Difference between revisions of "Vision"

Revision as of 15:40, 1 October 2021

Introduction

In the character sheet for an entity, there are several stats related to vision that determine whether or no that entity can see certain tiles or other characters.

• Light radius
• Vision range
• Heightened Senses / Infravision
• Stealth
• See stealth
• Invisibility
• See invisibility
• Telepathy Range
• Telepathy

Also, terrain may have 3 different states that will affect what you may or may not see.

A tile may be:

• Lit: These tiles are lit by the sun, or through magically field, and do not hinder your sight.
• Unlit: You may not see these tiles unless your lite reaches to it (determined by your light radius).
• Covered in magical darkness: Blocks all vision and light, can be only lit up with Sun Infusion and certain artifacts.

Similarly, there are several stats that help you hide from your enemies:

• Stealth
• Invisibility
• Blindness

Light Radius

How far your light reaches. Tiles within this range and line of sight will receive the lit status.

Vision Range

This is how far your normal vision for lit tiles can reach. You cannot see entities farther than this distance even if they are reached by your lite. Most actors will have a vision range of 10.

Entities that fall under your normal vision will be marked as "in sight", and this condition is check by many talents.

In order for unknown terrain to be permanently revealed, the tile must be lit and fall under your normal vision once.

Heightened Senses / Infravision

Allows you to see creatures standing in unlit tiles within a certain radius and your line of sight.

This effectively lights up the tile that the creature is standing on, showing items on the ground and any effects in the tile too.

Even though a tile may be temporarily lit with infravision, this does not technically reveal the terrain. As a result, ranged attacks may not take the correct path to the target. For example, if an enemy is poking their head out from behind a corner that you are not aware of, and you can only see the enemy with infravision, then your ranged attack could end up hitting that corner. You must see a tile with normal vision in order for the terrain to be permanently revealed.

Seeing Stealth or Invisible Entities

The following information is an interpretation of the game code from ..\tome.team\mod\class\Actor.lua and ..\tome.team\mod\class\interface\Combat.lua, based on how stealth and invisibility checks appear to use the checkHitOld function

The chance for a character to see another one hiding under stealth or invisibility is determined by the following variables and formula:

Note: see stealth appears to be a rescaled stat, whereas see invisibility is not.

S: seeing power, the number given for "see stealth" or "see invisibility" in the character sheet of the observer

H: hiding power, the number given for "stealth" or "invisibility" in the character sheet of the hider

See Chance = (A + B) * 50%

A = 1 / ( 1 + exp( (H - S) / 7 ) )

B = S / ( S + H )

The table in the image below shows the percentage see chance, given the seeing power in the first column, and the hiding power in the first row:

Observers with zero "see invisible" power will not be able to see invisible entities at all, and will not even get a chance to participate in the invisibility check.

Observers with zero "see stealth" power can still can still participate in the stealth check, and will see stealthed entities with the chance shown in the table above. This situation can occur if the observer is significantly debuffed.

If the hiding entity is both stealthed and invisible, then the observer will have to pass both a stealth and invisibility check in order to see the hider.

Trivia: the A term is a Fermi-Dirac distribution

Telepathy

Allows you to perceive certain kinds of creatures with your mind, and light them up like infravision.

Diggable walls, doors, blindness, invisibility or magical darkness do not affect telepathy. Undiggable walls, such as those surrounding vaults, may block telepathy.

Talents related to vision

• Stealth: grants stealth power
• Invisibility: grants invisibility power
• Ethereal Rune: grants invisibility power
• Heightened Senses: increase see stealth and see invisibility
• Overseer of Nations: increase vision range
• Shadow Shot: decrease vision range
• Chant Adept: increase light radius
• Hymn Adept: increase infravision
• Armour of Shadows: make tiles unlit
• Vision: reveals terrain
• Smoke Bomb: blocks line of sight
• Creeping Darkness: blocks line of sight
• Dark Vision: see through magical darkness

Artifacts related to vision

• Umbraphage: turn tiles lit
• Burning Star: reveals terrain