Improved performance

Author: Reputeless

PerlinNoise.cpp

@@ -14,14 +14,14 @@ PerlinNoise::PerlinNoise( unsigned seed )
 		seed = std::mt19937::default_seed;
 	}
 
-	// "permutation" contains all numbers in [0..255] in random order
-	std::array<int,256> permutation;		
-	std::iota(permutation.begin(),permutation.end(),0);
-	std::shuffle(permutation.begin(),permutation.end(),std::mt19937(seed));
+	// p[0]..p[255] contains all numbers in [0..255] in random order		
+	std::iota(std::begin(p),std::begin(p)+256,0);
+	
+	std::shuffle(std::begin(p),std::begin(p)+256,std::mt19937(seed));
 
 	for(int i=0; i<256; ++i)
 	{
-		p[256+i] = p[i] = permutation[i];
+		p[256+i] = p[i];
 	}
 }