Fix several undefined global warnings, fix cart movement when over maximum speed, fix cart reattachment to sloped track

mods/CORE/mcl_util/init.lua

@@ -1207,7 +1207,7 @@ function mcl_util.assign_uuid(obj)
 	end
 
 	-- Update the cache with this new id
-	aoid = mcl_util.get_active_object_id(obj)
+	local aoid = mcl_util.get_active_object_id(obj)
 	uuid_to_aoid_cache[le._uuid] = aoid
 
 	return le._uuid

mods/ENTITIES/mcl_minecarts/carts.lua

@@ -352,7 +352,7 @@ end
 function mod.create_minecart(entity_id, pos, dir)
 	-- Setup cart data
 	local uuid = mcl_util.gen_uuid()
-	data = make_staticdata( nil, pos, dir )
+	local data = make_staticdata( nil, pos, dir )
 	data.uuid = uuid
 	data.cart_type = entity_id
 	update_cart_data(data)
@@ -390,28 +390,21 @@ function mod.place_minecart(itemstack, pointed_thing, placer)
 	-- Create the entity with the staticdata already setup
 	local sd = minetest.serialize({ uuid=uuid, seq=1 })
 	local cart = minetest.add_entity(spawn_pos, entity_id, sd)
+	local staticdata = get_cart_data(uuid)
 
 	cart:set_yaw(minetest.dir_to_yaw(cart_dir))
 
-	-- Update static data
-	local le = cart:get_luaentity()
-	if le then
-		le._staticdata = data
-	end
-
 	-- Call placer
+	local le = cart:get_luaentity()
 	if le._mcl_minecarts_on_place then
 		le._mcl_minecarts_on_place(le, placer)
 	end
 
 	if railpos then
-		handle_cart_enter(data, railpos)
+		handle_cart_enter(staticdata, railpos)
 	end
 
-	local pname = ""
+	local pname = placer and placer:get_player_name() or ""
-	if placer then
-		pname = placer:get_player_name()
-	end
 	if not minetest.is_creative_enabled(pname) then
 		itemstack:take_item()
 	end

mods/ENTITIES/mcl_minecarts/movement.lua

@@ -9,6 +9,7 @@ local mcl_debug,DEBUG = mcl_util.make_mcl_logger("mcl_logging_minecart_debug", "
 --mcl_debug = function(msg) print(msg) end
 
 -- Imports
+local mcl_physics = mcl_physics or false
 local FRICTION = mcl_minecarts.FRICTION
 local MAX_TRAIN_LENGTH = mod.MAX_TRAIN_LENGTH
 local SPEED_MAX = mod.SPEED_MAX
@@ -315,7 +316,6 @@ local function do_movement_step(staticdata, dtime)
 		        ",v_0="..tostring(v_0)..
 		        ",x_0="..tostring(x_0)..
 			",dtime="..tostring(dtime)..
-		        ",timestep="..tostring(timestep)..
 		        ",dir="..tostring(staticdata.dir)..
 			",connected_at="..tostring(staticdata.connected_at)..
 			",distance="..tostring(staticdata.distance)
@@ -347,7 +347,7 @@ local function do_movement_step(staticdata, dtime)
 
 	-- Truncate timestep to prevent v_1 from being larger that speed_max
 	local v_max = SPEED_MAX
-	if (v_0 ~= v_max) and ( v_0 + a * timestep > v_max) then
+	if (v_0 < v_max) and ( v_0 + a * timestep > v_max) then
 		timestep = ( v_max - v_0 ) / a
 	end
 
@@ -519,7 +519,18 @@ local function do_detached_movement(self, dtime)
 	end
 
 	-- Try to reconnect to rail
-	local pos_r = vector.round(self.object:get_pos())
+	local pos = self.object:get_pos()
+	local yaw = self.object:get_yaw()
+	local yaw_dir = minetest.yaw_to_dir(yaw)
+	local test_positions = {
+		pos,
+		vector.offset(vector.add(pos, vector.multiply(yaw_dir, 0.5)),0,-0.3,0),
+		vector.offset(vector.add(pos, vector.multiply(yaw_dir,-0.5)),0,-0.3,0),
+	}
+
+	for i=1,#test_positions do
+		test_pos = test_positions[i]
+		local pos_r = vector.round(test_pos)
 		local node = minetest.get_node(pos_r)
 		if minetest.get_item_group(node.name, "rail") ~= 0 then
 			staticdata.connected_at = pos_r
@@ -531,10 +542,13 @@ local function do_detached_movement(self, dtime)
 			-- Use vector projection to only keep the velocity in the new direction of movement on the rail
 			-- https://en.wikipedia.org/wiki/Vector_projection
 			staticdata.velocity = vector.dot(staticdata.dir,freebody_velocity)
+			print("Reattached velocity="..tostring(staticdata.velocity)..", freebody_velocity="..tostring(freebody_velocity))
 
 			-- Clear freebody movement
 			self.object:set_velocity(vector.new(0,0,0))
 			self.object:set_acceleration(vector.new(0,0,0))
+			return
+		end
 	end
 end