By now everyone has heard the news: Microsoft is closing down ACES.
This is not a happy day; there is no joy in people losing their jobs in this economy. And having your product canceled really hurts. I have worked on programs that have been killed after I left the team, and I have worked on programs that have been killed while I was working on them, and either way, it really, really sucks.
What does this mean for X-Plane? That is something we are trying to figure out now. Halting development on MSFS is an earthquake within the flight simulation world; it was not a scenario we were planning for last week. In some ways, it changes everything, but in others it does not.
In particular, a lot of things have become high priority that were always important, but are now on a much shorter time table. Improving our documentation, simplifying the user experience, etc. Our current users have already learned the quirks of X-Plane, but we now have more people trying X-Plane for the first time and tripping over those stumbling blocks.
We are only a few days away from going beta with X-Plane 930. 930 was a huge patch for us already, with lots of new features “saved up” over several months, but now it is even more stuffed, since there are also last minute features to make the sim easier for new users, and to add in new capabilities that we are being asked about.
So to current X-Plane users, I ask two things:
* Please be patient with us, and with new users – this is a very busy time and a lot is changing very quickly.
* As always, don’t panic. The first beta always has a few problems with certain video cards, and one or two really gross bugs. The quality of the betas will improve very quickly in the first week or so. Squeamish users should simply wait a few weeks, or skip beta entirely. Third party authors: please test your add-ons as soon as you can! The sooner you report the bug, the sooner we can fix it!
Our mission with X-Plane has not changed: it always was, and still is, to make the best flight simulator we possibly can!
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Ben Supnik |
930 will have some new options for attached objects. One is to declare a “glass” object. When an object is declared to be glass, it is moved to the very end of the drawing order – even after the cockpit object.
The idea of glass objects is to let you make translucency that works from any view angle. To make multiple layers of glass, the trick is to use pairs of one-sided triangles. The glass (visible from the inside only) goes first, then the glass (visible only from the outside) goes second. All of this goes into the object with the “glass” property in Plane-Maker.
One side benefit of the two-triangle approach is that the inside and outside of the windows can be tinted differently.
Having glass objects does three things for us architecturally:
- It takes pressure off the interior cockpit object. The interior cockpit is the only object that can have manipulators, so texture space in the interior cockpit object is quite valuable. By allowing translucency in an attached object, you can put your window textures somewhere else and save texture space for the cockpit object.
- It gets around the current weirdness where the interior cockpit object is drawn last but the exterior cockpit object is drawn first. The glass object is always drawn last. Period.
- It sets us up someday for some kind of shadowing scheme in the cockpit. This is a bit pie in the sky, but most pixel-based shadowing algorithms go a bit bonkers on translucent geometry; by flagging the whole object as “glass” we can simply omit it from shadow calculations.
The 921 draw order has the exterior cockpit object drawn first (if drawn) and the interior cockpit object drawn last (if drawn). This made sense at the time – the exterior cockpit object was being used primarily for a pilot figure, with windows in the ACF paint – so it had to be drawn before the ACF fuselage. The interior cockpit object has to be drawn last because the coordinate system is changed to a super-close-to-the-user coordinate system that has to be drawn last.
Now that there are attached objects, people are modeling a lot more of the airplane, the usual approach is to have all 3-d present all the time, so that a roaming camera won’t reveal missing parts of the airplane.
I have found the cause of a rather serious bug in Plane-Maker: sometimes instruments disappear from the hierarchy (but are still visible in the main window).
The problem is that the cut-paste facility, when used with multiple-instrument selections, was corrupting the hierarchy information. Because of the way instrument hierarchies are managed, this corruption persists – even if it isn’t visible. So if you manage to ungroup everything, it looks okay until you work more, then the instruments disappear again!
This is a really bad bug of mine, particularly since a panel is such a time investment. Here is what we’ll be able to do in 930 to get around this:
- A new “flatten panel” command simply ungroups everything and completely cleans the hierarchy. All corruption of hierarchy is fixed with this command, finally exposing every instrument. From that point on, you can then re-group and things should be okay.
- I am fixing the cut-paste commands to not trash the hierarchy, and I am looking for any more hierarchy-corruption problems.
- 930 has export/import of instrument groups to text files. So another way around instrument corruption problems would be to export the panel to a text file, fix the grouping problems (which is a matter of moving the GROUP/END_GROUP lines) and then re-importing. If you do not have a selection, the entire panel is exported, including any hidden items in the hierarchy.
I believe that text-based panel import/export will also be useful for sharing individual instruments (or clusters of grouped generic instruments), archiving work, and making large-scale changes using search-and-replace.
These two issues have been discussed a lot in the forums, so I thought I’d mention them:
First, I finally found and nuked that star-burst pattern in the rain. It turns out that for some textures, compression was destroying the lower res
mip-maps, causing the geometry that the rain drops are drawn on to show up as that starburst pattern. It should be fixed for 930 beta 1.
Second, it turns out that the code that converts the 900-format generic instruments to 920-format generic instruments* was being run on the user’s airplane whenever a multiplayer airplane older than version 920 was being run. That could cause generic instruments to disappear, appear incorrectly, or just crash the sim, because the aircraft data in the user’s plane (once the user is flying) is already in 920 format…if you interpret it as 900 format again, you get non-sense.
I am fixing this for 930 beta 1; there may be other bugs relating to multiplayer and generics, so we’ll see if this fixes most of the problems, or others crop up. The panel system is essentially “global” (that is, there is one panel for the user in all of x-plane) but the instrument data is per-plane…so there is always a risk of code mistakes where the multiplayer planes affect the user’s panel.
When will 930 beta 1 be out? I don’t know. Hopefully pretty soon – when bug fixes make it into the blog, we’re usually in the push to get to beta. But I’m working on features on a few fronts, so it’s hard to say which ones will be done first.
* X-Plane 920 revised the ACF format from version 900. The file format for generic instruments was pretty much completely changed to accommodate new features like key frames. 920 has code that converts the 900 generic instruments into 920. For example, simple key frame tables are built out of the older offset-scale parameters per instrument.
I have recently started leaving pieces of email and notes on the Wiki. To see this mess, just view Category:Unfinished.
The problem is that often I don’t know what people don’t know but want to know. So when I get an email question whose answer is not already posted somewhere, I make a wiki page and dump the info.
This
stub is in response to some work I did this morning. In particular, lights in X-Plane often have visibility much larger than the objects they come with. This used to be true for the cars, but I broke the code in 921 and didn’t notice. In 921 headlights do persist beyond the car object’s visibility distance, but not by much. 930 will fix this, restoring the “string of lights” look on the roads at night.
I’ve also tuned the headlights to be visible from a wider viewing angle, to try to make them more noticeable from above. (In real life, the lights illuminate an area of the pavement, which is visible, but we don’t do this.)
If there is a scenery subject that is poorly or not-at-all documented, shoot me an email and I’ll stub out a Wiki page – it’s a first step to getting comprehensive documentation.
(Note that I have not added pages for tutorial steps like “how do I add a manipulator to my object” because I am doing the tools work for ac3d now … better to write a tutorial for manipulators the easy way with ac3d than to write one on the hard way – editing the OBJ – and changing it later. That is to say, I am trying to documetn tools, not temporary work-arounds!)
As of X-Plane 9, life was simple: ATTR_cockpit and ATTR_cockpit_region caused your triangles to be textured by the panel, and they could be clicked. ATTR_no_cockpit went back to regular texture and no clicking.
Well, it turns out that secretly ATTR_cockpit was two attributes jammed into one:
- Panel texture – that is, changing the texture from the object texture to the panel texture.
- Panel clickability – that is, mouse clicks are sent to the 2-d panel and act on those instruments.
With X-Plane 920 and the manipulator commands, this “clickability” aspect is revealed as a separate attribute, e.g. ATTR_manip_none sets no clickability, and ATTR_manip_command makes a command be run when the triangle is clicked. These attributes can be applied to any kind of texture – panel texture or object texture.
So how does ATTR_cockpit work in this context? Basically you can think of ATTR_cockpit as two “hidden” attributes:
ATTR_texture_panel
ATTR_manip_panel
and similarly, ATTR_no_cockpit is likeATTR_texture_object
ATTR_manip_none
With this you can actually get any number of combinations of attributes, but the code is sometimes unexpected. In particular: if you want a manipulator other than the panel or none, you have to specify it again. Example:# set command manip
ATTR_manip_command hand sim/operation/pause Pause
TRIS 0 3
ATTR_cockpit
# we now have to reset the cmd manipulator!
ATTR_manip_command hand sim/operation/pause Pause
TRIS 3 3
ATTR_no_cockpit
# we have to reset the cmd manipulator again!
ATTR_manip_command hand sim/operation/pause Pause
TRIS 6 3
Similarly, if you want the panel manipulator, you may have to reset the cockpit!ATTR_cockpit
TRIS 0 3
# now make the mesh not clickable
ATTR_manip_none
TRIS 3 3
# Mesh clickable again
ATTR_cockpit
TRIS 6 3
The good news is: this isn’t nearly as wasteful as it seems. X-Plane’s object attribute optimizer is smart enough that it will remove the unnecessary attributes in both cases. In the first one, what you end up with is one manipulator change (to the command manipulator), and the panel texture change is done without changing manipulator state at all. In the second case, you end up with the manipulator change, but the panel texture is kept loaded the whole time.
In other words, even though the double-attributes or duplicate attrbibutes might seem to be inefficient, the optimizer will fix them for you.
One reason you might care: the cost of panel texture is one-time – that is, you pay for the size of the panel texture once per frame. But the cost of manipulatable triangles is per-triangle! So having more is bad. With ATTR_manip_none, you can use the panel texture but not have it be clickable, which can be a big performance win.
930 will handle manipulatable triangles a lot faster than 920 — but that’s still not a good reason to have all of your triangles be clickable!
This article is still
unfinished, but I am trying to put together some info on how to detect performance problems like too many clickable triangles.
X-Plane 910 was an update to X-Plane 9 for our professional customers. But all of the new features that they got in 910, everyone got in 920. Here’s how it happened:
X-Plane 9 had a very long beta, and the end of that beta was mostly spent with a finished sim and me trying to fix the pixel shaders for five thousand flavors of video card, driver, and operating system. During this time, Austin started work on new systems modeling features for professional level sims. We branched the code, with my work going into 900 and his going into 910.
When he finished his systems code and I got the pixel shaders fixed and both were fixed, the two were combined into what became 920.
So that’s how we “lost” the 910 version number – some professional customers have the version number, but everyone got the features.
There are two ways to make 3-d instruments in your 3-d cockpit:
- Create 2-d instruments on a panel and use the “panel texture” (ATTR_cockpit or ATTR_cockpit_region in your OBJ) to show those 2-d instruments in the 3-d cockpit.
- Model the instruments in 3-d using animation.
So…which gives better framerate? Well, it turns out that they are actually almost the same…a few details:
- If your card can’t directly render-to-texture, there is an extra step for the panel texture. But that would be a weird case – all modern cards can render directly to textures unless you have hosed drivers.
- For very small amounts of geometry, there’s pretty much no difference between rotating a needle using the CPU and telling the GPU to do it by changing the coordinate system.
- The panel texture does put pressure on VRAM – if you’ve had to go to a 2048×2048 panel texture to have enough space, it’s going to hurt you.
Both approaches are actually quite inefficient – you get best vertex throughput on the card when you have at least 100 vertices per batch. But if a panel has 800 batches, you don’t necessarily want to do this – you’d pick up 80,000 vertices just trying to “utilize” the graphics card. That’s not a huge number, but it’s big enough to consider. Panels have enough moving parts that they’re going to push the CPU more than the GPU.
A number of authors like the 3-d approach because they are more comfortable with 3-d tools, and because it can look sharper (since there is no intermediate limiting texture resolution).
There is only one case where I would advise against the 3-d approach: if it takes a huge number of animation commands to accomplish what can be done in one generic, use the panel texture; the generic instruments are all coded cleanly and none of them take that much CPU power. But some of them produce effects that would be relatively difficult to reproduce with animation.
The X-Plane export plugin for AC3D doesn’t handle panel textures very well. The current plugin tries to identify cases where you have used your panel background as a texture – this queues it to generate ATTR_cockpit. This scheme has a number of problems:
- The search paths for the panel background are not up-to-date. The plugin doesn’t know about the new naming conventions or the cockpit_3d folder.
- The scheme doesn’t address panel regions at all – there is some support for them but it doesn’t work well.
- Most important: panel editing is not WYSIWYG. Since you are using the panel background as your texture, you can’t actually see where all the moving parts are! Doh!
That last point is perhaps the most important one, and it is why, for the next version of the plugin, I am introducing panel previews.
Basically a panel preview is a screenshot of your panel with the instruments on it, sitting in your cockpit_3d/-PANELS- folder. AC3D will recognize and use the panel preview when possible. This will solve problems (1) and (3) – there will be only one naming convention for previews, and they will be screenshots of the panel in action, so you can texture with a preview of the instruments.
Plane-Maker 930 will contain a facility to generate panel previews; if you are using X-Plane 920, you can generate the preview manually by taking a screenshot in X-Plane.
For panel regions, we will have one preview file for each region (e.g. Panel_preview0.png, panel_preview1.png). This addresses issue 2 – usage of the region previews will invoke ATTR_cockpit_region.
Finally, I am moving the panel sub-region information from the preferences to the .ac file (hopefully) so that it will be saved with your plane.
Hopefully this will make a work-flow which is much simpler. To make a 3-d cockpit you will simply pick “generate previews” in Plane-Maker, and then start using the previews as textures.
I really like what he’s done with the new page – see it for yourself here!
