Mapgen: Combine generateBiomes, dustTopNodes, and generateCaves

This commit condenses the above methods into a single implementation used by
V7, V5, Flat, Fractal, and Valleys mapgens and introduces MapgenBasic.

1 files changed, 236 insertions, 0 deletions

diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index e269bf454..f491ed9eb 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -39,6 +39,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/numeric.h"
 #include "filesys.h"
 #include "log.h"
+#include "cavegen.h"
 
 FlagDesc flagdesc_mapgen[] = {
 	{"trees",       MG_TREES},
@@ -370,6 +371,241 @@ void Mapgen::spreadLight(v3s16 nmin, v3s16 nmax)
 
 
 ////
+//// MapgenBasic
+////
+
+MapgenBasic::MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emerge)
+	: Mapgen(mapgenid, params, emerge)
+{
+
+}
+
+MgStoneType MapgenBasic::generateBiomes()
+{
+	v3s16 em = vm->m_area.getExtent();
+	u32 index = 0;
+	MgStoneType stone_type = STONE;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index++) {
+		Biome *biome = NULL;
+		u16 depth_top = 0;
+		u16 base_filler = 0;
+		u16 depth_water_top = 0;
+		u32 vi = vm->m_area.index(x, node_max.Y, z);
+
+		// Check node at base of mapchunk above, either a node of a previously
+		// generated mapchunk or if not, a node of overgenerated base terrain.
+		content_t c_above = vm->m_data[vi + em.X].getContent();
+		bool air_above = c_above == CONTENT_AIR;
+		bool water_above = (c_above == c_water_source || c_above == c_river_water_source);
+
+		// If there is air or water above enable top/filler placement, otherwise force
+		// nplaced to stone level by setting a number exceeding any possible filler depth.
+		u16 nplaced = (air_above || water_above) ? 0 : U16_MAX;
+
+		for (s16 y = node_max.Y; y >= node_min.Y; y--) {
+			content_t c = vm->m_data[vi].getContent();
+
+			// Biome is recalculated each time an upper surface is detected while
+			// working down a column. The selected biome then remains in effect for
+			// all nodes below until the next surface and biome recalculation.
+			// Biome is recalculated:
+			// 1. At the surface of stone below air or water.
+			// 2. At the surface of water below air.
+			// 3. When stone or water is detected but biome has not yet been calculated.
+			if ((c == c_stone && (air_above || water_above || !biome))
+					|| ((c == c_water_source || c == c_river_water_source)
+						&& (air_above || !biome))) {
+				biome = biomegen->getBiomeAtIndex(index, y);
+
+				depth_top = biome->depth_top;
+				base_filler = MYMAX(depth_top
+						+ biome->depth_filler
+						+ noise_filler_depth->result[index], 0.f);
+				depth_water_top = biome->depth_water_top;
+
+				// Detect stone type for dungeons during every biome calculation.
+				// This is more efficient than detecting per-node and will not
+				// miss any desert stone or sandstone biomes.
+				if (biome->c_stone == c_desert_stone)
+					stone_type = DESERT_STONE;
+				else if (biome->c_stone == c_sandstone)
+					stone_type = SANDSTONE;
+			}
+
+			if (c == c_stone) {
+				content_t c_below = vm->m_data[vi - em.X].getContent();
+
+				// If the node below isn't solid, make this node stone, so that
+				// any top/filler nodes above are structurally supported.
+				// This is done by aborting the cycle of top/filler placement
+				// immediately by forcing nplaced to stone level.
+				if (c_below == CONTENT_AIR
+						|| c_below == c_water_source
+						|| c_below == c_river_water_source)
+					nplaced = U16_MAX;
+
+				if (nplaced < depth_top) {
+					vm->m_data[vi] = MapNode(biome->c_top);
+					nplaced++;
+				} else if (nplaced < base_filler) {
+					vm->m_data[vi] = MapNode(biome->c_filler);
+					nplaced++;
+				} else {
+					vm->m_data[vi] = MapNode(biome->c_stone);
+				}
+
+				air_above = false;
+				water_above = false;
+			} else if (c == c_water_source) {
+				vm->m_data[vi] = MapNode((y > (s32)(water_level - depth_water_top))
+						? biome->c_water_top : biome->c_water);
+				nplaced = 0;  // Enable top/filler placement for next surface
+				air_above = false;
+				water_above = true;
+			} else if (c == c_river_water_source) {
+				vm->m_data[vi] = MapNode(biome->c_river_water);
+				nplaced = depth_top;  // Enable filler placement for next surface
+				air_above = false;
+				water_above = true;
+			} else if (c == CONTENT_AIR) {
+				nplaced = 0;  // Enable top/filler placement for next surface
+				air_above = true;
+				water_above = false;
+			} else {  // Possible various nodes overgenerated from neighbouring mapchunks
+				nplaced = U16_MAX;  // Disable top/filler placement
+				air_above = false;
+				water_above = false;
+			}
+
+			vm->m_area.add_y(em, vi, -1);
+		}
+	}
+
+	return stone_type;
+}
+
+
+void MapgenBasic::dustTopNodes()
+{
+	if (node_max.Y < water_level)
+		return;
+
+	v3s16 em = vm->m_area.getExtent();
+	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++) {
+		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index]);
+
+		if (biome->c_dust == CONTENT_IGNORE)
+			continue;
+
+		u32 vi = vm->m_area.index(x, full_node_max.Y, z);
+		content_t c_full_max = vm->m_data[vi].getContent();
+		s16 y_start;
+
+		if (c_full_max == CONTENT_AIR) {
+			y_start = full_node_max.Y - 1;
+		} else if (c_full_max == CONTENT_IGNORE) {
+			vi = vm->m_area.index(x, node_max.Y + 1, z);
+			content_t c_max = vm->m_data[vi].getContent();
+
+			if (c_max == CONTENT_AIR)
+				y_start = node_max.Y;
+			else
+				continue;
+		} else {
+			continue;
+		}
+
+		vi = vm->m_area.index(x, y_start, z);
+		for (s16 y = y_start; y >= node_min.Y - 1; y--) {
+			if (vm->m_data[vi].getContent() != CONTENT_AIR)
+				break;
+
+			vm->m_area.add_y(em, vi, -1);
+		}
+
+		content_t c = vm->m_data[vi].getContent();
+		if (!ndef->get(c).buildable_to && c != CONTENT_IGNORE && c != biome->c_dust) {
+			vm->m_area.add_y(em, vi, 1);
+			vm->m_data[vi] = MapNode(biome->c_dust);
+		}
+	}
+}
+
+
+void MapgenBasic::generateCaves(s16 max_stone_y, s16 large_cave_depth)
+{
+	if (max_stone_y < node_min.Y)
+		return;
+
+	noise_cave1->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
+	noise_cave2->perlinMap3D(node_min.X, node_min.Y - 1, node_min.Z);
+
+	v3s16 em = vm->m_area.getExtent();
+	u32 index2d = 0;
+
+	for (s16 z = node_min.Z; z <= node_max.Z; z++)
+	for (s16 x = node_min.X; x <= node_max.X; x++, index2d++) {
+		bool column_is_open = false;  // Is column open to overground
+		bool is_tunnel = false;  // Is tunnel or tunnel floor
+		u32 vi = vm->m_area.index(x, node_max.Y, z);
+		u32 index3d = (z - node_min.Z) * zstride_1d + csize.Y * ystride +
+			(x - node_min.X);
+		// Biome of column
+		Biome *biome = (Biome *)bmgr->getRaw(biomemap[index2d]);
+
+		// Don't excavate the overgenerated stone at node_max.Y + 1,
+		// this creates a 'roof' over the tunnel, preventing light in
+		// tunnels at mapchunk borders when generating mapchunks upwards.
+		// This 'roof' is removed when the mapchunk above is generated.
+		for (s16 y = node_max.Y; y >= node_min.Y - 1; y--,
+				index3d -= ystride,
+				vm->m_area.add_y(em, vi, -1)) {
+
+			content_t c = vm->m_data[vi].getContent();
+			if (c == CONTENT_AIR || c == biome->c_water_top ||
+					c == biome->c_water) {
+				column_is_open = true;
+				continue;
+			}
+			// Ground
+			float d1 = contour(noise_cave1->result[index3d]);
+			float d2 = contour(noise_cave2->result[index3d]);
+
+			if (d1 * d2 > cave_width && ndef->get(c).is_ground_content) {
+				// In tunnel and ground content, excavate
+				vm->m_data[vi] = MapNode(CONTENT_AIR);
+				is_tunnel = true;
+			} else {
+				// Not in tunnel or not ground content
+				if (is_tunnel && column_is_open &&
+						(c == biome->c_filler || c == biome->c_stone))
+					// Tunnel entrance floor
+					vm->m_data[vi] = MapNode(biome->c_top);
+
+				column_is_open = false;
+				is_tunnel = false;
+			}
+		}
+	}
+
+	if (node_max.Y > large_cave_depth)
+		return;
+
+	PseudoRandom ps(blockseed + 21343);
+	u32 bruises_count = ps.range(0, 2);
+	for (u32 i = 0; i < bruises_count; i++) {
+		CaveV5 cave(this, &ps);       ////caves version varies  ---- todo- fix this!
+		cave.makeCave(node_min, node_max, max_stone_y);
+	}
+}
+
+
+////
 //// GenerateNotifier
 ////