Microsoft standardizes variable-rate shading as a part of DirectX 12

Nvidia's Turing graphics cards came along with quite a few new technologies. The big one of course is their RTX real-time ray-tracing feature, but Deep-Learning Super-Sampling (DLSS) has gotten its share of time in the spotlight as well. However, perhaps the most interesting technology to toddle along with Nvidia's Turing architecture is the one that's been mostly overlooked: variable-rate shading (VRS).

Jeff wrote about "content-adaptive shading" (an implementation of VRS) back when it was added to Wolfenstein II: The New Colossus in a patch. Now, Microsoft has announced that the technology has been added to DirectX 12 as an API feature for anyone to use. In a blog post titled "Variable Rate Shading: a scalpel in a world of sledgehammers," Microsoft's Jacques van Rhyn explains the concept of VRS and briefly examines the benefits it offers using a demo especially constructed using Civilization VI and a GeForce RTX 2060.

Red areas are shaded at the full rate, while blue areas are shaded at a reduced rate.

Variable-rate shading as implemented in DirectX 12 differs slightly based on the capabilities of the hardware on which you're implementing it. Microsoft divides hardware into "Tier 1" and "Tier 2", which currently translates into "most DirectX 12-capable hardware" and "Turing cards." The difference comes into whether or not the graphics card can vary the shading rate within a single draw call; Tier 1 GPUs are limited to changing things up between separate draw calls.

Perhaps ironically, the Civilization demo that Firaxis created actually sees a larger performance improvement on Tier 1 cards, but as Microsoft notes, the game does take a small hit to visual quality due to the reduced shader work done in certain areas. Firaxis says that implementing terrain and water at a lower shading rate than vehicles, buildings, and UI afforded a 20% performance improvement on the RTX 2060 card while playing in 4K. The Tier 2 implementation sees a smaller speed gain—"only" 14% over full-rate shading—but is visually indistinguishable from the full-rate shaded image.

This was apparently captured on an Intel Gen11 graphics part.

While Nvidia's Turing GPUs are the only Tier 2-capable designs at this time, Intel more or less created the idea way back in 2014 with its "coarse pixel shading" concept. Unsurprisingly then, Chipzilla's upcoming Gen11 graphics hardware—which will be found in both its next-generation "Sunny Cove" desktop CPUs as well as its "Elkhart Lake" low-power processors—will support variable-rate shading in hardware as well. The technology offers decent gains on Nvidia's powerful graphics hardware, but it could prove to be a real boon to Intel's more resource-constrained integrated offerings.

Microsoft says virtually everyone who's anyone is looking at adding VRS to their game engines, including such names as Unity, Unreal, Activision, Ubisoft, and a few smaller developers. DirectX developers keen to get cracking on the new tech will be pleased to hear that the PIX performance tuning and debugging tool already has full support for the feature. The company will be talking about VRS at its sessions during the 2019 Game Developers Conference, and interested parties can hit up the DirectX forums for more details.

Comments closed
    • chuckula
    • 8 months ago

    For once DoomGuy64 is right: Ngreedia [b<]REALLY DID GIMP PASCAL[/b<]!!! They added some (not as complex as what Turing does) ray-tracing functionality to Pascal: [url<]https://www.pcper.com/news/Graphics-Cards/NVIDIA-Add-Real-Time-Ray-Tracing-Support-Pascal-GPUs[/url<] We all know that Ray Tracing == Gimping, so DoomGuy.... CONFIRMED!

      • Redocbew
      • 8 months ago

      I just don’t know who you are anymore.

        • chuckula
        • 8 months ago

        Two words:

        YOU’RE WELCOME

          • euricog
          • 8 months ago

          [quote=”chuckula”<] Two words: YOU'RE WELCOME [/quote<] My native language is not English, but I'm pretty sure that YOU'RE is not 1 word. EDIT: Never mind, I see that although it may be debatable, it's commonly accepted that contractions are single words: [url<]https://english.stackexchange.com/questions/80635/counting-contractions-as-one-or-two-words[/url<]

            • freebird
            • 8 months ago

            REALLY?!? Now you are saying that Chuckula is also teaching us about English? What’s going to happen next? I suppose he is now going to try and convince me the world isn’t FLAT and we all are not living in a 2D Hologram…

            • euricog
            • 8 months ago

            What do you mean it’s flat? The world’s obviously triangular, how else could it be rendered efficiently?

            • K-L-Waster
            • 8 months ago

            NURBS of course…

      • ozzuneoj
      • 8 months ago

      Crap. So much for my plan to buy a cheap second hand 1070 eventually. This will probably make the prices\demand go back up a bit, even if RT isn’t all that useful on them (or anything else for that matter).

        • sweatshopking
        • 8 months ago

        shouldn’t as the performance level will almost certainly not be playable with these effects on.

        • K-L-Waster
        • 8 months ago

        I’d be stunned if there is pent up demand for 1070’s that was just waiting for ray tracing support before pulling the trigger.

      • DoomGuy64
      • 8 months ago

      Your Retarded. [spoiler<]spelling on purpose, because chuckie cheese = no reality zone.[/spoiler<] Anyways, I love how all these features are getting rolled out. Better late than never? But it does seem suspicious, and appears as Microsoft / others are dropping the PC downgrade agenda, possibly due to MS finally supporting PC gaming as an equal platform to xbox. We've known current graphics cards have supported these technologies for years. Devs just haven't been implementing them, possibly due to anti-competitive console port practices. Now that we're not a 2nd class platform, the chains are coming off. Great, but it also proves we have been getting shafted. Same with dx12 on windows 7. Chuckie can't come up with a believable excuse for this, so he just resorts to this garbage, and no this isn't a Nvidia issue. Microsoft and the console market have been colluding to downgrade PC games for years. The only thing Nvidia has played a hand in is gameworks. They aren't the ones downgrading PC games.

        • Redocbew
        • 8 months ago

        Thank you. When Chuck posted I felt as if millions of voices suddenly cried out in terror, and were suddenly silenced. I feared something terrible had happened.

        If being Krogothed is to be unimpressed, then I suppose being Doomed is to steadfastly spew nonsense in the face of all available evidence to the contrary. I always feel like I should temper the snark with something more substantive when making a post like this, but in this case I’m honestly not sure where to start.

          • DoomGuy64
          • 8 months ago

          Or you could just copypasta Chucko, and post nothing of value, which is what you just did.

          Also,

          [quote<]nonsense in the face of all available evidence to the contrary.[/quote<] That statement requires said evidence to be posted, which you did none of. /citation needed. In fact, the "evidence" easily points to the opposite. Watchdogs+ / E3 downgrades galore. You have nothing to contradict this. NOW, we have dx12 on windows7, and Halo coming to PC, and SUDDENLY WE START GETTING PROPER PC GRAPHICS, AND RELEVANT FEATURES BEING ENABLED. Explain that, and no I don't think you can. This was all PC downgrade collusion, which stopped with Microsoft supporting the PC again.

            • Redocbew
            • 8 months ago

            [quote<]You have nothing to contradict this[/quote<] These are not the drones I'm looking for? I'll save you the line about your Jedi mind tricks not working on me, because impersonating Jabba the Hutt makes me uncomfortable, and nobody wants to relive Episode 2. Or, you know... after nearly four years of pulling teeth Microsoft decides to throw a bone to the millions of users around the world who have yet to leave Windows 7 behind. They may not have acted according to plan, but I'm sure Microsoft doesn't mind still having them as potential customers. That could be a tacit admission that all the shenanigans around upgrading to Windows 10 have failed at least in part, or it could be a tiny unraveled thread from a vast conspiracy involving Microsoft, "the console market"(wait, what?) and seemingly everyone else in the entire world. But hey, don't take my word for it. I'm just some random dude on the Internet engaged in meme-ception while I'm waiting for files to download.

            • DoomGuy64
            • 8 months ago

            Take your word for it? What does that even mean when you haven’t said anything that I can vaguely acknowledge as a point? There is no word to take!

            So far, seems like you acknowledge Microsoft giving dx12 to windows 7, but it’s done in a passive aggressive dismissive way, like you’re mad that it happened. Not that I care about windows 7, but it is a thing that exists.

            So yes, that is “tacit admission” from Microsoft that they were holding back PC gaming, at least on the OS.

            As far as the rest of your post, you ignored that e3 downgrades happen, and insinuate this as some “vast conspiracy” theory. Sure dude, it doesn’t exist, but only in your delusional mind. (Google E3 downgrade if you aren’t schizophrenic.)

            We have had graphic features since GCN 1.0 / Kepler, that have hardly been implemented on PC, and are just now gaining traction. Then we have variable rate shading making a sudden appearance only after Halo gets greenlit for Steam. Conspiracy? I don’t care what you call it, this is all basic facts and history of PC gaming. You can call my interpretation of it whatever, but the facts stand for themself. Why has it taken so long to get proper support of these features on PC? Why were we getting downgrades until now? You have no answer, and are simply dismissing what you can’t account for.

            Not only that, but anyone who’s been on PC since the OG Xbox, knows that we have been treated as second class citizens from Microsoft ever since, and have gotten nothing but console ports and broken features (like GFWL) intended to push PC gamers onto consoles from sheer irritation. Maybe you’re just not old enough to remember 90’s PC gaming, and have accepted this poor treatment as your base reality? That’s the only excuse I can come up with to justify your mentality, because otherwise it’s plain as day that we have been getting the shaft. We still don’t have decent HRTF in games, and I wouldn’t be surprised if that starts making a comeback too, because that was part of Microsoft’s push to cripple windows and force gamers onto the console.

            • Redocbew
            • 8 months ago

            Doomed!! Doomed I say!

            • DoomGuy64
            • 8 months ago

            Really? PC is dead? Looks like it’s actually the other way around now.

    • jihadjoe
    • 8 months ago

    [quote<]Variable Rate Shading: a scalpel in a world of sledgehammers[/quote<] I feel like they got the scalpel and slegehammer transposed in the title. The problem now is that current shading routines (aside from Nvidia) use scalpels all over, when sometimes a sledgehammer is more appropriate. Variable rate shading via DX12 gives everyone a sledgehammer.

      • DataMeister
      • 8 months ago

      Using scalpels all over is like the imprecision of the sledge hammer. Current shading routings are like the sledge hammer because they can’t be precise in where they focus the full force of the GPU.

      The Variable Rate Shading is more like the scalpel because it applies power more precisely where it’s needed and less where it isn’t needed. The scalpel analogy isn’t that you can precisely adjust power to every part of the image, it’s that you can focus the GPU power more precisely.

      A better tool analogy may have been a sledge hammer and a chisel (instead of scalpel). If You are the GPU when you swing a sledge hammer all your power is applied to wide chunks of the sculpture. A chisel focuses your power more accurately to add more detail in some areas and less detail in other areas.

    • Voldenuit
    • 8 months ago

    [quote<]Perhaps ironically, the Civilization demo that Firaxis created actually sees a larger performance improvement on Tier 1 cards[/quote<] Are they using the GPU Benchmark in Civ VI, that reports a higher benchmark score when the system is bottlenecked, perchance? Purportedly.

      • frenchy2k1
      • 8 months ago

      There is nothing surprising in tier1 cards seeing a greater improvement: the whole frames will be downgraded in quality, while tier2 will keep the same visual quality as before the optimization. (Only the parts that don’t need the high quality will be downgraded).
      Not sure how they select which frame to downgrade for tier1…

      It’s easy to be faster if you do less work.
      Just drop a level or two of quality if you want more frames…

        • Zizy
        • 8 months ago

        Nah, it doesn’t downgrade whole frames, this is per draw call – there are multiple draw calls per image. For the civ example, water and land are rendered with 2×2 blocks with everything else using 1×1 blocks. But the problem happens on the texture edges, and this is a pain/impossible to fix by looking at draw calls.

        “For this game, isolating the visual degradations on the righthand image and fixing them is not as simple as pointing to individual draw calls and adjusting their shading rates.
        Parts of assets in the same draw require different shading rates to get optimal GPU performance without sacrificing visual quality, but luckily Tier 2’s screenspace image is here to help.
        Using an edge detection filter to work out where high detail is required and then setting a screenspace image, Firaxis was still able to gain a performance win, while preserving lots of detail.”

      • Zizy
      • 8 months ago

      Nah, it is simply caused by Tier1 rendering ALL water and land at the coarser 2×2 rate.
      Tier2 is checking for edges and these are excluded from the coarser rendering rate, so more of the image is rendered at 1×1 (plus edge detection isn’t free).

      If Firaxis performed edge detection and use 1×1 for all calls that contain some edges (or split draw call in two based on these edges), Tier1 image would look as good as Tier2… at a severe cost of performance, possibly resulting even in worse framerate than the default sledgehammer approach.

    • sweatshopking
    • 8 months ago

    Dx12 is DOA long live vulkan

      • chuckula
      • 8 months ago

      You mean: Live long and Prosper Vulkan.

        • sweatshopking
        • 8 months ago

        You wish nerd
        <3

          • Growler
          • 8 months ago

          There’s life, Jim, but not as we know it.
          Not as we know it.
          Not as we know it.

          There’s life, Jim, but not as we know it.
          Not as we know it, Captain.

            • NTMBK
            • 8 months ago

            Captain Kirk is climbing a mountain
            Why is he climbing the mountain?

            • Chrispy_
            • 8 months ago

            I am the captain of the starship Enterprise.
            Captain Kirk, this is Spock, please step on the transporter.
            Dilithium crystals, hit by Klingon missiles!

            • sweatshopking
            • 8 months ago

            HOW RIGHT DO YOU WANT ME TO BE GUIZE??

            • Chrispy_
            • 8 months ago

            Shock news at 10: Water is wet.

            • alloyD
            • 8 months ago

            No!
            Mr. Chekhov, Mr. Chekhov
            I am firing torpedoes

            • gecko575
            • 8 months ago

            We come in peace! Shoot to kill, shoot to kill, shoot to kill.
            We come in peace, shoot to kill, shoot to kill, men 😛

            • deruberhanyok
            • 8 months ago

            There’s Klingons on the starboard bow, starboard bow, starboard bow.

            There’s Klingons on the starboard bow, starboard bow, Jim.

        • Krogoth
        • 8 months ago

        Dammit chuck, I’m a shill not a 3D graphics professional!

      • LostCat
      • 8 months ago

      I’m sure it will…in Android.

      • Krogoth
      • 8 months ago

      DirectX12 : The Search for Vulkan

        • freebird
        • 8 months ago

        Isn’t Vulkan really just the crust? Underneath the crust is “Mantle” and the mantle can get pretty hot, so maybe Vulkan is really just a phoenix “reborn” from the hot mantle….

        [url<]https://www.pcworld.com/article/2894036/mantle-is-a-vulkan-amds-dead-graphics-api-rises-from-the-ashes-as-opengls-successor.html[/url<] So maybe they can name the next version "Dark Phoenix", since we are using movie name retreads.

        • Mr Bill
        • 8 months ago

        Windows10: The Genesis Project

          • Redocbew
          • 8 months ago

          Windows7: Days of Future Past

          I have no idea what that means.

            • Mr Bill
            • 8 months ago

            [url=https://www.youtube.com/watch?v=6JDLrTmLo8M<]Project Genesis[/url<] can take a lifeless PC and introduce into its dead matter, an operating system, windows 10. A useful property of the genesis effect is that it destroys any previously existing operating system.

            • Redocbew
            • 8 months ago

            Fascinating.

            /eyebrow

            • freebird
            • 8 months ago

            {/sub-rant begin}
            “Your old PC. Unresponsive. A system barely alive.”

            “Gentlemen, we can rebuild it. We have the technology. We have the capability to make the world’s first Window 10+ PC. Your PC will be that system. Better than it was before. Better. Stronger. Faster.”

            -Project Genesis
            {/sub-rant over}

            • K-L-Waster
            • 8 months ago

            Every time it does something “fast” it triggers a slow-mo effect along with a chika-chika-chika sound.

          • freebird
          • 8 months ago

          Don’t know about “The Genesis Project”, but “The Genesis Machine” was an excellent novel by James P. Hogan.

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