VoxeLibre/mods/PLAYER/mcl_sprint/wsprint.lua

--[[
Sprint mod for Minetest by GunshipPenguin

To the extent possible under law, the author(s)
have dedicated all copyright and related and neighboring rights 
to this software to the public domain worldwide. This software is
distributed without any warranty. 
]]

local players = {}

minetest.register_on_joinplayer(function(player)
	local playerName = player:get_player_name()
	players[playerName] = {
		state = 0, 
		timeOut = 0, 
		moving = false, 
	}
end)
minetest.register_on_leaveplayer(function(player)
	local playerName = player:get_player_name()
	players[playerName] = nil
end)
minetest.register_globalstep(function(dtime)
	--Get the gametime
	local gameTime = minetest.get_gametime()

	--Loop through all connected players
	for playerName,playerInfo in pairs(players) do
		local player = minetest.get_player_by_name(playerName)
		if player ~= nil then
			--Check if they are moving or not
			players[playerName]["moving"] = player:get_player_control()["up"]
			
			--If the player has tapped w longer than SPRINT_TIMEOUT ago, set his/her state to 0
			if playerInfo["state"] == 2 then
				if playerInfo["timeOut"] + SPRINT_TIMEOUT < gameTime then
					players[playerName]["timeOut"] = nil
					setState(playerName, 0)
				end

			--If the player is sprinting, create particles behind him/her 
			elseif playerInfo["state"] == 3 and gameTime % 0.1 == 0 then
				local numParticles = math.random(1, 2)
				local playerPos = player:getpos()
				local playerNode = minetest.get_node({x=playerPos["x"], y=playerPos["y"]-1, z=playerPos["z"]})
				if playerNode["name"] ~= "air" then
					for i=1, numParticles, 1 do
						minetest.add_particle({
							pos = {x=playerPos["x"]+math.random(-1,1)*math.random()/2,y=playerPos["y"]+0.1,z=playerPos["z"]+math.random(-1,1)*math.random()/2},
							vel = {x=0, y=5, z=0},
							acc = {x=0, y=-13, z=0},
							expirationtime = math.random(),
							size = math.random()+0.5,
							collisiondetection = true,
							vertical = false,
							texture = "default_dirt.png",
						})
					end
				end
			end

			--Adjust player states
			if players[playerName]["moving"] == false and playerInfo["state"] == 3 then --Stopped
				setState(playerName, 0)
			elseif players[playerName]["moving"] == true and playerInfo["state"] == 0 then --Moving
				setState(playerName, 1)
			elseif players[playerName]["moving"] == false and playerInfo["state"] == 1 then --Primed
				local sprinting
				-- Prevent sprinting if standing on soul sand
				if not playerplus[playerName].nod_stand ~= "mcl_nether:soul_sand" then
					setState(playerName, 2)
				else
					setState(playerName, 0)
				end
			elseif players[playerName]["moving"] == true and playerInfo["state"] == 2 then --Sprinting
				-- Prevent sprinting if standing on soul sand
				if not playerplus[playerName].nod_stand ~= "mcl_nether:soul_sand" then
					setState(playerName, 3)
				else
					setState(playerName, 1)
				end
			end
			
		end
	end
end)

function setState(playerName, state) --Sets the state of a player (0=stopped, 1=moving, 2=primed, 3=sprinting)
	local player = minetest.get_player_by_name(playerName)
	local gameTime = minetest.get_gametime()
	if players[playerName] then
		players[playerName]["state"] = state
		-- Don't overwrite physics when standing on soul sand
		if playerplus[playerName].nod_stand ~= "mcl_nether:soul_sand" then
			if state == 0 then--Stopped
				player:set_physics_override({speed=1.0})
			elseif state == 2 then --Primed
				players[playerName]["timeOut"] = gameTime
			elseif state == 3 then --Sprinting
				player:set_physics_override({speed=SPRINT_SPEED})
			end
			return true
		end
	end
	return false
end