Basic powered rails implementation

mods/ENTITIES/mcl_minecarts/functions.lua

@@ -138,13 +138,3 @@ function mcl_minecarts:get_rail_direction(pos_, dir, ctrl, old_switch, railtype)
 	return {x=0, y=0, z=0}
 end
 
-function mcl_minecarts:boost_rail(pos, amount)
-	minetest.get_meta(pos):set_string("cart_acceleration", tostring(amount))
-	for _,obj_ in ipairs(minetest.get_objects_inside_radius(pos, 0.5)) do
-		if not obj_:is_player() and
-				obj_:get_luaentity() and
-				obj_:get_luaentity().name == "mcl_minecarts:minecart" then
-			obj_:get_luaentity():on_punch()
-		end
-	end
-end

mods/ENTITIES/mcl_minecarts/init.lua

@@ -31,6 +31,7 @@ local function register_entity(entity_id, mesh, textures, drop, on_rightclick)
 		_start_pos = nil, -- Used to calculate distance for “On A Rail” achievement
 		_old_dir = {x=0, y=0, z=0},
 		_old_pos = nil,
+		_old_vel = {x=0, y=0, z=0},
 		_old_switch = 0,
 		_railtype = nil,
 	}
@@ -128,6 +129,18 @@ local function register_entity(entity_id, mesh, textures, drop, on_rightclick)
 				ctrl = player:get_player_control()
 			end
 		end
+
+		-- Stop cart if velocity vector flips
+		if self._old_vel and self._old_vel.y == 0 and
+				(self._old_vel.x * vel.x < 0 or self._old_vel.z * vel.z < 0) then
+			self._old_vel = {x = 0, y = 0, z = 0}
+			self._old_pos = pos
+			self.object:setvelocity(vector.new())
+			self.object:setacceleration(vector.new())
+			return
+		end
+		self._old_vel = vector.new(vel)
+
 		if self._old_pos then
 			local diff = vector.subtract(self._old_pos, pos)
 			for _,v in ipairs({"x","y","z"}) do
@@ -187,17 +200,9 @@ local function register_entity(entity_id, mesh, textures, drop, on_rightclick)
 			-- Slow down or speed up
 			local acc = dir.y * -1.8
 
-			local speed_mod = tonumber(minetest.get_meta(pos):get_string("cart_acceleration"))
+			local speed_mod = minetest.registered_nodes[minetest.get_node(pos).name]._rail_acceleration
 			if speed_mod and speed_mod ~= 0 then
-				if speed_mod > 0 then
-					for _,v in ipairs({"x","y","z"}) do
-						if math.abs(vel[v]) >= max_vel then
-							speed_mod = 0
-							break
-						end
-					end
-				end
-				acc = acc + (speed_mod * 8)
+				acc = acc + speed_mod
 			else
 				acc = acc - 0.4
 			end
@@ -214,6 +219,7 @@ local function register_entity(entity_id, mesh, textures, drop, on_rightclick)
 		for _,v in ipairs({"x","y","z"}) do
 			if math.abs(vel[v]) > max_vel then
 				vel[v] = mcl_minecarts:get_sign(vel[v]) * max_vel
+				new_acc[v] = 0
 				update.vel = true
 			end
 		end

mods/ENTITIES/mcl_minecarts/rails.lua

@@ -33,11 +33,26 @@ minetest.register_craft({
 	}
 })
 
--- Rail to speed up
-minetest.register_node("mcl_minecarts:golden_rail", {
+-- Function that get the input/output rules of the powered rails
+local get_input_rules = function()
+	return {
+		{x = -1, y = 0, z = 0},
+		{x = 1, y = 0, z = 0},
+		{x = 0, y = 0, z = -1},
+		{x = 0, y = 0, z = 1},
+	}
+end
+
+local get_output_rules = function()
+	return {}
+end
+
+-- Powered rail
+
+local powered_rail_template = {
 	description = "Powered Rail",
-	_doc_items_longdesc = "Rails can be used to build transport tracks for minecarts. Powered rails will accelerate moving minecarts, up to a maximum speed.",
-	_doc_items_usagehelp = railuse,
+	_doc_items_longdesc = "Rails can be used to build transport tracks for minecarts. Powered rails are able to accelerate and brake minecarts.",
+	_doc_items_usagehelp = railuse .. "\n" .. "Without redstone power, the rail will brake minecarts. To make this rail accelerate minecarts, power it with redstone power.",
 	drawtype = "raillike",
 	tiles = {"carts_rail_pwr.png", "carts_rail_curved_pwr.png", "carts_rail_t_junction_pwr.png", "carts_rail_crossing_pwr.png"},
 	inventory_image = "carts_rail_pwr.png",
@@ -47,31 +62,61 @@ minetest.register_node("mcl_minecarts:golden_rail", {
 	walkable = false,
 	selection_box = {
 		type = "fixed",
-		-- but how to specify the dimensions for curved and sideways rails?
 		fixed = {-1/2, -1/2, -1/2, 1/2, -1/2+1/16, 1/2},
 	},
 	groups = {handy=1,pickaxey=1, attached_node = 1, rail = 1, connect_to_raillike = 1, dig_by_water = 1,destroy_by_lava_flow=1, transport = 1},
 
-	after_place_node = function(pos, placer, itemstack)
-		if not mesecon then
-			minetest.get_meta(pos):set_string("cart_acceleration", "0.5")
-		end
-	end,
 	sounds = mcl_sounds.node_sound_metal_defaults(),
 	mesecons = {
 		effector = {
 			action_on = function(pos, node)
-				mcl_minecarts:boost_rail(pos, 0.5)
+				minetest.swap_node(pos, {name = "mcl_minecarts:golden_rail_on", param2 = node.param2 })
+				mesecon:receptor_on(pos, get_input_rules())
 			end,
+		},
+		receptor = {
+			state = mesecon.state.off,
+			rules = get_output_rules,
+		},
+	},
 
-			action_off = function(pos, node)
-				minetest.get_meta(pos):set_string("cart_acceleration", "0")
-			end,
-		},
-	},
+	_rail_acceleration = -3,
 	_mcl_blast_resistance = 3.5,
 	_mcl_hardness = 0.7,
-})
+}
+minetest.register_node("mcl_minecarts:golden_rail", powered_rail_template)
+
+
+-- Powered rail (activated by redstone)
+local powered_rail_on = table.copy(powered_rail_template)
+powered_rail_on.description = nil
+powered_rail_on._doc_items_create_entry = false
+powered_rail_on._doc_items_longdesc = nil
+powered_rail_on._doc_items_usagehelp = nil
+powered_rail_on.tiles = {"mcl_minecarts_rail_golden_powered.png", "mcl_minecarts_rail_golden_curved_powered.png", "mcl_minecarts_rail_golden_t_junction_powered.png", "mcl_minecarts_rail_golden_crossing_powered.png"}
+powered_rail_on.inventory_image = "mcl_minecarts_rail_golden_powered.png"
+powered_rail_on.wield_image = "mcl_minecarts_rail_golden_powered.png"
+powered_rail_on.groups.not_in_creative_inventory = 1
+powered_rail_on.groups.transport = nil
+powered_rail_on.mesecons = {
+	effector = {
+		action_off = function(pos, node)
+			minetest.swap_node(pos, {name = "mcl_minecarts:golden_rail", param2 = node.param2 })
+			mesecon:receptor_off(pos, get_input_rules())
+		end,
+	},
+	receptor = {
+		state = mesecon.state.on,
+		rules = get_output_rules,
+	}
+}
+powered_rail_on._rail_acceleration = 4
+
+minetest.register_node("mcl_minecarts:golden_rail_on", powered_rail_on)
+
+if minetest.get_modpath("doc") then
+	doc.add_entry_alias("nodes", "mcl_minecarts:golden_rail", "nodes", "mcl_minecarts:golden_rail_on")
+end
 
 minetest.register_craft({
 	output = "mcl_minecarts:golden_rail 6",