Subject: General Tech, Graphics Cards, Shows and Expos | August 15, 2014 - 08:33 PM | Scott Michaud
Tagged: siggraph 2014, Siggraph, OpenGL Next, opengl 4.5, opengl, nvidia, Mantle, Khronos, Intel, DirectX 12, amd
Let's be clear: there are two stories here. The first is the release of OpenGL 4.5 and the second is the announcement of the "Next Generation OpenGL Initiative". They both occur on the same press release, but they are two, different statements.
OpenGL 4.5 Released
OpenGL 4.5 expands the core specification with a few extensions. Compatible hardware, with OpenGL 4.5 drivers, will be guaranteed to support these. This includes features like direct_state_access, which allows accessing objects in a context without binding to it, and support of OpenGL ES3.1 features that are traditionally missing from OpenGL 4, which allows easier porting of OpenGL ES3.1 applications to OpenGL.
It also adds a few new extensions as an option:
ARB_pipeline_statistics_query lets a developer ask the GPU what it has been doing. This could be useful for "profiling" an application (list completed work to identify optimization points).
ARB_sparse_buffer allows developers to perform calculations on pieces of generic buffers, without loading it all into memory. This is similar to ARB_sparse_textures... except that those are for textures. Buffers are useful for things like vertex data (and so forth).
ARB_transform_feedback_overflow_query is apparently designed to let developers choose whether or not to draw objects based on whether the buffer is overflowed. I might be wrong, but it seems like this would be useful for deciding whether or not to draw objects generated by geometry shaders.
KHR_blend_equation_advanced allows new blending equations between objects. If you use Photoshop, this would be "multiply", "screen", "darken", "lighten", "difference", and so forth. On NVIDIA's side, this will be directly supported on Maxwell and Tegra K1 (and later). Fermi and Kepler will support the functionality, but the driver will perform the calculations with shaders. AMD has yet to comment, as far as I can tell.
Image from NVIDIA GTC Presentation
If you are a developer, NVIDIA has launched 340.65 (340.23.01 for Linux) beta drivers for developers. If you are not looking to create OpenGL 4.5 applications, do not get this driver. You really should not have any use for it, at all.
Next Generation OpenGL Initiative Announced
The Khronos Group has also announced "a call for participation" to outline a new specification for graphics and compute. They want it to allow developers explicit control over CPU and GPU tasks, be multithreaded, have minimal overhead, have a common shader language, and "rigorous conformance testing". This sounds a lot like the design goals of Mantle (and what we know of DirectX 12).
And really, from what I hear and understand, that is what OpenGL needs at this point. Graphics cards look nothing like they did a decade ago (or over two decades ago). They each have very similar interfaces and data structures, even if their fundamental architectures vary greatly. If we can draw a line in the sand, legacy APIs can be supported but not optimized heavily by the drivers. After a short time, available performance for legacy applications would be so high that it wouldn't matter, as long as they continue to run.
Add to it, next-generation drivers should be significantly easier to develop, considering the reduced error checking (and other responsibilities). As I said on Intel's DirectX 12 story, it is still unclear whether it will lead to enough performance increase to make most optimizations, such as those which increase workload or developer effort in exchange for queuing fewer GPU commands, unnecessary. We will need to wait for game developers to use it for a bit before we know.
Subject: General Tech, Displays | August 14, 2014 - 04:59 PM | Scott Michaud
Tagged: amd, freesync, g-sync, Siggraph, siggraph 2014
At SIGGRAPH, Richard Huddy of AMD announced the release windows of FreeSync, their adaptive refresh rate technology, to The Tech Report. Compatible monitors will begin sampling "as early as" September. Actual products are expected to ship to consumers in early 2015. Apparently, more than one display vendor is working on support, although names and vendor-specific release windows are unannounced.
As for cost of implementation, Richard Huddy believes that the added cost should be no more than $10-20 USD (to the manufacturer). Of course, the final price to end-users cannot be derived from this - that depends on how quickly the display vendor expects to sell product, profit margins, their willingness to push new technology, competition, and so forth.
If you want to take full advantage of FreeSync, you will need a compatible GPU (look for "gaming" support in AMD's official FreeSync compatibility list). All future AMD GPUs are expected to support the technology.
Subject: General Tech, Graphics Cards, Processors, Mobile, Shows and Expos | August 13, 2014 - 09:55 PM | Scott Michaud
Tagged: siggraph 2014, Siggraph, microsoft, Intel, DirectX 12, directx 11, DirectX
Along with GDC Europe and Gamescom, Siggraph 2014 is going on in Vancouver, BC. At it, Intel had a DirectX 12 demo at their booth. This scene, containing 50,000 asteroids, each in its own draw call, was developed on both Direct3D 11 and Direct3D 12 code paths and could apparently be switched while the demo is running. Intel claims to have measured both power as well as frame rate.
Variable power to hit a desired frame rate, DX11 and DX12.
The test system is a Surface Pro 3 with an Intel HD 4400 GPU. Doing a bit of digging, this would make it the i5-based Surface Pro 3. Removing another shovel-load of mystery, this would be the Intel Core i5-4300U with two cores, four threads, 1.9 GHz base clock, up-to 2.9 GHz turbo clock, 3MB of cache, and (of course) based on the Haswell architecture.
While not top-of-the-line, it is also not bottom-of-the-barrel. It is a respectable CPU.
Intel's demo on this processor shows a significant power reduction in the CPU, and even a slight decrease in GPU power, for the same target frame rate. If power was not throttled, Intel's demo goes from 19 FPS all the way up to a playable 33 FPS.
Intel will discuss more during a video interview, tomorrow (Thursday) at 5pm EDT.
Maximum power in DirectX 11 mode.
For my contribution to the story, I would like to address the first comment on the MSDN article. It claims that this is just an "ideal scenario" of a scene that is bottlenecked by draw calls. The thing is: that is the point. Sure, a game developer could optimize the scene to (maybe) instance objects together, and so forth, but that is unnecessary work. Why should programmers, or worse, artists, need to spend so much of their time developing art so that it could be batch together into fewer, bigger commands? Would it not be much easier, and all-around better, if the content could be developed as it most naturally comes together?
That, of course, depends on how much performance improvement we will see from DirectX 12, compared to theoretical max efficiency. If pushing two workloads through a DX12 GPU takes about the same time as pushing one, double-sized workload, then it allows developers to, literally, perform whatever solution is most direct.
Maximum power when switching to DirectX 12 mode.
If, on the other hand, pushing two workloads is 1000x slower than pushing a single, double-sized one, but DirectX 11 was 10,000x slower, then it could be less relevant because developers will still need to do their tricks in those situations. The closer it gets, the fewer occasions that strict optimization is necessary.
If there are any DirectX 11 game developers, artists, and producers out there, we would like to hear from you. How much would a (let's say) 90% reduction in draw call latency (which is around what Mantle claims) give you, in terms of fewer required optimizations? Can you afford to solve problems "the naive way" now? Some of the time? Most of the time? Would it still be worth it to do things like object instancing and fewer, larger materials and shaders? How often?
Subject: General Tech, Graphics Cards, Mobile, Shows and Expos | July 24, 2013 - 05:15 PM | Scott Michaud
Tagged: Siggraph, kepler, mobile, tegra, nvidia, unreal engine 4
SIGGRAPH 2013 is wrapping up in the next couple of days but, now that NVIDIA removed the veil surrounding Mobile Kepler, people are chatting about what is to follow Tegra 4. Tim Sweeney, founder of Epic Games, contributed to NVIDIA Blogs the number of ways that certain attendees can experience Unreal Engine 4 at the show. As it turns out, NVIDIA engineers have displayed the engine both on Mobile Kepler as well as behind closed doors on desktop PCs.
Not from SIGGRAPH, this is a leak from, I believe, GTC late last March.
Also, this is Battlefield 3, not Unreal Engine 4.
Tim, obviously taking the developer standpoint, is very excited about OpenGL 4.3 support within the mobile GPU. In all, he did not say too much of note. They are targeting Unreal Engine 4 at a broad range of platforms: mobile, desktop, console, and, while absent from this editorial, web standards. Each of these platforms are settling on the same set of features, albeit with huge gaps in performance, allowing developers to focus on a scale of performance instead of a flowchart of capabilities.
Unfortunately for us, there have yet to be leaks from the trade show. We will keep you up-to-date if we find any, however.
Subject: General Tech, Graphics Cards, Mobile, Shows and Expos | August 7, 2012 - 03:33 PM | Scott Michaud
Tagged: Siggraph, opengl, OpenGL ES, OpenGL 4.3, OpenGL ES 3.0
OpenGL turned 20 as of the start of this year. Two new versions of the API have just been released during SIGGRAPH: OpenGL 4.3 and OpenGL ES 3.0. Ars Technica put together a piece to outline the changes in these versions – most importantly: feature parity between Direct3D 11 and OpenGL 4.3.
As much attention as Direct3D gets for PC gamers – you cannot ignore OpenGL.
Reigning in graphics hardware is a real challenge. We desire to make use of all the computational performance of our devices but also make it easy to develop for in as few times as possible. Regardless of what mobile, desktop, or other device you own – if it contains a GPU it almost definitely supports either OpenGL or OpenGL ES.
Even certain up-and-coming websites utilize the GPU to break new ground.
The Khronosgraph says 20 years.
Two new versions of OpenGL were recently published: OpenGL 4.3 as well as OpenGL ES 3.0. For the first time OpenGL allows programmers to access compute shaders which makes it easier to accelerate computations which do not work upon pixels, vertices, or geometry without bringing in OpenCL or some other API. Unfortunately this feature does not appear to carry over to OpenGL ES 3.0.
OpenGL ES is also important, not just for native mobile development as it is intended, but also because it is considered the basis of WebGL. It is likely that a future WebGL revision will contain the OpenGL ES 3.0 enhancements such as many rendering targets, more complex shaders, and so forth.
But it seems like the major reason why these two revisions were released together – apart from their timing aligning with the SIGGRAPH trade show – is because OpenGL and OpenGL ES have been somewhat merged. OpenGL ES 3.0 is now a subset of OpenGL 4.3 rather than some heavily overlapping Venn diagram. Porting from one specification to the other should be substantially easier.
So happy birthday, OpenGL – just don’t go down the toilet on your 21st.