This weekend we’ll be in Cosford for Flight Sim 2019. Well, not me personally, but Philipp, Marty and Thomson are there.

This summer when Marty asked if we could run the Vulkan version of X-Plane on our machines at the show I laughed a bit and then said “hell no” – at the time we were running scenery packs in the sim with default aircraft, but Vulkan was still a work in progress.

Vulkan is still a work in progress, but there has been a lot of progress, so when the marketing guys asked again I said “sure, yeah, what could go wrong” and Sidney cut them a build. We also told them not to throw out the shipping version, but if the app is well behaved people at the show may get to fly the Vulkan build for the first time.

Betas, Betas, Everywhere

At this point I’d judge us to be in the middle of the X-Plane 11.40 beta run. Beta 6 is reasonably stable and has fixed a bunch of problems that broke third party aircraft, and it’s now available to steam users. We’re still tracking down a bug where the physics code produces a NaN value. Since it just happens while flying and we haven’t gotten any useful reproduction steps, we’re pursing it by adding more checks and looking at automatic crash reports.

Please, always auto-report your crash. We don’t need you to fill out the description text field – just the auto-report and email is enough. We are looking for as many reports as possible, and we will probably stick with two betas a week until we chase this one down.

Third parties: if you haven’t yet, please test your add-on with the experimental flight model off against beta 6 – we don’t have any known bugs with the legacy flight model and third party aircraft at this point.

We are also killing off the last beta bugs in the new version of X-Plane mobile. There’s some really cool tech going into the lighting on mobile that I’ll write up soon in a blog post.

About Ben Supnik

Ben is a software engineer who works on X-Plane; he spends most of his days drinking coffee and swearing at the computer -- sometimes at the same time.

18 comments on “Cosford, Etc.

  1. The last Facebook post about Vulkan teases us with claims of 100% stability using 3rd party aircraft on long distance flights (butter sans stutter!)…where does the checklist of major Vulkan “fish to fry” stand now?

    1. Only one fish left – texture paging – Sidney’s trying to scale it now. It’s actually one of the trickier ones – a lot of the things we’ve had to do were a lot of work but when they were done we knew it. Texture paging isn’t quite like that…it’s going to take a lot of in-field testing to know if our texture paging algo is usable. I’ll write up more details next week.

      Basically when Sidney flies _without_ texturing paging, he has to simply set his texture res to _not run out of VRAM_. Since he has a pretty serious video card, this isn’t that hard to do for normal testing, but if he mixes in every add-on he owns, he can out-of-VRAM the driver. When texturing paging is done, the sim will dynamically resize things and change settings to cope with VRAM limits.

      1. Have you considered removing or hiding the “Maximum (uncompressed)” texture quality setting?

        Currently it does nothing but confuse and frustrate people; they choose it thinking it will offer increased quality over “Maximum”, but all they get from it is stuttering due to texture paging.

        1. Yes! We are probably going to do a recalibrate of the settings and remove a few “over the top” settings that just kill perf without a lot of benefit.

  2. Did somebody mention Vulkan?
    Vulkan Vulkan Vulkan Vulkan Vulkan Vulkan Vulkan Vulkan Vulkan Vulkan!
    Look forward tot racking down a stream or youtube video.
    Thank you for closing out the remaining bugs.

  3. Excellent presentation in Cosford. Will Vulcan update keep VR functional? Can we assume better desktop performance will also translate into better VR experience? Definitely looking forward to beta testing VR in Vulcan.

    1. Our goal is to ship Vulkan _with_ VR working – we sent a Vulkan VR build to the show so tomorrow I’ll find out if it worked or blew up. Generally better overall/desktop perf means a better VR experience.

    2. All Sunday long, we were running VR (using the WMR headset Samsung Odyssey+) with Vulkan. So, everyone who test flew VR on our machine at the booth on Sunday flew with Vulkan.

      It was stable enough to keep people flying on Sunday, but it is still quite rough. We had Orbx True Earth Great Britain installed on the machine, and that is quite a demanding scenery when it comes to VRAM usage. Currently, the Vulkan version will just crash if you go over VRAM – and we only had 8GB available on our GTX1070. So we occasionally ran out of VRAM when we loaded a different plane or airport and had to restart X-Plane. If we had had 16GB of VRAM, it would probably have worked without the need to restart, ever.

      However, we can’t require 16GB VRAM for everybody! That’s why it is important that VRAM management works correctly without crashing! That’s the major remaining to-do item before we can give you a beta.

      1. I watched the X-Plane 11 presentation on Saturday from the live stream and heard what you said about Vulkan and Metal.

        I tried to get him to go over to the X-Plane 11 booth when he was streaming the floor on Sunday because I thought you would be running the Vulkan build but did not happen.

        I am so happy that we are this close to a beta and can’t wait to be able test and especially want to see if there are any improvements on VR for Linux.

        I have a 1080Ti here so looking forward to putting it to work.

        Thanks Bill

      2. Hi Philipp, so grateful for Laminar’s VR support and I’m hopeful there can be greater gains via optimisations using Vulkan down the line.
        However one thing that is quite resource intensive is parallel projection required for canted HMD’s which now seem to be the cutting edge (Index, Pimax 8K+)
        Can anything be done to hard code for these displays so that parallel projection is not required?

        1. Last I checked, SteamVR didn’t have API support for canted displays, so even if we had canted support, we couldn’t use it. Right now we don’t have canted support though, so we’re blocked on us and SteamVR.

          1. Ah right, thanks.
            I was under the mistaken impression they had Steam support for the Index release.
            Well at least we will get better performance purely on the back of Vulkan efficiency.

          2. I am successfully using the Valve Index with SteamVR running at 45fps and cannot see any negative effect as a result of the lack of overt support for canted lenses. Given the close relationship of Steam and Valve, I would assume that SteamVR automatically takes care of it.

        2. @Maurice Cohen.
          It is my understanding now that the Index software takes care of the algorithm that corrects the image for canted displays just as the Pimax does for its.
          The issue is these are not efficient so I was hoping that Xplane could hard code in the required adjustments for canted displqys which would be much more efficient.
          For example the algorithm Pimax use costs around 20% in Xplane performance by all accounts but this can be tested by turning off support for parallel projection and noting any difference.
          I’m not sure why Valve have not incorporated into steam VR instead but my thought was that if Xplane coded for canted displays it would not be necessary but apprarently that is incorrect.

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