[Discussion] Should Floaters and Gliders enter the exit in mid air?

[IchoTolot]

So this came up a few times in IRC now and it always ended in some raging and discussing.

Let's end this once and for all, as I am sick of the back and forth :

Should it stay as it is: They can enter mid-air!

Or change: You always need solid ground under the lems feet to enter the exit!

I would vote for a change here as direct drop in general should not be possible and I count gliders + floaters in here as well.

[Nepster]

I am in favor of removing direct drops for floaters and gliders as well, but acknowledge that there are valid reasons to keep this (both regarding existing content and regarding in-game physics explanations).
Reading some of the chat discussions, it seemed to me that there is some support for keeping "floaters and gliders may exit", but mostly from players who are usually less vocal in the game physics discussions on the forums here.

Existing discussions on this topic:
[DISCUSSION][PLAYER] Game mechanics in general
"Disable direct drop" and "Timed bombers" options

[mobius]

imo; if they can't directly fall into the exit it makes more sense to diss-allow floating into the exit as well.
Another reason is that floating exits, imo look kind of tacky.

[namida]

Hm.

How many levels exist where this will make a difference?

I know Colorful Arty has one such level that pretty much relies on this. Out of my own levels, off the top of my head the only one I can think of is

Lemmings Plus Omega solution spoiler (click to show/hide)

Perplexing 20 "Current Affairs" from Lemmings Plus Omega

.

If this number is low enough, then we'll make the damn change just to end this discussion.

[ccexplore]

If fallers currently already cannot enter the exit in mid-air (which I presume is the case, as you pretty much need that to prevent direct drop for most exit trigger setups, yes even when the exit is placed on land), then it would seem more consistent that floaters and gliders cannot as well, though I'm not completely adverse to floaters and gliders have this extra ability.

What specifically is the "can" camp clamoring for?  That fallers can exit without splatting on a long fall (aka direct-drop)?  Or that they specifically actually want the behavior where fallers cannot exit, but floaters and gliders can?

[namida]

Decision on direct drop for fallers was finalized a long time ago, in a very long-lasting debate. This is not going to change back.

Currently, floaters and gliders retain the ability to exit; this behaviour is completely intentional, not a bug. Some people would prefer this ability was removed. I'm open to removing it if it can be shown that (a) not too many levels rely on it, and (b) most of those that do can be modified not to need it (I know my level could; I'm not sure about anyone else's); if only to put this goddamn debate to rest for good.

[Simon]

Don't let fallers, floaters, gliders exit. I haven't collected or polished any arguments for this post. Most were given throughout Disable direct-drop option.

Until a week ago, I was afraid of checking terrain for gadgets. I would have checked lem activity. I still believe in classifying lem activities into free-choice-activities like walking, bashing, building, and into highly-captive activities like falling, floating, maybe ohnoing too. Then only the free-choice activities can exit or disarm.

But exits and disarmers already consider the lem's groundedness in NL 1.48. This is a break from L1, but much in line with NL releases throughout 2016. See namida's explanation on Wheel of Misfortune. I accept this rule design as a viable alternative to checking lem activity.

if only to put this goddamn debate to rest for good.

<SimonMath> I still want another long and grindy debate. Want want want
<Nepster> Then deal with all the suggestions for new skills :P
<SimonMath> but I don't want to scare away the peaceful suggestors
<SimonMath> I want a meaty debate with people who have thick skin and deep insights into the matter [physics details]

-- Simon

[ccexplore]

Until a week ago, I was afraid of checking terrain for gadgets. I would have checked lem activity. I still believe in classifying lem activities into free-choice-activities like walking, bashing, building, and into highly-captive activities like falling, floating, maybe ohnoing too. Then only the free-choice activities can exit or disarm.

But exits and disarmers already consider the lem's groundedness in NL 1.48. This is a break from L1, but much in line with NL releases throughout 2016. See namida's explanation on Wheel of Misfortune. I accept this rule design as a viable alternative to checking lem activity

Interesting.  Haven't read up on those NL-specific details, but assuming I didn't misunderstand Simon or that he didn't misread the physics (I assume the latter unlikely given the references to specific versions of NL), I was kind of expecting that an explicit terrain check (like it apparently already has) would be unnecessary with respect to dealing with direct-drop to exit, and that the activity state of the lemming would suffice.

Indeed, even in DOS L1 fallers cannot exit, unless my memory completely screwed up.  And I'm pretty sure there is no terrain checks either for exiting.  Direct drop actually happens in DOS L1 because splatterers can exit.  This is not directly observable externally since all the relevant physics update all happen on the same update cycle, so you just see falling -> exiting rather than the falling -> splattering -> exiting that happens "behind the scenes" (ie. in the programming code).

In any case, most of those direct-drop talking points are probably somewhat irrelevant now, as namida already said the current exit-related behaviors of fallers is off the table with regards to changes.  So you're truly left with just the case of a probably uncommon setup where the exit is left in mid air, and fallers may simply fall through without exiting (but otherwise survive), while floaters and gliders would not be able to fall past the exit trigger in current behavior, but can with the proposed change.

[namida]

Indeed, even in DOS L1 fallers cannot exit, unless my memory completely screwed up.

Fallers can't, floaters can (unless Lemmix got this wrong; I didn't test on actual DOS).

[Simon]

explicit terrain check (like it apparently already has) would be unnecessary

We could prevent direct drop without considering terrain at all, yes.

Even now, I would still design all gadget interaction without considering the terrain. We have to look at the activity anyway. A grounded splatter shall not exit, a grounded walker shall exit. If we have to look at the activity, and there is a solution that only looks at activity, that solution sounds like a viable candidate.

This reasoning offers answers for peculiarities that seem to have no obvious answer. There is the issue Jumper shall continue jumping after in-jump disarm. If we classify jumping as highly-captivating, then a jumper cannot be assigned builder, it cannot exit, and it cannot disarm. But this is unnatural within NL's gadget logic. We could now have traps in a walker path that are deadly to disarmers.

I don't know how big a difference the terrain check for exiting makes in 1.48. I don't know how extensive the activity check should be that must supplement the terrain check.

Watch out for special cases like faller hovers above the ground with effective coordinate in the ground, and the faller would splat soon, but hasn't splat yet. This faller satisfies the groundedness check and isn't dead yet. It shouldn't exit nonetheless.

-- Simon

[Dullstar]

Most exits are designed such that they are on the ground.^{[citation needed]} In the Sky set specifically, it seems to make logical sense for floaters and gliders to be able to exit. In other sets, generally, I don't think there would be much difference between the two behaviors, as lemmings would hit the ground then immediately enter the exit with no risk of death unless someone put a trap immediately underneath the exit or something.

[namida]

Most exits are designed such that they are on the ground.[citation needed]

As far as I'm aware, the Sky set is the only exception. In the past, there were a fair few levels that expected a fall into it. Nowdays, at least as far as my own levels go, there is one where you're expected to glide into it. Most of the time, the midair exits are designed to be built (or rarely, platformed) to.

One other case that could differ - if one were to create a direct drop (at a survivable fall distance) onto an exit, then remove the terrain underneath the exit. A floater could still exit, but a faller would fall past.

[Simon]

exit is left in mid air, and fallers may simply fall through without exiting (but otherwise survive), while floaters and gliders would not be able to fall past the exit trigger in current behavior, but can with the proposed change.

Yes, exactly the problematic case.

Flopsy rages at Arty's trick level, or rather the issue-showcasing level.

-- Simon

[Nepster]

Apart from the two level, that were already mentioned above, I don't know of any further level that requires exiting floaters/gliders. But I expect that a few replays of glider-levels will break, where gliders will now pass over the exit when they jumped into the exit before.

[...] I was kind of expecting that an explicit terrain check (like it apparently already has) would be unnecessary with respect to dealing with direct-drop to exit, and that the activity state of the lemming would suffice.

There is only one case where I see the necessity to do a terrain check:
- Falling OhNoers should not exit, because they are essentially fallers with a different animation to show that they will soon explode.
- Standing OhNoers should exit, because OhNoers react to all all other objects like traps or teleporters (even though they cannot start disarming a trap, because this counts as starting a new action).

All other checks regarding exiting can translated into pure lemmings action checks (as far as I am aware).

If disarmer checks were rewritten to take only the lemming action into account, there would be only minimal, but existing, differences in the game physics.

[namida]

But I expect that a few replays of glider-levels will break, where gliders will now pass over the exit when they jumped into the exit before.

This could actually be an important case. Although rare, there are levels that are designed such that an exit is impossible to glide past without exiting. This would be a lot harder to set up (and existing setups would break), especially if the levels in question expect that the glider will not land just before the exit either.