Array of all RGB permutations in PHP - php

Question

I am trying to make an array of all the possible colours made out of RGB values. Every permutation between r=0 b=0 g=0 to r=255 b=255 g=255. The idea of my function is that when it's called you supply a limit number so that the function returns an array of RGB values up to this number to stop it returning all 16 million. The code I have below returns 767 permutations (256 * 3) how do I get this to return the full 16 million up to the limit number I provide?
function colourArray($number) {
$r = 0;
$g = 0;
$b = 0;
$i = 0;
while ($i <= $number) {
$colours[] = array($r,$g,$b);
$r++;
$i++;
}
$i = 0;
while ($i <= $number) {
$colours[] = array($r,$g,$b);
$g++;
$i++;
}
$i = 0;
while ($i <= $number) {
$colours[] = array($r,$g,$b);
$b++;
$i++;
}
return $colours;
}

Answer 1

Nesting your loops is the trick. Try the following example. I've replaced your while-loops by foreach-loops with the PHP range function, and nested (i.e. loop-inside-a-loop) them inside eachother:
function colourArray($number) {
$colours = array();
foreach(range(0,$number) as $r) {
foreach(range(0,$number) as $g) {
foreach(range(0,$number) as $b) {
$colours[] = array($r,$g,$b);
}
}
}
return $colours;
}
References:
http://php.net/range
http://php.net/manual/en/control-structures.foreach.php

Answer 2

I almost agree with DickW, but I'm partial to for() loops for numeric ranges.
<?php
function color_array($range)
{
$result = array();
for ($r = 0; $r <= $range; $r++) {
for ($g = 0; $g <= $range; $g++) {
for ($b = 0; $b <= $range; $b++) {
$result[] = array($r, $g, $b);
}
}
}
return $result;
}
print_r(color_array(5));