Line of sight

Version 0.31: This article may not be up to date for the latest stable release of Crawl.

Line of sight (often abbreviated to LOS) refers to the portion of the Dungeon that you can see. Usually, you can only attack or be attacked by monsters inside your LOS.

Useful Info

The default LOS radius used by most species is out to 7 spaces, or a 15x15 square.

The following picture shows tiles within the default field of view with their grid distance.

777777777777777
766666666666667
765555555555567
765444444444567
765433333334567
765432222234567
765432111234567
7654321@1234567
765432111234567
765432222234567
765433333334567
765444444444567
765555555555567
766666666666667
777777777777777

There are a few ways to increase or reduce your line of sight:

• A scarf of shadows reduces LOS by 1.
• The Robe of Night reduces LOS by 25%, with your LOS rounded down.
• Kobolds start with rank 3 of Nightstalker, reducing LOS by 3 tiles to 4 spaces (9x9 square).
• Barachim have an innate mutation that increases their default LOS by 1, to a total of 8 spaces (17x17 square).

Line of sight is similar to, but distinct from, "line of effect" (i.e. the area of the Dungeon you may interact with). Most of the time, they are interchangeable, but some situations may result in places you can see but not affect (such as tiles behind transparent walls) or can affect but cannot see (such as Fireball's explosions hitting foes around corners).

Strategy

If you can't see them, they can't see you. With very few exceptions, enemies that can't see you can't attack you.

There are several ways to break your line of sight with an enemy:

• Teleporting/blinking out of range
• Closing doors
• Turning a corner
• Reading a scroll of fog
• Going up/down stairs or shafts
• Imprisoning them, or yourself
• Running away faster than they can chase you.

Because LOS is square, exploring in a diagonal direction will reveal more tiles than exploring in a cardinal one (all else equal). If you want to find an Abyss exit or uncover the most tiles for Human regeneration, move diagonally.

Attacking Outside LOS

Like monsters, most of your attacks cannot harm targets outside your LOS. For example, ranged weapons only shoot up to your LOS, your summons cannot attack if either them or their target are out of sight, and any clouds you create vanish when leaving sight. There are a few exceptions; an incomplete list is displayed below:

• Many types of "explosion" attacks: Damnation, Fireball, Fire Storm, Iceblast, Inner Flame, Lee's Rapid Deconstruction (cannot hit on the other side of a wall), tin of tremorstones.
• Certain types of allied/neutral monsters: Beogh orcs, charmed monsters, bribed monsters, frenzied monsters, Fedhas non-summoned non-stationary plants, humans from Kirke's band.
• Passive effects: poison and Sticky Flame.

Note that there is no way to attack an enemy from a different floor without entering it.

Being Attacked Outside LOS

When no targets are in their line of sight, monsters can still cast the following spells:

• Dig
• Major Healing
• Minor Healing

In addition, monsters can target your allies even if the monster itself is outside the player's line of sight. If a monster uses an explosion, area-of-effect, cloud, or other sort of 'lasting' attack, it can end up hitting you.

History

• Prior to 0.17, line of sight was circular, with a radius of about 8. You could see slightly less tiles overall, and saw much less in diagonal directions. Characters could reach their target in 5 squares (instead of 8) at certain angles.

Ranges were also circular; up to 2 tiles of range were lost when shooting diagonally. For example, Bolt of Fire could shoot 7 tiles in a cardinal direction, 5 in a diagonal one, and 6 in-between. Base ranges across the board were 1 higher than they are in current versions.

• Prior to 0.7, abilities and spells had rectangular ranges instead of circular ranges.

Changing LOS

• In 0.26, the LOS-reducing shadows ego was added, the Darkness spell was removed, and Nightstalker was changed from a potential Demonspawn mutation to a Kobold innate ability.
• In 0.20, Barachim and their unique +LOS mutation were added.
• Prior to 0.19, the Shadow card existed and could be used to further reduce the player's LOS.
• Prior to 0.18, the lantern of shadows existed and could be used to further reduce the player's LOS.