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.

3 files changed, 22 insertions, 9 deletions

diff --git a/src/mapgen/mg_ore.cpp b/src/mapgen/mg_ore.cpp
index 979135ed4..297472420 100644
--- a/src/mapgen/mg_ore.cpp
+++ b/src/mapgen/mg_ore.cpp
@@ -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;
 		}
diff --git a/src/mapgen/mg_ore.h b/src/mapgen/mg_ore.h
index e715f348b..2bbc8c578 100644
--- a/src/mapgen/mg_ore.h
+++ b/src/mapgen/mg_ore.h
@@ -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 @@ public:
 
 	NoiseParams np_stratum_thickness;
 	Noise *noise_stratum_thickness = nullptr;
+	u16 stratum_thickness;
 
 	OreStratum() = default;
 	virtual ~OreStratum();
diff --git a/src/script/lua_api/l_mapgen.cpp b/src/script/lua_api/l_mapgen.cpp
index 01f9d1c41..e39370323 100644
--- a/src/script/lua_api/l_mapgen.cpp
+++ b/src/script/lua_api/l_mapgen.cpp
@@ -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: