Mgv5: Change tunnel parameters to those of other mapgens (#7641)

Make tunnels wider and use the noise parameters of most other mapgens.
All other underground features are already identical to all other
non-mgv6 mapgens, this final change modernises and improves the tunnels.

builtin/settingtypes.txt

@@ -1314,7 +1314,7 @@ mg_biome_np_humidity_blend (Humidity blend noise) noise_params_2d 0, 1.5, (8, 8,
 mgv5_spflags (Mapgen V5 specific flags) flags caverns caverns,nocaverns
 
 #    Controls width of tunnels, a smaller value creates wider tunnels.
-mgv5_cave_width (Cave width) float 0.125
+mgv5_cave_width (Cave width) float 0.09
 
 #    Y of upper limit of large caves.
 mgv5_large_cave_depth (Large cave depth) int -256
@@ -1350,10 +1350,10 @@ mgv5_np_factor (Factor noise) noise_params_2d 0, 1, (250, 250, 250), 920381, 3,
 mgv5_np_height (Height noise) noise_params_2d 0, 10, (250, 250, 250), 84174, 4, 0.5, 2.0, eased
 
 #    First of 2 3D noises that together define tunnels.
-mgv5_np_cave1 (Cave1 noise) noise_params_3d 0, 12, (50, 50, 50), 52534, 4, 0.5, 2.0
+mgv5_np_cave1 (Cave1 noise) noise_params_3d 0, 12, (61, 61, 61), 52534, 3, 0.5, 2.0
 
 #    Second of 2 3D noises that together define tunnels.
-mgv5_np_cave2 (Cave2 noise) noise_params_3d 0, 12, (50, 50, 50), 10325, 4, 0.5, 2.0
+mgv5_np_cave2 (Cave2 noise) noise_params_3d 0, 12, (67, 67, 67), 10325, 3, 0.5, 2.0
 
 #    3D noise defining giant caverns.
 mgv5_np_cavern (Cavern noise) noise_params_3d 0, 1, (384, 128, 384), 723, 5, 0.63, 2.0

minetest.conf.example

@@ -1654,7 +1654,7 @@
 
 #    Controls width of tunnels, a smaller value creates wider tunnels.
 #    type: float
-# mgv5_cave_width = 0.125
+# mgv5_cave_width = 0.09
 
 #    Y of upper limit of large caves.
 #    type: int
@@ -1731,9 +1731,9 @@
 # mgv5_np_cave1 = {
 #    offset      = 0,
 #    scale       = 12,
-#    spread      = (50, 50, 50),
+#    spread      = (61, 61, 61),
 #    seed        = 52534,
-#    octaves     = 4,
+#    octaves     = 3,
 #    persistence = 0.5,
 #    lacunarity  = 2.0,
 #    flags       = ""
@@ -1744,9 +1744,9 @@
 # mgv5_np_cave2 = {
 #    offset      = 0,
 #    scale       = 12,
-#    spread      = (50, 50, 50),
+#    spread      = (67, 67, 67),
 #    seed        = 10325,
-#    octaves     = 4,
+#    octaves     = 3,
 #    persistence = 0.5,
 #    lacunarity  = 2.0,
 #    flags       = ""

src/mapgen/mapgen_v5.cpp

@@ -87,8 +87,8 @@ MapgenV5Params::MapgenV5Params():
 	np_factor       (0, 1,  v3f(250, 250, 250), 920381, 3, 0.45, 2.0),
 	np_height       (0, 10, v3f(250, 250, 250), 84174,  4, 0.5,  2.0),
 	np_ground       (0, 40, v3f(80,  80,  80),  983240, 4, 0.55, 2.0, NOISE_FLAG_EASED),
-	np_cave1        (0, 12, v3f(50,  50,  50),  52534,  4, 0.5,  2.0),
-	np_cave2        (0, 12, v3f(50,  50,  50),  10325,  4, 0.5,  2.0),
+	np_cave1        (0, 12, v3f(61,  61,  61),  52534,  3, 0.5,  2.0),
+	np_cave2        (0, 12, v3f(67,  67,  67),  10325,  3, 0.5,  2.0),
 	np_cavern       (0, 1,  v3f(384, 128, 384), 723,    5, 0.63, 2.0)
 {
 }

src/mapgen/mapgen_v5.h

@@ -32,7 +32,7 @@ extern FlagDesc flagdesc_mapgen_v5[];
 struct MapgenV5Params : public MapgenParams
 {
 	u32 spflags = MGV5_CAVERNS;
-	float cave_width = 0.125f;
+	float cave_width = 0.09f;
 	s16 large_cave_depth = -256;
 	s16 lava_depth = -256;
 	s16 cavern_limit = -256;