Symmetric Mirrored Control Surfaces

[Lisias]

Any part willing to use ModuleControlSurface needs to be aware of the following features:

• PartModule
  • OnEditorAttach event handler
  • symMethod field
  • symmetryCounterparts field
• ModuleControlSurface
  • usesMirrorDeploy field
  • mirrorDeploy field
  • partDeployInvert field

Your part module must hook a EventHandler to the OnEditorAttach:

	part.OnEditorAttach += new Callback(UpdateOnEditorAttach);

So, everytime the user attaches something with your module on another part on the Editor, you will be notified.

On the event handler, you need to check the Symmetry Method - on this case, we need to check for the Mirror one. And then set some ModuleControlSurface flags, as follows:

1. Check if the part has any Counter Parts on the Symmetry - no need to waste time when the part has no mirrored part! (technically, a bug but whatever - better safe than sorry).
   • To be really pick, one should check if the Count is exactly one, but if you get a situation where a mirrored part has more than one, the user have a lot of worse problems to cope wth.
2. Get a pointer to the ModuleControlSurface instance of the part.
3. Get a pointer to the mirror counterpart's ModuleControlSurface of this part.
4. set usesMirrorDeploy to TRUE
5. set mirrorDeploy differently for each part using some criteria (any one fits, the important part is that one gets TRUE and the other gets FALSE)
6. For a reason beyond my grasp, on B9 Procedural Control Surfaces you need to set partDeployInvert to the negation of the mirrorDeploy. Stock Control Surfaces doesn't use that.

And that's it.  

Here is the code I used on my pull request to B9's Procedural Wings (released under the MIT, by the way):

public void Start(
{
	part.OnEditorAttach += SetupMirroredCntrlSrf;
}
	
private void SetupMirroredCntrlSrf()
{
	if (part.symMethod == SymmetryMethod.Mirror && part.symmetryCounterparts.Count > 0)
		if (this.part.Modules.Contains<ModuleControlSurface>())
		{ 
			ModuleControlSurface m = this.part.Modules.GetModule<ModuleControlSurface>();
			m.usesMirrorDeploy = true;
			{
			    Part other = part.symmetryCounterparts[0];
			    m.mirrorDeploy = this.part.transform.position.x > other.transform.position.x;
			    m.partDeployInvert = !m.mirrorDeploy;
			}
		}
}

And that's it! Any part willing to implement mirrored behaviours (as elevons and flaps) and uses ModuleControlSurfaceonly need to do this, and that's it!

Edited February 6, 2019 by Lisias
Eternal typos from the englishless mind.

[Lisias]

By the way, a tool to "fix" broken or unset mirrored control surfaces would be hugely welcomed. Editor Extensions Redux is probably the tool that should implement it.

[Lisias]

I found an issue with Atmospheric Autopilot. The first time you load your pre-existent (or downloaded) crafts, you loose the Control Surfaces configurations, as AA changes the name of that module to SyncModuleControSurface, and then the data under the ModuleControlSurface are lost.  

This used to work fine until 2014 more or less (see here), but obviously something changed in the mean time.

AA made a "hack" by resetting the mirror info by brute-force, but that way doesn't works with B9's control surfaces. So, currently, I'm trying to figure out a way to overcome that.