diff --git a/Generator/AdvNoiseGen.cs b/Generator/AdvNoiseGen.cs
index a57395984..5d1a3ac6e 100644
--- a/Generator/AdvNoiseGen.cs
+++ b/Generator/AdvNoiseGen.cs
@@ -21,22 +21,19 @@ using LibNoise;
 
 namespace MCGalaxy.Generator {
     public static class AdvNoiseGen {
-        
-        static Dictionary<string, Action<MapGenArgs>> generators
-            = new Dictionary<string, Action<MapGenArgs>>{
-            { "billow", GenBillow2D }, { "ridgedmultifractal", GenRidged2D },
-            { "perlin", GenPerlin2D }, { "checkerboard", GenCheckerboard },
-            { "spheres", GenSpheres }, { "cylinders", GenCylinders },
-            { "voronoi", GenVoronoi }, { "perlin3d", GenPerlin3D },
-            { "perlin3dyadjust", GenPerlin3DYAdjust }, { "billow3d", GenBillow3D }
-        };
 
-        public static bool Generate(MapGenArgs args) {
-            Action<MapGenArgs> generator;
-            generators.TryGetValue(args.Type, out generator);
-            if (generator != null) generator(args);
-            return generator != null;
-        } 
+        public static void RegisterGenerators() {
+            MapGen.RegisterAdvancedGen("billow", GenBillow2D);
+            MapGen.RegisterAdvancedGen("ridgedmultifractal", GenRidged2D);
+            MapGen.RegisterAdvancedGen("perlin", GenPerlin2D);
+            MapGen.RegisterAdvancedGen("checkerboard", GenCheckerboard);          
+            MapGen.RegisterAdvancedGen("spheres", GenSpheres);
+            MapGen.RegisterAdvancedGen("cylinders", GenCylinders);
+            MapGen.RegisterAdvancedGen("voronoi", GenVoronoi);            
+            MapGen.RegisterAdvancedGen("perlin3d", GenPerlin3D);
+            MapGen.RegisterAdvancedGen("perlin3dyadjust", GenPerlin3DYAdjust);
+            MapGen.RegisterAdvancedGen("billow3d", GenBillow3D);
+        }
         
         
         #region Implementations
diff --git a/Generator/MapGen.cs b/Generator/MapGen.cs
index f3453cbfa..e72027a77 100644
--- a/Generator/MapGen.cs
+++ b/Generator/MapGen.cs
@@ -22,42 +22,59 @@ namespace MCGalaxy.Generator {
     
     public struct MapGenArgs {
         public Level Level;
-        public string Type, RawArgs;
+        public string Theme, RawArgs;
         public bool UseSeed;
         public int Seed;
     }
     
     public static class MapGen {
+        
         public static bool IsRecognisedTheme(string s) {
             s = s.ToLower();
-            return Array.IndexOf<string>(types, s) >= 0 || Array.IndexOf<string>(advTypes, s) >= 0;
+            return simpleGens.ContainsKey(s) || advGens.ContainsKey(s);
         }
         
-        static string[] types = { "island", "mountains", "forest", "ocean", "flat",
-            "pixel", "empty", "desert", "space", "rainbow", "hell" };
-        static string[] advTypes = { "billow", "perlin", "checkerboard", "spheres", "cylinders",
-            "voronoi", "ridgedmultifractal", "perlin3d", "perlin3dyadjust" };
-
         public static void PrintThemes(Player p) {
-            Player.Message(p, "Simple themes: " + String.Join(", ", types));
-            Player.Message(p, "Advanced themes: " + String.Join(", ", advTypes));
+            Player.Message(p, "Simple themes: " + simpleGens.Keys.Concatenate(", "));
+            Player.Message(p, "Advanced themes: " + advGens.Keys.Concatenate(", "));
         }
         
         public static bool OkayAxis(int len) {
             return len >= 16 && len <= 8192 && (len % 16) == 0;
         }
 
-        public unsafe static void Generate(Level lvl, string type, string args) {
+        public static bool Generate(Level lvl, string theme, string args) {
             MapGenArgs genArgs = new MapGenArgs();
-            genArgs.Level = lvl; genArgs.Type = type;
+            genArgs.Level = lvl; genArgs.Theme = theme;
             genArgs.RawArgs = args;
             
             genArgs.UseSeed = args != "";
             if (genArgs.UseSeed && !int.TryParse(args, out genArgs.Seed))
                 genArgs.Seed = args.GetHashCode();
+            Action<MapGenArgs> generator = null;
             
-            if (!SimpleGen.Generate(genArgs))
-                AdvNoiseGen.Generate(genArgs);
+            simpleGens.TryGetValue(theme, out generator);
+            if (generator != null) { generator(genArgs); return true; }
+            advGens.TryGetValue(theme, out generator);
+            if (generator != null) { generator(genArgs); return true; }
+            return false;
+        }
+        
+        
+        static Dictionary<string, Action<MapGenArgs>> simpleGens, advGens;        
+        public static void RegisterSimpleGen(string theme, Action<MapGenArgs> gen) {
+            simpleGens[theme.ToLower()] = gen;
+        }
+        
+        public static void RegisterAdvancedGen(string theme, Action<MapGenArgs> gen) {
+            advGens[theme.ToLower()] = gen;
+        }
+        
+        static MapGen() {
+            simpleGens = new Dictionary<string, Action<MapGenArgs>>();
+            advGens = new Dictionary<string, Action<MapGenArgs>>();
+            SimpleGen.RegisterGenerators();
+            AdvNoiseGen.RegisterGenerators();
         }
     }
 }
diff --git a/Generator/SimpleGen.cs b/Generator/SimpleGen.cs
index 41b2843ba..ec7843540 100644
--- a/Generator/SimpleGen.cs
+++ b/Generator/SimpleGen.cs
@@ -20,25 +20,21 @@ using System.Collections.Generic;
 
 namespace MCGalaxy.Generator { 
     public static class SimpleGen {
-        
-        static Dictionary<string, Action<MapGenArgs>> generators
-            = new Dictionary<string, Action<MapGenArgs>>{
-            { "island", GenSimple }, { "mountains", GenSimple },
-            { "forest", GenSimple }, { "ocean", GenSimple }, 
-            { "flat", GenFlat }, { "pixel", GenPixel },
-            { "empty", GenEmpty }, { "desert", GenSimple },
-            { "space", GenSpace }, { "rainbow", GenRainbow }, 
-            { "hell", GenHell },
-        };
-        
-        public static bool Generate(MapGenArgs args) {
-            Action<MapGenArgs> generator;
-            generators.TryGetValue(args.Type, out generator);
-            if (generator != null) generator(args);
-            return generator != null;
+
+        public static void RegisterGenerators() {
+            MapGen.RegisterSimpleGen("island", GenSimple);
+            MapGen.RegisterSimpleGen("mountains", GenSimple);
+            MapGen.RegisterSimpleGen("forest", GenSimple);
+            MapGen.RegisterSimpleGen("ocean", GenSimple);            
+            MapGen.RegisterSimpleGen("flat", GenFlat);
+            MapGen.RegisterSimpleGen("pixel", GenPixel);
+            MapGen.RegisterSimpleGen("empty", GenEmpty);            
+            MapGen.RegisterSimpleGen("desert", GenSimple);
+            MapGen.RegisterSimpleGen("space", GenSpace);
+            MapGen.RegisterSimpleGen("rainbow", GenRainbow);
+            MapGen.RegisterSimpleGen("hell", GenHell);
         }
         
-        
         unsafe static void GenFlat(MapGenArgs args) {
             Level lvl = args.Level;
             int grassHeight = lvl.Height / 2;
@@ -154,7 +150,7 @@ namespace MCGalaxy.Generator {
         
         static void GenSimple(MapGenArgs args) {
             RealisticMapGen gen = new RealisticMapGen();
-            gen.GenerateMap(args.Level, args.Type, args.Seed, args.UseSeed);
+            gen.GenerateMap(args.Level, args.Theme, args.Seed, args.UseSeed);
         }
     }
 }