Dice distribution

Handy library written off Amit Patel's RedBlob Game blog post Probability and Games: Damage Rolls

This library is my implementation (mostly 1:1 I would say) of a few handy functionalities about dice distribution. I highly reccomend heading over the blog post to read out the full thing.

Installation

Download the libray and require it in you code

local dd = require('dicedistribution')

Function

reseed(seed)

(Re)Seed the system. seed parameter is optional, the default is os.time()

roll(dice, shift)

Roll a single dice up to dice (maximum number), optionally shifted by shift.

-- roll a single d6
dd.roll(6)

-- roll a single d6 and add 1
dd.roll(6, 1)

rollMaxOf(dice, times, shift)

Roll a single dice times time and choose the maximum, optionally shifted by shift.

-- roll 3 times a single d6 and choose the maximum of the three
dd.rollMaxOf(6, 3)

-- roll 3 times a single d6 and choose the maximum of the three and add 1
dd.rollMaxOf(6, 3, 1)

rollMinOf(dice, times, shift)

Roll a single dice times time and choose the minimum, optionally shifted by shift.

-- roll 3 times a single d6 and choose the minimum of the three
dd.rollMinOf(6, 3)

-- roll 3 times a single d6 and choose the minimum of the three and add 1
dd.rollMinOf(6, 3, 1)

rolls(dice, times, shift)

Rolls a number of dice, optionally shifted by shift and return a table with the values.

-- roll 3 times a single d6 and return a table
dd.rolls(6, 3)

-- returns {x1, x2, x3}

`rollsMaxOf(dice, times, rolls, shift)

Rolls times times a dice, each roll several rolls times of which choosing the maximum and return the table of values. Optionally shifted by shift.

-- Roll a d6 2 times, choose the maximum: three times
dd.rollsMaxOf(6, 3, 2)

-- Roll a d6 2 times, choose the maximum and add 1: three times
dd.rollsMaxOf(6, 3, 2, 1)

rollsMinOf(dice, times, rolls, shift)

Rolls times times a dice, each roll several rolls times of which choosing the minimum and return the table of values. Optionally shifted by shift.

-- Roll a d6 2 times, choose the minimum: three times
dd.rollsMinOf(6, 3, 2)

-- Roll a d6 2 times, choose the minimum and add 1: three times
dd.rollsMinOf(6, 3, 2, 1)

rollsAndSum(dice, times, shift)

Same as rolls, but return the sum of the rolls instead.

rollsMaxOfAndSum

Same as rollsMaxOf, but return the sum of the rolls instead.

rollsMinOfAndSum

Same as rollsMinOf, but return the sum of the rolls instead.

custom_distribution(distribution)

Roll a dice from a custom distribution. The distribution is a table in the following format: {{weight1,value1}, ... ,{weight1,value1}}

local distribution = {{50, 1}, {50, 2}}

dd.custom_distribution(distribution)
-- return 50% 1 and 50% 2

Similar

I actually remember after coding this there is something already out there, checkout 8bitskull/dicebag.