Schematics: Add core.place_schematic_on_vmanip API

Fix memory leak in minetest.place_schematic
Slightly refactor Schematic code

doc/lua_api.txt

@@ -2294,6 +2294,15 @@ These functions return the leftover itemstack.
     * `replacements` = `{["old_name"] = "convert_to", ...}`
     * `force_placement` is a boolean indicating whether nodes other than `air` and
       `ignore` are replaced by the schematic
+    * Returns nil if the schematic could not be loaded.
+
+* `minetest.place_schematic_on_vmanip(vmanip, pos, schematic, rotation, replacement, force_placement)`:
+    * This function is analagous to minetest.place_schematic, but places a schematic onto the
+      specified VoxelManip object `vmanip` instead of the whole map.
+    * Returns false if any part of the schematic was cut-off due to the VoxelManip not
+      containing the full area required, and true if the whole schematic was able to fit.
+    * Returns nil if the schematic could not be loaded.
+    * After execution, any external copies of the VoxelManip contents are invalidated.
 
 * `minetest.serialize_schematic(schematic, format, options)`
     * Return the serialized schematic specified by schematic (see: Schematic specifier)

src/mg_decoration.cpp

@@ -351,7 +351,7 @@ size_t DecoSchematic::generate(MMVManip *vm, PseudoRandom *pr, v3s16 p)
 
 	bool force_placement = (flags & DECO_FORCE_PLACEMENT);
 
-	schematic->blitToVManip(p, vm, rot, force_placement);
+	schematic->blitToVManip(vm, p, rot, force_placement);
 
 	return 1;
 }

src/mg_schematic.cpp

@@ -94,7 +94,7 @@ void Schematic::resolveNodeNames()
 }
 
 
-void Schematic::blitToVManip(v3s16 p, MMVManip *vm, Rotation rot, bool force_place)
+void Schematic::blitToVManip(MMVManip *vm, v3s16 p, Rotation rot, bool force_place)
 {
 	sanity_check(m_ndef != NULL);
 
@@ -175,20 +175,21 @@ void Schematic::blitToVManip(v3s16 p, MMVManip *vm, Rotation rot, bool force_pla
 }
 
 
-void Schematic::placeStructure(Map *map, v3s16 p, u32 flags,
+bool Schematic::placeOnVManip(MMVManip *vm, v3s16 p, u32 flags,
 	Rotation rot, bool force_place)
 {
-	assert(schemdata != NULL); // Pre-condition
+	assert(vm != NULL);
+	assert(schemdata != NULL);
 	sanity_check(m_ndef != NULL);
 
-	MMVManip *vm = new MMVManip(map);
-
+	//// Determine effective rotation and effective schematic dimensions
 	if (rot == ROTATE_RAND)
 		rot = (Rotation)myrand_range(ROTATE_0, ROTATE_270);
 
 	v3s16 s = (rot == ROTATE_90 || rot == ROTATE_270) ?
-				v3s16(size.Z, size.Y, size.X) : size;
+		v3s16(size.Z, size.Y, size.X) : size;
 
+	//// Adjust placement position if necessary
 	if (flags & DECO_PLACE_CENTER_X)
 		p.X -= (s.X + 1) / 2;
 	if (flags & DECO_PLACE_CENTER_Y)
@@ -196,25 +197,60 @@ void Schematic::placeStructure(Map *map, v3s16 p, u32 flags,
 	if (flags & DECO_PLACE_CENTER_Z)
 		p.Z -= (s.Z + 1) / 2;
 
-	v3s16 bp1 = getNodeBlockPos(p);
-	v3s16 bp2 = getNodeBlockPos(p + s - v3s16(1,1,1));
-	vm->initialEmerge(bp1, bp2);
+	blitToVManip(vm, p, rot, force_place);
 
-	blitToVManip(p, vm, rot, force_place);
+	return vm->m_area.contains(VoxelArea(p, p + s - v3s16(1,1,1)));
+}
 
+void Schematic::placeOnMap(Map *map, v3s16 p, u32 flags,
+	Rotation rot, bool force_place)
+{
 	std::map<v3s16, MapBlock *> lighting_modified_blocks;
 	std::map<v3s16, MapBlock *> modified_blocks;
-	vm->blitBackAll(&modified_blocks);
+	std::map<v3s16, MapBlock *>::iterator it;
 
+	assert(map != NULL);
+	assert(schemdata != NULL);
+	sanity_check(m_ndef != NULL);
+
+	//// Determine effective rotation and effective schematic dimensions
+	if (rot == ROTATE_RAND)
+		rot = (Rotation)myrand_range(ROTATE_0, ROTATE_270);
+
+	v3s16 s = (rot == ROTATE_90 || rot == ROTATE_270) ?
+			v3s16(size.Z, size.Y, size.X) : size;
+
+	//// Adjust placement position if necessary
+	if (flags & DECO_PLACE_CENTER_X)
+		p.X -= (s.X + 1) / 2;
+	if (flags & DECO_PLACE_CENTER_Y)
+		p.Y -= (s.Y + 1) / 2;
+	if (flags & DECO_PLACE_CENTER_Z)
+		p.Z -= (s.Z + 1) / 2;
+
+	//// Create VManip for effected area, emerge our area, modify area
+	//// inside VManip, then blit back.
+	v3s16 bp1 = getNodeBlockPos(p);
+	v3s16 bp2 = getNodeBlockPos(p + s - v3s16(1,1,1));
+
+	MMVManip vm(map);
+	vm.initialEmerge(bp1, bp2);
+
+	blitToVManip(&vm, p, rot, force_place);
+
+	vm.blitBackAll(&modified_blocks);
+
+	//// Carry out post-map-modification actions
+
+	//// Update lighting
 	// TODO: Optimize this by using Mapgen::calcLighting() instead
 	lighting_modified_blocks.insert(modified_blocks.begin(), modified_blocks.end());
 	map->updateLighting(lighting_modified_blocks, modified_blocks);
 
+	//// Create & dispatch map modification events to observers
 	MapEditEvent event;
 	event.type = MEET_OTHER;
-	for (std::map<v3s16, MapBlock *>::iterator
-		it = modified_blocks.begin();
-		it != modified_blocks.end(); ++it)
+	for (it = modified_blocks.begin(); it != modified_blocks.end(); ++it)
 		event.modified_blocks.insert(it->first);
 
 	map->dispatchEvent(&event);

src/mg_schematic.h

@@ -106,8 +106,9 @@ public:
 	bool serializeToLua(std::ostream *os, const std::vector<std::string> &names,
 		bool use_comments, u32 indent_spaces);
 
-	void blitToVManip(v3s16 p, MMVManip *vm, Rotation rot, bool force_place);
-	void placeStructure(Map *map, v3s16 p, u32 flags, Rotation rot, bool force_place);
+	void blitToVManip(MMVManip *vm, v3s16 p, Rotation rot, bool force_place);
+	bool placeOnVManip(MMVManip *vm, v3s16 p, u32 flags, Rotation rot, bool force_place);
+	void placeOnMap(Map *map, v3s16 p, u32 flags, Rotation rot, bool force_place);
 
 	void applyProbabilities(v3s16 p0,
 		std::vector<std::pair<v3s16, u8> > *plist,

src/script/lua_api/l_mapgen.cpp

@@ -1271,12 +1271,54 @@ int ModApiMapgen::l_place_schematic(lua_State *L)
 		return 0;
 	}
 
-	schem->placeStructure(map, p, 0, (Rotation)rot, force_placement);
+	schem->placeOnMap(map, p, 0, (Rotation)rot, force_placement);
 
 	lua_pushboolean(L, true);
 	return 1;
 }
 
+int ModApiMapgen::l_place_schematic_on_vmanip(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	SchematicManager *schemmgr = getServer(L)->getEmergeManager()->schemmgr;
+
+	//// Read VoxelManip object
+	MMVManip *vm = LuaVoxelManip::checkobject(L, 1)->vm;
+
+	//// Read position
+	v3s16 p = check_v3s16(L, 2);
+
+	//// Read rotation
+	int rot = ROTATE_0;
+	const char *enumstr = lua_tostring(L, 4);
+	if (enumstr)
+		string_to_enum(es_Rotation, rot, std::string(enumstr));
+
+	//// Read force placement
+	bool force_placement = true;
+	if (lua_isboolean(L, 6))
+		force_placement = lua_toboolean(L, 6);
+
+	//// Read node replacements
+	StringMap replace_names;
+	if (lua_istable(L, 5))
+		read_schematic_replacements(L, 5, &replace_names);
+
+	//// Read schematic
+	Schematic *schem = get_or_load_schematic(L, 3, schemmgr, &replace_names);
+	if (!schem) {
+		errorstream << "place_schematic: failed to get schematic" << std::endl;
+		return 0;
+	}
+
+	bool schematic_did_fit = schem->placeOnVManip(
+		vm, p, 0, (Rotation)rot, force_placement);
+
+	lua_pushboolean(L, schematic_did_fit);
+	return 1;
+}
+
 // serialize_schematic(schematic, format, options={...})
 int ModApiMapgen::l_serialize_schematic(lua_State *L)
 {
@@ -1355,5 +1397,6 @@ void ModApiMapgen::Initialize(lua_State *L, int top)
 	API_FCT(generate_decorations);
 	API_FCT(create_schematic);
 	API_FCT(place_schematic);
+	API_FCT(place_schematic_on_vmanip);
 	API_FCT(serialize_schematic);
 }

src/script/lua_api/l_mapgen.h

@@ -85,9 +85,13 @@ private:
 	// create_schematic(p1, p2, probability_list, filename)
 	static int l_create_schematic(lua_State *L);
 
-	// place_schematic(p, schematic, rotation, replacement)
+	// place_schematic(p, schematic, rotation, replacements, force_placement)
 	static int l_place_schematic(lua_State *L);
 
+	// place_schematic_on_vmanip(vm, p, schematic,
+	//     rotation, replacements, force_placement)
+	static int l_place_schematic_on_vmanip(lua_State *L);
+
 	// serialize_schematic(schematic, format, options={...})
 	static int l_serialize_schematic(lua_State *L);