Improved logic of persistence

A1essandro · May 16, 2016 · 82b612f · 82b612f
1 parent cdfd0b7
commit 82b612f
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Showing 2 changed files with 4 additions and 2 deletions.
diff --git a/demo/visual.php b/demo/visual.php
@@ -6,7 +6,7 @@
 
 $size = 8;
 
-$gen->setPersistence(200);
+$gen->setPersistence(1.8);
 $gen->setSize($size);
 $gen->setMapSeed(uniqid());
 $map = $gen->generate();

diff --git a/src/DiamondAndSquare.php b/src/DiamondAndSquare.php
@@ -242,7 +242,9 @@ private function diamond($x, $y, $size, $offset)
      */
     private function getOffset($stepSize)
     {
-        return (float)$stepSize / $this->size * mt_rand(-$this->getPersistence() / 2, $this->getPersistence() / 2);
+        $stepOffset = $stepSize / $this->size * mt_rand(-$this->size, $this->size);
+        $sign = $stepOffset < 0 ? -1 : 1;
+        return $sign * pow(abs($stepOffset), 1 / sqrt($this->getPersistence()));
     }
 
     /**