engineer for Valve and RAD Game Tools, and current hater of open-office spaces.​

Valve has given funding to LunarG, an organization that works within the Mesa development community. They work on the Mesa 3D Graphics Library, an open-source implementation of OpenGL, which is the graphics driver in the Mesa branch of the SteamOS. A year ago, it was found that Dota 2 had a 20-second reduction in loading time with an added patch to SteamOS Mesa.


Alex Vlachos, an experienced 3D graphics engineer at Valve who's been responsible for L4D2's wounding system, Portal 2's water flow, and The Orange Box's post-processing techniques, will present methods of rendering games efficiently using Virtual Reality. As described by his GDC session's webpage, some topics will include:
  • Efficient stereo rendering
  • Reducing rendering latency
  • Saturating the GPU despite synchronization points
  • Reducing pixel cost for low-priority pixels
  • Specular antialiasing
  • Constrained anisotropic lighting
These are very important topics because, without improving on them, the immersive experience of virtual reality would be less than desirable.

What's interesting, though, is that apparently Vlachos has been responsible for engineering virtual reality support in Source 2, as told by Gabe Newell in his Reddit AMA last year. This means that, whatever Vlachos presents in this session, it is likely that it's all going to be implemented in Source 2 to enhance its support for virtual reality. So we can assume that the six points above are going to be additional features of the Source 2 engine, in general.

A Brief History of Valve and Virtual Reality

Valve has had a vested interest in virtual reality for awhile now, mostly starting with Michael Abrash and his R&D. He introduced us to the concept of "wearable computing" and augmented reality, but it wasn't until three months after that initial blog post when Abrash finally uttered the words "VR" (once). Fast forward one more month and Abrash, Palmer Luckey, and John Carmack are sharing the stage at Quakecon talking about virtual reality.


Abrash and his efforts were supported by other software engineers at Valve, like Joe Ludwig. Joe and the team were responsible for creating a real-world application of virtual reality from Valve, and bringing it to consumers. So, around 2011 and 2012, they worked on porting Team Fortress 2 to VR. Since then, they have been continuing to update TF2's virtual reality support.

In 2013, Valve released an update to the Source SDK, bringing official support for virtual reality and the Oculus Rift. In 2014, they released SteamVR, an update to Steam allowing for virtual reality support within the Big Picture Interface.

What's next? That brings us back to Alex Vlachos and Source 2, all of which we'll learn more about in March.


Both Valve's Sergiy Migdalskiy and Dirk Gregorius will be discussing physics simulation & optimization techniques. Specifically, Gregorius' session is called "Robust Contact Creation for Physics Simulation," and Migdalskiy's is called "Physics Optimization Strategies." The two presentations may cover in combination:
  • Numerical Integration
  • Contact Manifolds
  • Destruction
  • Solvers
  • Networking
  • Optimization
This stuff is all pretty technical and requires math and programming skills, so I won't go into it.


At last year's GDC, Migdalskiy and Gregorius both covered similar topics in physics - "Debugging Physics" and "QuickHull," respectively. And in 2013, Gregorious also presented "The Separating Axis Test." These are all very general topics, so it's not likely they'll explicitly expand on any Source 2 information.

We'll talk more about Valve's plans for game physics in an upcoming ValveTime video, so look out for that!


So there you have it. GDC 2015 will run from March 2 thru 5, and so stay tuned to ValveTime as we cover the event. It's going to be a good one for fans of Valve!
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Mr. Sir Shpee

Space Core
Apr 30, 2014
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I'm hoping that glNext is showcased with Source 2, and then Valve teases more for E3. I'm also rather excited about the fact that Eidos is showing some Deus Ex 4 tech at GDC. TressFX 3.0, I think.


Mar 8, 2012
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Nice compiled article Smash - doth soothe my madness! - Just a few more weeks away!!!


Apr 29, 2004
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Hey man, how's that virtual anti-mass spectrometer coming along? I know some people have said that your development of the software might cause a resonance cascade, but I'm pretty sure they don't know what they're talking about.


Feb 23, 2015
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really exited for GDC, lots of news and great opportunities in one place


Feb 27, 2015
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just found out about this Website here, excellent pool of Information!
As part of my excitement for Valve and Steam etc. I actually post once in a while (lengthy) Videos on my YT-channel covering especially business, sales, distribution topics on Steam, Steam-Machines, PC-Consoles etc.

imo it's pretty safe that Valve shows off at least the new Source engine at the glNext introduction, because - at the end of the day - why should Valve take the presentation lead with two persons instead of only one and show nothing new Valve Content at all. I would see that as a waste of resources and a disappointment.
What I see as at least "possible", is the introduction of a new Valve game, be it within the glNext event or within the mysterious Developer session on march 13th.
After all, the point of time to reveal of new game couldn't be better for Valve. They would kill two birds with one stone, gathering buzz for both the game ifself and the simultaneously presented Steam-Machines, Steam-Controller and SteamVR.
Anyway, let's watch what they have to unveil, I'm pretty sure that next week will be one of the most exciting ones in Valve's history.