Add sprinting with double-W

init.lua

@@ -1 +1,6 @@
+local modname = minetest.get_current_modname()
+local modpath = minetest.get_modpath(modname)
 
+for _, f in ipairs({"sprint"}) do
+	dofile(modpath .. "/" .. f .. ".lua")
+end

sprint.lua

@@ -0,0 +1,72 @@
+-- set up our initial values
+local running = false
+local run_discharge_timer = 0
+local old_up = false
+local channel
+local channel_name
+
+-- receive the server states
+minetest.register_on_modchannel_message(function(cname, sender, message)
+	if sender == "" and cname == channel_name then
+		running = false
+		run_discharge_timer = 0
+	end
+end)
+
+-- check player's input on the "up" key
+minetest.register_globalstep(function(dtime)
+	local player = minetest.localplayer
+
+	if not player then
+		return
+	elseif not channel then
+		channel_name = "mcl_sprint:" .. player:get_name()
+		channel = minetest.mod_channel_join(channel_name)
+	end
+
+	local old_running = running
+	
+	local control = player:get_control()
+	local velocity = player:get_velocity()
+	local last_velocity = player:get_last_velocity()
+
+	-- cancel running if the player bumps into something
+	if running and (velocity.x == 0 and last_velocity.x ~= 0 or velocity.z == 0 and last_velocity.z ~= 0) then
+		running = false
+		run_discharge_timer = 0
+	end
+
+	-- reset the run flag
+	if running and (not control.up or control.sneak or control.down) then
+		running = false
+	end
+
+	-- half second window to double tap running
+	if run_discharge_timer > 0 then
+		run_discharge_timer = run_discharge_timer - dtime
+		
+		-- initialize double tap run
+		if not old_up and control.up == true and velocity.x ~= 0 and velocity.z ~= 0 then
+			run_discharge_timer = 0
+			running = true
+		end
+	end
+
+	-- check if new input of walking forwards
+	if control.up and not control.down and not control.sneak and not old_up and not running and run_discharge_timer <= 0 then
+		run_discharge_timer = 0.2
+	end
+	
+	-- add this here so the player can sneak
+	if control.sneak then
+		running = false
+		run_discharge_timer = 0
+	end
+	
+	-- only send if state has changed
+	if running ~= old_running then
+		channel:send_all(running and "true" or "false")
+	end
+
+	old_up = control.up
+end)