Fall distance challenge

[Minim]

OK, let's see if this next challenge is as interesting as the others.

For this challenge, you use the default skillset and the default requirements. The only difference is that the lemmings can't fall quite as far as they usually can. I've sent a PM to namida about changing the fall distance to work on Lemmix, and mentioned that 47 pixels would be the proposed new max fall distance, so that most of the levels should still provide a solid challenge. The most notable level that won't work at all will be "We all fall down", so we'll leave that one out and focus on all the others.

Of course, we might need an agreement first before we can get this set up properly. We might even need to lower the height on some of the trapdoors (For example, Wicked 18) to prevent the challenge from being too unfair.

[Simon]

Consider spawning new lemmings with -16 pixels already fallen, such that the max fall distance from hatch is still 63. Then you can keep hatch positions as they are.

What was the idea behind exactly 47 pixels? Simply because kill distance is then 3/4 of 64 and those are nice numbers? Or are there frequently stacked objects in the levels with a height of 48?

-- Simon

[namida]

MiniMac doesn't seem to be online, so here:

http://www.mediafire.com/download/5vaw07blvvkzaj5/LP47.zip

The versions with "IB" in the names also have the instant bomber mechanic.

[ccexplore]

Given what namida had been able to do with modifying Lemmix, I'd actually like the ability to actually set the fall distance via the INI file.  Then the challenge can actually be configured as finding the smallest max-fall distance where the level remains solvable.  47 (actually more likely 48--see next paragraph) can still be use as a starting point for people, so that it doesn't get too tedious hunting down the exact smallest number.  We can optionally report a second set of results where we apply the exemption on the initial spawn-falling as Simon suggested (perhaps configurable also via the INI file).

Note that in terms of the actual implementation of the game mechanics, the number the game is using is really 60 to get the effect of a maximum cliff height of 63 pixels being safe for a walker falling off.  I also seem to recall that due to the way the code updates the various variables involved, unless you change that code (rather than just changing the numeric constant it uses in the comparison that determines splat/no-splat), you would only be able to change the max safe-fall distance in decrements of 3 when you just change the number, because certain numbers would have equivalent effect in the code with respect to the fall distance.  (If you still have some questions about this, PM me and I can explain in detail what I mean.)

[Proxima]

Since I don't see the rationale for choosing 47 in particular, I suggest a starting-point of 36 -- the smallest max-fall distance in which the training levels (Fun 1-7) can be passed if no other changes are made. (The highest non-floater fall in these levels is from the trapdoor in Fun 4.)

minimac highlighted Wicked 18. The fall from the trapdoor on this level is 60 pixels, but you get two floaters, so I don't see any reason to lower the trapdoor. (Indeed, if you don't, the level is trivial for this challenge, since there are no other medium or long falls in the normal solution!)

[Proxima]

Anyway, I've now played through the Fun levels in the 47 version. No huge surprises; all 100%able levels (except of course WAFD) remain 100%able. A few points of interest:

* Fun 8 and 11 now have splat falls at the start. This makes Tricky 22 impossible, as you only have one floater, and no way to turn him round quickly enough to build a landing platform. Taxing 18 remains possible, but no longer 100%able.
* On Fun 24, if you dig through the thin platform left of the one-way wall, the digger survives but walkers do not. This probably makes Mayhem 3 impossible.
* On Fun 27, the "shortcut" route is still possible: if you dig through the first platform as far left as possible, and build so the bridge juts out beyond the right end of the platform, the fall is survivable.

[namida]

If you *mine* through that platform, the effect is reversed - the others survive but the miner does not, but you have one faller.

I did look through, while I didn't go into huge detail, I didn't find that many levels to be impossible. I PM'ed Minimac the list, but I can't remember it off-hand. I do know the majority of the impacted levels were in Taxing - Mayhem, I believe, was only Mayhem 20 and Mayhem 30, and *possibly* Mayhem 3.

[Clam]

the challenge can actually be configured as finding the smallest max-fall distance where the level remains solvable.

This is what I imagined when I first saw the topic. If not then that's a natural progression anyway, like how we went from "one type of skill" to "fewest different skills".


Taxing 20 can be done with no fall distance, i.e. give a floater to every lemming that falls at any point. (If we consider walking downhill then you need a max-fall of 1 - see below.) I actually found this while trying to do levels in the least time, since the faller and jumper/ascender waste time in terms of moving towards the exit.

This raises a couple of questions about the case of extremely small max-fall distance:
- The faller animation only happens when descending 4 pixels or more. If you set the max-fall distance less than that, will they splat while walking downhill? Or does it only affect fallers?
- Floaters have a delay before opening their umbrella. If the max-fall distance is too small, can they splat in that time?

[Proxima]

I agree that that's a natural progression, but I want to finish the 47 version first. I haven't played the regular levels with music for a long time, so I'm enjoying this!

I've done Tricky now. Tricky 22 (already mentioned) is the only impossible one, and all 100%able levels remain 100%able (including Cascade). Points of interest:

* Tricky 1 and 4 have splat starts, both easily dealt with as you have plenty of skills. Taxing 7 is impossible (no floaters!). Tricky 1 has no repeat.
* The drop at the end of Tricky 7 can still be broken into just two survivable falls.
* On Tricky 8, the fall from the middle platform to the bottom-left corner is fatal. Easily dealt with, but there are so few levels where the solution is affected at all, I have to mention every little thing 
* Tricky 12 needs four bridges before the initial drop is survivable, unless you create extra space by bashing into the wall. (Of course, since you have 50 floaters anyway....)
* I solved Tricky 13 in a completely different and ridiculously complicated way just for fun 

[ccexplore]

Technically you'd need to ask namida because I haven't tried out his LemmixPlayer or know what exactly he changed.  But, assuming relatively small changes were made, I believe the below answers off top of my head:

This raises a couple of questions about the case of extremely small max-fall distance:
- The faller animation only happens when descending 4 pixels or more. If you set the max-fall distance less than that, will they splat while walking downhill? Or does it only affect fallers?

Only fallers are affected, as the only splat check that happens in the game's programming is when a falling faller detects landing ground and prepares for the faller->walker transition.  I think that's a more reasonable interpretation frankly than splatting walkers walking on uneven (but hardly steep) terrain.

- Floaters have a delay before opening their umbrella. If the max-fall distance is too small, can they splat in that time?

Good catch.  Yes, they can splat in this scenario.  Granted, perhaps we can modify the mechanics to prevent this as well?  There is a different numeric constant (16) governing this umbrella-opening delay.

[Proxima]

And now Taxing. As namida said, there are more affected levels in this rating:

* Taxing 5, 7 and 13 are impossible because of a splat start and no floaters.
* Taxing 6 is non-100%able for obvious reasons, and 18 is non-100%able because it has a splat start. I haven't tested the 100% solution to 16, but I think it leaves enough builders spare that you can compensate for the decreased fall distance.
* Taxing 10 cannot be solved conventionally, as there is no way to get down the large drop in the middle. Fortunately, direct drop still works!
* Taxing 14 is easy because the right edge of Nessie's neck is not perfectly vertical, which I never noticed before.
* Taxing 22 can still be solved without going round the outside (replay attached).
* Taxing 24 is impossible because there is no way to get down to the bottom part of the level.
* On Taxing 28, building up from the floor no longer works because there is no way to avoid the fatal drop after cutting through the pillar. (If you try bashing through its base, the lemmings drown!)

[Proxima]

And finally, Mayhem 

* Mayhem 1 is still possible but non-100%able.
* Mayhem 3 is probably impossible for reasons discussed above.
* On Mayhem 10, building up from the floor requires five bridges before the fall is survivable. If you use all three floaters, the number of survivors will be just one short of the level's save requirement. Of course, the level is still possible by using climbers (or sliding!) to start the bridge at the top.
* Mayhem 20 is impossible because you have to cut the bridge at its top, and the fall at that point is too high.
* Mayhem 22 has a splat start, but with the high number of skills, it's even still possible to save 100%.
* Mayhem 29 is much harder because the drop after the large pillar can't be broken into two survivable stages. The level is still solvable without glitches (replay attached).
* Mayhem 30 is impossible because you have a splat start on both sides and only one floater.

[namida]

Mayhem 3, I can acheive 96%, and I could also save 100% (with a completely different method) if it weren't for the time limit - it's far more than the pause glitch would make up, though, but at any rate, here's the two solutions in case anyone can get ideas from them.

It should probably be noted - all I did was change the max fall distance variable from 60 to 47; so any impact of other mechanics will still occur as normal (such as Orig having a maximum distance 3 pixels shorter or OhNo's 3 greater, whichever the case is). Depending on whether this makes Orig 44 and OhNo47, or Orig 47 and OhNo 50, it might be possible to beat Mayhem 3 at an actual 47 fall distance - because the fall that prevents it being completed is exactly one pixel too far, so this *would* make a difference.

[ccexplore]

It should probably be noted - all I did was change the max fall distance variable from 60 to 47

For a simple modification of that variable M, I believe the resulting maximum safe-fall distance would be as follows:

f(M) + 3 where f(n) is the greatest multiple of 3 less than or equal to n, so for example f(60), f(61) and f(62) all evaluates to 60, while f(63) evaluates to 63.

So the "47" currently in used is actually translating to a maximum safe-fall distance of 48.  This is consistent with the Mayhem 3 setup (ie. just one pixel past the safe maximum) as I've just checked in the editor.

Mayhem 3, I can acheive 96%, and I could also save 100% (with a completely different method) if it weren't for the time limit - it's far more than the pause glitch would make up, though, but at any rate, here's the two solutions in case anyone can get ideas from them.

I briefly looked into it independently myself, and my current belief is that anyone successful in getting it to work for this challenge, will also have found effectively a different way to solve the level normally that has previously not been seen, solutions that could potentially affect results of other challenges such as "skills you can't live without" for example.  This sets the bar high enough that I think it's unlikely for Mayhem 3 to be solvable for this challenge.

[Proxima]

Interesting. And helpful, since we would only need to look at multiples of 3    For example, we now know the minimum safe fall distance for Mayhem 3 must be 51.

I hope we soon get the version ccexplore mentioned, where we can set the safe fall distance via the INI rather than requesting a new version for each value. Also, I would like to see a version with Simon's idea, where lemmings are spawned with a (negative) number of pixels already fallen. In particular, rather than a chaos of different results, I think we should separate this into two challenges: (1) Find, for each level, the minimum safe fall distance, without using Simon's idea; (2) Find a list of levels that can be solved with Simon's idea and safe fall distance 0.