Allow nodes to specify which sides to connect to.

NDT_CONNECTED attempts to connect to any side of nodes that it can
connect to, which is troublesome for FACEDIR type nodes that generally
may only have one usable face, and can be rotated.

We introduce a node parameter `connect_sides` that is valid for
any node type. If specified, it lists faces of the node (in "top",
"bottom", "front", "left", "back", "right", form, as array) that
connecting nodeboxes can connect to. "front" corresponds to the south
facing side of a node with facedir = 0.

If the node is rotatable using *simple* FACEDIR, then the attached
face is properly rotated before checking. This allows e.g. a chest
to be attached to only from the rear side.

1 files changed, 28 insertions, 0 deletions

diff --git a/src/script/common/c_content.cpp b/src/script/common/c_content.cpp
index ababf0718..06e20c2a0 100644
--- a/src/script/common/c_content.cpp
+++ b/src/script/common/c_content.cpp
@@ -547,6 +547,34 @@ ContentFeatures read_content_features(lua_State *L, int index)
 	}
 	lua_pop(L, 1);
 
+	lua_getfield(L, index, "connect_sides");
+	if (lua_istable(L, -1)) {
+		int table = lua_gettop(L);
+		lua_pushnil(L);
+		while (lua_next(L, table) != 0) {
+			// Value at -1
+			std::string side(lua_tostring(L, -1));
+			// Note faces are flipped to make checking easier
+			if (side == "top")
+				f.connect_sides |= 2;
+			else if (side == "bottom")
+				f.connect_sides |= 1;
+			else if (side == "front")
+				f.connect_sides |= 16;
+			else if (side == "left")
+				f.connect_sides |= 32;
+			else if (side == "back")
+				f.connect_sides |= 4;
+			else if (side == "right")
+				f.connect_sides |= 8;
+			else
+				warningstream << "Unknown value for \"connect_sides\": "
+					<< side << std::endl;
+			lua_pop(L, 1);
+		}
+	}
+	lua_pop(L, 1);
+
 	lua_getfield(L, index, "selection_box");
 	if(lua_istable(L, -1))
 		f.selection_box = read_nodebox(L, -1);