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Stratum ore: Add option for a constant thickness stratum

Add a 'stratum thickness' integer parameter, as an alternative
to providing a 2nd noise parameter for thickness variation.
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paramat committed Nov 18, 2017
1 parent c655984 commit 4b553ece09908dfdee59e9841fdc9420350eda9f
Showing with 35 additions and 18 deletions.
  1. +13 −9 doc/lua_api.txt
  2. +14 −5 src/mapgen/mg_ore.cpp
  3. +2 −0 src/mapgen/mg_ore.h
  4. +6 −4 src/script/lua_api/l_mapgen.cpp
@@ -1206,20 +1206,25 @@ computationally expensive than any other ore.
Creates a single undulating ore stratum that is continuous across mapchunk
borders and horizontally spans the world.

The 2D perlin noise described by `noise_params` varies the Y co-ordinate of the
The 2D perlin noise described by `noise_params` defines the Y co-ordinate of the
stratum midpoint. The 2D perlin noise described by `np_stratum_thickness`
varies the stratum's vertical thickness (in units of nodes). Due to being
defines the stratum's vertical thickness (in units of nodes). Due to being
continuous across mapchunk borders the stratum's vertical thickness is
unlimited.

If the noise parameter `noise_params` is omitted the ore will occur from y_min
to y_max in a simple horizontal stratum.

A parameter `stratum_thickness` can be provided instead of the noise parameter
`np_stratum_thickness`, to create a constant thickness.

Leaving out one or both noise parameters makes the ore generation less intensive,
useful when adding multiple strata.

`y_min` and `y_max` define the limits of the ore generation and for performance
reasons should be set as close together as possible but without clipping the
stratum's Y variation.

If either of the 2 noise parameters are omitted the ore will occur from y_min
to y_max in a simple horizontal stratum. As this does not compute noise
performance improves, and is ideal for placing many layers.

Each node in the stratum has a 1-in-`clust_scarcity` chance of being ore, so a
solid-ore stratum would require a `clust_scarcity` of 1.

@@ -4880,7 +4885,6 @@ Definition tables
},
-- ^ See 'Ore types' section above.
-- ^ The above 2 parameters are only valid for "puff" ore.
-- ^ Additional noise parameters needed for "puff" ore.
random_factor = 1.0,
-- ^ See 'Ore types' section above.
-- ^ Only valid for "vein" ore.
@@ -4892,9 +4896,9 @@ Definition tables
octaves = 3,
persist = 0.7
},
stratum_thickness = 8,
-- ^ See 'Ore types' section above.
-- ^ Only valid for "stratum" ore.
-- ^ Additional noise parameter needed for "stratum" ore.
-- ^ The above 2 parameters are only valid for "stratum" ore.
}

### Biome definition (`register_biome`)
@@ -434,13 +434,20 @@ void OreStratum::generate(MMVManip *vm, int mapseed, u32 blockseed,
MapNode n_ore(c_ore, 0, ore_param2);

if (flags & OREFLAG_USE_NOISE) {
if (!(noise && noise_stratum_thickness)) {
if (!noise) {
int sx = nmax.X - nmin.X + 1;
int sz = nmax.Z - nmin.Z + 1;
noise = new Noise(&np, 0, sx, sz);
noise_stratum_thickness = new Noise(&np_stratum_thickness, 0, sx, sz);
}
noise->perlinMap2D(nmin.X, nmin.Z);
}

if (flags & OREFLAG_USE_NOISE2) {
if (!noise_stratum_thickness) {
int sx = nmax.X - nmin.X + 1;
int sz = nmax.Z - nmin.Z + 1;
noise_stratum_thickness = new Noise(&np_stratum_thickness, 0, sx, sz);
}
noise_stratum_thickness->perlinMap2D(nmin.X, nmin.Z);
}

@@ -458,11 +465,13 @@ void OreStratum::generate(MMVManip *vm, int mapseed, u32 blockseed,
int y1;

if (flags & OREFLAG_USE_NOISE) {
float nhalfthick = ((flags & OREFLAG_USE_NOISE2) ?
noise_stratum_thickness->result[index] : (float)stratum_thickness) /
2.0f;
float nmid = noise->result[index];
float nhalfthick = noise_stratum_thickness->result[index] / 2.0f;
y0 = MYMAX(nmin.Y, nmid - nhalfthick);
y0 = MYMAX(nmin.Y, ceil(nmid - nhalfthick));
y1 = MYMIN(nmax.Y, nmid + nhalfthick);
} else {
} else { // Simple horizontal stratum
y0 = nmin.Y;
y1 = nmax.Y;
}
@@ -35,6 +35,7 @@ class MMVManip;
#define OREFLAG_PUFF_CLIFFS 0x02
#define OREFLAG_PUFF_ADDITIVE 0x04
#define OREFLAG_USE_NOISE 0x08
#define OREFLAG_USE_NOISE2 0x10

enum OreType {
ORE_SCATTER,
@@ -139,6 +140,7 @@ class OreStratum : public Ore {

NoiseParams np_stratum_thickness;
Noise *noise_stratum_thickness = nullptr;
u16 stratum_thickness;

OreStratum() = default;
virtual ~OreStratum();
@@ -1116,7 +1116,7 @@ int ModApiMapgen::l_register_ore(lua_State *L)
ore->flags |= OREFLAG_USE_NOISE;
} else if (ore->NEEDS_NOISE) {
errorstream << "register_ore: specified ore type requires valid "
"noise parameters" << std::endl;
"'noise_params' parameter" << std::endl;
delete ore;
return 0;
}
@@ -1161,11 +1161,13 @@ int ModApiMapgen::l_register_ore(lua_State *L)
OreStratum *orestratum = (OreStratum *)ore;

lua_getfield(L, index, "np_stratum_thickness");
// If thickness noise missing unset 'use noise' flag
if (!read_noiseparams(L, -1, &orestratum->np_stratum_thickness))
ore->flags &= ~OREFLAG_USE_NOISE;
if (read_noiseparams(L, -1, &orestratum->np_stratum_thickness))
ore->flags |= OREFLAG_USE_NOISE2;
lua_pop(L, 1);

orestratum->stratum_thickness = getintfield_default(L, index,
"stratum_thickness", 8);

break;
}
default:

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