Cavegen: Move V5-style caves to CavesNoiseIntersection

9 files changed, 151 insertions, 82 deletions

diff --git a/src/cavegen.cpp b/src/cavegen.cpp
index 5f0af9699..51309ad60 100644
--- a/src/cavegen.cpp
+++ b/src/cavegen.cpp
@@ -23,10 +23,106 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "mapgen_v5.h"
 #include "mapgen_v6.h"
 #include "mapgen_v7.h"
+#include "mg_biome.h"
 #include "cavegen.h"
 
 NoiseParams nparams_caveliquids(0, 1, v3f(150.0, 150.0, 150.0), 776, 3, 0.6, 2.0);
 
+
+////
+//// CavesNoiseIntersection
+////
+
+CavesNoiseIntersection::CavesNoiseIntersection(
+	INodeDefManager *nodedef, BiomeManager *biomemgr, v3s16 chunksize,
+	NoiseParams *np_cave1, NoiseParams *np_cave2, int seed, float cave_width)
+{
+	assert(nodedef);
+	assert(biomemgr);
+
+	m_ndef = nodedef;
+	m_bmgr = biomemgr;
+
+	m_csize = chunksize;
+	m_cave_width = cave_width;
+
+	m_ystride    = m_csize.X;
+	m_zstride_1d = m_csize.X * (m_csize.Y + 1);
+
+	// Noises are created using 1-down overgeneration
+	// A Nx-by-1-by-Nz-sized plane is at the bottom of the desired for
+	// re-carving the solid overtop placed for blocking sunlight
+	noise_cave1 = new Noise(np_cave1, seed, m_csize.X, m_csize.Y + 1, m_csize.Z);
+	noise_cave2 = new Noise(np_cave2, seed, m_csize.X, m_csize.Y + 1, m_csize.Z);
+}
+
+
+CavesNoiseIntersection::~CavesNoiseIntersection()
+{
+	delete noise_cave1;
+	delete noise_cave2;
+}
+
+
+void CavesNoiseIntersection::generateCaves(MMVManip *vm,
+	v3s16 nmin, v3s16 nmax, u8 *biomemap)
+{
+	assert(vm);
+	assert(biomemap);
+
+	noise_cave1->perlinMap3D(nmin.X, nmin.Y - 1, nmin.Z);
+	noise_cave2->perlinMap3D(nmin.X, nmin.Y - 1, nmin.Z);
+
+	v3s16 em = vm->m_area.getExtent();
+	u32 index2d = 0;
+
+	for (s16 z = nmin.Z; z <= nmax.Z; z++)
+	for (s16 x = nmin.X; x <= nmax.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, nmax.Y, z);
+		u32 index3d = (z - nmin.Z) * m_zstride_1d + m_csize.Y * m_ystride +
+			(x - nmin.X);
+		// Biome of column
+		Biome *biome = (Biome *)m_bmgr->getRaw(biomemap[index2d]);
+
+		// Don't excavate the overgenerated stone at nmax.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 = nmax.Y; y >= nmin.Y - 1; y--,
+				index3d -= m_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 > m_cave_width && m_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;
+			}
+		}
+	}
+}
+
+
 ////
 //// CavesRandomWalk
 ////
diff --git a/src/cavegen.h b/src/cavegen.h
index 68e0c8bc5..da0894635 100644
--- a/src/cavegen.h
+++ b/src/cavegen.h
@@ -26,6 +26,43 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 class GenerateNotifier;
 
 /*
+	CavesNoiseIntersection is a cave digging algorithm that carves smooth,
+	web-like, continuous tunnels at points where the density of the intersection
+	between two separate 3d noises is above a certain value.  This value,
+	cave_width, can be modified to set the effective width of these tunnels.
+
+	This algorithm is relatively heavyweight, taking ~80ms to generate an
+	80x80x80 chunk of map on a modern processor.  Use sparingly!
+
+	TODO(hmmmm): Remove dependency on biomes
+	TODO(hmmmm): Find alternative to overgeneration as solution for sunlight issue
+*/
+class CavesNoiseIntersection {
+public:
+	CavesNoiseIntersection(INodeDefManager *nodedef, BiomeManager *biomemgr,
+		v3s16 chunksize, NoiseParams *np_cave1, NoiseParams *np_cave2,
+		int seed, float cave_width);
+	~CavesNoiseIntersection();
+
+	void generateCaves(MMVManip *vm, v3s16 nmin, v3s16 nmax, u8 *biomemap);
+
+private:
+	INodeDefManager *m_ndef;
+	BiomeManager *m_bmgr;
+
+	// configurable parameters
+	v3s16 m_csize;
+	float m_cave_width;
+
+	// intermediate state variables
+	u16 m_ystride;
+	u16 m_zstride_1d;
+
+	Noise *noise_cave1;
+	Noise *noise_cave2;
+};
+
+/*
 	CavesRandomWalk is an implementation of a cave-digging algorithm that
 	operates on the principle of a "random walk" to approximate the stochiastic
 	activity of cavern development.
diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index 09671d845..7e959533d 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -542,56 +542,10 @@ 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);
+	CavesNoiseIntersection caves_noise(ndef, bmgr, csize,
+		&np_cave1, &np_cave2, seed, cave_width);
 
-	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;
-			}
-		}
-	}
+	caves_noise.generateCaves(vm, node_min, node_max, biomemap);
 
 	if (node_max.Y > large_cave_depth)
 		return;
diff --git a/src/mapgen.h b/src/mapgen.h
index 3ec148296..8db01f5c1 100644
--- a/src/mapgen.h
+++ b/src/mapgen.h
@@ -220,8 +220,6 @@ public:
 	BiomeManager *bmgr;
 
 	Noise *noise_filler_depth;
-	Noise *noise_cave1;
-	Noise *noise_cave2;
 
 	v3s16 node_min;
 	v3s16 node_max;
@@ -235,7 +233,8 @@ public:
 	content_t c_sandstone;
 
 	int ystride;
-	int zstride_1d;
+	NoiseParams np_cave1;
+	NoiseParams np_cave2;
 	float cave_width;
 
 	MapgenBasic(int mapgenid, MapgenParams *params, EmergeManager *emerge);
diff --git a/src/mapgen_flat.cpp b/src/mapgen_flat.cpp
index 2cbf9ace0..a541a54f3 100644
--- a/src/mapgen_flat.cpp
+++ b/src/mapgen_flat.cpp
@@ -58,8 +58,6 @@ MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge
 	//// amount of elements to skip for the next index
 	//// for noise/height/biome maps (not vmanip)
 	this->ystride = csize.X;
-	// 1-down overgeneration
-	this->zstride_1d = csize.X * (csize.Y + 1);
 
 	this->heightmap = new s16[csize.X * csize.Z];
 
@@ -78,10 +76,8 @@ MapgenFlat::MapgenFlat(int mapgenid, MapgenParams *params, EmergeManager *emerge
 	noise_terrain      = new Noise(&sp->np_terrain,      seed, csize.X, csize.Z);
 	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
 
-	//// 3D noise
-	// 1-down overgeneraion
-	noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 1, csize.Z);
-	noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 1, csize.Z);
+	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave2 = sp->np_cave2;
 
 	//// Initialize biome generator
 	biomegen = emerge->biomemgr->createBiomeGen(
@@ -119,8 +115,6 @@ MapgenFlat::~MapgenFlat()
 {
 	delete noise_terrain;
 	delete noise_filler_depth;
-	delete noise_cave1;
-	delete noise_cave2;
 
 	delete biomegen;
 
diff --git a/src/mapgen_fractal.cpp b/src/mapgen_fractal.cpp
index 3217d52e2..dca10d253 100644
--- a/src/mapgen_fractal.cpp
+++ b/src/mapgen_fractal.cpp
@@ -56,8 +56,6 @@ MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *
 	//// amount of elements to skip for the next index
 	//// for noise/height/biome maps (not vmanip)
 	this->ystride = csize.X;
-	// 1-down overgeneration
-	this->zstride_1d = csize.X * (csize.Y + 1);
 
 	this->heightmap = new s16[csize.X * csize.Z];
 
@@ -79,10 +77,8 @@ MapgenFractal::MapgenFractal(int mapgenid, MapgenParams *params, EmergeManager *
 	noise_seabed       = new Noise(&sp->np_seabed, seed, csize.X, csize.Z);
 	noise_filler_depth = new Noise(&sp->np_filler_depth, seed, csize.X, csize.Z);
 
-	//// 3D terrain noise
-	// 1-down overgeneraion
-	noise_cave1 = new Noise(&sp->np_cave1, seed, csize.X, csize.Y + 1, csize.Z);
-	noise_cave2 = new Noise(&sp->np_cave2, seed, csize.X, csize.Y + 1, csize.Z);
+	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave2 = sp->np_cave2;
 
 	//// Initialize biome generator
 	biomegen = emerge->biomemgr->createBiomeGen(
@@ -123,8 +119,6 @@ MapgenFractal::~MapgenFractal()
 {
 	delete noise_seabed;
 	delete noise_filler_depth;
-	delete noise_cave1;
-	delete noise_cave2;
 
 	delete biomegen;
 
diff --git a/src/mapgen_v5.cpp b/src/mapgen_v5.cpp
index 6c1441bc2..0c063dc6f 100644
--- a/src/mapgen_v5.cpp
+++ b/src/mapgen_v5.cpp
@@ -54,8 +54,6 @@ MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	// amount of elements to skip for the next index
 	// for noise/height/biome maps (not vmanip)
 	this->ystride = csize.X;
-	// 1-down overgeneration
-	this->zstride_1d = csize.X * (csize.Y + 1);
 
 	this->heightmap = new s16[csize.X * csize.Z];
 
@@ -72,9 +70,9 @@ MapgenV5::MapgenV5(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	// 3D terrain noise
 	// 1-up 1-down overgeneration
 	noise_ground = new Noise(&sp->np_ground, seed, csize.X, csize.Y + 2, csize.Z);
-	// 1-down overgeneraion
-	noise_cave1  = new Noise(&sp->np_cave1,  seed, csize.X, csize.Y + 1, csize.Z);
-	noise_cave2  = new Noise(&sp->np_cave2,  seed, csize.X, csize.Y + 1, csize.Z);
+
+	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave2 = sp->np_cave2;
 
 	//// Initialize biome generator
 	biomegen = emerge->biomemgr->createBiomeGen(
@@ -113,8 +111,6 @@ MapgenV5::~MapgenV5()
 	delete noise_filler_depth;
 	delete noise_factor;
 	delete noise_height;
-	delete noise_cave1;
-	delete noise_cave2;
 	delete noise_ground;
 
 	delete biomegen;
diff --git a/src/mapgen_v7.cpp b/src/mapgen_v7.cpp
index e6801a24b..e297a1d3e 100644
--- a/src/mapgen_v7.cpp
+++ b/src/mapgen_v7.cpp
@@ -61,8 +61,6 @@ MapgenV7::MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	this->ystride = csize.X;
 	// 1-up 1-down overgeneration
 	this->zstride_1u1d = csize.X * (csize.Y + 2);
-	// 1-down overgeneration
-	this->zstride_1d = csize.X * (csize.Y + 1);
 
 	this->heightmap       = new s16[csize.X * csize.Z];
 	this->ridge_heightmap = new s16[csize.X * csize.Z];
@@ -85,9 +83,9 @@ MapgenV7::MapgenV7(int mapgenid, MapgenParams *params, EmergeManager *emerge)
 	// 1-up 1-down overgeneration
 	noise_mountain = new Noise(&sp->np_mountain, seed, csize.X, csize.Y + 2, csize.Z);
 	noise_ridge    = new Noise(&sp->np_ridge,    seed, csize.X, csize.Y + 2, csize.Z);
-	// 1-down overgeneraion
-	noise_cave1    = new Noise(&sp->np_cave1,    seed, csize.X, csize.Y + 1, csize.Z);
-	noise_cave2    = new Noise(&sp->np_cave2,    seed, csize.X, csize.Y + 1, csize.Z);
+
+	MapgenBasic::np_cave1 = sp->np_cave1;
+	MapgenBasic::np_cave2 = sp->np_cave2;
 
 	// TODO(hmmmm): should we have a way to disable biomemanager biomes?
 	//// Initialize biome generator
@@ -133,8 +131,6 @@ MapgenV7::~MapgenV7()
 	delete noise_ridge_uwater;
 	delete noise_mountain;
 	delete noise_ridge;
-	delete noise_cave1;
-	delete noise_cave2;
 
 	delete biomegen;
 
diff --git a/src/mapgen_valleys.h b/src/mapgen_valleys.h
index 2ab253430..4f87be6b6 100644
--- a/src/mapgen_valleys.h
+++ b/src/mapgen_valleys.h
@@ -100,6 +100,7 @@ private:
 	BiomeGenOriginal *m_bgen;
 
 	int zstride;
+	int zstride_1d;
 
 	float map_gen_limit;
 
@@ -120,6 +121,8 @@ private:
 	Noise *noise_inter_valley_fill;
 	Noise *noise_inter_valley_slope;
 	Noise *noise_rivers;
+	Noise *noise_cave1;
+	Noise *noise_cave2;
 	Noise *noise_massive_caves;
 	Noise *noise_terrain_height;
 	Noise *noise_valley_depth;