Cavegen: Remove CavesRandomWalk dependency on Mapgen

4 files changed, 98 insertions, 38 deletions

diff --git a/src/cavegen.cpp b/src/cavegen.cpp
index 59878c890..25e8473bc 100644
--- a/src/cavegen.cpp
+++ b/src/cavegen.cpp
@@ -31,23 +31,52 @@ NoiseParams nparams_caveliquids(0, 1, v3f(150.0, 150.0, 150.0), 776, 3, 0.6, 2.0
 //// CavesRandomWalk
 ////
 
-CavesRandomWalk::CavesRandomWalk(Mapgen *mg, PseudoRandom *ps)
+CavesRandomWalk::CavesRandomWalk(
+	INodeDefManager *ndef,
+	GenerateNotifier *gennotify,
+	int seed,
+	int water_level,
+	content_t water_source,
+	content_t lava_source)
 {
-	this->mg             = mg;
-	this->vm             = mg->vm;
-	this->ndef           = mg->ndef;
-	this->water_level    = mg->water_level;
-	this->ps             = ps;
-	c_water_source       = ndef->getId("mapgen_water_source");
-	c_lava_source        = ndef->getId("mapgen_lava_source");
-	c_ice                = ndef->getId("mapgen_ice");
+	assert(ndef);
+
+	this->ndef           = ndef;
+	this->gennotify      = gennotify;
+	this->seed           = seed;
+	this->water_level    = water_level;
 	this->np_caveliquids = &nparams_caveliquids;
-	this->ystride        = mg->csize.X;
 	this->lava_depth     = DEFAULT_LAVA_DEPTH;
 
-	if (c_ice == CONTENT_IGNORE)
-		c_ice = CONTENT_AIR;
+	c_water_source = water_source;
+	if (c_water_source == CONTENT_IGNORE)
+		c_water_source = ndef->getId("mapgen_water_source");
+	if (c_water_source == CONTENT_IGNORE)
+		c_water_source = CONTENT_AIR;
 
+	c_lava_source = lava_source;
+	if (c_lava_source == CONTENT_IGNORE)
+		c_lava_source = ndef->getId("mapgen_lava_source");
+	if (c_lava_source == CONTENT_IGNORE)
+		c_lava_source = CONTENT_AIR;
+}
+
+
+void CavesRandomWalk::makeCave(MMVManip *vm, v3s16 nmin, v3s16 nmax,
+	PseudoRandom *ps, int max_stone_height, s16 *heightmap)
+{
+	assert(vm);
+	assert(ps);
+
+	this->vm        = vm;
+	this->ps        = ps;
+	this->node_min  = nmin;
+	this->node_max  = nmax;
+	this->heightmap = heightmap;
+
+	this->ystride = nmax.X - nmin.X + 1;
+
+	// Set initial parameters from randomness
 	dswitchint = ps->range(1, 14);
 	flooded    = ps->range(1, 2) == 2;
 
@@ -57,13 +86,7 @@ CavesRandomWalk::CavesRandomWalk(Mapgen *mg, PseudoRandom *ps)
 	max_tunnel_diameter = ps->range(7, ps->range(8, 24));
 
 	large_cave_is_flat = (ps->range(0, 1) == 0);
-}
-
 
-void CavesRandomWalk::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height)
-{
-	node_min = nmin;
-	node_max = nmax;
 	main_direction = v3f(0, 0, 0);
 
 	// Allowed route area size in nodes
@@ -107,18 +130,22 @@ void CavesRandomWalk::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height)
 	);
 
 	// Add generation notify begin event
-	v3s16 abs_pos(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
-	GenNotifyType notifytype = GENNOTIFY_LARGECAVE_BEGIN;
-	mg->gennotify.addEvent(notifytype, abs_pos);
+	if (gennotify) {
+		v3s16 abs_pos(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
+		GenNotifyType notifytype = GENNOTIFY_LARGECAVE_BEGIN;
+		gennotify->addEvent(notifytype, abs_pos);
+	}
 
 	// Generate some tunnel starting from orp
 	for (u16 j = 0; j < tunnel_routepoints; j++)
 		makeTunnel(j % dswitchint == 0);
 
 	// Add generation notify end event
-	abs_pos = v3s16(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
-	notifytype = GENNOTIFY_LARGECAVE_END;
-	mg->gennotify.addEvent(notifytype, abs_pos);
+	if (gennotify) {
+		v3s16 abs_pos(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
+		GenNotifyType notifytype = GENNOTIFY_LARGECAVE_END;
+		gennotify->addEvent(notifytype, abs_pos);
+	}
 }
 
 
@@ -197,7 +224,7 @@ void CavesRandomWalk::carveRoute(v3f vec, float f, bool randomize_xz)
 	startp += of;
 
 	float nval = NoisePerlin3D(np_caveliquids, startp.X,
-		startp.Y, startp.Z, mg->seed);
+		startp.Y, startp.Z, seed);
 	MapNode liquidnode = (nval < 0.40 && node_max.Y < lava_depth) ?
 		lavanode : waternode;
 
@@ -388,7 +415,7 @@ void CavesV6::makeCave(MMVManip *vm, v3s16 nmin, v3s16 nmax,
 
 	// Add generation notify end event
 	if (gennotify != NULL) {
-		v3s16 abs_pos = v3s16(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
+		v3s16 abs_pos(of.X + orp.X, of.Y + orp.Y, of.Z + orp.Z);
 		GenNotifyType notifytype = large_cave ?
 			GENNOTIFY_LARGECAVE_END : GENNOTIFY_CAVE_END;
 		gennotify->addEvent(notifytype, abs_pos);
diff --git a/src/cavegen.h b/src/cavegen.h
index 5a41966fe..2db5e9d4f 100644
--- a/src/cavegen.h
+++ b/src/cavegen.h
@@ -25,17 +25,35 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 class GenerateNotifier;
 
+/*
+	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.
+
+	In summary, this algorithm works by carving a randomly sized tunnel in a
+	random direction a random amount of times, randomly varying in width.
+	All randomness here is uniformly distributed; alternative distributions have
+	not yet been implemented.
+
+	This algorithm is very fast, executing in less than 1ms on average for an
+	80x80x80 chunk of map on a modern processor.
+*/
 class CavesRandomWalk {
 public:
-	Mapgen *mg;
 	MMVManip *vm;
 	INodeDefManager *ndef;
+	GenerateNotifier *gennotify;
 	s16 *heightmap;
 
-	// variables
+	// configurable parameters
+	int seed;
+	int water_level;
 	int lava_depth;
 	NoiseParams *np_caveliquids;
 
+	// intermediate state variables
+	u16 ystride;
+
 	s16 min_tunnel_diameter;
 	s16 max_tunnel_diameter;
 	u16 tunnel_routepoints;
@@ -62,17 +80,26 @@ public:
 
 	content_t c_water_source;
 	content_t c_lava_source;
-	content_t c_ice;
 
-	int water_level;
-	u16 ystride;
+	// ndef is a mandatory parameter.
+	// If gennotify is NULL, generation events are not logged.
+	CavesRandomWalk(INodeDefManager *ndef,
+		GenerateNotifier *gennotify = NULL,
+		int seed = 0,
+		int water_level = 1,
+		content_t water_source = CONTENT_IGNORE,
+		content_t lava_source = CONTENT_IGNORE);
 
-	CavesRandomWalk(Mapgen *mg, PseudoRandom *ps);
-	void makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height);
+	// vm and ps are mandatory parameters.
+	// If heightmap is NULL, the surface level at all points is assumed to
+	// be water_level.
+	void makeCave(MMVManip *vm, v3s16 nmin, v3s16 nmax,
+		PseudoRandom *ps, int max_stone_height, s16 *heightmap);
+
+private:
 	void makeTunnel(bool dirswitch);
 	void carveRoute(v3f vec, float f, bool randomize_xz);
 
-private:
 	inline bool isPosAboveSurface(v3s16 p);
 };
 
@@ -97,11 +124,13 @@ public:
 	PseudoRandom *ps;
 	PseudoRandom *ps2;
 
+	// configurable parameters
 	s16 *heightmap;
 	content_t c_water_source;
 	content_t c_lava_source;
 	int water_level;
 
+	// intermediate state variables
 	u16 ystride;
 
 	s16 min_tunnel_diameter;
diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index 43ac6e51a..7e74ad642 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -599,8 +599,10 @@ void MapgenBasic::generateCaves(s16 max_stone_y, s16 large_cave_depth)
 	PseudoRandom ps(blockseed + 21343);
 	u32 bruises_count = ps.range(0, 2);
 	for (u32 i = 0; i < bruises_count; i++) {
-		CavesRandomWalk cave(this, &ps);
-		cave.makeCave(node_min, node_max, max_stone_y);
+		CavesRandomWalk cave(ndef, &gennotify, seed, water_level,
+			c_water_source, CONTENT_IGNORE);
+
+		cave.makeCave(vm, node_min, node_max, &ps, max_stone_y, heightmap);
 	}
 }
 
diff --git a/src/mapgen_valleys.cpp b/src/mapgen_valleys.cpp
index 77fa1ed06..af7a8b153 100644
--- a/src/mapgen_valleys.cpp
+++ b/src/mapgen_valleys.cpp
@@ -841,8 +841,10 @@ void MapgenValleys::generateCaves(s16 max_stone_y, s16 large_cave_depth)
 	if (node_max.Y <= large_cave_depth && !made_a_big_one) {
 		u32 bruises_count = ps.range(0, 2);
 		for (u32 i = 0; i < bruises_count; i++) {
-			CavesRandomWalk cave(this, &ps);
-			cave.makeCave(node_min, node_max, max_stone_y);
+			CavesRandomWalk cave(ndef, &gennotify, seed, water_level,
+				c_water_source, c_lava_source);
+
+			cave.makeCave(vm, node_min, node_max, &ps, max_stone_y, heightmap);
 		}
 	}
 }