Cavegen V6: Make all caves consistent with 0.4.12 stable

When tunnels entirely above ground were avoided, the
missing pseudorandom calls changed the allowed caves.
Now, above ground tunnels are not placed while
still running all previous pseudorandom calls.

2 files changed, 36 insertions, 20 deletions

diff --git a/src/cavegen.cpp b/src/cavegen.cpp
index 0c14375ee..8372f70b5 100644
--- a/src/cavegen.cpp
+++ b/src/cavegen.cpp
@@ -31,7 +31,8 @@ NoiseParams nparams_caveliquids(0, 1, v3f(150.0, 150.0, 150.0), 776, 3, 0.6, 2.0
 ///////////////////////////////////////// Caves V5
 
 
-CaveV5::CaveV5(MapgenV5 *mg, PseudoRandom *ps) {
+CaveV5::CaveV5(MapgenV5 *mg, PseudoRandom *ps)
+{
 	this->mg             = mg;
 	this->vm             = mg->vm;
 	this->ndef           = mg->ndef;
@@ -54,7 +55,8 @@ CaveV5::CaveV5(MapgenV5 *mg, PseudoRandom *ps) {
 }
 
 
-void CaveV5::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
+void CaveV5::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height)
+{
 	node_min = nmin;
 	node_max = nmax;
 	main_direction = v3f(0, 0, 0);
@@ -115,8 +117,8 @@ void CaveV5::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
 }
 
 
-void CaveV5::makeTunnel(bool dirswitch) {
-
+void CaveV5::makeTunnel(bool dirswitch)
+{
 	// Randomize size
 	s16 min_d = min_tunnel_diameter;
 	s16 max_d = max_tunnel_diameter;
@@ -201,7 +203,8 @@ void CaveV5::makeTunnel(bool dirswitch) {
 }
 
 
-void CaveV5::carveRoute(v3f vec, float f, bool randomize_xz) {
+void CaveV5::carveRoute(v3f vec, float f, bool randomize_xz) 
+{
 	MapNode airnode(CONTENT_AIR);
 	MapNode waternode(c_water_source);
 	MapNode lavanode(c_lava_source);
@@ -271,7 +274,8 @@ void CaveV5::carveRoute(v3f vec, float f, bool randomize_xz) {
 ///////////////////////////////////////// Caves V6
 
 
-CaveV6::CaveV6(MapgenV6 *mg, PseudoRandom *ps, PseudoRandom *ps2, bool is_large_cave) {
+CaveV6::CaveV6(MapgenV6 *mg, PseudoRandom *ps, PseudoRandom *ps2, bool is_large_cave)
+{
 	this->mg             = mg;
 	this->vm             = mg->vm;
 	this->ndef           = mg->ndef;
@@ -301,7 +305,8 @@ CaveV6::CaveV6(MapgenV6 *mg, PseudoRandom *ps, PseudoRandom *ps2, bool is_large_
 }
 
 
-void CaveV6::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
+void CaveV6::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height)
+{
 	node_min = nmin;
 	node_max = nmax;
 	max_stone_y = max_stone_height;
@@ -368,7 +373,8 @@ void CaveV6::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
 }
 
 
-void CaveV6::makeTunnel(bool dirswitch) {
+void CaveV6::makeTunnel(bool dirswitch)
+{
 	if (dirswitch && !large_cave) {
 		main_direction = v3f(
 			((float)(ps->next() % 20) - (float)10) / 10,
@@ -414,7 +420,8 @@ void CaveV6::makeTunnel(bool dirswitch) {
 		);
 	}
 
-	// Do not make caves that are entirely above ground.
+	// Do not make caves that are entirely above ground, to fix
+	// shadow bugs caused by overgenerated large caves.
 	// It is only necessary to check the startpoint and endpoint.
 	v3s16 orpi(orp.X, orp.Y, orp.Z);
 	v3s16 veci(vec.X, vec.Y, vec.Z);
@@ -441,8 +448,11 @@ void CaveV6::makeTunnel(bool dirswitch) {
 		h2 = water_level;
 	}
 
-	if (p1.Y > h1 && p2.Y > h2) // If startpoint and endpoint are above ground
-		return;
+	// If startpoint and endpoint are above ground,
+	// disable placing of nodes in carveRoute while
+	// still running all pseudorandom calls to ensure
+	// caves consistent with existing worlds.
+	bool tunnel_above_ground = p1.Y > h1 && p2.Y > h2;
 
 	vec += main_direction;
 
@@ -474,13 +484,14 @@ void CaveV6::makeTunnel(bool dirswitch) {
 
 	// Carve routes
 	for (float f = 0; f < 1.0; f += 1.0 / veclen)
-		carveRoute(vec, f, randomize_xz);
+		carveRoute(vec, f, randomize_xz, tunnel_above_ground);
 
 	orp = rp;
 }
 
 
-void CaveV6::carveRoute(v3f vec, float f, bool randomize_xz) {
+void CaveV6::carveRoute(v3f vec, float f, bool randomize_xz, bool tunnel_above_ground)
+{
 	MapNode airnode(CONTENT_AIR);
 	MapNode waternode(c_water_source);
 	MapNode lavanode(c_lava_source);
@@ -503,6 +514,9 @@ void CaveV6::carveRoute(v3f vec, float f, bool randomize_xz) {
 	for (s16 z0 = d0; z0 <= d1; z0++) {
 		s16 si = rs / 2 - MYMAX(0, abs(z0) - rs / 7 - 1);
 		for (s16 x0 = -si - ps->range(0,1); x0 <= si - 1 + ps->range(0,1); x0++) {
+			if (tunnel_above_ground)
+				continue;
+
 			s16 maxabsxz = MYMAX(abs(x0), abs(z0));
 			s16 si2 = rs / 2 - MYMAX(0, maxabsxz - rs / 7 - 1);
 			for (s16 y0 = -si2; y0 <= si2; y0++) {
@@ -553,7 +567,8 @@ void CaveV6::carveRoute(v3f vec, float f, bool randomize_xz) {
 ///////////////////////////////////////// Caves V7
 
 
-CaveV7::CaveV7(MapgenV7 *mg, PseudoRandom *ps) {
+CaveV7::CaveV7(MapgenV7 *mg, PseudoRandom *ps)
+{
 	this->mg             = mg;
 	this->vm             = mg->vm;
 	this->ndef           = mg->ndef;
@@ -576,7 +591,8 @@ CaveV7::CaveV7(MapgenV7 *mg, PseudoRandom *ps) {
 }
 
 
-void CaveV7::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
+void CaveV7::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height)
+{
 	node_min = nmin;
 	node_max = nmax;
 	max_stone_y = max_stone_height;
@@ -638,8 +654,8 @@ void CaveV7::makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height) {
 }
 
 
-void CaveV7::makeTunnel(bool dirswitch) {
-
+void CaveV7::makeTunnel(bool dirswitch)
+{
 	// Randomize size
 	s16 min_d = min_tunnel_diameter;
 	s16 max_d = max_tunnel_diameter;
@@ -724,7 +740,8 @@ void CaveV7::makeTunnel(bool dirswitch) {
 }
 
 
-void CaveV7::carveRoute(v3f vec, float f, bool randomize_xz) {
+void CaveV7::carveRoute(v3f vec, float f, bool randomize_xz)
+{
 	MapNode airnode(CONTENT_AIR);
 	MapNode waternode(c_water_source);
 	MapNode lavanode(c_lava_source);
@@ -790,4 +807,3 @@ void CaveV7::carveRoute(v3f vec, float f, bool randomize_xz) {
 		}
 	}
 }
-
diff --git a/src/cavegen.h b/src/cavegen.h
index 5d150802a..b9662587b 100644
--- a/src/cavegen.h
+++ b/src/cavegen.h
@@ -113,7 +113,7 @@ public:
 	CaveV6(MapgenV6 *mg, PseudoRandom *ps, PseudoRandom *ps2, bool large_cave);
 	void makeCave(v3s16 nmin, v3s16 nmax, int max_stone_height);
 	void makeTunnel(bool dirswitch);
-	void carveRoute(v3f vec, float f, bool randomize_xz);
+	void carveRoute(v3f vec, float f, bool randomize_xz, bool tunnel_above_ground);
 };
 
 class CaveV7 {