With 11.10 there is a new way aircraft only shadows are done, as well as how aircraft icons are generated. The big change is how we calculate the volume of the aircraft which up until now was based on all OBJ files that the aircraft ships with, including things like ground- and fuel trucks, stairs etc. The reason this is undesirable is because the greater the volume of the aircraft, the worse its realtime shadow quality will be because we use the volume of the aircraft to calculate our shadow map area. The bigger that area, the worse the shadow quality and the more pixelated it will look like. In an ideal world, the aircraft volume tightly hugs around the actual aircraft and we get the best shadow quality possible. With 11.10, hopefully this ideal world is finally here!
Why and how we failed before
Before 11.10 the aircraft volume was based on the volume of, well, the aircraft. However, this includes things such as the aforementioned ground trucks, fuel trucks and what have you, that artificially blow up the volume calculation. The problem is, all these objects are technically part of the aircraft (eg. we move them around with the aircraft), but they are for the most part invisible and most people wouldn’t actually consider them to be part of the aircraft proper.
In 11.05 we added a change to also consider the physical volume which kind of has the right size for the plane but doesn’t include OBJs. It is based on the physical size of the plane only, which sounds like it’s the right thing. However, as it turns out, this volume breaks badly for things such as helicopters because the rotor of some third party helicopters are attached OBJs and won’t be considered part of the physical volume of the helicopter.
At this point I should probably also quickly note what happens if the shadow volume is too small: Everything that gets clipped by the shadow volume will cast a shadow into infinity and beyond due to the way the shadow mapping works. This is especially bad for the helicopters that now have very quickly rotating bits that are constantly clipped by the shadow volume resulting in shadows flickering all over the place.
In short: What we want is a shadow volume that is as tight as possible around the aircraft for shadow quality, but not too tight because that also leads to problems.
What’s new in 11.10
In 11.10 the algorithm to compute the shadow volume has been completely changed. Instead of trying to jiggle around with the physical volume and the volume of all OBJs together and then coming up with a sane value, X-Plane now looks at what is actually being rendered. We start out with the physical bounding volume as before, but then we look at what is actually rendered! For that, we go through every OBJ that is marked as casting shadows and run the OBJ engine as if we were to render the whole thing. So OBJ animations as well as kill datarefs etc are considered. This happens during the first frame, so everything is set up the way it would be during normal rendering. Everything that is visible will be marked as such and the shadow volume will be expanded to include this OBJ.
The result is a volume with a tight fit around what is actually visible and therefore considered “aircraft”. Everything else is not included in the shadow volume and therefore stops casting shadows altogether. Of course, this is only in aircraft only shadow mode and is not used when scenery shadows are on. In that case, everything is handled like it was before and everything that is supposed to cast shadows does cast shadows. So, if you see missing shadows in aircraft only shadow mode, this is probably due to this change.
To visualize the differences, here are 4 screenshots showing the quality difference as well as the new shadow volume:
11.10
11.05
11.10
11.05
One thing that should be noted though is that going forwards these kinds of extra OBJs should really be done via the new drawing API in the 3.0 SDK! This allows us to very accurately determine the size of the aircraft but it also means that culling will become more accurate. The old method will of course continue to work, but it’s not the best or most efficient way to approach ground vehicles and other ground clutter.
Aircraft icons
The calculated volume for the whole aircraft with attached OBJs was also used for the aircraft icon generation. This led to some weird cases where the camera was positioned in such way that the aircraft was incredibly tiny due to the fact that we tried to get “everything” in at once. So far the recommendation was for authors to create a version of their aircraft without all the extra OBJs attached, but now that we have an adequate measure of the aircraft volume this is fixed as well! Aircraft icons should be correctly generated now with the camera positioned to capture the plane at the right distance.
There is one more fix for aircraft icons: Some authors created aircraft that did some clever culling based on where the pilots head is and then using the kill dataref to prevent parts of the aircraft from being rendered. Reading the view dataref now correctly reports the camera as being an external camera so that those custom culling solutions work with the aircraft icon generator. If your aircraft still doesn’t generate proper icons after 11.10, please file a bug report and let us know!
Tyler posted about some of the new features coming to the X-Plane SDK version 3.0 API (available with 11.10 once we find the last bug and move it somewhere else). Here’s how compatibility works for the windowing system.
First, since the 2.0 SDK, XPLMCreateWindowEx has taken all of its arguments in a structure, a XPLMCreateWindow_t. That structure, in turn has a structSize variable that is meant to be initialized like this:
Now when we revise the SDK, the size of the XPLMCreateWindow_t structure grows when you #define XPLM300. This results in new plugins compiled with the new SDK sending in a large struct (with more callbacks) and older plugins compiled against the old SDK sending in a small struct.
This is how the SDK “knows” what SDK you are using and provides new behavior to new plugins but provides compatible behavior to existing plugins, compiled years ago.
(This technique isn’t in any way new or unique to the X-Plane SDK – you can tell by the coding conventions that it is cough, cough, borrowed from the Win32 SDK.)
AI aircraft are often way more resource-intensive than they need to be. Users are fine paying a performance penalty to load, say, a super detailed 3-D cockpit model for their own aircraft, but for AI planes, where you’re never going to be in the cockpit, there’s no reason for that sort of thing. A significantly “dumbed down” version of the same aircraft would allow users to load more AI planes at once, with no visible downsides during normal use.
Many aircraft, for one reason or another, simply won’t function at all when used as AI planes. This is most commonly due to one of two issues:
reliance on third-party plugins (which only work for the user’s plane)
lack of support from X-Plane for flying aircraft like this (for instance, the X-Plane AI doesn’t know how to fly gliders, seaplanes, or rockets)
As a user, this is really frustrating, because it’s difficult or impossible to know in advance which aircraft will work as AI planes and which will either a) just sit on the runway, never able to take off, and/or b) tank your frame rate.
Coming in X-Plane 11.10: AI-Only and User-Only Aircraft
In the upcoming X-Plane 11.10 beta, we’ve added two new options to Plane Maker’s Author window: “supports user flight” and “supports AI flight.” By default, all aircraft support user flight, and do not support use as AI aircraft.
If a plane is configured for AI flight only, it will never be shown in the normal aircraft grid—only in the AI aircraft window.
If a plane is configured for user-flight only (or if it’s a pre–11.10 aircraft with no “supported flight type” info), it will be hidden in the AI aircraft window by default, but for the sake of backward compatibility with old planes, users will still be able to reveal them by checking a box labeled “Show aircraft without AI support.”
The upshot for aircraft authors
In the Glorious Future, we envision third parties shipping two versions of their aircraft:
one marked user only, which include all the bells and whistles, plugin-enhancements, and as much detail as possible
one marked AI only, which is stripped down for performance, only using plugin enhancements that have been tested in AI configurations.
The result will be a faster, more consistent, less error prone experience for users.
These smaller features are likely to be overshadowed by the release of the G1000 for default aircraft in 11.10, so I decided to dedicate a blog post to promote the articles I’ve written – you can find them among all the guides for aircraft developers: http:/docs/aircraft/
Electric and remote gyro systems
Back in April, I flew a Mooney M20J with a KCS55A HSI in it, and realised that it was impossible to model in X-Plane correctly, so I got to work. See the manual for an explanation of this popular HSI/remote gyro system.
I’ve written a usage guide on the new datarefs and commands that I added, along with some more detailed explanation of all the different gyro systems X-Plane simulates, in this guide for aircraft developers. I also talked about the systems at length in a Youtube live stream earlier this year.
Separate GPSS autopilot mode
This is a feature that many add-on aircraft already simulate to some degree, but by means of more or less reliable plugin trickery. The X-Plane 11 default 737 and 747 are no exception. With X-Plane 11.10, a separate GPS steering mode for the autopilot becomes a standard feature.
The new datarefs and commands are explained in detail here.
Screen-only popup instrument windows
Several people who build home-cockpit setups have asked about removing the bezels from the popup displays, so they can have only the screen of a GNS430/530, FMS or G1000 instrument to put on an external monitor, with a hardware bezel around it. While this can already be achieved through some clever hacking in the Miscellaneous.prf file, we now offer a more straightforward way to do this: The popup and pop-out windows now get their bezel graphics from the library system, so you can override the bezel graphics. How to override the bezel with nothing, if your bezel is made of hardware? Simply supply a 1×1 pixel blank .png as a bezel graphic, and X-Plane will know that you really want no bezel at all. In the case of a bezel-less 430, you’d put a 1×1 pixel png as the “cockpit/radios/GPS FMS/Garmin_430_2d.png” resource of your plane.
These both come from third party developers – one I was aware of and one was completely new to me.
The Debug Heap Is Slow
Veteran Windows C++ developers know this, but if you don’t spend a lot of time with MSVC, this might be new.
The default configuration of MSVC is to force use of the debug heap when the debugger is attached; this applies even to release builds of binaries that aren’t yours.
What this means is: if you do nothing else but start your plugin “inside” X-Plane, X-Plane will use Microsoft’s debug heap.
We avoid doing this internally because it is really, really, really slow. The debug heap provides some great tracking for finding memory problems, but the cost is really, really slow load time.
The fix is simple: add _NO_DEBUG_HEAP=1 to the environment variables for your debugger. You can do this in the control panel as shown in the linked article, or you can add it to MSVC’s debugger properties.
Other Things To Go Fast
As a side tangent, when debugging a plugin, find ways to load X-Plane faster. A few things that can help:
Turn off AI aircraft.
Pick a simple aircraft to fly (e.g. not the 747).
Go somewhere without scenery (or without much scenery, e.g. PMDY).
If you have to have scenery, turn 3-d all the way off.
My Plugin Won’t Reload
We receive periodic bug reports that plugins won’t reload on Windows. This is miserable for you as a third party developer – it means rebooting the sim instead of just reloading your plugin. But why does it happen?
I thought we had a bug, but a third party developer found this:
I did searched the registry for the names I’ve used for X-Plane 11 folder and found this items at
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windws NT\CurrentVersion\AppCompatFlags\Layers
Each name used was included there with “$IgnoreFreeLibrary<win.xpl>”
value, after removing them and restarting X-Plane I got able to compile the plugin using the names again.
I have not found any official Microsoft documentation on this, just a lot of ranting from really annoyed programmers who want to know why the hell Microsoft would do this. If anyone has better Google-Fu than me and can find official docs, please do share. So what follows is my wild speculation of what’s going on.
In some old version of Windows, FreeLibrary probably didn’t actually (or immediately) free a DLL under certain circumstances. Application developers then wrote buggy apps that relied on this behavior, e.g. they freed a library while it was in use and their app didn’t crash.
Microsoft updated Windows and made FreeLibrary do what it says on the label, always, and old buggy apps started crashing left and right.
Microsoft, being Microsoft, did not say “you app developers are idiots, why don’t you go rewrite your buggy apps”. Instead, they added a feature to the App Compatibility Wizard that watches your app and, if it crashes after a DLL was unloaded and the moon is the right shade of Rondele, it adds a registry key marking this library as “never to be unloaded, even if this app says so”.
From that point on, the app doesn’t crash because the old semantics of FreeLibrary (“ha ha ha, you don’t mean that do you”) are restored in that one case.
The above is entirely made up – it’s my mental model for what might have happened, unless Raymond Chen someday gives us some back story.
Still, you can see what has gone wrong here – Windows decided that for compatibility reasons, plugins should not actually be unloaded, and since all of your DLLs are named win.xpl, this one plugin crash has caused plugins to never be unloaded. Thus the plugin unload/reload never releases the DLL and you can’t swap in new code.
Nuke the registry key and you’re back in business, at least until you crash again.
X-Plane 11.05 release candidate Two is now the official version of X-Plane 11. You’ll be prompted to auto-update.
11.05’s purpose in life was to release new gateway airports. We will do another release of gateway airports for X-Plane 11.10, which we are working on now.
When Will X-Plane 11.10 Be Released?
I don’t know! I don’t have a crystal ball. How can it be that I am tasked with making the final release-not-release decision and I don’t know when the first beta will be released?
X-Plane 11.10 is limited by bugs, not a particular release date. In particular, we intend to ship X-Plane 11.10 with our latest rendering code, and our latest rendering code currently has a few serious bugs. So it will be released when we fix these bugs, but I can’t predict how long it will take to fix them.
Some of our releases are date driven, and we remove functionality to hit the date. Other releases are feature driven, and we release when the bugs are fixed. 11.10 is in that later category.
We’ll post a lot more details on 11.10 once we get into beta; 11.10 is going to be a long beta, to give third parties time to help us flush out compatibility bugs. We’ve changed a lot of code.
11.10 will (as planned) ship without VR support, but will contain all of the rendering engine changes necessary to make VR work. We are working on VR in parallel, and can hopefully public beta VR as soon as 11.10 is out of beta.
The upcoming X-Plane 11.10 release (and before you ask, we’ll let you know as soon as we have an ETA! 🙂 ) will include Version 3.0 of the X-Plane SDK (XPLM).
NB: The code samples linked below will not work yet—in part because X-Plane 11.10 isn’t in beta yet, and in part because we haven’t updated the sample code downloads with the new XPLM300 headers. But, that doesn’t mean you can’t look at the code itself right now!
There are a handful of really important features here for plugin developers:
Instanced drawing (via the new XPLMInstance header). This is a really important one for improving plugin drawing performance. More info on the theory behind this in Ben’s recent post. The good news for developers still working on X-Plane 10 plugins is that we’ve created a “wrapper” to provide backward compatibility with old versions of the SDK. Using the wrapper, you don’t get the performance benefit that you’d see in X-Plane 11, but you’ll at least be able to use the same API. See the sample project here.
Map APIs (via the new XPLMMap header). Based on our RFC, this provides an interface for drawing text labels, PNG icons, and arbitrary OpenGL within the X-Plane 11 maps. See the sample project here.
Aircraft-specific menus. Plugins that get loaded with the user’s aircraft will now have access to XPLMFindAircraftMenu(), to which you can append new menu items or submenus.
Menu items that show keyboard shortcuts. When you add a menu item via XPLMAppendMenuItemWithCommand(), if the user has a key bound to that command, the key will be displayed on the right-hand side of the menu, just like X-Plane’s native menus.
More joystick axes & buttons, to match X-Plane 11.10’s support for 20 USB devices (up from the previous cap of 10).
Lots and lots of new features for plugin-created UI in the XPLMDisplay API, including:
Support for styling windows like the built-in X-Plane 11 windows (sample project here)
Support for “popping out” windows into first-class OS windows (demoed in the same sample project above)
Support for automatic UI scaling of all drawing in your window (this comes for free in all windows created with XPLMCreateWindowEx that are compiled against the XPLM300 API)—this means users with hi-DPI/4k monitors who have set a 150% or 200% scale for the X-Plane UI will get the experience they do with built-in windows.
Support for windows that automatically “stick” to certain edges of the screen, via the XPLMSetWindowGravity() API (sample project here)
Just to be 100% clear, to get any of these features (with the exception of the backward-compatibility wrapper for instanced drawing, of course), you’ll need to compile against the XPLM300 API.
[Edited to add:] Using the XPLM300 API is 100% optional. Old plugins will continue to function, and you could even write new plugins and compile them against the old API (I’m not sure why you would you want to…), and they’ll work in X-Plane 11.10 and beyond.
#294 – A case where autodetect off was not fully trusting the author for Aircraft exports
An uncaught spelling mistake __upgradeLocRot vs __updateLocRot. The fix for the updater altering the animation types was written for object’s dataref animations and bone’s dataref animation troubles. However, with this spelling mistake and Blender’s uncanny ability to eat exceptions from addons, it wasn’t realized until later that bone’s weren’t also getting updated. Fortunately, the updater can be run-again without fear of messing something else up.
At the bottom of the Scene Settings, check “Plugin Development Tools”. Use the Re-run Updater tool at the bottom: Put in 3.3.9 in Fake Version, and click the button. You should see your bone values corrected, as long as you successfully reverted any bad changes from v3.4.0-beta.1. Please e-mail me if you have problems!
Improvements
Some spelling and capitalization in the UI. Great care has been taken to ensure that none of the actual value or order of the addon properties has changed!
11.05r2 is now available – if you have 11.05r1, you’ll be notified to auto-update. We fixed the broken SIDs/STARs at KMCO, removed a few custom Aerosoft lego brick airports to reveal the gateway one, and we have some updates to KLAS from Julian.
This should come out on Steam in a day or two if no one finds something on fire and hopefully be final this week.
We’re working full time to get 11.10 ready for beta, hopefully very shortly after 11.05r2 is final.
Update: Steam users can get 11.05r2 as well by opting into betas.
