Mgv7: Add 'mount_zero_level' parameter

Allows setting of the mountain 'zero level' (y where density gradient is zero).

It is easy to vertically shift smooth terrain by editing noise parameter 'offset',
but vertically shifting mountain terrain was complex and imprecise, involving
making a calculation based on an average of the mountain height parameter.

diff --git a/builtin/settingtypes.txt b/builtin/settingtypes.txt
index c1a645dcac6a39eb37b3bee8c4c81540475822a5..383caac13d7716b82b7f9e5e66651ebd688d7b86 100644 (file)
--- a/builtin/settingtypes.txt
+++ b/builtin/settingtypes.txt
@@ -1157,6 +1157,9 @@ mgv6_np_apple_trees (Apple trees noise) noise_params 0, 1, (100, 100, 100), 3429
 #    Flags starting with 'no' are used to explicitly disable them.
 mgv7_spflags (Mapgen v7 specific flags) flags mountains,ridges,nofloatlands,caverns,biomerepeat mountains,ridges,floatlands,caverns,biomerepeat,nomountains,noridges,nofloatlands,nocaverns,nobiomerepeat
 
+#    Y of mountain density gradient zero level. Used to shift mountains vertically.
+mgv7_mount_zero_level (Mountain zero level) int 0
+
 #    Controls width of tunnels, a smaller value creates wider tunnels.
 mgv7_cave_width (Cave width) float 0.09
 

diff --git a/minetest.conf.example b/minetest.conf.example
index 9e4a0e2ee204769e335cda4681dc39da71a9ad73..becc793bff728b5a1aaf46ca34bb02b8041476bc 100644 (file)
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -1397,6 +1397,10 @@
 #    type: flags possible values: mountains, ridges, floatlands, caverns, biomerepeat, nomountains, noridges, nofloatlands, nocaverns, nobiomerepeat
 # mgv7_spflags = mountains,ridges,nofloatlands,caverns,biomerepeat
 
+#    Y of mountain density gradient zero level. Used to shift mountains vertically.
+#    type: int
+# mgv7_mount_zero_level = 0
+
 #    Controls width of tunnels, a smaller value creates wider tunnels.
 #    type: float
 # mgv7_cave_width = 0.09

diff --git a/src/mapgen_v7.cpp b/src/mapgen_v7.cpp
index cdf76993d5ce67defbf575c752de5833d82cf0c1..4b74825fdcd9fbd8edc20ca00b8d1023a06cb886 100644 (file)
--- a/src/mapgen_v7.cpp
+++ b/src/mapgen_v7.cpp
@@ -56,6 +56,7 @@ MapgenV7::MapgenV7(int mapgenid, MapgenV7Params *params, EmergeManager *emerge)
        : MapgenBasic(mapgenid, params, emerge)
 {
        spflags             = params->spflags;
+       mount_zero_level    = params->mount_zero_level;
        cave_width          = params->cave_width;
        large_cave_depth    = params->large_cave_depth;
        lava_depth          = params->lava_depth;
@@ -149,6 +150,7 @@ MapgenV7Params::MapgenV7Params()
 void MapgenV7Params::readParams(const Settings *settings)
 {
        settings->getFlagStrNoEx("mgv7_spflags",           spflags, flagdesc_mapgen_v7);
+       settings->getS16NoEx("mgv7_mount_zero_level",      mount_zero_level);
        settings->getFloatNoEx("mgv7_cave_width",          cave_width);
        settings->getS16NoEx("mgv7_large_cave_depth",      large_cave_depth);
        settings->getS16NoEx("mgv7_lava_depth",            lava_depth);
@@ -180,6 +182,7 @@ void MapgenV7Params::readParams(const Settings *settings)
 void MapgenV7Params::writeParams(Settings *settings) const
 {
        settings->setFlagStr("mgv7_spflags",           spflags, flagdesc_mapgen_v7, U32_MAX);
+       settings->setS16("mgv7_mount_zero_level",      mount_zero_level);
        settings->setFloat("mgv7_cave_width",          cave_width);
        settings->setS16("mgv7_large_cave_depth",      large_cave_depth);
        settings->setS16("mgv7_lava_depth",            lava_depth);
@@ -397,7 +400,7 @@ bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
 {
        float mnt_h_n =
                        MYMAX(NoisePerlin2D(&noise_mount_height->np, x, z, seed), 1.0f);
-       float density_gradient = -((float)y / mnt_h_n);
+       float density_gradient = -((float)(y - mount_zero_level) / mnt_h_n);
        float mnt_n = NoisePerlin3D(&noise_mountain->np, x, y, z, seed);
 
        return mnt_n + density_gradient >= 0.0;
@@ -407,7 +410,7 @@ bool MapgenV7::getMountainTerrainAtPoint(s16 x, s16 y, s16 z)
 bool MapgenV7::getMountainTerrainFromMap(int idx_xyz, int idx_xz, s16 y)
 {
        float mounthn = MYMAX(noise_mount_height->result[idx_xz], 1.0f);
-       float density_gradient = -((float)y / mounthn);
+       float density_gradient = -((float)(y - mount_zero_level) / mounthn);
        float mountn = noise_mountain->result[idx_xyz];
 
        return mountn + density_gradient >= 0.0;

diff --git a/src/mapgen_v7.h b/src/mapgen_v7.h
index aededa7f5de2a5aea8febcf67e0691461959428b..aec28dfb4dbafcaf8f32c005cca03fa46ec995f8 100644 (file)
--- a/src/mapgen_v7.h
+++ b/src/mapgen_v7.h
@@ -38,6 +38,7 @@ extern FlagDesc flagdesc_mapgen_v7[];
 struct MapgenV7Params : public MapgenParams {
        u32 spflags = MGV7_MOUNTAINS | MGV7_RIDGES |
                MGV7_CAVERNS | MGV7_BIOMEREPEAT;
+       s16 mount_zero_level = 0;
        float cave_width = 0.09f;
        s16 large_cave_depth = -33;
        s16 lava_depth = -256;
@@ -92,6 +93,7 @@ public:
        void generateRidgeTerrain();
 
 private:
+       s16 mount_zero_level;
        s16 large_cave_depth;
        float float_mount_density;
        float float_mount_height;