--- deliantra/server/common/noise.C	2011/04/23 04:56:46	1.5
+++ deliantra/server/common/noise.C	2011/04/23 05:42:11	1.6
@@ -25,6 +25,7 @@
 /////////////////////////////////////////////////////////////////////////////
 
 // http://www-wales.ch.cam.ac.uk/~wales/CCD/Thomson/table.html, random permutation
+// used as gradient vectors for noise3d
 static const float charges[256][3] = {
   6.32096444e-01, -6.11406706e-01, 4.76062943e-01, 5.19172442e-01, 8.08229585e-01, -2.77893708e-01,
   -8.81072422e-01, -4.68301230e-01, 6.63727731e-02, -1.92122323e-01, 9.81341519e-01, -7.60505942e-03,
@@ -156,6 +157,25 @@
   -3.07350590e-01, -9.14677987e-01, 2.62487703e-01, 5.60298616e-01, 1.74821302e-01, 8.09631381e-01,
 };
 
+/////////////////////////////////////////////////////////////////////////////
+
+template<int N, typename T>
+template<class random_generator>
+void
+permutation<N,T>::seed (random_generator &rng)
+{
+  for (int i = 0; i < N; ++i)
+    pmap[i] = i;
+
+  // fisher-yates to randomly perturb
+  for (int i = N; --i; )
+    ::swap (pmap[i], pmap[rng (i + 1)]);
+}
+
+template class permutation<256, uint8_t>;
+
+/////////////////////////////////////////////////////////////////////////////
+
 static vec2d
 floor (vec2d v)
 {
@@ -172,7 +192,7 @@
 {
   seedable_rand_gen rng (seed);
 
-#if 1
+#if 0
   for (int i = 0; i < 256; ++i)
     {
       vec2d rv (rng () - 0.5f, rng () - 0.5f);
@@ -187,12 +207,12 @@
     }
 #endif
 
-#if 0
-  float offset = rng () * 3.14159265;
+#if 1
+  float offset = rng () * M_PI;
 
   for (int i = 0; i < 256; ++i)
     {
-      float phi = i * (3.14159265 * 2 / 256) + offset;
+      float phi = i * (M_PI * 2 / 256) + offset;
 
       rvec[i][0] =  sinf (phi);
       rvec[i][1] = -cosf (phi);