Dungeons: Generalise use, add capabilities, various modifications

- Generalise node names to c_wall and c_alt_wall
- Remove 'mossratio' and instead disable alt_wall loop if
  c_alt_wall == CONTENT_IGNORE
- Use one generalised 3D noise for alternative wall nodes and in
  mgv6 create moss distribution similar to the previous

- Rename rarity noise to density noise and enable the option of multiple
  dungeons per chunk determined by the value. Recreate previous distribution
- Add parameters for min and max rooms per dungeon
- Add dungeon y limits

- Integrate river water properly

Generalisation is needed now that we have sandstone and desert stone
dungeons by default and can choose any node for alternative structure.
The current code is based around cobble dungeons with mossycobble
alternative nodes, the 2 noises controlling the alternative nodes
are based on wetness.

Enabling multiple dungeons per chunk with definable number of rooms
allows the option of very dense and complex underground structures
that could interconnect to create megastructures.
Y limits are added to be consistent with other mapgen elements, and
enable locaton of dungeon or megastructure realms as part of our
'stacked realms' philosophy.

1 files changed, 52 insertions, 48 deletions

diff --git a/src/dungeongen.cpp b/src/dungeongen.cpp
index 6be7e9086..78573da04 100644
--- a/src/dungeongen.cpp
+++ b/src/dungeongen.cpp
@@ -30,9 +30,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 //#define DGEN_USE_TORCHES
 
-NoiseParams nparams_dungeon_rarity(0.0, 1.0, v3f(500.0, 500.0, 500.0), 0, 2, 0.8, 2.0);
-NoiseParams nparams_dungeon_wetness(0.0, 1.0, v3f(40.0, 40.0, 40.0), 32474, 4, 1.1, 2.0);
-NoiseParams nparams_dungeon_density(0.0, 1.0, v3f(2.5, 2.5, 2.5), 0, 2, 1.4, 2.0);
+NoiseParams nparams_dungeon_density(0.9, 0.5, v3f(500.0, 500.0, 500.0), 0, 2, 0.8, 2.0);
+NoiseParams nparams_dungeon_alt_wall(-0.4, 1.0, v3f(40.0, 40.0, 40.0), 32474, 6, 1.1, 2.0);
 
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -55,26 +54,27 @@ DungeonGen::DungeonGen(INodeDefManager *ndef,
 	} else {
 		dp.seed = 0;
 
-		dp.c_water  = ndef->getId("mapgen_water_source");
-		dp.c_cobble = ndef->getId("mapgen_cobble");
-		dp.c_moss   = ndef->getId("mapgen_mossycobble");
-		dp.c_stair  = ndef->getId("mapgen_stair_cobble");
+		dp.c_water       = ndef->getId("mapgen_water_source");
+		dp.c_river_water = ndef->getId("mapgen_river_water_source");
+		dp.c_wall        = ndef->getId("mapgen_cobble");
+		dp.c_alt_wall    = ndef->getId("mapgen_mossycobble");
+		dp.c_stair       = ndef->getId("mapgen_stair_cobble");
+
+		if (dp.c_river_water == CONTENT_IGNORE)
+			dp.c_river_water = ndef->getId("mapgen_water_source");
 
 		dp.diagonal_dirs = false;
-		dp.mossratio     = 3.0;
 		dp.holesize      = v3s16(1, 2, 1);
 		dp.roomsize      = v3s16(0, 0, 0);
+		dp.rooms_min     = 2;
+		dp.rooms_max     = 16;
+		dp.y_min         = -MAX_MAP_GENERATION_LIMIT;
+		dp.y_max         = MAX_MAP_GENERATION_LIMIT;
 		dp.notifytype    = GENNOTIFY_DUNGEON;
 
-		dp.np_rarity  = nparams_dungeon_rarity;
-		dp.np_wetness = nparams_dungeon_wetness;
-		dp.np_density = nparams_dungeon_density;
+		dp.np_density  = nparams_dungeon_density;
+		dp.np_alt_wall = nparams_dungeon_alt_wall;
 	}
-
-	// For mapgens using river water
-	dp.c_river_water = ndef->getId("mapgen_river_water_source");
-	if (dp.c_river_water == CONTENT_IGNORE)
-		dp.c_river_water = ndef->getId("mapgen_water_source");
 }
 
 
@@ -83,7 +83,11 @@ void DungeonGen::generate(MMVManip *vm, u32 bseed, v3s16 nmin, v3s16 nmax)
 	assert(vm);
 
 	//TimeTaker t("gen dungeons");
-	if (NoisePerlin3D(&dp.np_rarity, nmin.X, nmin.Y, nmin.Z, dp.seed) < 0.2)
+	if (nmin.Y < dp.y_min || nmax.Y > dp.y_max)
+		return;
+
+	float nval_density = NoisePerlin3D(&dp.np_density, nmin.X, nmin.Y, nmin.Z, dp.seed);
+	if (nval_density < 1.0f)
 		return;
 
 	this->vm = vm;
@@ -107,23 +111,23 @@ void DungeonGen::generate(MMVManip *vm, u32 bseed, v3s16 nmin, v3s16 nmax)
 		}
 	}
 
-	// Add it
-	makeDungeon(v3s16(1, 1, 1) * MAP_BLOCKSIZE);
+	// Add them
+	for (u32 i = 0; i < floor(nval_density); i++)
+		makeDungeon(v3s16(1, 1, 1) * MAP_BLOCKSIZE);
 
-	// Convert some cobble to mossy cobble
-	if (dp.mossratio != 0.0) {
-		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++) {
-				if (vm->m_data[i].getContent() == dp.c_cobble) {
-					float wetness = NoisePerlin3D(&dp.np_wetness, x, y, z, dp.seed);
-					float density = NoisePerlin3D(&dp.np_density, x, y, z, blockseed);
-					if (density < wetness / dp.mossratio)
-						vm->m_data[i].setContent(dp.c_moss);
-				}
-				i++;
+	// Optionally convert some structure to alternative structure
+	if (dp.c_alt_wall == CONTENT_IGNORE)
+		return;
+
+	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++) {
+			if (vm->m_data[i].getContent() == dp.c_wall) {
+				if (NoisePerlin3D(&dp.np_alt_wall, x, y, z, blockseed) > 0.0f)
+					vm->m_data[i].setContent(dp.c_alt_wall);
 			}
+			i++;
 		}
 	}
 
@@ -189,7 +193,7 @@ void DungeonGen::makeDungeon(v3s16 start_padding)
 	*/
 	v3s16 last_room_center = roomplace + v3s16(roomsize.X / 2, 1, roomsize.Z / 2);
 
-	u32 room_count = random.range(2, 16);
+	u32 room_count = random.range(dp.rooms_min, dp.rooms_max);
 	for (u32 i = 0; i < room_count; i++) {
 		// Make a room to the determined place
 		makeRoom(roomsize, roomplace);
@@ -265,7 +269,7 @@ void DungeonGen::makeDungeon(v3s16 start_padding)
 
 void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 {
-	MapNode n_cobble(dp.c_cobble);
+	MapNode n_wall(dp.c_wall);
 	MapNode n_air(CONTENT_AIR);
 
 	// Make +-X walls
@@ -278,7 +282,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 		{
 			v3s16 p = roomplace + v3s16(roomsize.X - 1, y, z);
@@ -287,7 +291,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 	}
 
@@ -301,7 +305,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 		{
 			v3s16 p = roomplace + v3s16(x, y, roomsize.Z - 1);
@@ -310,7 +314,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 	}
 
@@ -324,7 +328,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 		{
 			v3s16 p = roomplace + v3s16(x,roomsize. Y - 1, z);
@@ -333,7 +337,7 @@ void DungeonGen::makeRoom(v3s16 roomsize, v3s16 roomplace)
 			u32 vi = vm->m_area.index(p);
 			if (vm->m_flags[vi] & VMANIP_FLAG_DUNGEON_UNTOUCHABLE)
 				continue;
-			vm->m_data[vi] = n_cobble;
+			vm->m_data[vi] = n_wall;
 		}
 	}
 
@@ -417,7 +421,7 @@ void DungeonGen::makeCorridor(v3s16 doorplace, v3s16 doordir,
 				makeFill(p + v3s16(-1, -1, -1),
 					dp.holesize + v3s16(2, 3, 2),
 					VMANIP_FLAG_DUNGEON_UNTOUCHABLE,
-					MapNode(dp.c_cobble),
+					MapNode(dp.c_wall),
 					0);
 				makeHole(p);
 				makeHole(p - dir);
@@ -435,18 +439,18 @@ void DungeonGen::makeCorridor(v3s16 doorplace, v3s16 doordir,
 					int facedir = dir_to_facedir(dir * make_stairs);
 
 					u32 vi = vm->m_area.index(p.X - dir.X, p.Y - 1, p.Z - dir.Z);
-					if (vm->m_data[vi].getContent() == dp.c_cobble)
+					if (vm->m_data[vi].getContent() == dp.c_wall)
 						vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 
 					vi = vm->m_area.index(p.X, p.Y, p.Z);
-					if (vm->m_data[vi].getContent() == dp.c_cobble)
+					if (vm->m_data[vi].getContent() == dp.c_wall)
 						vm->m_data[vi] = MapNode(dp.c_stair, 0, facedir);
 				}
 			} else {
 				makeFill(p + v3s16(-1, -1, -1),
 					dp.holesize + v3s16(2, 2, 2),
 					VMANIP_FLAG_DUNGEON_UNTOUCHABLE,
-					MapNode(dp.c_cobble),
+					MapNode(dp.c_wall),
 					0);
 				makeHole(p);
 			}
@@ -488,8 +492,8 @@ bool DungeonGen::findPlaceForDoor(v3s16 &result_place, v3s16 &result_dir)
 			randomizeDir();
 			continue;
 		}
-		if (vm->getNodeNoExNoEmerge(p).getContent() == dp.c_cobble &&
-				vm->getNodeNoExNoEmerge(p1).getContent() == dp.c_cobble) {
+		if (vm->getNodeNoExNoEmerge(p).getContent() == dp.c_wall &&
+				vm->getNodeNoExNoEmerge(p1).getContent() == dp.c_wall) {
 			// Found wall, this is a good place!
 			result_place = p;
 			result_dir = m_dir;
@@ -502,7 +506,7 @@ bool DungeonGen::findPlaceForDoor(v3s16 &result_place, v3s16 &result_dir)
 		*/
 		// Jump one up if the actual space is there
 		if (vm->getNodeNoExNoEmerge(p +
-				v3s16(0, 0, 0)).getContent() == dp.c_cobble &&
+				v3s16(0, 0, 0)).getContent() == dp.c_wall &&
 				vm->getNodeNoExNoEmerge(p +
 				v3s16(0, 1, 0)).getContent() == CONTENT_AIR &&
 				vm->getNodeNoExNoEmerge(p +
@@ -510,7 +514,7 @@ bool DungeonGen::findPlaceForDoor(v3s16 &result_place, v3s16 &result_dir)
 			p += v3s16(0,1,0);
 		// Jump one down if the actual space is there
 		if (vm->getNodeNoExNoEmerge(p +
-				v3s16(0, 1, 0)).getContent() == dp.c_cobble &&
+				v3s16(0, 1, 0)).getContent() == dp.c_wall &&
 				vm->getNodeNoExNoEmerge(p +
 				v3s16(0, 0, 0)).getContent() == CONTENT_AIR &&
 				vm->getNodeNoExNoEmerge(p +