Month: December 2018

X-Plane 11.30 Release Candidate 1 and Toe Brakes

X-Plane 11.30 Release Candidate 1 is out – we fixed a lot of bugs!

As you can tell by the release name, we’re getting ready to kick this thing out the door.  Most of the team is no longer working on 11.30, and those of us who are are trying to make very small, tactical changes to not further screw things up. I wouldn’t bet against an RC2 (we’ve needed more than one try for all of the “really big” patches we’ve done in the last decade) but at this point if you haven’t tested your add-on against 11.30, you’re really late to the party.

Auto Toe Brakes

Flight simulators sometimes have to deal with unrealistic problems specific to being simulators and not real airplanes. One category of these “unrealistic problems” is dealing with user input hardware that is less complex than the real control inputs of the airplane. You might have a single throttle lever on your joystick, and not the 4 throttles with reversers of the 747. You might not have a twist axis or rudder pedals. You might be flying with a mouse!

Automatic toe brakes are a feature where X-Plane automatically applies differential toe brakes at times that we think might be useful if you don’t have toe brake hardware and no plugin is controlling the toe brakes. For example, an aircraft with a free-castering nose-wheel might be impossible to steer at low speeds without toe brakes. (You can’t turn the nose wheel directly, and the rudder will lack authority at low speed.) X-Plane can apply the left toe brake for you when you apply a lot of left rudder to help you turn.

In previous versions of X-Plane, this automatic toe-brake behavior was automatically applied based on some rules that Austin coded into X-Plane. When they worked, they really helped (and we know they sometimes worked because when we removed some of them in 11.30 we got bug reports), but at other times they weren’t tuned properly for a particular aircraft.

Starting in X-Plane 11.30 release candidate 1, aircraft authors can now explicitly control whether toe brakes are auto-applied for users without hardware, and if so, how aggressively. This control is auto-populated for older aircraft with the choices X-Plane 11.26 and earlier would have made, so you shouldn’t see a change in older aircraft behavior. The aircraft updating guide has the full details.

I believe that changes to these automatic rules may have been responsible for changes in third party aircraft ground handling in late 11.30 betas; hopefully with the new code, we should see complete compatibility.

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X-Plane 11.30 Beta 6 and 7, and Winding Down the Beta

X-Plane 11.30 beta 7 is out – full notes here. Hopefully the next beta will be a release candidate; we’re down to a small number of bugs, almost all of which are in the particle system, or are regressions (meaning the behavior was fine in 11.26 and is borked in 11.30).

If you have a bug that dates back to 11.26 or earlier and it hasn’t been fixed yet, it probably is not getting fixed in 11.30 – we’re out of time with this release.

Here are a few details on bugs we’re still working on and bugs we recently fixed.

Drawing Callbacks and Plugins

Beta 6 fixed a bug where plugins would receive extra window-phase drawing callbacks if a modern plugin had a new-style XPLMDisplay window on screen. This should fix a wide variety of plugins-interfering-with-each-others-drawing bugs, particularly where the “culprit” was a new plugin and the victim was SASL-based.

As a general guideline, please use XPLMDisplay windows with the modern SDK and new APIs whenever you can – it will give you the most compatible results going forward. The only drawing phase we recommend at this point is the panel/gauge drawing phases for custom panels.

N1/N2 for Turboprops

X-Plane’s free turboprop model uses the “N1” engine dataref to represent the gas turbine speed, and ties “N2” to the compressor tied to the prop.  When you turn on the starter but don’t bring in fuel, N1 will rise up to 16%, but N2 will stay much lower.

11.30 introduces the “new” free turboprop model – a second engine model that’s designed to more closely emulate the PT-6. For most of the beta, Austin was using an opposite convention: N2 represented the compressor turbine and N1 represented the prop turbine. Austin’s logic was that this was analogous to a high-bypass jet engine: N2 makes the high pressure and N1 spins the big fan-like thing.

In beta 7, Austin changed this; the new free turboprop model now follows the same convention as the old free turboprop model. This should make it a lot easier in the long term for authors whose aircraft have real PT-6’s to use the new model and take advantage of the improved accuracy.

Particles In the Cockpit

In beta 6, we fixed the bug where the new partilcle effects could not be seen from within the cockpit. This had the unfortunate effect of making them visible when the particles were inside the aircraft. This problem can be hard to avoid – depending on the wind and location of the exhaust on your aircraft, it’s possible the smoke just blows through the cockpit, making an artifact.

This is my plan for how we will ship particles in 11.30:

  • Particle emitters attached to objects with “outside” lighting objects will create particles that appear outside the aircraft; they will be masked out so that they don’t appear in the cabin.
  • Particle emitters attached to objects with “inside” lighting will be ignored and produce a log warning.  We are reserving this capability for a future update when we can have interior-pass particles; for now, don’t use this capability, as you can’t know how it will look in future versions of X-Plane.

This is one of the scariest “not done yet” parts of 11.30, because the logic to control interior vs exterior drawing is very complicated – it has to take into account different hardware capabilities, different rendering settings, etc.

Particle Light Levels

I am still working with Alex on particle light levels.  A recent beta included logic in the particle lighting code to match the clouds (e.g. direct sun makes them brighter) – without this, contrails don’t match the clouds.

But with this logic, particles look too dark on the ground. So we are tweaking things. The take-away here is: don’t ship your add-on with particles until we go final, as these things are subject to change during beta.

Automatic Toe Brakes and the C172

Automatic Toe Brakes is a feature where X-Plane automatically applies toe brakes when a user who does not have toe-brake hardware deflects the rudder pedals to near their maximum position. The idea is that on some aircraft, you can’t steer tightly or hold a heading in a cross-wind without the toe brakes. (This feature does not run if a plugin is controlling toe brakes or hardware is available.)

Early X-Plane 11.30 betas caused us to apply automatic toe brakes to aircraft where it was not appropriate, e.g. airliners. X-Plane 11.30 beta 6 removed this behavior from the airliners but also removed it from some third party GA aircraft where it was accidentally (but usefully) being applied.

We’re looking at this now, but at a minimum, I expect we’ll restore legacy aircraft to acting as they did before, and probably widen the steering range of our 172 a bit. I’ll write more in a separate post once we make a decision.

 

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