Make the collision mode configurable

If the advtrains_forgiving_collision setting is set to true, then the
train only collides with nodes that do not have normal
drawtype. Otherwise the old behavior is restored. This change is being
made because there were users and mods relying on the old behavior,
such as the railroad_paraphernalia mod's track blocker.

advtrains/settingtypes.txt

@@ -56,3 +56,8 @@ advtrains_dtime_limit (DTime Limit for slow-down) float 0.2 0 5
 #    Time interval in seconds in which advtrains stores its save data to disk
 #    Nevertheless, advtrains saves all data when shutting down the server.
 advtrains_save_interval (Save Interval) int 60 20 3600
+
+#    Enable forgiving collision mode
+#    If enabled, trains only collide with nodes with "normal" drawtype.
+advtrains_forgiving_collision (Forgiving Collision mode) bool false
+

advtrains/trainlogic.lua

@@ -1368,17 +1368,61 @@ function advtrains.invalidate_path(id)
 end
 
 --not blocking trains group
-function advtrains.train_collides(node)
-	if node and minetest.registered_nodes[node.name] then
-		local ndef = minetest.registered_nodes[node.name]
-		-- if the node is drawtype normal (that is a full cube) then it does collide
-		if ndef.drawtype == "normal" then
-			-- except if it is not_blocking_trains
-			if ndef.groups.not_blocking_trains and ndef.groups.not_blocking_trains ~= 0 then
-				return false
+
+if minetest.settings:get_bool("advtrains_forgiving_collision") then
+	function advtrains.train_collides(node)
+		if node and minetest.registered_nodes[node.name] then
+			local ndef = minetest.registered_nodes[node.name]
+			-- if the node is drawtype normal (that is a full cube) then it does collide
+			if ndef.drawtype == "normal" then
+				-- except if it is not_blocking_trains
+				if ndef.groups.not_blocking_trains and ndef.groups.not_blocking_trains ~= 0 then
+					return false
+				end
+				return true
 			end
+		end
+		return false
+	end
+else
+	function advtrains.train_collides(node)
+		if node and minetest.registered_nodes[node.name] and minetest.registered_nodes[node.name].walkable then
+		if not minetest.registered_nodes[node.name].groups.not_blocking_trains then
 			return true
 		end
+		end
+		return false
 	end
-	return false
+	
+	local nonblocknodes={
+		"default:fence_wood",
+		"default:fence_acacia_wood",
+		"default:fence_aspen_wood",
+		"default:fence_pine_wood",
+		"default:fence_junglewood",
+		"default:torch",
+		"bones:bones",
+		
+		"default:sign_wall",
+		"signs:sign_wall",
+		"signs:sign_wall_blue",
+		"signs:sign_wall_brown",
+		"signs:sign_wall_orange",
+		"signs:sign_wall_green",
+		"signs:sign_yard",
+		"signs:sign_wall_white_black",
+		"signs:sign_wall_red",
+		"signs:sign_wall_white_red",
+		"signs:sign_wall_yellow",
+		"signs:sign_post",
+		"signs:sign_hanging",
+		
+	}
+	minetest.after(0, function()
+							for _,name in ipairs(nonblocknodes) do
+								if minetest.registered_nodes[name] then
+									minetest.registered_nodes[name].groups.not_blocking_trains=1
+								end
+							end
+	end)
 end