Potion of object detection
! 
| |
|---|---|
| Name | object detection |
| Appearance | random |
| Base price | 150 zm |
| Weight | 20 |
| Monster use | Will not be used by monsters. |
A potion of object detection is a type of potion that appears in NetHack.
Contents
Generation
Wizards can start the game with a potion of object detection as any of their three random potions.[1]
Potions of object detection make up 21⁄500 (4.2%) of all potions randomly generated on the floor, in general shops, or as death drops. Liquor emporiums can also stock potions of object detection.
In The Gnome King's Wine Cellar map of Mines' End, a potion of object detection is always generated within the titular wine cellar at level creation.[2]
Nymphs have a 1⁄2 chance of being generated with a potion of object detection.[3]
Description
A hero quaffing the potion will be shown all objects on the current level and exercise wisdom if at least one object is detected, with the exact effects dependent on the potion's beatitude:[4][5]
- An uncursed potion displays the current position of all objects on the level using a blank map, including buried and underwater objects[6][7]—objects not known to the hero will be displayed as their object type, i.e. "a scroll", "a potion", "a bag", etc.
- A cursed potion will behave the same as an uncursed one, but will additionally display cloaked mimics as though they were actual objects (with the "item's" class selected randomly per mimic).[8][9][10]
- A blessed potion will display objects as an uncursed one does, but items that are not in a monster's inventory are treated as though the hero handled them up close, and so will have their full object appearance shown (including identified ones where possible).[11][12][13][14][15] The hero also learns the appearance of all items in their inventory if applicable.
Stale object markings are always cleared when mapping item locations from this effect.[16][17] Floor items are mapped over buried items, items on the top of piles are mapped over the rest of the pile, and the first item in a monster's inventory is mapped over any items they are standing on.[18][19][20][21][22][23] The hero can navigate the resulting screen from quaffing the potion by moving their cursor to highlight particular objects, and any other key that does not perform a navigation action will exit this screen[24][25]—the locations of those objects are recorded when returning to normal play. Monsters will not use this potion.
Quaffing the potion while hallucinating will have the same effects as described above, but will print different messages and display items as their hallucinated glyphs. If the glyph of a previously-detected object suddenly disappears when it would be within the hero's line of sight, the item(s) in question are buried or submerged.
Strategy
Potions of object detection can be quite useful for item detection, whether it involves checking for gold in vaults (unless they were looted by a digging dwarf, rock mole or other monster), or learning which tower at the Castle has the chest containing the wand of wishing. They can also be very useful on mapped levels, allowing a hero to prioritize which loot they want—be on the lookout for detected wands, since monsters may be carrying them! Object detection is especially valued when combined with magic mapping in Gehennom, which reduces the tedium of the mazes and can alert the hero to attack wands carried by major demons and other humanoid hostiles, or a wand of digging carried by a minotaur.
The detect treasure spell has the same effect as quaffing the potion, but casting it is generally much more difficult and generally left to heroes playing dedicated spell-focused builds—however, the spell will not detect cloaked mimics as objects like the cursed potion can, and does not cut into carrying capacity as much for more weight-conscious players, especially if they opt to stash its spellbook. Remember that buried and submerged objects will have their glyphs vanish when their squares become visible to the hero—digging down with a pick-axe or dwarvish mattock on a buried object's formerly-marked square will reveal them, and items that sitting on or embedded in the same square may obscure further buried treasure.
As they are fairly common due to the presence of nymphs, potions of object detection can be saved up and diluted en masse for holy (or unholy) water production. Blessed potions of object detection are especially welcome for conduct play, with zen being the most notable example: since the hero will be blind for the entirety of the game, they will not normally see or learn the identities of some objects they pick up, unless those items are bought from a shop; shopping is also very risky for a zen hero until they gain telepathy to avoid bumping into unseen shopkeepers, and learning object identities often requires selling the item(s) in question to the shop, then buying them back if necessary. The blessed potion is thus one of the better aids a zen hero can obtain for learning object identities.
Smoky potions of object detection are among the best smoky potions to have in a given game when shooting for wishes: they are plentiful and relatively easy to amass as a result of nymph generation, do not potentially replace a vital necessity as smoky potions of full healing can, and will not be used by monsters—the most detrimental effect it has besides producing a hostile djinn is potentially mis-identifying a mimic from quaffing a cursed potion.
Since tiles ports show unique tiles for unique object descriptions, you can determine the appearance of an object in tiles mode using an uncursed potion; once you've detected it, compare the tile to a list to see what appearance it has.
History
The potion of object detection first appears in Hack 1.21, Hack for PDP-11 and PC/IX Hack, which are all based on Jay Fenlason's Hack. It is included in the initial item list for Hack 1.0.
From NetHack 3.1.0 to NetHack 3.1.3, applying a cursed bell can be exploited to summon nymphs indefinitely with their usual starting inventory, and there is no risk of extinction, paralysis or generating a fast nymph.[26] Among other benefits, this is commonly used to accumulate potions of object detection for dilution, alchemy, polypiling, or even wishes if potions of object detection are smoky potions.[27] NetHack 3.2.0 fixes this by ensuring that the summoned nymph has no starting inventory.
Messages
- You have a <strange/normal> feeling for a moment, then it passes.
- You quaffed the potion as a beginner and found no objects on the level, with "normal" used if you are also hallucinating.
- You sense the presence of <objects/something>.
- You quaffed the potion and detected objects, with "something" used if you are also hallucinating.
- You sense <objects/something> nearby.
- You quaffed the potion and the only detected objects were on your square, with "something" used if you are also hallucinating.
- You sense the absence of objects.
- As above, but no objects were detected.
- You feel a lack of something.
- As above, but the potion also cleared the screen of remembered object locations.
Variants
SLASH'EM
In SLASH'EM, Flame Mages, Ice Mages, Necromancers, and Wizards may be given a potion of object detection as any of the random potions in their starting inventories.[28][29][30][31]
ZAPM
In ZAPM, the equivalent to the potion of object detection from NetHack is the floppy disk of object detection.
dNetHack
In dNetHack, notdNetHack and notnotdNetHack, yuki-onna heroes start the game with knowledge of the randomized appearance for the potion of object detection, as they are a race of playable nymph.
Spa shops in Elshava can stock potions of object detection.
Invoking The Marauder's Map detects objects identically to a potion of the same beatitude as the artifact, then detects other artifacts on the level, mapping them over existing marked objects if necessary.
SlashTHEM
In SlashTHEM, in addition to SLASH'EM details, Acid Mages, Drunks and Electric Mages may start with a potion of object detection as any of the random potions in their starting inventory.
References
- ↑ src/u_init.c in NetHack 3.6.7, line 166
- ↑ dat/mines.des in NetHack 3.6.7, line 1042
- ↑ src/makemon.c in NetHack 3.6.7, line 703
- ↑ src/potion.c in NetHack 3.6.7, line 849
- ↑ src/potion.c in NetHack 3.6.7, line 853
- ↑ src/potion.c in NetHack 3.6.7, line 851: calls object_detect() in detect.c
- ↑ src/detect.c in NetHack 3.6.7, line 582: object_detect() function
- ↑ src/detect.c in NetHack 3.6.7, line 588
- ↑ src/detect.c in NetHack 3.6.7, line 658
- ↑ src/detect.c in NetHack 3.6.7, line 733
- ↑ src/detect.c in NetHack 3.6.7, line 589
- ↑ src/detect.c in NetHack 3.6.7, line 619
- ↑ src/detect.c in NetHack 3.6.7, line 630
- ↑ src/detect.c in NetHack 3.6.7, line 641
- ↑ src/detect.c in NetHack 3.6.7, line 655
- ↑ src/detect.c in NetHack 3.6.7, line 284: clear_stale_map()
- ↑ src/detect.c in NetHack 3.6.7, line 666: call from object_detect() if there were no stale markings to clear
- ↑ src/detect.c in NetHack 3.6.7, line 608
- ↑ src/detect.c in NetHack 3.6.7, line 648
- ↑ src/detect.c in NetHack 3.6.7, line 683
- ↑ src/detect.c in NetHack 3.6.7, line 702
- ↑ src/detect.c in NetHack 3.6.7, line 719
- ↑ src/detect.c in NetHack 3.6.7, line 744
- ↑ src/detect.c in NetHack 3.6.7, line 679
- ↑ src/detect.c in NetHack 3.6.7, line 762: temporary map navigation
- ↑ apply.c in NetHack 3.1.0, line 1315
- ↑ The NetHack Code 1.1, a resource used by players to communicate their precise playstyle for NetHack 3.1.3 and variants of the time
- ↑ u_init.c in SLASH'EM 0.0.7E7F2, line 66
- ↑ u_init.c in SLASH'EM 0.0.7E7F2, line 96
- ↑ u_init.c in SLASH'EM 0.0.7E7F2, line 137
- ↑ u_init.c in SLASH'EM 0.0.7E7F2, line 246
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