[DISC][PLAYER] Behavior of horizontally-flipped portals

[namida]

For teleporters/receivers we have a defined behavior: Either both objects must be flipped, or else neither is flipped. If they are flipped, the lemming comes out the receiver facing the opposite direction they entered the teleporter.

For portals, currently, flipping doesn't do anything (aside from adjusting the graphic / repositioning the trigger area in the same way it would do for any object). The question that arises is - what should happen?

I see three possibilities here:
1. Flipped portals have no special effect and behave the same as ordinary portals. Not keen on this one (unless flipping portals is prohibited altogether, rather than being allowed but having no physics effect), in particular due to it being inconsistent with what teleporters do.
2. Paired portals can be flipped individually. If either the sending or receiving portal is flipped, the lemming reverses direction when exiting the receiving portal. If both are flipped, this cancels out and the lemming's direction does not change.
3. Paired portals must either be both flipped, or neither flipped, much like teleporter/receiver pairs. If the pair is flipped, the lemming reverses direction when exiting the receiving portal. This is my preferred approach.

Thoughts?

[IchoTolot]

I would initially be with 3 as well, but as portals are more defined like a vortex that suck lemmings in and therefore most likely don't have an "IN" and "OUT" sign that signals the flip, or distinct features that show the flip, why do we need to flip them?

Therefore, I would throw in the possibility of "prohibiting flipping portals altogether". As why do we need to flip an object that has no visual features that signal the flip?

Otherwise I would tend to 3 as well, but here we would need a visual clue that the vortex is indeed flipped just like in the case of teleporters.

[namida]

That's a good point - it did cross my mind also that portal designs are likely to be symmetric (or at least close enough that one can't quickly tell whether they're flipped or not), which may lend stronger support to #1.

[WillLem]

3. Paired portals must either be both flipped, or neither flipped, much like teleporter/receiver pairs. If the pair is flipped, the lemming reverses direction when exiting the receiving portal. This is my preferred approach.

+1 for suggestion #3. If it's established for teleporters, it makes sense to keep things the same for portals. Also reduces potential headaches of trying to keep up with which are flipped and which aren't (which suggestion #2 could cause), particularly if the graphics have no left/right-facing indications or characteristics.

It's also consistent with the flipping of other direction-related objects, such as entrance hatches, teleporters, OWW, OWF, etc. Ideally, it follows that there should be some actual change in lemming behaviour when flipping occurs.

Suggestion #1 feels somewhat redundant, although would keep the option to at least flip the graphic without otherwise affecting object behaviour, if this is what is ultimately decided. This feels like it would be similar to flipping a flamethrower graphic, which is sometimes done for aesthetic purposes.

why do we need to flip them?

Good question. I'm thinking that level designers may wish to have the lemming facing a certain direction once they've exited the teleporter/portal. Having it as a characteristic of the object itself reduces the need for messy design.

Therefore, I would throw in the possibility of "prohibiting flipping portals altogether". As why do we need to flip an object that has no visual features that signal the flip?

Strongly opposed to this, for these reasons:

a) All other objects can be flipped, even if only aesthetically. Suggestion #1 has this covered if it's decided that there should be no change in lemming direction upon interaction with the object, so there's no need to outright prevent flipping altogether.

b) Style creators may in fact design their portals to include such visual features/indications, even if default ones don't. If the concern is that designers might include misleading features which suggest direction, this could happen with or without flipping behaviour.

Otherwise I would tend to 3 as well, but here we would need a visual clue that the vortex is indeed flipped just like in the case of teleporters.

Agreed This could be done with something as simple as arrows, for example.

It doesn't even have to be that clinical, though. A portal designed with a more ethereal effect like a vortex, such as this one below, could be said to be facing "to the right", since the direction of its swirl is right-facing:



Here's what the same portal would look like when facing "to the left":

[Proxima]

It doesn't even have to be that clinical, though. A portal designed with a more ethereal effect like a vortex, such as this one below, could be said to be facing "to the right", since the direction of its swirl is right-facing:

Lemmings may be walking in either direction. Why should a pair of right-facing portals mean "don't flip" and a pair of left-facing ones mean "flip"?

Far more logical would be #2: Portals facing in opposite directions mean "flip".

[WillLem]

Lemmings may be walking in either direction. Why should a pair of right-facing portals mean "don't flip" and a pair of left-facing ones mean "flip"?

Hmm, I didn't think of that. Good question, to which I'd add a part b):

Why is this behaviour applied to teleporters? I'm guessing it's simply a result of NL's processing of the object physics rather than being a deliberate choice...

Far more logical would be #2: Portals facing in opposite directions mean "flip".

Agreed, this does make far more sense since it makes it easier for the player to predict what will happen to lems entering and exiting.

I'd update my preference to option #2* on this basis, but suggest that this option requires some indication of direction, at least in CPM, and ideally on the graphic itself (so does option #3 really, as previously stated by myself and Icho).



*Having said this, it does mean that portals and teleporters would behave differently in this regard, which could potentially cause confusion. So, option #3 still has my support unless option #2 could also be retroactively applied to teleporters, which I imagine is highly unlikely due to the "no new suggestions" policy and potential for existing content breakage.

[Dullstar]

I think perhaps we should work on some visual design for these objects first (I mean, custom styles can do what they want, of course, but a lot of object types are fairly readily identifiable even without clear physics). The visual design with teleporters at least makes the flipping easy to recognize, since that IN and OUT text is already there to differentiate between teleporters and receivers, but with portals being 2-way, it's less clear what people might use to indicate a portal flips lemmings. If we agree to go with WillLem's interpretation of approximately what they should look like, for instance, then 2 is fair, because 2 opposite facing portals = flip, and then 3 is unfair because it's not particularly clear which way is which and a potential disaster if a style creator does it the other way (at least with teleporters, why would anyone not intentionally creating a troll style write the words backwords?). And what if someone early on in the object's lifespan makes a symmetrical graphic and then almost all the style creators decide, "Yep, that's what portals look like?" Then only 1 is fair, because it's impossible to tell if the graphic is flipped or not.

As for 1, completely prohibited flips don't seem ideal, but it's a safe starting point: you can always add flipping behavior later and lift the restriction without breaking content regardless of what behavior you decide to go with long-term.

[namida]

As for 1, completely prohibited flips don't seem ideal, but it's a safe starting point: you can always add flipping behavior later and lift the restriction without breaking content regardless of what behavior you decide to go with long-term.

This is a good point. I don't want to keep this open for ages, but perhaps we can consider: Flipping portals prohibited altogether in the initial version. The next major update will (likely) allow flipping, and decide the behavior of it based on feedback from actual use, in particular the graphical designs that emerge and whether level creators come up with ideas that need the flipping behavior.

[namida]

Why is this behaviour applied to teleporters? I'm guessing it's simply a result of NL's processing of the object physics rather than being a deliberate choice...

To go back to this question - in the early days, flipping the graphic and flipping the lemming direction were two independent settings. They were merged later as culling the flip option didn't seem appropriate, but it needed a clear visual indicator, and simply merging the physics flip and visual flip together was the easiest way to do this. Nepster later extended this to that if the teleporter was flipped, the receiver would automatically be flipped too (and likewise, if the teleporter wasn't, the receiver wouldn't be), whereas prior to this, it was on the basis of "if both are flipped, it cancels out".

[namida]

Okay so, I'm going to indeed go with prohibiting flipping altogether in the initial release. This may be reconsidered (and the behavior determined) for the following major update.