Add Seed function

simplex.lua

@@ -539,4 +539,21 @@ function simplex.Turbulence(func, direction, iter, ...)
     return math.sin(dir_component+ret)
 end
 
-return simplex
+function simplex.Seed(seed)
+    math.randomseed(seed)
+    local integers = {}
+    perm = {}
+    for i = 1, 256 do
+        integers[i] = i
+    end
+    while next(integers) do
+        perm[#perm + 1] = table.remove(integers, math.random(1, #integers))
+    end
+    perm[0] = perm[#perm]
+    perm[#perm] = nil
+    for i=0,255 do
+        perm[i+256] = perm[i]
+    end
+end
+
+return simplex