Energy randomisation

Trunk-only: This article pertains to a feature of Crawl which is being tested. It will likely change before the next release, and may even be removed entirely.

Energy randomisation (also called random energy or speed randomisation) is a game mechanic that makes monster movement unpredictable. Monsters normally get to take a number of monster turns per player turn based on their speed: fast monsters act more often, slow act less. When moving, this can be modified.

Useful Info

In 0.31, random energy only applies when a hostile monster moves towards a player that's moving away.

When this is the case, the monster has a 1/3 chance to move either +0.1 turn quicker, -0.1 turn slower, or at normal speed.

When a monster gets an attack of opportunity, it does not get random energy. Instead, it has a 1/2 chance to either get -0.1 turn, or move normally. This can be thought of as "negative random energy".

Concept of Energy

Specifically' a monster's actions are measured by "energy". Energy accumulates based off monster speed: a normal, 10-speed monster gets 10 energy / 1.0 decaAut, while a 20-speed monster gets 20 energy / 1.0 decaAut.

It normally takes 10 energy to do an action. Every action, monsters act only if they have enough energy.

• Say a 10-speed monster has 9 energy left over. It gains +10 energy per turn. If it gets +1 from "random energy", it has a total of 20 energy, allowing for 2 movements at once.
• Said monster is left at 0 energy. If it gets a -1 from random energy, it ends up at 9 energy - thus, it lags behind.

An incredibly lucky monster can get an extra turn every 10 rounds, but more often, it causes the move-twice, lag-behind pattern as shown above.

History

• In 0.31, energy randomisation will be re-introduced, with the intent to make attacks of opportunity less harsh. Compared to previous versions, it only happens when monsters pursue a player that's moving away.

Previously, monsters could move twice even when waiting, attacking, etc.

• Energy randomisation was removed in 0.29. Its anti-pillar dancing purpose was replaced with the much stricter attacks of opportunity.
• In 0.7, enemies can no longer spend a random energy turn in order to attack twice.
• Energy randomisation was first introduced in 0.6.