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Revision as of 16:52, 6 October 2012 by Game Hunter (Talk | contribs)

Accuracy is important for two separate but connected actions in AliensRL: hitting an enemy and dealing damage to said enemy. Unlike many games, which keep the two actions completely disjoined and involve different properties for their calculations, accuracy governs both whether or not you hit an enemy and how much damage you deal to that enemy.


Melee Attacks

Melee attacks ignore accuracy calculations entirely and hit 100% of the time. See the article on aliens to learn how much damage these attacks deal.

Ranged Weapons


Roll Outcomes, by Rating
Rating Roll Value Percent Chance
-100 1-2 2%
-3 3-5 3%
-2 6-10 5%
-1 11-30 30%
0 31-70 40%
+1 71-90 30%
+2 91-95 5%
+3 96-98 3%
+100 99-100 2%

First and foremost, the accuracy of a shot depends on a random d100 roll. This roll's outcome is then categorized into more sizable "roll ratings" that are part of the calculation. These ratings can be found in the table on the right. (Lower ratings are better for the purposes of accuracy.)

Next, the "skill rating" of the attack is determined. This is done in the following steps:

  • Begin with a rating of 1.
  • Check the weapon type of the weapon being fired.
    • If there are no ranks invested in that weapon type's skill, subtract 1 from the rating.
    • If there are ranks invested in that weapon type's skill, add the number of skill ranks to the rating. (Basic is 1, advanced is 2, expert is 3, and master is 4.)
  • Reduce the rating by the amount of pain currently inflicted on the player (e.g., "Pain (-3)" reduces the rating by 3).
  • Add the weapon's accuracy to the rating.
  • Check the distance from you to your target. (This is measured using the Angband metric: add the long axis by half the short axis and round down.)
    • Take this distance, subtract five, and divide the result by three (rounding down). If it is greater than zero, reduce the rating by this value. (As a formula: rating = rating - max( floor(distance-5) / 3), 0)
    • If this distance is less than four, subtract it from four and reduce the rating by this result (i.e., rating = rating - (4 - distance)).
Damage Quality, by Description
Description Quality Damage Dealt
barely scratched 1 10%
barely hit 2-3 20-30%
lightly hit 4-5 40-50%
hit 6-7 60-70%
heavily hit 8-9 80-90%
perfectly hit 10 100%
critically hit 11 200%

Finally, subtract the roll rating from the skill rating. This is the quality of the accuracy, and can be no less than 1 and no more than 10 (if the subtraction would lead to a value less than 1, set it equal to 1; similar with values greater than 10). Quality determines the most significant part of damage from the attack: a single "point" of quality is equal to one-tenth the damage value indicated by the weapon's ammo type. Thus, a quality of 1 deals 10% damage and a quality of 10 deals 100% damage. The exception to quality is a "critical hit", and is automatically granted if the roll rating is equal to -100. In this case, the quality is set to 11, and the attack deals 200% damage. See the table on the right to identify qualities (and therefore damage amounts) by an attack's description.

Hit Chance

To begin, all shots that are fired in the direction of the targeted square that also land on the targeted square will hit: this is an absolute certainty. The main concern for hit chance, then, is whether or not a projectile strays from its intended target. This stray chance depends primarily on two factors:

  • Accuracy ratings (see the above section on how to find these ratings). Namely, if the difference between roll rating and the skill rating is positive, the shot is allowed to stray: otherwise, the shot stays on target and the next factor is ignored.
  • Distance (from the player to the targeted square). If this value is at least 5, then the shot strays randomly to any adjacent square; if this value is at least 9, the shot strays randomly to any square two tiles away.

It is important to note that a stray shot is the same thing as the target square being relocated. This distinction is necessary because all shots that hit a being that isn't in the targeted square automatically have a 6-in-10 chance to miss entirely. This counts not only for shots that stray and happen to hit a being, but also for shots that stay on target but approach a being before reaching the targeted square.

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