Blindness

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Blindness is an inability to see. When blind, normal movement will result in you using your hands to feel for items on the ground. Unseen items generally only appear as their object class, without even randomized appearance - for example, you will only feel "a wand" or "a potion". Items seen prior to blinding will continue to be identified with their randomized appearance.

The zen unofficial conduct consists of playing the entire game blinded.

Dangers

If you move normally while blind, you will attack anything represented by I (or warning symbol) you walk into, as if it were invisible. Also, moving onto a seemingly empty square with a monster on it, will cost you a move (without attacking), show the monster as I and anger it if peaceful. This makes it very dangerous to move around while blind, because you could inadvertently kill your pet or anger a shopkeeper.

To partially avoid this, be sure to move with m followed by a direction. This causes you to move without feeling on the ground for items and generally without attacking monsters. But this still angers any peacefuls you bump into that weren't already shown in any way. If a stethoscope is only used once per turn, it can determine if there is something in the way without giving that monster a chance to move, since the stethoscope can be applied for free once per turn. If you are fairly confident that there are no monsters on the level that could seriously damage you in one hit, you could also wait for them to attack you first. Although if the monsters are faster than you, they can attack you and move away before you having a chance to react to the I that you discovered when they attacked you. In rare cases, #chatting is useful to test for non-silent monsters since it does not use a turn if you get no answer.

Monsters seen via telepathy or monster detection are handled normally, both moving normally and with m. You always attack warning symbols, unless you are m-moving into one that covers an I. Beware that even telepathy and warning put together don't show all types of monsters. (Further corner cases stem from hiders, mimics, Stormbringer, F, and deactivating safe_pet.)

Special care should be taken on levels with cockatrices on them. If there is a cockatrice corpse and you move around normally while blind, you may stumble on to the corpse and feel for it. If your character is not wearing gloves, this will result in instant stoning. Use the m movement prefix (as above) to avoid touching the corpse while moving. Additionally, if you try to : (look) or , (pick up) on a square with a cockatrice corpse while blind you feel the square and will also be stoned! Even worse, if you are blind and warned, moving with m into a cockatrice without a wielding anything or wearing gloves will still stone you in some cases: namely whenever the warning symbol does not cover an undisplayed I.

Pardon me, foo.
You moved with m into a pet either displayed as I or properly seen.[1]
You move right into foo.
You moved with m into a non-tame monster either displayed I or properly seen.[2]
Wait! There's something there you can't see!
You moved onto a seemingly empty square. Does not attack, but does anger peacefuls.[3]

Benefits

If you have telepathy, though, blindness can be quite useful as it enables you to see all monsters with brains on the level. Intrinsic telepathy is only active when you are blind; extrinsic telepathy will work like intrinsic telepathy when you are blind.

Being blind has the beneficial "side effects" of protecting against Medusa and pyrolisks, as well as any other monster with a gaze attack (including the passive floating eye gaze).

Ways to be blinded

In addition to this list, most of the methods to blind monsters also work on yourself.

Inflicting blindness

A blind enemy will move and attack erratically, suffer a to-hit penalty and generally be much less dangerous, especially if you can keep moving. There are six main ways to inflict blindness.

Beware, blinded creatures do not respect Elbereth.

Curing blindness

There are a few ways to cure intrinsic blindness - that is, blindness not from being blindfolded, cream pies, venom or applying cursed towels.

Extrinsic blindness, from cream pies, venom or applying cursed towels, can be cured by waiting, wiping your face using the #wipe command, applying a noncursed towel, or prayer.

Otherwise, you can remove whatever it is that is blindfolding you. Having a cursed blindfold or towel stuck to your face is considered a major problem, so if it is safe to pray, your god is likely to help you out of this predicament.

Resisting blindness

A few items allow you to resist blindness. While this can be useful in the early game, you usually have a unicorn horn by the time you have one of these (except for the potion of blindness, which is probably a bug).

While you are wielding Sunsword, you will be protected from some "visual" sources of blindness;[6][7] this includes yellow lights,[8] magic traps,[9] and wands of lightning.[10][11]

Wielding (or otherwise equipping, including quivering) a potion of blindness will also protect you the same way Sunsword does.[12][13] This is likely a bug.

The Eyes of the Overworld will not prevent blinding, but you will still be able to see while wearing them.

Object appearances

Until you have seen them, objects show up only as "a potion", "a ring", "a long sword" etc. A gray stones or rock is a "stone", glass or gem is a "gem". Only amulets and food are treated as seen.

An elven or orcish shield is just a "shield", and a shield of reflection is a "smooth shield". Even an artifact is "a long sword".

You cannot class-name such objects, and any individual name will not be displayed (but will affect stacking and artifact naming). You can dip items in holy/unholy water when blind, thus "a cursed scroll". Poisoning and erosion status is shown. Dilution is only displayed if you know the appearance. Erodeproofing and charges are only shown if formally identified (even if you erodeproofed it yourself while blind).

A full list of ways to make an object "seen" while still being blind, e.g. for zen conduct:

You hear the appearance of a scroll a monster is reading, so you can name another one later. Since you cannot generally "see" the result of the scroll directly, scrolls will not usually auto-identify. The same is true for potions, you will hear the potion being quaffed, but will not see the result.

Polymorphing any object, alchemy, and #dip-cancelling a potion will render it unseen.

Internals

It is worthwhile considering the internals of blindness, which are quite complex, but their details shed light on the actions and exceptions described above.

The source recognises three forms of blindness:

Blinded

"Blinded"[28] refers to all forms of blindness that are intrinsic; that is, you would be blind if you were not wearing or wielding anything and polymorphed into a monster form with eyes.

The number of turns for which you are blinded is recorded.

Creamed

Being "creamed"[29] means you have a substance over your eyes physically restricting your vision. It is a subset of being "blinded", and stacks with blindness.

The number of turns you are creamed is recorded. It is always less than or equal to the number of turns you are blinded.

Items causing or curing creaming affect both the number of turns creamed and blinded by the same amount.

Actions that cream are:

  • Being hit by, or applying a cream pie
  • Being hit by blinding venom
  • Applying a cursed towel

Actions that cure creaming are:

  • wiping your face
  • Applying a noncursed towel

All other actions and cures affect blindness only if it cures either, except prayer, which will cure both creaming and blinding.

The "creamed" status times out first. To understand how this works, consider the following hypothetical scenario wherein you are blinded for 100 turns. After 50 turns have elapsed, you will still be blind for 50 more turns. If, however, on that turn, you become creamed for a duration of 20 turns, you will be blinded for a total of 70 more turns - the first 20 of which you are considered creamed.

Blind

"Blind"[30] means you currently cannot see. You can be "blind" without being "blinded", if your eyes are covered by a blindfold or a towel, or you polymorph into a monster with no eyes. You can be "blinded" without being "blind" if you have astral vision.

References

  1. src/hack.c in NetHack 3.6.0, line 1409
  2. src/hack.c in NetHack 3.6.0, line 1411
  3. src/uhitm.c in NetHack 3.6.0, line 137
  4. src/mcastu.c in NetHack 3.6.0, line 559
  5. src/region.c in NetHack 3.6.0, line 929
  6. src/mondata.c in NetHack 3.6.0, line 153
  7. include/artilist.h in NetHack 3.6.0, line 153
  8. src/mhitu.c in NetHack 3.6.0, line 1929
  9. src/trap.c in NetHack 3.6.0, line 3051
  10. src/zap.c in NetHack 3.6.0, line 2157
  11. src/zap.c in NetHack 3.6.0, line 3978
  12. src/mondata.c in NetHack 3.6.0, line 164
  13. src/objects.c in NetHack 3.6.0, line 796
  14. src/quest.c in NetHack 3.6.0, line 213
  15. src/quest.c in NetHack 3.6.0, line 227
  16. object_detect in detect.c in NetHack 3.6.0
  17. src/shk.c in NetHack 3.6.0, line 2323
  18. src/zap.c in NetHack 3.6.0, line 434
  19. src/zap.c in NetHack 3.6.0, line 1811
  20. src/zap.c in NetHack 3.6.0, line 2369
  21. src/u_init.c in NetHack 3.6.0, line 1074
  22. src/dog.c in NetHack 3.6.0, line 193
  23. src/sit.c in NetHack 3.6.0, line 305
  24. src/artifact.c in NetHack 3.6.0, line 1261
  25. src/artifact.c in NetHack 3.6.0, line 1278
  26. src/artifact.c in NetHack 3.6.0, line 1308
  27. src/artifact.c in NetHack 3.6.0, line 1324
  28. include/youprop.h in NetHack 3.6.0, line 85
  29. include/you.h in NetHack 3.6.0, line 320
  30. include/youprop.h in NetHack 3.6.0, line 88

This page may need to be updated for NetHack 3.6.0.

It may contain text specific to NetHack 3.4.3. Information on this page may be out of date.

Editors: After reviewing this page and making necessary edits, please change the {{nethack-343}} tag to {{nethack-360}} or {{noversion}} as appropriate.