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PHP Perlin Noise Class
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<?php | |
//This is a port of Ken Perlin's "Improved Noise" | |
// http://mrl.nyu.edu/~perlin/noise/ | |
// Originally from http://therandomuniverse.blogspot.com/2007/01/perlin-noise-your-new-best-friend.html | |
// but the site appears to be down, so here is a mirror of it | |
class Perlin { | |
var $p, $permutation, $seed; | |
var $_default_size = 64; | |
function Perlin ($seed=NULL) { | |
//Initialize the permutation array. | |
$this->p = array(); | |
$this->permutation = array( 151,160,137,91,90,15, | |
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23, | |
190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33, | |
88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166, | |
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244, | |
102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196, | |
135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123, | |
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42, | |
223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9, | |
129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228, | |
251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107, | |
49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254, | |
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180 | |
); | |
//Populate it | |
for ($i=0; $i < 256 ; $i++) { | |
$this->p[256+$i] = $this->p[$i] = $this->permutation[$i]; | |
} | |
//And set the seed | |
if ($seed === NULL) $this->seed = time(); | |
else $this->seed = $seed; | |
} | |
function noise($x,$y,$z,$size=NULL) { | |
if ($size == NULL) $size = $this->_default_size; | |
//Set the initial value and initial size | |
$value = 0.0; $initialSize = $size; | |
//Add finer and finer hues of smoothed noise together | |
while($size >= 1) { | |
$value += $this->smoothNoise($x / $size, $y / $size, $z / $size) * $size; | |
$size /= 2.0; | |
} | |
//Return the result over the initial size | |
return $value / $initialSize; | |
} | |
//This function determines what cube the point passed resides in | |
//and determines its value. | |
function smoothNoise($x, $y, $z) { | |
//Offset each coordinate by the seed value | |
$x+=$this->seed; $y+=$this->seed; $z+=$this->seed; | |
$orig_x = $x; | |
$orig_y = $y; | |
$orig_z = $z; | |
$X1 = (int)floor($x) & 255; // FIND UNIT CUBE THAT | |
$Y1 = (int)floor($y) & 255; // CONTAINS POINT. | |
$Z1 = (int)floor($z) & 255; | |
$x -= floor($x); // FIND RELATIVE X,Y,Z | |
$y -= floor($y); // OF POINT IN CUBE. | |
$z -= floor($z); | |
$u = $this->fade($x); // COMPUTE FADE CURVES | |
$v = $this->fade($y); // FOR EACH OF X,Y,Z. | |
$w = $this->fade($z); | |
$A = $this->p[$X1]+$Y1; | |
$AA = $this->p[$A]+$Z1; | |
$AB = $this->p[$A+1]+$Z1; // HASH COORDINATES OF | |
$B = $this->p[$X1+1]+$Y1; | |
$BA = $this->p[$B]+$Z1; | |
$BB = $this->p[$B+1]+$Z1; // THE 8 CUBE CORNERS, | |
//Interpolate between the 8 points determined | |
$result = $this->lerp($w, $this->lerp($v, $this->lerp($u, $this->grad($this->p[$AA ], $x , $y , $z ), // AND ADD | |
$this->grad($this->p[$BA ], $x-1, $y , $z )), // BLENDED | |
$this->lerp($u, $this->grad($this->p[$AB ], $x , $y-1, $z ), // RESULTS | |
$this->grad($this->p[$BB ], $x-1, $y-1, $z ))),// FROM 8 | |
$this->lerp($v, $this->lerp($u, $this->grad($this->p[$AA+1], $x , $y , $z-1 ), // CORNERS | |
$this->grad($this->p[$BA+1], $x-1, $y , $z-1 )), // OF CUBE | |
$this->lerp($u, $this->grad($this->p[$AB+1], $x , $y-1, $z-1 ), | |
$this->grad($this->p[$BB+1], $x-1, $y-1, $z-1 )))); | |
return $result; | |
} | |
function fade($t) { | |
return $t * $t * $t * ( ( $t * ( ($t * 6) - 15) ) + 10); | |
} | |
function lerp($t, $a, $b) { | |
//Make a weighted interpolaton between points | |
return $a + $t * ($b - $a); | |
} | |
function grad($hash, $x, $y, $z) { | |
$h = $hash & 15; // CONVERT LO 4 BITS OF HASH CODE | |
$u = $h<8 ? $x : $y; // INTO 12 GRADIENT DIRECTIONS. | |
$v = $h<4 ? $y : ($h==12||$h==14 ? $x : $z); | |
return (($h&1) == 0 ? $u : -$u) + (($h&2) == 0 ? $v : -$v); | |
} | |
//This function I've added. It creates one dimension of noise. | |
function random1D($x) { | |
if ($size === NULL) $size = $this->_default_size; | |
$x += $this->seed; | |
$value = 0.0; $initialSize = $size = 3; | |
while($size >= 1){ | |
$value += $this->smoothNoise($x*3 / $size, 100 / $size, 100 / $size); | |
$size--; | |
} | |
if ($value < -1) $value = -1; | |
if ($value > 1) $value = 1; | |
return $value; | |
} | |
//Same as random1D() only for 2 dimensions. | |
function random2D($x,$y) { | |
if ($size === NULL) $size = $this->_default_size; | |
$x += $this->seed; | |
$y += $this->seed; | |
$value = 0.0; $initialSize = $size = 3; | |
while($size >= 1) { | |
$value += $this->smoothNoise($x*3 / $size, $y*3 / $size, 100 / $size); | |
$size--; | |
} | |
if ($value < -1) $value = -1; | |
if ($value > 1) $value = 1; | |
return $value; | |
} | |
} | |
/* | |
//This is a small test snippet that will output an example with DIV tags. | |
//Feel free to fiddle with it. | |
$bob = new Perlin(2000); | |
$size = 1; | |
$smooth = 42; | |
$gridsize = 125; | |
for($y=0; $y<$gridsize; $y+=1) { | |
for($x=0; $x<$gridsize; $x+=1) { | |
$num = $bob->noise($x,$y,0,$smooth); | |
$raw = ($num/2)+.5; | |
//if ($num == 0) $raw = 0; | |
//else $raw = 1/abs( $num ); | |
//$raw = pow((5*$raw)-4,3)+.5; | |
//$raw = 1-pow(50 * ($raw - 1), 2); | |
//if ($raw > .9) $raw = 1; | |
//else $raw = 0; | |
if ($raw < 0) $raw = 0; | |
$num = dechex( $raw*255 ); | |
if (strlen($num) < 2) $num = "0".$num; | |
echo ' | |
'; | |
} | |
} | |
//*/ | |
/* | |
$bob = new Perlin(1); | |
$place = 0; | |
//for ($i=0; $i<100000; $i+=100) { | |
for ($i=0; $i<1000; $i++) { | |
$num = round(($bob->random1D($i)/2)+.5,2); | |
echo $num.' | |
'; | |
echo ''; | |
$place++; | |
} | |
//*/ |
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