X-Plane 11.50b4 is now available if you update via the Laminar Research installer. (Steam users: it’s on the servers and we’ll hit go in a few hours if we don’t hear reports of massive crashing and pain again.)
This update was focused on crash fixes and better triaging. We’ve been seeing a huge uptick in volume of bug reports and auto reported crashes since the initial 11.50 public beta release. We are trying to cut through the noise and provide better information in logs and in the remaining crash reports to fix issues faster, and let our support team (primarily me) get the inbox under control.
The best way to help us handle crashes on Windows and Linux is still to submit the auto report form. You can include your email if you want us to be able to find your specific crash, but we do not need the message field–the log and back trace will have pretty much all the info we need. If you send an auto report, please do not also send a bug report form email.
Mac users do not have the ability to auto report, so they should fill out the bug report form, and include the Apple crash report as well as the log.txt. This can be found under your username /Libraries/Logs/DiagnosticReports. The name will include the date & time of the crash and will end in .crash. You may need to show hidden folders to access it.
We were discussing a particularly exasperated sounding bug report on one of the internal Slack channels when I realized that this might not be obvious: a crash with the error message “pipeline must not be null” – it’s one error message that covers a whole category of bugs. We fixed one major case (skycolors were broken) in b1 and added one major case (custom billboard lights on aircraft) in b2 – conservation of pipeline bugs!
Null pipelines are a new category of crash in X-Plane 11.50, so here are a few notes on what this error is and what you can do to help us fix them (and what you don’t need to bother with).
What Is a Pipeline?
A pipeline is just the Vulkan and Metal term for a shader (plus some extra gak (1)) that we use to do our drawing.
X-Plane 11.41 would ask the OpenGL driver to build shaders as it needed them, and then the driver would turn those GL shaders into hardware pipelines on the fly as it got presented with different scenarios.
Not 11.50. We build everything up front. Vulkan has two rules:
Using a pipeline is fast.
Building a pipeline is not fast.
This is a great pair of rules for us – it means if we build our pipelines at load time, we are not going to have stutters mid-frame.
Why Are We Crashing?
There is one down-side to the 11.50 way of doing things: if we don’t build all of the pipelines we need up front during load, then when it comes time to draw, we’re toast. That’s what a “pipeline must not be null” error is – it just means the loading code did not create the pipeline the drawing code needs.
Why not just build every pipeline we could ever possibly need? Load time. X-Plane can build hundreds of thousands of pipelines depending on rendering settings, scenery packs, custom aircraft, etc. We actually did “just build everything” early in our development process and the sim could take half an hour to load.
So we try to build only the pipelines we need. If we build too many, we slow load, and if we build too low, you see this error.
What Do You Do When You See This Error?
On Windows and Linux, it’s really easy: close the alert box and when the auto crash report form comes up, please press “send”. Don’t bother with you email or a message; everything we need to kill this bug is already in the auto report! (Jennifer’s edit: please DO include your email address with any auto report if you want us to be able to confirm we have your specific report! This is the only way we have of identifying who it came from.)
The good news is: the auto crash reports for the pipeline crashes are insanely easy to find and fix.
Mac users: if you see one of these, we need the Apple crash report – please send it in a bug report.
(1) for the plugin developers that know some OpenGL: a pipeline is basically a GLprogram (shader) plus a bunch of the fixed function state that goes with it: blending, depth/stencil, vertex format, FBO format, and some rando stuff thrown in.
The idea is to have the pipeline contain so much information that there is no risk that the driver has to build two hardware shaders for one Vulkan shader (to cope with other fixed function state) no matter how weird the hardware is.
On lots of actual hardware, the pipeline has stuff that’s not actually in the shader, but some surprising things, like vertex format, actually often are.
X-Plane 11.50b3 is now available if you update via the Laminar Research installer. (Steam users: it’s on the servers and we’ll hit go in a few hours if we don’t hear reports of massive crashing and pain like we did last night.)
We waited on releasing beta 2 on Steam after we started hearing reports of new, unintended crashes, and we spent the last 24 hours coding and testing the fixes. The only new fixes in beta 3 are for crashing with Linux + Vulkan, and null pipeline crashes with third party aircraft.
Hopefully this update will be more stable and we can get back to our regularly scheduled programming of working on a wider range of fixes for beta 4 next week.
Updated 4/8/2020 8:25 PM: Beta 2 is…not our best work. It crashes on start on Linux and crashes on load for a wide variety of third party aircraft (but not LR ones). We are cutting a beta 3 with these two issues fixed; it should be live in the next twenty four hours. We are holding with Beta 1 on Steam until Beta 3 is available.
X-Plane 11.50 Beta 2 is now available. (Steam users: it’s on the servers and we’ll hit go in a few hours if we don’t hear reports of massive crashing and pain.)
We received a lot of bug reports from X-Plane 11.50 beta 1. This is good! I’d much rather have multiple reports of a bug than no reports. Every now and then someone tells us about something and we go “how long has this been going on” and they so “oh for a year now” and we’re, like “why didn’t you file a bug???” Don’t assume someone else will file it!
So with beta two, here’s what we need:
Read the release notes – Jennifer puts real effort into documenting everything that is fixed to save you time.
If your bug is listed as fixed and you still see it, please file a new bug. If you mention the bug number that we listed as fixed in your “it’s still broken” report, this is really helpful for us.
If your bug is not listed as fixed, please do not re-file it. If we didn’t say it was fixed in the release notes, we already know it is still broken, and a re-file of the bug just takes time away from other bug reports.
Beta 2 does not fix all bugs – it doesn’t even come close, so most bugs do not need to be refiled.
With that in mind, there are a few high profile bug fixes in beta 2:
The sky colors dialog box does not crash! We are actually astonished at how many people reported this – we didn’t think it was a heavily used feature, but … who knew.
VR – the right eye is fixed! It turns out this was broken twice; we have fixed both bugs.
Plugins: object drawing in OpenGL for legacy plugins turns out to have been massively borked; this could cause wrong drawing and crashes in all of the pilot clients, ground traffic, push back add-ons, etc. So a large swathe of popular add-ons should work better in OpenGL mode.
Older NVidia cards should now work and not have a black screen. This covers the 600, 700, 800, and some 900 NVidia cards.
Mac users who were getting “out of memory” – this should be a lot better now.
Users with multiple GPUs and SLI should be able to launch without disabling things.
Probably the most common and annoying bug report we get that is not fixed here is blurry textures. Basically if X-Plane thinks it is running out of VRAM, it will lower the resolution on textures where it is allowed to lower the resolution. We have seen cases of this code behaving very poorly and turning texture resolution all the way down.
First, just to state the obvious, this is a bug. You do not need more VRAM to run with Vulkan than OpenGL, we just need to fix the pager. If you have less than 8 GB of VRAM, do not panic.
I am not surprised that we have seen this bug – texture paging is very much about tuning our decisions to match real-world use, and we have shipped with something that works decently in our test cases and sometimes quite badly in real-world use cases that are very different from our test cases. So we will adapt the algorithm over time based on data we collect, and it will take a few betas to get better.
X-Plane 11.50 has been out for a little bit more than 24 hours, and things have been a little bit nuts. Here are a few quick notes, in no particular order.
Bug Fixes and Work Arounds
While I don’t have work-arounds for the missing right eye in VR or older NVidia cards that won’t run in Vulkan, the good news is that we have fixes for these already. We are going to start testing beta two on Monday and try to get the fixes we have out as soon as possible. While we don’t have every major reported bug fixed, beta two should make a real difference.
Users who can’t start and have SLI setups: disable SLI in the Nvidia control panel and you will be able to run Vulkan. We are still investigating this – our goal is a bug fix so you don’t need to turn SLI off. (We do not expect X-Plane to leverage both cards – we expect it to run without failing.)
Finally, one thing I should have mentioned in the announcement: if you have scripts that modify art controls, please remove them, and don’t put them back.
The art controls are undocumented and subject to change, and they have changed a lot since X-Plane 11.41. Realistically the authors of these tweak scripts need to go back and re-evaluate every one of their tweaks in 11.50 to see if they actually help or are actually making things worse.
This is not like plugins or scenery; we tell you to get a second installation for the beta not because we want you to run add-on free but rather so that if the beta fails you are not locked out of X-Plane. We expect add-ons to work and we are taking plugin, scenery and aircraft bugs seriously.
By comparison, the art controls are “do what you want, but you void the warranty if you mess with this.” If you are running scripts that hack the art controls, we cannot tell the difference between real bugs in the early betas and art controls screwing things up.
The Road Map For Betas
Looking over the bug reports we have received, I think we are going to take on the 11.50 bugs in three phases:
Stability and compatibility. We’ll start by making sure that we run Vulkan and Metal on every platform that should be able to run them, with add-ons just working in the cases where we expect them to. We’ll start by focusing on fixing crashes, black screens, device lost, unstable plugins, etc.
VRAM use. We’ve received a number of reports that make it sound like VRAM management is not working properly. Once we can run, we’ll dig into blurry textures, running out of VRAM, etc. Sidney has built some great tools to get a good picture of how VRAM is being managed. VRAM management is one of the newest and most complex parts of 11.50 so it isn’t surprising that we’ve seen things that look buggy.
Performance. Once we are running where we should and using VRAM that we should, we can look at the cases where users are not seeing performance benefits from Metal and Vulkan, as well as remaining stutters. Once again, Sidney has built some fantastic tools that should help us dig into this quite efficiently.
This is the only order that we can reasonably approach the bugs. If the app won’t run on all qualifying hardware, we can’t test our VRAM use everywhere, and if our VRAM use isn’t correct, it can bias performance testing.
Today is the day. X-Plane 11.50 public beta 1 is now available for download to everyone. (Steam users: the beta is staged on the servers, and we’ll let it loose this afternoon if it isn’t setting people’s machines on fire.)
I want to extend my appreciation to the 50+ third party developers who participated in the eleven (!) private developer previews. This is probably the most complex single patch we have developed with regards to third party add-ons; their help testing and trouble-shooting issues was invaluable.
Like all public betas with the number “one” in the title, this is a very new, very untested beta; if you wish to try it, maybe keep your regular X-Plane install around. If you post in the comments that you got the beta and now you can’t fly and you are sad, probably the other commenters are just going to say “I told you so” a few hundred times.
Getting The Beta
Non-Steam users can get the update by running the installer, checking the “get betas” box, and running; Steam users will be able to get beta soon by picking public betas in the application properties.
If you can run X-Plane 11, you should be able to run X-Plane 11.50; if you have an old operating system or hardware, you may be stuck running X-Plane 11.50 with only OpenGL as the driver. Here’s a break-down of what you need to run with the Vulkan or Metal drivers:
Operating System:
Mac users need 10.13 or newer.
Windows users need Windows 10—we do not support Vulkan on Windows 7.(1)
Linux users need a distro that can run reasonably recent proprietary NVidia or AMD drivers.
GPU Hardware (Windows and Linux):
NVidia: GeForce 600 seres or newer
Any GCN or newer AMD card (E.g. HD7000 series or newer)
GPU Hardware (Mac):
Any GPU that comes with a Mac that can run 10.13 or newer or
Any eGPU supported by Apple
Hackintoshes: we have heard anecdotally that GeForce 10 series on a Hackintosh does work, but we do not have this hardware in the company, so YMMV.
Drivers (Windows and Linux):
NVidia: 440.26 or newer
AMD: 19.12.3 or newer
To run with Vulkan or Metal, there is a new check-box in the rendering settings screen – just check the box and restart. If Vulkan or Metal crashes on startup, we will turn the check-box off automatically so you are not locked out of X-Plane.
(1) In theory Vulkan should run on Windows 8, but our devs are all running Windows 10. If you have Windows 7, please update your OS – Microsoft isn’t security patching Windows 7, so it’s more than time.
The First Run Will Take a While To Load
For some users, the first time you start the sim in Metal or Vulkan you may see several extra minutes of load time while X-Plane compiles shaders. This will not happen every time you start the sim, so my advice is: get a beverage appropriate to the time of day and let the sim load.
What you’re seeing is shaders compiling. X-Plane 11.40 compiled shaders while you flew, resulting in stutters. Try this in 11.40: start the sim cold and dark at night, and turn on the battery and landing light. Feel those stutters? That’s the sim going “oh noes, I need the terrain shader with the landing light now”.
X-Plane 11.50 loads every shader it could need up front during preload of scenery, but that’s a lot of combinations. On the first load, the compiled shaders are saved to a disk cache, so load times will be back to normal the next time around.
We are working to make the first load faster, but because it’s a one-time thing it didn’t seem like a good reason to keep everyone out of the beta.
Will My Add-Ons Work?
First, we expect every add-on that does not use undocumented hacking to “just work” in OpenGL – if you find this is not the case, please report a bug.
We expect most add-ons to just work in Vulkan and Metal; we are keeping a list in the release notes of add-ons that we know do not work and require an update from the developer.
Please go easy on your third party developers – in some cases they will need to update code that has “just worked” for over a decade, and the author of a popular add-on will probably hear from users about updating to Vulkan hundreds of times a day. Some add-on authors are part-time or have day jobs, so as a community we will need to be patient.
Third party developers: we should have public docs and an SDK update by the end of the week with complete info about 11.50, but if you were not in the developer preview program and want to dig in now, ping us.
I Found A Stutter!
While we have made tremendous progress with stutters compared to X-Plane 11.41, I can tell you that as of 11.50 beta 1, we are not done, because Sidney is working on fixes for stutters that did not make the first public beta.
The good news is, we’ve reached a point where we can identify and kill stutters in a straight-forward manner – it’s never just “dark matter in the OpenGL driver” anymore. We also have tools built into the sim to collect stutter reports from users – we’ll help you use that once we kill off the remaining known ones (which appear to be in Windows itself – that’s how far we’ve come).
I Found A Bug!
The release notes do list some known bugs, some of which we already have fixed for an upcoming beta 2. If you find something you think is a bug, please file it. Commenting about the bug here, emailing us, and discussing it on a forum do not count! If you file it, it goes into our tracking system so we don’t lose it.
It has been almost a month since my last post on Vulkan and the state of development; a lot has happened since then, both for Laminar Research and the world.
COVID-19
First, at this point, no one working for Laminar Research has COVID-19. We have people working on X-Plane in at least six countries, including northern Italy. The team news on Slack as of Tuesday was that everyone is in some degree of lockdown and/or voluntary social distancing, varying by country. Schools in the US are temporarily closed, so both Chris and I have the kids at home.
Being sequestered at home has not affected our internal pace of development because our entire team is distributed and works at home; we have no office to close. This work-at-home pattern started almost twenty years ago when Austin had people like me working on part-time contracts to modify specific parts of the sim – it never made sense to relocate people to South Carolina and open up an office. Being remote also lets us hire people anywhere in the world who have the unique blend of skills we’re looking for.
At this point we haven’t seen any operational issues either; mostly running our business requires that our devs have internet and electricity and that the data centers we use for our cloud servers remain open and operational.
So in summary, we are very fortunate that the new coronavirus is not affecting our development and operations; other industries are paying a high price to stop the spread early. We have several things we are working on right now, and this spring is a critical time in our development schedule.
Vulkan and Metal
Update: I have gone in and changed Vulkan to Vulkan/Metal in a bunch of places – Mac users were confused as to whether we had silently dropped support for Metal at the last minute – we have not!
We are posting developer preview nine to our private testers today; hopefully this will be the last private build before a public beta candidate. We acknowledge we’re reaching public beta much later than we had hoped/wished/anticipated, but we are now aiming for a public Vulkan/Metal beta by the end of March. If you are already rolling your eyes at a public beta date that is less than two weeks away, I don’t blame you; having been this late, it’s on us to post the beta to show progress. With that in mind, I am going to describe what we’ve been doing for the last three months and why it has taken so long to get here.
The Vulkan/Metal public beta is several months later than we had anticipated because of “scope growth” – that’s manager nerd speak for “we added more stuff to it than we originally planned.” Scope growth (adding more features/code/tricks than you originally planned) is one of the big ways that projects miss original deadlines, so the big question is: what did you add and why did you add it?
The first thing we added was better handling of plugin drawing. The rewritten plugin compatibility layer provides better drawing compatibility for more plugins, including weather plugins on Windows. We went with the rewrite mostly because of the level of bugginess we saw with third party add-ons in the early developer previews.
Plugin drawing was definitely a case where we learned how to do a better job from the first version of the feature (plugin compatibility that went into the first private beta); if we had received that second-generation design via time machine we probably could have shipped faster. Adding weather support was pure feature creep–a new thing we didn’t plan on, but something that we thought was worth extra schedule time.
The second thing we added was better handling of texture paging. Once again, this was a feature where we had to rewrite the feature (multiple times in fact!) based on the feedback we got from our testers to really come up with something solid.
Our first generation texture paging around the first private developer preview was very simple: most stuff lived in VRAM, with a little bit of code to move unused stuff out of VRAM. It was a minimalist strategy that let us develop the rest of the sim and worked great on high-end cards. It was clear from day one that it wouldn’t be good enough for public beta.
Our second generation strategy added automatic movement of texture res up and down with VRAM pressure and code to page out textures that weren’t being used. This shipped about half way through the private beta, and was better, but suffered from one fatal flaw: as you turn your head, the stuff behind you isn’t being used. Under heavy memory pressure users would constantly turn their head and see blurry textures that would then “res up”. The results were distracting and unacceptable quality-wise.
We now have finished our third generation strategy: besides automatic texture res control based on VRAM pressure, we now set the relative resolution of non-orthophoto textures by distance to the aircraft. A background task on another core “crawls” the scenery near your aircraft and reevaluates the texture res of nearby scenery constantly, effectively transferring VRAM to where it is needed most. This process is completely transparent; authors do not need to modify scenery in any way for it to work, and since it runs on another core (as does the paging), it does not affect framerate.
In these pictures, you can see the new pager at work. I have parked my aircraft on the ramp at SeaTac and moved the camera across the city, so that the distant autogen (from the pilot’s perspective) is now close and the airport is in the background.
Texture Paging – Camera moved to reveal “far away” areas
In this first picture, green represents full-res textures, with the next levels down being yellow, then magenta. You can see some nearby autogen down one level and far-off autogen down two levels; the loss of res is put far from the user.
Why is there so much green (full res) near the magenta autogen? Texture reuse. If a texture is used near the user and far from the user, it gets high res because it might be seen up-close.
Texture Paging – VRAM artificially reduced to simulate low-end GPU
In this next picture, I artifically lowered my machine from 4 to 1 GB of VRAM using a developer tool. Now you can see magneta autogen close to the airport, yellow even closer, and some really dark green (the next level down) where we had magenta. In other words, everything got a little bit lower res because we were tight on VRAM, but again nearby sceney is prioritized.
It looks like this third strategy is a keeper – it combines the careful management of VRAM to use it where it is most needed with a stable heuristic that isn’t constantly changing, which avoids chaos and unreliable behavior.
So at this point we are just fixing bugs. This is a big step forward for the private beta because past betas were dominated by coding new things, which in turn creates new bugs. At this point we just have to kill bugs off to the point where the build is high enough quality for a public beta.
I cannot promise a particular build number or date will be the public beta full stop, because I do not know yet what other bugs we may find. But I can say that we are in the part of bug fixing where things are getting locked down.
Vulkan is Not the Only Iron In the Fire
A flight simulator is more than its rendering engine (or at least, people tell me that). While we are pushing as hard as we can to get Vulkan and Metal to public beta, we also have several other irons in the fire. This includes new features for mobile, next-gen features for desktop in several feature areas, and even a few extra non-Vulkan/Metal features that have snuck into 11.50. We’ll post more about the mobile and 11.50 features as they become available; the rest is still in stealth mode. Often when the dev blog is quiet, it means we’re working on new things and putting features in the bank; this is the case right now.
The latest update for World Editor is out of beta testing and considered the official version. It can now be used to upload scenery to the Gateway, and is an incremental update that features the ability to preview facades in 3D, faster loading, and up to 100 “undo” operations.
See README.WorldEditor for the full list of changes, or Michael’s extended release notes here. Download this version for Linux, Mac, or Windows here.
For the last few weeks we’ve had the Vulkan/Metal version of X-Plane in a private test program with third party developers, letting them kick the tires to discover the limits and bugs in our plugin compatibility code.
While the initial bridge to connect OpenGL-based plugins to X-Plane worked pretty well, compatibility wasn’t perfect and we had a few bugs. We also realized that we needed to change the design of that bridge to get much better compatibility. That rework of the bridge is now done and things are looking quite a bit better on all fronts.
We found one unexpected result from this redesign: when we finished rewriting the bridge, we ended up with code that could, in the case of Vulkan only, be used for 3-d drawing. This means we can now support OpenGL-based weather/cloud plugins from inside a Vulkan render, which we did not think was possible before.
The Skymaxx and xEnviro developers are in our private test program and have been great about jumping on new builds while remaining radio silent while we test this new tech. I am pleased to now be able to say: it works!
Those pics are a special build of SkyMaxx running in 11.50 in Vulkan mode. No more having to pick – you can have your third party clouds and Vulkan at the same time.
The Details: Vulkan, not Metal
3-d drawing compatibility will be available for Vulkan, but not Metal. The technique we are using is not available on OS X, so running a cloud plugin on Mac will require the OpenGL driver, not Metal. This isn’t something we can fix with some future bit of cleverness – it’s a limitation of OS X’s APIs. (We would revisit this if Apple introduced a new API but I do not expect this to happen.)
To be clear: on Windows what we are supporting is 3-d OpenGL drawing by plugins inside the Vulkan renderer, not native Vulkan rendering by plugins inside the Vulkan renderer. Native Vulkan rendering by plugins is an incredibly complex SDK problem, and not something we are looking at for 11.50.
2-d Drawing Just Works; 3-d Drawing Requires a New Plugin
For plugins that draw in 2-d we’ve gone for a “just works” level of compatibility; while we have seen some plugins that need to update due to illegal techniques and bugs, our goal is that a well-authored add-on just works even when Vulkan and Metal are in use.
By comparison, OpenGL drawing inside Vulkan is going to require plugin authors to sign up for a new 3-d drawing callback. We’re making this opt-in because, during the beta, we’ve found a lot of add-ons using 3-d drawing callbacks inappropriately, and 3-d drawing callbacks are no longer free. By requiring plugins to opt-in when they _really_ want 3-d drawing in Vulkan, we should get better performance.
The new 3-d drawing callbacks are really only meant for custom drawing like clouds. Other techniques like adding objects to the sim and drawing markings are better handled with other APIs. Our plan is to have detailed guidance on what technique is best for developers by the time we are ready for public beta.
As I announced in my previous post, X-Plane 11.50, featuring native Vulkan and Metal driver support, is in a private beta made up of people in our dev-rel program (E.g. third party developers). We’ve gotten some really good bug reports from them – the reports are good, not the bugs – and based on that, it’s clear that 11.50 will not be ready to go public this year (meaning tomorrow).
This is disappointing to us – we burned candle at both ends to try to get all the way to public beta this year, but at this point the build just isn’t ready yet.
I’ll describe in detail below what the one bug is that is really holding back public beta, and I’ll try to do a general FAQ about Vulkan and Metal tomorrow; based on the 150+ comments from the last post, I think it’s clear that we have a lot of basic info to get out there, some of which has only been shared with third party developers until very recently.
Please don’t bombard me with “can I please be in the private beta” (or even “you’re a giant pile of moose poop for not letting me into the private beta”). Here’s the thing about the private beta: our goal is to kill off the bugs so everyone can use the beta, and to kill them off as rapidly as possible.
At this point the dozen or so third party developers who are banging on the beta are generating bug reports faster than Sidney and I can fix them – if we add more people to the beta, our bug fix rate will slow down as we have to spend more time triaging the reports coming in. So as long as we’re fixing the worst bugs productively, more people in the private beta means everyone waits longer to get to public beta. I think the best thing here is for Sidney and I to just try to fix things ASAP.
(I think there’s also a win to getting this into the hands of third party developers – in some cases we’ve seen add-ons that accidentally use the wrong APIs for processing and are thus incompatible with Vulkan when they don’t need to be – developers can get a head start on updating this code.) If you are a third party developer, we can get you into the beta program – I don’t want to favor some third party developers over others.
Blurry Textures
A short summary of performance feedback from our internal beta might go like this: smoothness and FPS are good, VRAM management is not.
Most of the crashes while flying we have seen look like the sim runs out of VRAM and isn’t able to recover, and for users with smaller GPUs (e.g. 4 GB of VRAM) X-Plane gets into a tight VRAM situation and solves it by making everything on screen low res and blurry.
The VRAM management path, which is entirely new code written for the Vulkan/Metal back-ends, is…well, it’s entirely new, and it’s going to need a bunch of testing, debugging and iteration to get solid. On an 8 GB card, VRAM is so plentiful that X-Plane’s somewhat naive VRAM allocation scheme works fine. On a 4 GB card, we’re just a tiny bit short (a few hundred MB) but the result is an alarming loss of texture resolution.
This is something we can make better! It is under our control and is thus being worked on now. (By Sidney that is – I’m writing this blog post while he gets the real work done here.) But until we have better VRAM management, it’s too soon to go public. If we did, we would just be inundated with hundreds of “my textures are blurry” reports. It’s a bug too noisy to ship with.
Why Wasn’t This a Problem on OpenGL?
One might ask: why don’t you just do whatever OpenGL did to manage VRAM? The problem is: OpenGL’s solution is to stutter.
The OpenGL driver swaps textures between VRAM and system memory based on what you really need to draw now. If you are looking away from Seattle, the space needle’s texture can live in system memory, but you might need mountain textures for Rainier.
We try to do that too – the big difference is: OpenGL will stop rendering while it moves the textures around, and we will not. The result is that OpenGL always shows you a perfect image at the texture resolution you picked – no blurred images. But you might have stutters! You can see this if you’re on the margins of VRAM by flying and then changing views or circling the camera – if your FPS go “chunk chunk chunk VROOOM” you’re eating some stutters while textures move around, then you go fast again.
The OpenGL way is a solution that we never thought was acceptable – our goal is the best image quality without sacrificing smoothness. It’s going to take a little more time to iron out low VRAM situations, but once we get there I think it will be worth it.
