Mgv6: Add optional snow biomes

2 files changed, 190 insertions, 107 deletions

diff --git a/src/mapgen_v6.cpp b/src/mapgen_v6.cpp
index 612ea82b4..92b9c7af4 100644
--- a/src/mapgen_v6.cpp
+++ b/src/mapgen_v6.cpp
@@ -42,6 +42,7 @@ FlagDesc flagdesc_mapgen_v6[] = {
 	{"jungles",    MGV6_JUNGLES},
 	{"biomeblend", MGV6_BIOMEBLEND},
 	{"mudflow",    MGV6_MUDFLOW},
+	{"snowbiomes", MGV6_SNOWBIOMES},
 	{NULL,         0}
 };
 
@@ -73,7 +74,10 @@ MapgenV6::MapgenV6(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	noise_height_select  = new Noise(&sp->np_height_select,  seed, csize.X, csize.Y);
 	noise_mud            = new Noise(&sp->np_mud,            seed, csize.X, csize.Y);
 	noise_beach          = new Noise(&sp->np_beach,          seed, csize.X, csize.Y);
-	noise_biome          = new Noise(&sp->np_biome,          seed, csize.X, csize.Y);
+	noise_biome          = new Noise(&sp->np_biome,          seed,
+			csize.X + 2 * MAP_BLOCKSIZE, csize.Y + 2 * MAP_BLOCKSIZE);
+	noise_humidity       = new Noise(&sp->np_humidity,       seed,
+			csize.X + 2 * MAP_BLOCKSIZE, csize.Y + 2 * MAP_BLOCKSIZE);
 
 	//// Resolve nodes to be used
 	INodeDefManager *ndef = emerge->ndef;
@@ -88,6 +92,11 @@ MapgenV6::MapgenV6(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	c_cobble          = ndef->getId("mapgen_cobble");
 	c_desert_sand     = ndef->getId("mapgen_desert_sand");
 	c_desert_stone    = ndef->getId("mapgen_desert_stone");
+	c_dirt_with_snow  = ndef->getId("mapgen_dirt_with_snow");
+	c_snow            = ndef->getId("mapgen_snow");
+	c_snowblock       = ndef->getId("mapgen_snowblock");
+	c_ice             = ndef->getId("mapgen_ice");
+
 	c_mossycobble     = ndef->getId("mapgen_mossycobble");
 	c_sandbrick       = ndef->getId("mapgen_sandstonebrick");
 	c_stair_cobble    = ndef->getId("mapgen_stair_cobble");
@@ -116,6 +125,7 @@ MapgenV6::~MapgenV6()
 	delete noise_mud;
 	delete noise_beach;
 	delete noise_biome;
+	delete noise_humidity;
 
 	delete[] heightmap;
 }
@@ -127,17 +137,17 @@ MapgenV6Params::MapgenV6Params()
 	freq_desert = 0.45;
 	freq_beach  = 0.15;
 
-	np_terrain_base   = NoiseParams(-4,  20.0, v3f(250.0, 250.0, 250.0), 82341,  5, 0.6, 2.0);
-	np_terrain_higher = NoiseParams(20,  16.0, v3f(500.0, 500.0, 500.0), 85039,  5, 0.6, 2.0);
-	np_steepness      = NoiseParams(0.85,0.5,  v3f(125.0, 125.0, 125.0), -932,   5, 0.7, 2.0);
-	np_height_select  = NoiseParams(0,   1.0,  v3f(250.0, 250.0, 250.0), 4213,   5, 0.69, 2.0);
-	np_mud            = NoiseParams(4,   2.0,  v3f(200.0, 200.0, 200.0), 91013,  3, 0.55, 2.0);
-	np_beach          = NoiseParams(0,   1.0,  v3f(250.0, 250.0, 250.0), 59420,  3, 0.50, 2.0);
-	np_biome          = NoiseParams(0,   1.0,  v3f(250.0, 250.0, 250.0), 9130,   3, 0.50, 2.0);
-	np_cave           = NoiseParams(6,   6.0,  v3f(250.0, 250.0, 250.0), 34329,  3, 0.50, 2.0);
-	np_humidity       = NoiseParams(0.5, 0.5,  v3f(500.0, 500.0, 500.0), 72384,  4, 0.66, 2.0);
-	np_trees          = NoiseParams(0,   1.0,  v3f(125.0, 125.0, 125.0), 2,      4, 0.66, 2.0);
-	np_apple_trees    = NoiseParams(0,   1.0,  v3f(100.0, 100.0, 100.0), 342902, 3, 0.45, 2.0);
+	np_terrain_base   = NoiseParams(-4,   20.0, v3f(250.0, 250.0, 250.0), 82341,  5, 0.6,  2.0);
+	np_terrain_higher = NoiseParams(20,   16.0, v3f(500.0, 500.0, 500.0), 85039,  5, 0.6,  2.0);
+	np_steepness      = NoiseParams(0.85, 0.5,  v3f(125.0, 125.0, 125.0), -932,   5, 0.7,  2.0);
+	np_height_select  = NoiseParams(0,    1.0,  v3f(250.0, 250.0, 250.0), 4213,   5, 0.69, 2.0);
+	np_mud            = NoiseParams(4,    2.0,  v3f(200.0, 200.0, 200.0), 91013,  3, 0.55, 2.0);
+	np_beach          = NoiseParams(0,    1.0,  v3f(250.0, 250.0, 250.0), 59420,  3, 0.50, 2.0);
+	np_biome          = NoiseParams(0,    1.0,  v3f(250.0, 250.0, 250.0), 9130,   3, 0.50, 2.0);
+	np_cave           = NoiseParams(6,    6.0,  v3f(250.0, 250.0, 250.0), 34329,  3, 0.50, 2.0);
+	np_humidity       = NoiseParams(0.5,  0.5,  v3f(500.0, 500.0, 500.0), 72384,  4, 0.66, 2.0);
+	np_trees          = NoiseParams(0,    1.0,  v3f(125.0, 125.0, 125.0), 2,      4, 0.66, 2.0);
+	np_apple_trees    = NoiseParams(0,    1.0,  v3f(100.0, 100.0, 100.0), 342902, 3, 0.45, 2.0);
 }
 
 
@@ -194,10 +204,8 @@ s16 MapgenV6::find_stone_level(v2s16 p2d)
 	s16 y;
 
 	for (y = y_nodes_max; y >= y_nodes_min; y--) {
-		MapNode &n = vm->m_data[i];
-		content_t c = n.getContent();
-		if (c != CONTENT_IGNORE && (
-			c == c_stone || c == c_desert_stone))
+		content_t c = vm->m_data[i].getContent();
+		if (c != CONTENT_IGNORE && (c == c_stone || c == c_desert_stone))
 			break;
 
 		vm->m_area.add_y(em, i, -1);
@@ -214,7 +222,7 @@ bool MapgenV6::block_is_underground(u64 seed, v3s16 blockpos)
 	// Nah, this is just a heuristic, just return something
 	s16 minimum_groundlevel = water_level;
 
-	if(blockpos.Y*MAP_BLOCKSIZE + MAP_BLOCKSIZE <= minimum_groundlevel)
+	if(blockpos.Y * MAP_BLOCKSIZE + MAP_BLOCKSIZE <= minimum_groundlevel)
 		return true;
 	else
 		return false;
@@ -266,7 +274,7 @@ float MapgenV6::baseTerrainLevelFromNoise(v2s16 p)
 							p.X, 0.5, p.Y, 0.5, seed);
 
 	return baseTerrainLevel(terrain_base, terrain_higher,
-							steepness,    height_select);
+							steepness, height_select);
 }
 
 
@@ -288,7 +296,7 @@ float MapgenV6::baseTerrainLevelFromMap(int index)
 	float height_select  = noise_height_select->result[index];
 
 	return baseTerrainLevel(terrain_base, terrain_higher,
-							steepness,    height_select);
+							steepness, height_select);
 }
 
 
@@ -322,7 +330,8 @@ bool MapgenV6::getHaveBeach(v2s16 p)
 
 BiomeV6Type MapgenV6::getBiome(v2s16 p)
 {
-	int index = (p.Y - node_min.Z) * ystride + (p.X - node_min.X);
+	int index = (p.Y - full_node_min.Z) * (ystride + 2 * MAP_BLOCKSIZE)
+			+ (p.X - full_node_min.X);
 	return getBiome(index, p);
 }
 
@@ -334,7 +343,9 @@ float MapgenV6::getHumidity(v2s16 p)
 		seed+72384, 4, 0.66);
 	noise = (noise + 1.0)/2.0;*/
 
-	float noise = NoisePerlin2D(np_humidity, p.X, p.Y, seed);
+	int index = (p.Y - full_node_min.Z) * (ystride + 2 * MAP_BLOCKSIZE)
+			+ (p.X - full_node_min.X);
+	float noise = noise_humidity->result[index];
 
 	if (noise < 0.0)
 		noise = 0.0;
@@ -355,7 +366,7 @@ float MapgenV6::getTreeAmount(v2s16 p)
 	if (noise < zeroval)
 		return 0;
 	else
-		return 0.04 * (noise-zeroval) / (1.0-zeroval);
+		return 0.04 * (noise - zeroval) / (1.0 - zeroval);
 }
 
 
@@ -404,22 +415,44 @@ BiomeV6Type MapgenV6::getBiome(int index, v2s16 p)
 			seed+9130, 3, 0.50);*/
 
 	float d = noise_biome->result[index];
-	if (d > freq_desert)
-		return BT_DESERT;
-
-	if ((spflags & MGV6_BIOMEBLEND) &&
-		(d > freq_desert - 0.10) &&
-		((noise2d(p.X, p.Y, seed) + 1.0) > (freq_desert - d) * 20.0))
-		return BT_DESERT;
-
-	return BT_NORMAL;
+	float h = noise_humidity->result[index];
+
+	if (spflags & MGV6_SNOWBIOMES) {
+		float blend = (spflags & MGV6_BIOMEBLEND) ? noise2d(p.X, p.Y, seed) / 40 : 0;
+
+		if (d > FREQ_HOT + blend) {
+			if (h > FREQ_JUNGLE + blend)
+				return BT_JUNGLE;
+			else
+				return BT_DESERT;
+		} else if (d < FREQ_SNOW + blend) {
+			if (h > FREQ_TAIGA + blend)
+				return BT_TAIGA;
+			else
+				return BT_TUNDRA;
+		} else {
+			return BT_NORMAL;
+		}
+	} else {
+		if (d > freq_desert)
+			return BT_DESERT;
+
+		if ((spflags & MGV6_BIOMEBLEND) && (d > freq_desert - 0.10) &&
+				((noise2d(p.X, p.Y, seed) + 1.0) > (freq_desert - d) * 20.0))
+			return BT_DESERT;
+
+		if ((spflags & MGV6_JUNGLES) && h > 0.75)
+			return BT_JUNGLE;
+		else
+			return BT_NORMAL;
+	}
 }
 
 
 u32 MapgenV6::get_blockseed(u64 seed, v3s16 p)
 {
-	s32 x=p.X, y=p.Y, z=p.Z;
-	return (u32)(seed%0x100000000ULL) + z*38134234 + y*42123 + x*23;
+	s32 x = p.X, y = p.Y, z = p.Z;
+	return (u32)(seed % 0x100000000ULL) + z * 38134234 + y * 42123 + x * 23;
 }
 
 
@@ -446,14 +479,14 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 	v3s16 blockpos_max = data->blockpos_max;
 
 	// Area of central chunk
-	node_min = blockpos_min*MAP_BLOCKSIZE;
-	node_max = (blockpos_max+v3s16(1,1,1))*MAP_BLOCKSIZE-v3s16(1,1,1);
+	node_min = blockpos_min * MAP_BLOCKSIZE;
+	node_max = (blockpos_max + v3s16(1, 1, 1)) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 
 	// Full allocated area
-	full_node_min = (blockpos_min-1)*MAP_BLOCKSIZE;
-	full_node_max = (blockpos_max+2)*MAP_BLOCKSIZE-v3s16(1,1,1);
+	full_node_min = (blockpos_min - 1) * MAP_BLOCKSIZE;
+	full_node_max = (blockpos_max + 2) * MAP_BLOCKSIZE - v3s16(1, 1, 1);
 
-	central_area_size = node_max - node_min + v3s16(1,1,1);
+	central_area_size = node_max - node_min + v3s16(1, 1, 1);
 	assert(central_area_size.X == central_area_size.Z);
 
 	int volume_blocks = (blockpos_max.X - blockpos_min.X + 1)
@@ -511,17 +544,7 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 		dp.np_density = nparams_dungeon_density;
 		dp.np_wetness = nparams_dungeon_wetness;
 		dp.c_water = c_water_source;
-		if (getBiome(0, v2s16(node_min.X, node_min.Z)) == BT_NORMAL) {
-			dp.c_cobble  = c_cobble;
-			dp.c_moss    = c_mossycobble;
-			dp.c_stair   = c_stair_cobble;
-
-			dp.diagonal_dirs = false;
-			dp.mossratio  = 3.0;
-			dp.holesize   = v3s16(1, 2, 1);
-			dp.roomsize   = v3s16(0, 0, 0);
-			dp.notifytype = GENNOTIFY_DUNGEON;
-		} else {
+		if (getBiome(0, v2s16(node_min.X, node_min.Z)) == BT_DESERT) {
 			dp.c_cobble  = c_sandbrick;
 			dp.c_moss    = c_sandbrick; // should make this 'cracked sandstone' later
 			dp.c_stair   = c_stair_sandstone;
@@ -531,6 +554,16 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 			dp.holesize   = v3s16(2, 3, 2);
 			dp.roomsize   = v3s16(2, 5, 2);
 			dp.notifytype = GENNOTIFY_TEMPLE;
+		} else {
+			dp.c_cobble  = c_cobble;
+			dp.c_moss    = c_mossycobble;
+			dp.c_stair   = c_stair_cobble;
+
+			dp.diagonal_dirs = false;
+			dp.mossratio  = 3.0;
+			dp.holesize   = v3s16(1, 2, 1);
+			dp.roomsize   = v3s16(0, 0, 0);
+			dp.notifytype = GENNOTIFY_DUNGEON;
 		}
 
 		DungeonGen dgen(this, &dp);
@@ -540,7 +573,7 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 	// Add top and bottom side of water to transforming_liquid queue
 	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 
-	// Grow grass
+	// Add surface nodes
 	growGrass();
 
 	// Generate some trees, and add grass, if a jungle
@@ -565,6 +598,8 @@ void MapgenV6::calculateNoise()
 {
 	int x = node_min.X;
 	int z = node_min.Z;
+	int fx = full_node_min.X;
+	int fz = full_node_min.Z;
 
 	if (!(flags & MG_FLAT)) {
 		noise_terrain_base->perlinMap2D_PO(x, 0.5, z, 0.5);
@@ -575,7 +610,11 @@ void MapgenV6::calculateNoise()
 	}
 
 	noise_beach->perlinMap2D_PO(x, 0.2, z, 0.7);
-	noise_biome->perlinMap2D_PO(x, 0.6, z, 0.2);
+
+	noise_biome->perlinMap2D_PO(fx, 0.6, fz, 0.2);
+	noise_humidity->perlinMap2D_PO(fx, 0.0, fz, 0.0);
+	// Humidity map does not need range limiting 0 to 1,
+	// only humidity at point does
 }
 
 
@@ -584,9 +623,10 @@ int MapgenV6::generateGround()
 	//TimeTaker timer1("Generating ground level");
 	MapNode n_air(CONTENT_AIR), n_water_source(c_water_source);
 	MapNode n_stone(c_stone), n_desert_stone(c_desert_stone);
+	MapNode n_ice(c_ice);
 	int stone_surface_max_y = -MAP_GENERATION_LIMIT;
-	u32 index = 0;
 
+	u32 index = 0;
 	for (s16 z = node_min.Z; z <= node_max.Z; z++)
 	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
 		// Surface height
@@ -596,7 +636,7 @@ int MapgenV6::generateGround()
 		if (surface_y > stone_surface_max_y)
 			stone_surface_max_y = surface_y;
 
-		BiomeV6Type bt = getBiome(index, v2s16(x, z));
+		BiomeV6Type bt = getBiome(v2s16(x, z));
 
 		// Fill ground with stone
 		v3s16 em = vm->m_area.getExtent();
@@ -605,10 +645,12 @@ int MapgenV6::generateGround()
 			if (vm->m_data[i].getContent() == CONTENT_IGNORE) {
 				if (y <= surface_y) {
 					vm->m_data[i] = (y >= DESERT_STONE_BASE
-								&& bt == BT_DESERT) ?
+							&& bt == BT_DESERT) ?
 						n_desert_stone : n_stone;
 				} else if (y <= water_level) {
-					vm->m_data[i] = n_water_source;
+					vm->m_data[i] = (y >= ICE_BASE
+							&& bt == BT_TUNDRA) ?
+						n_ice : n_water_source;
 				} else {
 					vm->m_data[i] = n_air;
 				}
@@ -642,7 +684,7 @@ void MapgenV6::addMud()
 		if (surface_y == vm->m_area.MinEdge.Y - 1)
 			continue;
 
-		BiomeV6Type bt = getBiome(index, v2s16(x, z));
+		BiomeV6Type bt = getBiome(v2s16(x, z));
 		addnode = (bt == BT_DESERT) ? n_desert_sand : n_dirt;
 
 		if (bt == BT_DESERT && surface_y + mud_add_amount <= water_level + 1) {
@@ -650,25 +692,25 @@ void MapgenV6::addMud()
 		} else if (mud_add_amount <= 0) {
 			mud_add_amount = 1 - mud_add_amount;
 			addnode = n_gravel;
-		} else if (bt == BT_NORMAL && getHaveBeach(index) &&
+		} else if (bt != BT_DESERT && getHaveBeach(index) &&
 				surface_y + mud_add_amount <= water_level + 2) {
 			addnode = n_sand;
 		}
 
-		if (bt == BT_DESERT && surface_y > 20)
+		if ((bt == BT_DESERT || bt == BT_TUNDRA) && surface_y > 20)
 			mud_add_amount = MYMAX(0, mud_add_amount - (surface_y - 20) / 5);
 
-		// If topmost node is grass, change it to mud.  It might be if it was
+		/* If topmost node is grass, change it to mud.  It might be if it was
 		// flown to there from a neighboring chunk and then converted.
 		u32 i = vm->m_area.index(x, surface_y, z);
 		if (vm->m_data[i].getContent() == c_dirt_with_grass)
-			vm->m_data[i] = n_dirt;
+			vm->m_data[i] = n_dirt;*/
 
 		// Add mud on ground
 		s16 mudcount = 0;
 		v3s16 em = vm->m_area.getExtent();
 		s16 y_start = surface_y + 1;
-		i = vm->m_area.index(x, y_start, z);
+		u32 i = vm->m_area.index(x, y_start, z);
 		for (s16 y = y_start; y <= node_max.Y; y++) {
 			if (mudcount >= mud_add_amount)
 				break;
@@ -685,10 +727,10 @@ void MapgenV6::addMud()
 void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 {
 	// 340ms @cs=8
-	TimeTaker timer1("flow mud");
+	//TimeTaker timer1("flow mud");
 
 	// Iterate a few times
-	for(s16 k = 0; k < 3; k++) {
+	for (s16 k = 0; k < 3; k++) {
 		for (s16 z = mudflow_minpos; z <= mudflow_maxpos; z++)
 		for (s16 x = mudflow_minpos; x <= mudflow_maxpos; x++) {
 			// Invert coordinates every 2nd iteration
@@ -704,18 +746,16 @@ void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 			u32 i = vm->m_area.index(p2d.X, node_max.Y, p2d.Y);
 			s16 y = node_max.Y;
 
-			while(y >= node_min.Y)
-			{
+			while (y >= node_min.Y) {
 
-			for(;; y--)
-			{
+			for (;; y--) {
 				MapNode *n = NULL;
 				// Find mud
-				for(; y >= node_min.Y; y--) {
+				for (; y >= node_min.Y; y--) {
 					n = &vm->m_data[i];
 					if (n->getContent() == c_dirt ||
-						n->getContent() == c_dirt_with_grass ||
-						n->getContent() == c_gravel)
+							n->getContent() == c_dirt_with_grass ||
+							n->getContent() == c_gravel)
 						break;
 
 					vm->m_area.add_y(em, i, -1);
@@ -727,8 +767,7 @@ void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 					break;
 
 				if (n->getContent() == c_dirt ||
-					n->getContent() == c_dirt_with_grass)
-				{
+						n->getContent() == c_dirt_with_grass) {
 					// Make it exactly mud
 					n->setContent(c_dirt);
 
@@ -737,20 +776,20 @@ void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 						u32 i2 = i;
 						vm->m_area.add_y(em, i2, -1);
 						// Cancel if out of area
-						if(vm->m_area.contains(i2) == false)
+						if (vm->m_area.contains(i2) == false)
 							continue;
 						MapNode *n2 = &vm->m_data[i2];
 						if (n2->getContent() != c_dirt &&
-							n2->getContent() != c_dirt_with_grass)
+								n2->getContent() != c_dirt_with_grass)
 							continue;
 					}
 				}
 
 				v3s16 dirs4[4] = {
-					v3s16(0,0,1), // back
-					v3s16(1,0,0), // right
-					v3s16(0,0,-1), // front
-					v3s16(-1,0,0), // left
+					v3s16(0, 0, 1), // back
+					v3s16(1, 0, 0), // right
+					v3s16(0, 0, -1), // front
+					v3s16(-1, 0, 0), // left
 				};
 
 				// Check that upper is air or doesn't exist.
@@ -758,11 +797,11 @@ void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 				u32 i3 = i;
 				vm->m_area.add_y(em, i3, 1);
 				if (vm->m_area.contains(i3) == true &&
-					ndef->get(vm->m_data[i3]).walkable)
+						ndef->get(vm->m_data[i3]).walkable)
 					continue;
 
 				// Drop mud on side
-				for(u32 di=0; di<4; di++) {
+				for(u32 di = 0; di < 4; di++) {
 					v3s16 dirp = dirs4[di];
 					u32 i2 = i;
 					// Move to side
@@ -788,7 +827,7 @@ void MapgenV6::flowMud(s16 &mudflow_minpos, s16 &mudflow_maxpos)
 						n2 = &vm->m_data[i2];
 						// if out of known area
 						if(vm->m_area.contains(i2) == false ||
-							n2->getContent() == CONTENT_IGNORE) {
+								n2->getContent() == CONTENT_IGNORE) {
 							dropped_to_unknown = true;
 							break;
 						}
@@ -857,21 +896,22 @@ void MapgenV6::placeTreesAndJungleGrass()
 			node_min.Z + sidelen + sidelen * z0 - 1
 		);
 
-		// Amount of trees, jungle area
-		u32 tree_count = area * getTreeAmount(p2d_center);
+		// Get biome at center position of part of division
+		BiomeV6Type bt = getBiome(p2d_center);
 
-		float humidity;
-		bool is_jungle = false;
-		if (spflags & MGV6_JUNGLES) {
-			humidity = getHumidity(p2d_center);
-			if (humidity > 0.75) {
-				is_jungle = true;
+		// Amount of trees
+		u32 tree_count;
+		if (bt == BT_JUNGLE || bt == BT_TAIGA || bt == BT_NORMAL) {
+			tree_count = area * getTreeAmount(p2d_center);
+			if (bt == BT_JUNGLE)
 				tree_count *= 4;
-			}
+		} else {
+			tree_count = 0;
 		}
 
 		// Add jungle grass
-		if (is_jungle) {
+		if (bt == BT_JUNGLE) {
+			float humidity = getHumidity(p2d_center);
 			u32 grass_count = 5 * humidity * tree_count;
 			for (u32 i = 0; i < grass_count; i++) {
 				s16 x = grassrandom.range(p2d_min.X, p2d_max.X);
@@ -900,24 +940,27 @@ void MapgenV6::placeTreesAndJungleGrass()
 			s16 y = heightmap[mapindex];
 			// Don't make a tree under water level
 			// Don't make a tree so high that it doesn't fit
-			if(y < water_level || y > node_max.Y - 6)
+			if (y < water_level || y > node_max.Y - 6)
 				continue;
 
-			v3s16 p(x,y,z);
+			v3s16 p(x, y, z);
 			// Trees grow only on mud and grass
 			{
 				u32 i = vm->m_area.index(p);
-				MapNode *n = &vm->m_data[i];
-				if (n->getContent() != c_dirt &&
-					n->getContent() != c_dirt_with_grass)
+				content_t c = vm->m_data[i].getContent();
+				if (c != c_dirt &&
+						c != c_dirt_with_grass &&
+						c != c_dirt_with_snow)
 					continue;
 			}
 			p.Y++;
 
 			// Make a tree
-			if (is_jungle) {
+			if (bt == BT_JUNGLE) {
 				treegen::make_jungletree(*vm, p, ndef, myrand());
-			} else {
+			} else if (bt == BT_TAIGA) {
+				treegen::make_pine_tree(*vm, p, ndef, myrand());
+			} else if (bt == BT_NORMAL) {
 				bool is_apple_tree = (myrand_range(0, 3) == 0) &&
 							getHaveAppleTree(v2s16(x, z));
 				treegen::make_tree(*vm, p, is_apple_tree, ndef, myrand());
@@ -928,32 +971,54 @@ void MapgenV6::placeTreesAndJungleGrass()
 }
 
 
-void MapgenV6::growGrass()
+void MapgenV6::growGrass() // Add surface nodes
 {
+	MapNode n_dirt_with_grass(c_dirt_with_grass);
+	MapNode n_dirt_with_snow(c_dirt_with_snow);
+	MapNode n_snowblock(c_snowblock);
+	MapNode n_snow(c_snow);
+	v3s16 em = vm->m_area.getExtent();
+
+	u32 index = 0;
 	for (s16 z = full_node_min.Z; z <= full_node_max.Z; z++)
-	for (s16 x = full_node_min.X; x <= full_node_max.X; x++) {
+	for (s16 x = full_node_min.X; x <= full_node_max.X; x++, index++) {
 		// Find the lowest surface to which enough light ends up to make
 		// grass grow.  Basically just wait until not air and not leaves.
 		s16 surface_y = 0;
 		{
-			v3s16 em = vm->m_area.getExtent();
 			u32 i = vm->m_area.index(x, node_max.Y, z);
 			s16 y;
 			// Go to ground level
 			for (y = node_max.Y; y >= full_node_min.Y; y--) {
 				MapNode &n = vm->m_data[i];
 				if (ndef->get(n).param_type != CPT_LIGHT ||
-					ndef->get(n).liquid_type != LIQUID_NONE)
+						ndef->get(n).liquid_type != LIQUID_NONE ||
+						n.getContent() == c_ice)
 					break;
 				vm->m_area.add_y(em, i, -1);
 			}
 			surface_y = (y >= full_node_min.Y) ? y : full_node_min.Y;
 		}
 
+		BiomeV6Type bt = getBiome(index, v2s16(x, z));
 		u32 i = vm->m_area.index(x, surface_y, z);
-		MapNode *n = &vm->m_data[i];
-		if (n->getContent() == c_dirt && surface_y >= water_level - 20)
-			n->setContent(c_dirt_with_grass);
+		content_t c = vm->m_data[i].getContent();
+		if (surface_y >= water_level - 20) {
+			if (bt == BT_TAIGA && c == c_dirt) {
+				vm->m_data[i] = n_snowblock;
+				vm->m_area.add_y(em, i, -1);
+				vm->m_data[i] = n_dirt_with_snow;
+			} else if (bt == BT_TUNDRA) {
+				if (c == c_dirt) {
+					vm->m_data[i] = n_dirt_with_snow;
+				} else if (c == c_stone) {
+					vm->m_area.add_y(em, i, 1);
+					vm->m_data[i] = n_snow;
+				}
+			} else if (c == c_dirt) {
+				vm->m_data[i] = n_dirt_with_grass;
+			}
+		}
 	}
 }
 
diff --git a/src/mapgen_v6.h b/src/mapgen_v6.h
index 6fd9d5e70..c729c04e7 100644
--- a/src/mapgen_v6.h
+++ b/src/mapgen_v6.h
@@ -25,11 +25,17 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #define AVERAGE_MUD_AMOUNT 4
 #define DESERT_STONE_BASE -32
+#define ICE_BASE 0
+#define FREQ_HOT 0.4
+#define FREQ_SNOW -0.4
+#define FREQ_TAIGA 0.5
+#define FREQ_JUNGLE 0.7
 
-/////////////////// Mapgen V6 flags
+//////////// Mapgen V6 flags
 #define MGV6_JUNGLES    0x01
 #define MGV6_BIOMEBLEND 0x02
 #define MGV6_MUDFLOW    0x04
+#define MGV6_SNOWBIOMES 0x08
 
 
 extern FlagDesc flagdesc_mapgen_v6[];
@@ -38,9 +44,13 @@ extern FlagDesc flagdesc_mapgen_v6[];
 enum BiomeV6Type
 {
 	BT_NORMAL,
-	BT_DESERT
+	BT_DESERT,
+	BT_JUNGLE,
+	BT_TUNDRA,
+	BT_TAIGA,
 };
 
+
 struct MapgenV6Params : public MapgenSpecificParams {
 	u32 spflags;
 	float freq_desert;
@@ -64,6 +74,7 @@ struct MapgenV6Params : public MapgenSpecificParams {
 	void writeParams(Settings *settings) const;
 };
 
+
 class MapgenV6 : public Mapgen {
 public:
 	EmergeManager *m_emerge;
@@ -85,6 +96,7 @@ public:
 	Noise *noise_mud;
 	Noise *noise_beach;
 	Noise *noise_biome;
+	Noise *noise_humidity;
 	NoiseParams *np_cave;
 	NoiseParams *np_humidity;
 	NoiseParams *np_trees;
@@ -102,6 +114,10 @@ public:
 	content_t c_cobble;
 	content_t c_desert_sand;
 	content_t c_desert_stone;
+	content_t c_dirt_with_snow;
+	content_t c_snow;
+	content_t c_snowblock;
+	content_t c_ice;
 
 	content_t c_mossycobble;
 	content_t c_sandbrick;
@@ -145,6 +161,7 @@ public:
 	virtual void generateCaves(int max_stone_y);
 };
 
+
 struct MapgenFactoryV6 : public MapgenFactory {
 	Mapgen *createMapgen(int mgid, MapgenParams *params, EmergeManager *emerge)
 	{
@@ -157,4 +174,5 @@ struct MapgenFactoryV6 : public MapgenFactory {
 	};
 };
 
+
 #endif