Repair vectors in cart data, mostly fix train movement bugs (still possible to have a furnace minecart flip, without the train also flipping)

mods/ENTITIES/mcl_minecarts/functions.lua

@@ -358,7 +358,8 @@ end
 
 function mod.get_cart_position(cart_staticdata)
 	local data = cart_staticdata
-	if not data.connected_at then return end
+	if not data then return nil end
+	if not data.connected_at then return nil end
 
 	return vector.add(data.connected_at, vector.multiply(data.dir or vector.zero(), data.distance or 0))
 end

mods/ENTITIES/mcl_minecarts/movement.lua

@@ -14,6 +14,7 @@ local update_train = mod.update_train
 local link_cart_ahead = mod.link_cart_ahead
 local update_cart_orientation = mod.update_cart_orientation
 local get_cart_data = mod.get_cart_data
+local get_cart_position = mod.get_cart_position
 
 local function detach_minecart(self)
 	local staticdata = self._staticdata
@@ -118,7 +119,8 @@ local function handle_cart_collision(cart1, prev_pos, next_dir)
 	local dirty = false
 	for uuid,v in pairs(carts) do
 		-- Clean up dead carts
-		if not get_cart_data(uuid) then
+		local data = get_cart_data(uuid)
+		if not data then
 			carts[uuid] = nil
 			dirty = true
 			uuid = nil
@@ -138,13 +140,9 @@ local function handle_cart_collision(cart1, prev_pos, next_dir)
 
 	minetest.log("action","cart #"..cart1._staticdata.uuid.." collided with cart #"..cart_uuid.." at "..tostring(pos))
 
-	local cart2_aoid = mcl_util.get_active_object_id_from_uuid(cart_uuid)
-	local cart2 = minetest.luaentities[cart2_aoid]
-	if not cart2 then return end
-
 	-- Standard Collision Handling
 	local cart1_staticdata = cart1._staticdata
-	local cart2_staticdata = cart2._staticdata
+	local cart2_staticdata = get_cart_data(cart_uuid)
 
 	local u1 = cart1_staticdata.velocity
 	local u2 = cart2_staticdata.velocity
@@ -153,7 +151,7 @@ local function handle_cart_collision(cart1, prev_pos, next_dir)
 
 	--print("u1="..tostring(u1)..",u2="..tostring(u2))
 	if u2 == 0 and u1 < 4 and train_length(cart1) < MAX_TRAIN_LENGTH then
-		link_cart_ahead(cart1, cart2)
+		link_cart_ahead(cart1, {_staticdata=cart2_staticdata})
 		cart2_staticdata.dir = mcl_minecarts:get_rail_direction(cart2_staticdata.connected_at, cart1_staticdata.dir)
 		cart2_staticdata.velocity = cart1_staticdata.velocity
 		return

mods/ENTITIES/mcl_minecarts/storage.lua

@@ -16,6 +16,13 @@ local function get_cart_data(uuid)
 	if not data then
 		cart_data_fail_cache[uuid] = true
 		return nil
+	else
+		-- Repair broken data
+		if not data.distance then data.distance = 0 end
+		if data.distance == 0/0 then data.distance = 0 end
+		if data.distance == -0/0 then data.distance = 0 end
+		data.dir = vector.new(data.dir)
+		data.connected_at = vector.new(data.connected_at)
 	end
 
 	cart_data[uuid] = data

mods/ENTITIES/mcl_minecarts/train.lua

@@ -72,13 +72,14 @@ function mod.update_train(cart)
 	-- Do no special processing if the cart is not part of a train
 	if not staticdata.ahead and not staticdata.behind then return end
 
-	-- Calculate the average velocity of all train cars
-	local sum_velocity = 0
+	-- Calculate the maximum velocity of all train cars
+	local velocity = 0
+	local count = 0
 	for cart in train_cars(cart) do
-		if cart.velocity or 0 > velocity then
-			velocity = cart.velocity
-		end
+		velocity = velocity + (cart.velocity or 0)
+		count = count + 1
 	end
+	velocity = velocity / count
 	print("Using velocity "..tostring(velocity))
 
 	-- Set the entire train to the average velocity
@@ -86,17 +87,19 @@ function mod.update_train(cart)
 	for c in train_cars(cart) do
 		local e = 0
 		local separation
+		local cart_velocity = velocity
 		if behind then
 			separation = distance_between_cars(behind, c)
 			local e = 0
-			if separation > 1.25 then
-				velocity = velocity * 0.9
+			if separation > 1.6 then
+				cart_velocity = velocity * 0.9
 			elseif separation < 1.15 then
-				velocity = velocity * 1.1
+				cart_velocity = velocity * 1.1
 			end
 		end
-		print(tostring(c.behind).."->"..c.uuid.."->"..tostring(c.ahead).."("..tostring(separation)..")  setting cart #"..c.uuid.." velocity to "..tostring(velocity))
-		c.velocity = velocity
+		print(tostring(c.behind).."->"..c.uuid.."->"..tostring(c.ahead).."("..tostring(separation)..")  setting cart #"..
+			c.uuid.." velocity from "..tostring(c.velocity).." to "..tostring(cart_velocity))
+		c.velocity = cart_velocity
 
 		behind = c
 	end