Lighting: Fix nearly all issues

The cause of a single light source seemingly being lit without spread
was due to its creation in the +Y mapblock boundary layer during map
generation, which was ignored as the overtop.  This overtop explicitly
needs to be omitted during sunlight propagation, however.  To accomplish
this, Mapgen::calcLighting() was split into separate functions taking
separate parameters.
Additionally, do not diminish light too early during spread.  This fixes the
output inconsistency between Map::updateLighting and Mapgen::calcLighting.

7 files changed, 54 insertions, 30 deletions

diff --git a/src/mapgen.cpp b/src/mapgen.cpp
index c1b8889a8..44df35a07 100644
--- a/src/mapgen.cpp
+++ b/src/mapgen.cpp
@@ -243,14 +243,28 @@ void Mapgen::lightSpread(VoxelArea &a, v3s16 p, u8 light)
 
 void Mapgen::calcLighting(v3s16 nmin, v3s16 nmax)
 {
-	VoxelArea a(nmin, nmax);
-	bool block_is_underground = (water_level >= nmax.Y);
-
 	ScopeProfiler sp(g_profiler, "EmergeThread: mapgen lighting update", SPT_AVG);
 	//TimeTaker t("updateLighting");
 
-	// first, send vertical rays of sunshine downward
+	propagateSunlight(
+		nmin - v3s16(1, 1, 1) * MAP_BLOCKSIZE,
+		nmax + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
+
+	spreadLight(
+		nmin - v3s16(1, 1, 1) * MAP_BLOCKSIZE,
+		nmax + v3s16(1, 1, 1) * MAP_BLOCKSIZE);
+
+	//printf("updateLighting: %dms\n", t.stop());
+}
+
+
+void Mapgen::propagateSunlight(v3s16 nmin, v3s16 nmax)
+{
+	//TimeTaker t("propagateSunlight");
+	VoxelArea a(nmin, nmax);
+	bool block_is_underground = (water_level >= nmax.Y);
 	v3s16 em = vm->m_area.getExtent();
+
 	for (int z = a.MinEdge.Z; z <= a.MaxEdge.Z; z++) {
 		for (int x = a.MinEdge.X; x <= a.MaxEdge.X; x++) {
 			// see if we can get a light value from the overtop
@@ -272,8 +286,17 @@ void Mapgen::calcLighting(v3s16 nmin, v3s16 nmax)
 			}
 		}
 	}
+	//printf("propagateSunlight: %dms\n", t.stop());
+}
+
+
+
+void Mapgen::spreadLight(v3s16 nmin, v3s16 nmax)
+{
+	//TimeTaker t("spreadLight");
+	VoxelArea a(nmin, nmax);
+	v3s16 em = vm->m_area.getExtent();
 
-	// now spread the sunlight and light up any sources
 	for (int z = a.MinEdge.Z; z <= a.MaxEdge.Z; z++) {
 		for (int y = a.MinEdge.Y; y <= a.MaxEdge.Y; y++) {
 			u32 i = vm->m_area.index(a.MinEdge.X, y, z);
@@ -289,21 +312,22 @@ void Mapgen::calcLighting(v3s16 nmin, v3s16 nmax)
 
 				u8 light = n.param1 & 0x0F;
 				if (light) {
-					lightSpread(a, v3s16(x,     y,     z + 1), light - 1);
-					lightSpread(a, v3s16(x,     y + 1, z    ), light - 1);
-					lightSpread(a, v3s16(x + 1, y,     z    ), light - 1);
-					lightSpread(a, v3s16(x,     y,     z - 1), light - 1);
-					lightSpread(a, v3s16(x,     y - 1, z    ), light - 1);
-					lightSpread(a, v3s16(x - 1, y,     z    ), light - 1);
+					lightSpread(a, v3s16(x,     y,     z + 1), light);
+					lightSpread(a, v3s16(x,     y + 1, z    ), light);
+					lightSpread(a, v3s16(x + 1, y,     z    ), light);
+					lightSpread(a, v3s16(x,     y,     z - 1), light);
+					lightSpread(a, v3s16(x,     y - 1, z    ), light);
+					lightSpread(a, v3s16(x - 1, y,     z    ), light);
 				}
 			}
 		}
 	}
 
-	//printf("updateLighting: %dms\n", t.stop());
+	//printf("spreadLight: %dms\n", t.stop());
 }
 
 
+
 void Mapgen::calcLightingOld(v3s16 nmin, v3s16 nmax)
 {
 	enum LightBank banks[2] = {LIGHTBANK_DAY, LIGHTBANK_NIGHT};
diff --git a/src/mapgen.h b/src/mapgen.h
index aaa89d3bc..2ac66d354 100644
--- a/src/mapgen.h
+++ b/src/mapgen.h
@@ -156,7 +156,11 @@ public:
 	void updateLiquid(UniqueQueue<v3s16> *trans_liquid, v3s16 nmin, v3s16 nmax);
 	void setLighting(v3s16 nmin, v3s16 nmax, u8 light);
 	void lightSpread(VoxelArea &a, v3s16 p, u8 light);
+
 	void calcLighting(v3s16 nmin, v3s16 nmax);
+	void propagateSunlight(v3s16 nmin, v3s16 nmax);
+	void spreadLight(v3s16 nmin, v3s16 nmax);
+
 	void calcLightingOld(v3s16 nmin, v3s16 nmax);
 
 	virtual void makeChunk(BlockMakeData *data) {}
diff --git a/src/mapgen_singlenode.cpp b/src/mapgen_singlenode.cpp
index 2e7b3dc88..5f81aba98 100644
--- a/src/mapgen_singlenode.cpp
+++ b/src/mapgen_singlenode.cpp
@@ -101,8 +101,7 @@ void MapgenSinglenode::makeChunk(BlockMakeData *data)
 
 	// Calculate lighting
 	if (flags & MG_LIGHT)
-		calcLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
-					 node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
+		calcLighting(node_min, node_max);
 
 	this->generating = false;
 }
diff --git a/src/mapgen_v5.cpp b/src/mapgen_v5.cpp
index 24c81e56d..16fe4be5d 100644
--- a/src/mapgen_v5.cpp
+++ b/src/mapgen_v5.cpp
@@ -290,8 +290,7 @@ void MapgenV5::makeChunk(BlockMakeData *data)
 
 	// Calculate lighting
 	if (flags & MG_LIGHT)
-		calcLighting(node_min - v3s16(0, 1, 0) - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
-			node_max + v3s16(0, 1, 0) + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
+		calcLighting(node_min - v3s16(0, 1, 0), node_max + v3s16(0, 1, 0));
 
 	this->generating = false;
 }
diff --git a/src/mapgen_v6.cpp b/src/mapgen_v6.cpp
index b97512535..3d9f4c517 100644
--- a/src/mapgen_v6.cpp
+++ b/src/mapgen_v6.cpp
@@ -534,7 +534,7 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 	}
 
 	// Add top and bottom side of water to transforming_liquid queue
-	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
+	//updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 
 	// Grow grass
 	growGrass();
@@ -551,8 +551,7 @@ void MapgenV6::makeChunk(BlockMakeData *data)
 
 	// Calculate lighting
 	if (flags & MG_LIGHT)
-		calcLighting(node_min - v3s16(1, 1, 1) * MAP_BLOCKSIZE,
-					 node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
+		calcLighting(node_min, node_max);
 
 	this->generating = false;
 }
diff --git a/src/mapgen_v7.cpp b/src/mapgen_v7.cpp
index 3b7c20b96..a7a56f378 100644
--- a/src/mapgen_v7.cpp
+++ b/src/mapgen_v7.cpp
@@ -260,8 +260,7 @@ void MapgenV7::makeChunk(BlockMakeData *data)
 	updateLiquid(&data->transforming_liquid, full_node_min, full_node_max);
 
 	if (flags & MG_LIGHT)
-		calcLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
-					 node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE);
+		calcLighting(node_min, node_max);
 	//setLighting(node_min - v3s16(1, 0, 1) * MAP_BLOCKSIZE,
 	//			node_max + v3s16(1, 0, 1) * MAP_BLOCKSIZE, 0xFF);
 
diff --git a/src/script/lua_api/l_vmanip.cpp b/src/script/lua_api/l_vmanip.cpp
index 6c12baf92..bf702eaff 100644
--- a/src/script/lua_api/l_vmanip.cpp
+++ b/src/script/lua_api/l_vmanip.cpp
@@ -168,10 +168,8 @@ int LuaVoxelManip::l_calc_lighting(lua_State *L)
 	EmergeManager *emerge = getServer(L)->getEmergeManager();
 	ManualMapVoxelManipulator *vm = o->vm;
 
-	v3s16 p1 = lua_istable(L, 2) ? read_v3s16(L, 2) :
-		vm->m_area.MinEdge + v3s16(0, 1, 0) * MAP_BLOCKSIZE;
-	v3s16 p2 = lua_istable(L, 3) ? read_v3s16(L, 3) :
-		vm->m_area.MaxEdge - v3s16(0, 1, 0) * MAP_BLOCKSIZE;
+	v3s16 p1 = lua_istable(L, 2) ? read_v3s16(L, 2) : vm->m_area.MinEdge;
+	v3s16 p2 = lua_istable(L, 3) ? read_v3s16(L, 3) : vm->m_area.MaxEdge;
 	sortBoxVerticies(p1, p2);
 
 	Mapgen mg;
@@ -179,7 +177,11 @@ int LuaVoxelManip::l_calc_lighting(lua_State *L)
 	mg.ndef        = ndef;
 	mg.water_level = emerge->params.water_level;
 
-	mg.calcLighting(p1, p2);
+	// Mapgen::calcLighting assumes the coordinates of
+	// the central chunk; correct for this
+	mg.calcLighting(
+		p1 + v3s16(1, 1, 1) * MAP_BLOCKSIZE,
+		p2 - v3s16(1, 1, 1) * MAP_BLOCKSIZE);
 
 	return 0;
 }
@@ -201,10 +203,8 @@ int LuaVoxelManip::l_set_lighting(lua_State *L)
 
 	ManualMapVoxelManipulator *vm = o->vm;
 
-	v3s16 p1 = lua_istable(L, 3) ? read_v3s16(L, 3) :
-		vm->m_area.MinEdge + v3s16(0, 1, 0) * MAP_BLOCKSIZE;
-	v3s16 p2 = lua_istable(L, 4) ? read_v3s16(L, 4) :
-		vm->m_area.MaxEdge - v3s16(0, 1, 0) * MAP_BLOCKSIZE;
+	v3s16 p1 = lua_istable(L, 3) ? read_v3s16(L, 3) : vm->m_area.MinEdge;
+	v3s16 p2 = lua_istable(L, 4) ? read_v3s16(L, 4) : vm->m_area.MaxEdge;
 	sortBoxVerticies(p1, p2);
 
 	Mapgen mg;