Add mapgen descriptions

src/mapgen/mapgen.cpp

@@ -62,6 +62,7 @@ const FlagDesc flagdesc_gennotify[] = {
 struct MapgenDesc {
 	const char *name;
 	bool is_user_visible;
+	const char *description;
 };
 
 ////
@@ -75,14 +76,14 @@ struct MapgenDesc {
 // Of the remaining, v5 last due to age, v7 first due to being the default.
 // The order of 'enum MapgenType' in mapgen.h must match this order.
 static MapgenDesc g_reg_mapgens[] = {
-	{"v7",         true},
-	{"valleys",    true},
-	{"carpathian", true},
-	{"v5",         true},
-	{"flat",       true},
-	{"fractal",    true},
-	{"singlenode", true},
-	{"v6",         true},
+	{"v7",         true,	"Default mapgen with large complex mountins and plains."},
+	{"valleys",    true,	"Large valleys with complex terrain and rivers."},
+	{"carpathian", true,	"Realistic looking world with vast plains."},
+	{"v5",         true,	"Old mapgen."},
+	{"flat",       true,	"World Flat terrain."},
+	{"fractal",    true,	"Wold with fractal structure."},
+	{"singlenode", true,	"Empty world, use for lua defined mapgens."},
+	{"v6",         true,	"Simple mapgen with few features, not recommended."},
 };
 
 static_assert(
@@ -207,6 +208,14 @@ void Mapgen::getMapgenNames(std::vector<const char *> *mgnames, bool include_hid
 	}
 }
 
+void Mapgen::getMapgenDescriptions(std::vector<const char *> *mgdescriptions, bool include_hidden)
+{
+	for (u32 i = 0; i != ARRLEN(g_reg_mapgens); i++) {
+		if (include_hidden || g_reg_mapgens[i].is_user_visible)
+			mgdescriptions->push_back(g_reg_mapgens[i].description);
+	}
+}
+
 void Mapgen::setDefaultSettings(Settings *settings)
 {
 	settings->setDefault("mg_flags", flagdesc_mapgen,