Attack speed
See Weapon Speed for tables summarising this information. This page goes into great detail about attack delay calculations.
When deciding between two different weapons, it can be helpful to understand exactly how attack speed works. Each physical attack in Crawl takes a certain amount of time. A character with a smaller attack delay will swing more frequently than a character with a larger attack delay. This can greatly multiply how often you can inflict damage in combat. So it is strongly recommended to get your attack delay as low as possible.
Contents
Attack Delay Calculations for Weapons and Missles
Base attack delay
All weapons, thrown objects, and launched objects have a base attack delay. You can find this information in game by examining the weapon or launcher. The base attack delay in game should be multiplied by 10 to give the delay in auts. The Weapon Speed page has a complete tables and includes thrown objects. It also lists the base delay in auts. For reference most species move and cast spells with a delay of 10 auts.
Minimum attack delay
By raising your skill with the weapon or launcher you can reduce attack delays to the minimum attack delay. The minimum delay is usually 1/2 the base delay rounded down. If this is greater than 7 then the minimum attack delay is set to 7. There are three exceptions to this rule:
- Short blades: The rapier with a base delay of 12 has a minimum delay of 5.
- All Crossbows have a minimum delay of 10.
- The Woodcutter's axe always has a delay of 10 irregardless of skills.
Skill adjustments
Weapon, launcher, or throwing skills brings down the attack delay by (skill level)/2 until you reach minimum weapon delay. Increasing your skill beyond that will not let you attack faster but it will slightly improve your damage and accuracy with the weapon. Normally you turn off your weapon skill when you hit minimum delay and dump experience points into increasing skills in other areas. The gods Ashenzari and Okawaru can increase your weapon skills and thus contribute to lowering your weapon delay.
Speed Brand
The speed brand further reduces the delay to 2/3 of the skill adjusted delay. With skill and speed brand improvements there is a hard coded minimum delay of 3.
Shield Penalties
Shields will slow down weapon speed. This slow down can be reduced by increasing your shield skill.
The detailed formula is 2*(shield encumberance)^2*(270-(10x shield skill))*scale/(5*(20-3*(size factor))/270.
The values for shield encumberance and size factor can be found on the shields page. The scale used in this formula is 20. The game does display the shield encumberance when describing the item, but it does not report the character size factor. Notice the shield penalty can be reduced to zero with a shield skill of 27.
God Given Abilities
The god Okawaru's Finesse ability will further cut the delay in half. Note that this will not stack with haste nor berserk.
Status modifiers
- Haste and berserk will further reduce the delay to 2/3 of its calculated value if you have not invoked Finesse. You cannot be both hasted and berserked.
- Statue Form, Petrifying, and Slowness will increase the delay to 3/2 of the calculated value. These status conditions do stack with haste resulting in a net cancellation of the two different statuses. Slowness can stack with both statue form and petrifying.
- In no case, will the delay be reduced below 2.
Unarmed Combat
Unarmed combat has a different attack delay calculation. It is 10-(unarmed combat skill)/54. You start with a delay of 10 with no unarmed combat skill and reach a minimum delay of 5 with an unarmed combat skill of 27. The shield penaties, god given abilities and status modifiers apply to unarmed combat as well.
Spells
Spells can be used for attacking and thus are included on this page. The base delay for casting a spell is 10. It can be modified by status modifiers but delay is not affected by skill, shields, or god abilities. An exception to this is the spell Manifold Assault. The delay of casting manifold assault is the calculated weapon or unarmed combat delay.
Movement Based Attacks
Some attacks are combined with movement. Even if the actual attack delay is not changed, they are mentioned here for completeness.
Martial Arts Attacks
The Wu Jian Council allows a player to make a number of different martial arts attacks. The number of attacks is based on the attack delay and the movement delay. The movement delay is:
- 10 if you have invoked the serpent's lash ability, or
- twice your movement delay if you have invoked the wall jump ability. (The wall jump ability takes two turns.)
- Otherwise your normal movement delay is used.
Your attack delay is the delay calculated in the previous sections. The number of attacks is the movement delay divided by the attack delay. If this is not an integer, the number of attacks could be rounded up or down. The number of attacks will average out to the non-integer number of attacks calculated. Extreme examples of the numbers of attacks would be a spriggan wielding a triple cross bow. With a movement delay of 6 and an attack delay of 23 the spriggan would only make one attack 6/23 of the time. The other extreme would be a naga wielding a quick blade with sufficient short blade skill. The naga's movement delay would be 14 and the weapon delay would be 3. For a wall jump which counts as two turns the expected number of attacks would be 28/3. So there could be 10 attacks 1/3 of the time.
- Note that the serpent's lash ability allows you to take two turns to make martial arts attacks without taking any time.
Charging Attacks
- The rampaging ego allows you to move towards a target and attack. The time taken is the attack delay and not the movement delay. Even a naga wielding a quick blade with sufficient short blade skill can move and attack a target with a delay of 3. Compare this with a naga's movement delay of 14.
- A palentonga's rolling charge allows you to move towards a target and attack. The time taken is the maximum of a movement delay or an attack delay.
Bolt Attacks
There are attacks that can hit multiple targets as you move through them like a bolt.
- Storm Form has the blink bolt ability to move through many targets at once doing damage to each.
- Uskayaw's line pass ability has the same properties.
Instintaneous attacks
Some spells and abilities let you appear somewhere else and immediately make an attack without any delay.
- Passwall takes time to set up on one side of a rock wall. But you appear on the other side and can attack without targets being able to react to you first. This is different than blink which moves you to a new location and then you stay there for the turn delay.
Detailed Calculations
The formulas above give you a very close approximation to the average attack delay. Most players can use the values above or the values on the weapon speed page without needing to know about the detailed calculations in this section.
Averaging Fractional Delays
Most calculations above can result in fractional delays. If you have a short sword with a base delay of 11 and a short blade skill of 5.7, the formula above would give you an average delay of 11-5.7/2 = 8.15. The game mechanics give you an average delay by rolling a delay of 8 85% of the time and a delay of 9 15% of the time. This is needed because all delays are integer values of auts.
Using Statistical Random Variables
The fractional delays do not give the entire story because each stage attack delay calculations involve creation of a new random variable. These random variables actually contain all possible integer delays and their weighted probabilities. This can result in a much wider range of attack delays than the averaging of fractional delays would imply. To complicate things, all calculations are done with a fixed precision. This is best explained by examples.
Example 1
Let's use the example of a human wielding a short sword and a buckler. The human has a short blade skill of 7.5 and a shield skill of 4. The buckler's encumberance is 5. The human size factor is zero and can be found on the shields page. There are three random variabls used.
- The first is the base delay of the short sword of 11 aut
- The second random variable encorporates the additional skill adjustment delay of -skill*10/scale = -75/20
- The third random variable encorporates the additional shield penalty delay of 8/20
- The final probabilities: delay=7 47.4%, delay=8 47.4%, delay=9 5.3%
| Delays| | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Explaination | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | Total Weight |
| Base delay short sword |
1 | 1 | |||||||
| Subtract Skill reduction 7.5*scale/20 |
15 | 5 | 20 | ||||||
| Add shield penalty 2*(5)^2*(270-(10*4))*20 |
15*12 | 15*8 + 5*12 | 5*8 | ||||||
| Shield Penalty Weights | 180 | 180 | 20 | 380 | |||||
- Note that there are three possible delays, not just two based upon one average
- A scale is used to create weights which avoids large integer division truncation inaccuracies
- A random number from 0-380 is created and a delay is selected based upon which bin the number would fall into.
References
History
- In 0.28, the penalty formula changed; before, certain skill thresholds (4 skill for buckler, 15 for kite shield, 25 for tower shield) negated it.
- In 0.27, the shield penalty was increased and was less random.
- Prior to 0.16, the amount of skill required to negate penalties for wearing a shield was more complex.
