GDScript utility functions

utils.gd

# add this as a singleton and access functions using
# util.<function_name>

extends Node

# choose a random item from an array
static func rand_choice(list):
    return list[randi() % list.size()]
	
# choose a random integer in range (start, end-1)
static func rand_int(start, end):
    return start + randi() % (end - start)
    
# Perform the Fisher–Yates shuffle dance to magically unsort given array
static func shuffle(array):
    var size = array.size()
    for i in range(size - 1):
        swap(array, i, rand_int(i, size))
    return array

# Swap items of index i and j in given array
static func swap(array, i, j):
    var tmp = array[i]
    array[i] = array[j]
    array[j] = tmp
    return array
    
static func weighted_rand(weights):
    # returns a random choice weighted by the given array
    # ex: weights = [75,20,5] (3 items, ordered)
    
    # sum up the weights
    var sum = 0
    for weight in weights:
        sum += weight
    # select a random number
    var num = rand_range(0, sum)
    # loop through weights
    for i in range(weights.size()):
        if num < weights[i]:
            return weights[i]
	num -= weights[i]