Dungeongen: Remove floating frames

Preserves the rare unbroken protruding dungeons
Fix random range for first room roomplace
Fix checked volume for first room 'fits' bool
and check for 'untouchable' flag instead of 'inside'
Remove 'enable floating dungeons' setting

minetest.conf.example

@@ -516,18 +516,19 @@
 #    Mapgen stuff
 #
 
-#    Name of map generator to be used.  Currently supported: v5, v6, v7, singlenode.
+#    Name of map generator to be used.
+#    Currently supported: v5, v6, v7, singlenode.
 #mg_name = v6
 #    Water surface level of map
 #water_level = 1
 #    Size of chunks to be generated, stated in mapblocks (16 nodes)
 #chunksize = 5
-#    Global map generation attributes.  Currently supported: trees, caves, flat, dungeons, light.
+#    Global map generation attributes.
+#    Currently supported: trees, caves, flat, dungeons, light.
 #    Flags that are not specified in the flag string are not modified from the default.
 #    To explicitly turn off a flag, prepend "no" to the beginning, e.g. nolight.
+#    'trees' and 'flat' flags only have effect in mgv6.
 #mg_flags = trees, caves, dungeons, light
-#    Enable/disable floating dungeons and dungeon slices
-#enable_floating_dungeons = true
 
 #    Map generation attributes specific to Mapgen V6.
 #    Currently supported: jungles, biomeblend, mudflow, snowbiomes.
@@ -540,11 +541,13 @@
 
 #    Map generation attributes specific to Mapgen V7.
 #    Currently supported: mountains, ridges.
+#    'ridges' are the rivers.
 #mgv7_spflags = mountains, ridges
 
 #    Perlin noise attributes for different map generation parameters.
 #    Noise parameters can be specified as a set of positional values:
 #    Offset, scale, (spread factors), seed offset, number of octaves, persistence, lacunarity.
+#    For example:
 #mgv6_np_terrain_base = -4, 20, (250, 250, 250), 82341, 5, 0.6, 2.0
 #    Or the new group format can be used instead, for example:
 #mgv6_np_terrain_base = {

src/defaultsettings.cpp

@@ -312,7 +312,6 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("chunksize", "5");
 	settings->setDefault("mg_flags", "dungeons");
 	settings->setDefault("mgv6_spflags", "jungles, snowbiomes");
-	settings->setDefault("enable_floating_dungeons", "true");
 
 	// IPv6
 	settings->setDefault("enable_ipv6", "true");

src/dungeongen.cpp

@@ -80,17 +80,14 @@ void DungeonGen::generate(u32 bseed, v3s16 nmin, v3s16 nmax)
 	// Dungeon generator doesn't modify places which have this set
 	vm->clearFlag(VMANIP_FLAG_DUNGEON_INSIDE | VMANIP_FLAG_DUNGEON_PRESERVE);
 
-	bool no_float = !g_settings->getBool("enable_floating_dungeons");
-
-	// Set all air and water (and optionally ignore) to be untouchable
+	// Set all air and water to be untouchable
 	// to make dungeons open to caves and open air
 	for (s16 z = nmin.Z; z <= nmax.Z; z++) {
 		for (s16 y = nmin.Y; y <= nmax.Y; y++) {
 			u32 i = vm->m_area.index(nmin.X, y, z);
 			for (s16 x = nmin.X; x <= nmax.X; x++) {
 				content_t c = vm->m_data[i].getContent();
-				if (c == CONTENT_AIR || c == dp.c_water ||
-						(no_float && c == CONTENT_IGNORE))
+				if (c == CONTENT_AIR || c == dp.c_water)
 					vm->m_flags[i] |= VMANIP_FLAG_DUNGEON_PRESERVE;
 				i++;
 			}
@@ -141,21 +138,21 @@ void DungeonGen::makeDungeon(v3s16 start_padding)
 		// start_padding is used to disallow starting the generation of
 		// a dungeon in a neighboring generation chunk
 		roomplace = vm->m_area.MinEdge + start_padding + v3s16(
-			random.range(0, areasize.X - roomsize.X - 1 - start_padding.X),
-			random.range(0, areasize.Y - roomsize.Y - 1 - start_padding.Y),
-			random.range(0, areasize.Z - roomsize.Z - 1 - start_padding.Z));
+			random.range(0, areasize.X - roomsize.X - start_padding.X),
+			random.range(0, areasize.Y - roomsize.Y - start_padding.Y),
+			random.range(0, areasize.Z - roomsize.Z - start_padding.Z));
 
 		/*
 			Check that we're not putting the room to an unknown place,
 			otherwise it might end up floating in the air
 		*/
 		fits = true;
-		for (s16 z = 1; z < roomsize.Z - 1; z++)
-		for (s16 y = 1; y < roomsize.Y - 1; y++)
-		for (s16 x = 1; x < roomsize.X - 1; x++) {
+		for (s16 z = 0; z < roomsize.Z; z++)
+		for (s16 y = 0; y < roomsize.Y; y++)
+		for (s16 x = 0; x < roomsize.X; x++) {
 			v3s16 p = roomplace + v3s16(x, y, z);
 			u32 vi = vm->m_area.index(p);
-			if ((vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_INSIDE) ||
+			if ((vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE) ||
 					vm->m_data[vi].getContent() == CONTENT_IGNORE) {
 				fits = false;
 				break;