Sample non-overlapping circles from a uniform square - useful for initialization of multiple objects

nonoverlapping_random_circles.sh

#!/bin/bash

function draw_uniform {
  # generates a random float in [a b)
  a=$1
  b=$2
  echo "$((a+RANDOM%(b-a))).$((RANDOM%999))"
}

function sample_circle {
  x = draw_uniform $1 $2
  y = draw_uniform $3 $4
}

n=20
r=0.75
w=30
h=30

circles_x=()
circles_y=()

while [ ${#circles_x[@]} -lt $n ]; do
    # Sample a new circle
    x=$(draw_uniform "-$w" $w)
    y=$(draw_uniform "-$h" $h)

    # Compare where the new circle is w.r.t the old circles 
    for i in "${!circles_x[@]}"; do
        # calculate distance from center of new circle to this circle
        dx=$(echo "$x - ${circles_x[$i]}" | bc)
        dy=$(echo "$y - ${circles_y[$i]}" | bc)
        d=$(echo "scale=4;sqrt($dx * $dx + $dy * $dy)" | bc)
            
        # skip if it is too close to previously sampled circles
        if (( $(echo "$d < 2 * $r" | bc -l)  )); then
            continue
        fi  
    done

    # If we've made it here, this circle does not overlap
    circles_x+=($x)
    circles_y+=($y)
done

echo "${circles_x[@]}"
echo "${circles_y[@]}"