added player_effects mod for stacking physics overrides

mods/player_effects/README.txt

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+Player effects mod
+==================
+By Kaadmy, for Pixture
+
+Adds functions to handle multiple physics overrides at the same time
+
+Source license: WTFPL

mods/player_effects/depends.txt

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+default

mods/player_effects/init.lua

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+--
+-- Player effects mod
+-- By Kaadmy, for Pixture
+--
+
+player_effects = {}
+
+player_effects.effects = {}
+player_effects.registered_effects = {}
+
+local update_time = 1 -- update every second
+local timer = 10
+local effects_file = minetest.get_worldpath() .. "/player_effects"
+
+local function save_effects()
+   local f = io.open(effects_file, "w")
+
+   f:write(minetest.serialize(player_effects.effects))
+
+   io.close(f)
+end
+
+local function load_effects()
+   local f = io.open(effects_file, "r")
+
+   if f then
+      player_effects.effects = minetest.deserialize(f:read("*all"))
+
+      io.close(f)
+   else
+      save_effects()
+   end
+end
+
+function player_effects.register_effect(name, def)
+   local rd = {
+      title = def.title or name, -- good-looking name of the effect
+      description = def.description or "The " .. name .. " effect", -- description of what the effect does
+      duration = def.duration or 1, -- how long the effect lasts, <0 is infinite and has to be disabled manually
+      additive = def.additive or false, -- if the same effect can be applied multiple times for a longer duration
+      physics = def.physics or {} -- physics overrides for the player
+   }
+
+   player_effects.registered_effects[name] = rd
+end
+
+function player_effects.apply_effect(player, ename)
+   local effect = player_effects.registered_effects[ename]
+
+   if player_effects.effects[player:get_player_name()][ename] == nil then
+      local phys = player:get_physics_override()
+      
+      if effect.physics.speed ~= nil then
+	 phys.speed = phys.speed * effect.physics.speed
+      end
+
+      if effect.physics.jump ~= nil then
+	 phys.jump = phys.jump * effect.physics.jump
+      end
+
+      if effect.physics.gravity ~= nil then
+	 phys.gravity = phys.gravity * effect.physics.gravity
+      end
+
+      player:set_physics_override(phys)
+   end
+
+   if effect.duration >= 0 then
+      player_effects.effects[player:get_player_name()][ename] = minetest.get_gametime() + effect.duration
+   else
+      player_effects.effects[player:get_player_name()][ename] = -1
+   end
+
+   save_effects()
+end
+
+function player_effects.remove_effect(player, ename)
+   if player_effects.effects[player:get_player_name()][ename] == nil then return end
+
+   local phys = player:get_physics_override()
+   local effect = player_effects.registered_effects[ename]
+   
+   if effect.physics.speed ~= nil then
+      phys.speed = phys.speed / effect.physics.speed
+   end
+
+   if effect.physics.jump ~= nil then
+      phys.jump = phys.jump / effect.physics.jump
+   end
+
+   if effect.physics.gravity ~= nil then
+      phys.gravity = phys.gravity / effect.physics.gravity
+   end
+
+   player:set_physics_override(phys)
+
+   player_effects.effects[player:get_player_name()][ename] = nil
+
+   save_effects()
+end
+
+function player_effects.clear_effects(player)
+   -- call this if you want to clear all effects, it's faster and more efficient
+   player:set_physics_override({speed = 1, jump = 1, gravity = 1})
+
+   player_effects.effects[player:get_player_name()] = nil
+
+   save_effects()
+end
+
+local function step(dtime)
+   timer = timer + dtime
+   if timer > update_time then
+      local gt = minetest.get_gametime()
+
+      for _, player in pairs(minetest.get_connected_players()) do
+	 local name = player:get_player_name()
+
+	 for ename, endtime in pairs(player_effects.effects[name]) do
+	    if endtime > 0 then
+	       local timeleft = endtime - gt
+	       print(timeleft)
+	       if timeleft <= 0 then
+		  player_effects.remove_effect(player, ename)
+	       end
+	    end
+	 end
+      end
+      timer = 0
+   end
+end
+
+local function on_joinplayer(player)
+   local name = player:get_player_name()
+
+   load_effects()
+
+   if player_effects.effects[name] == nil then
+      player_effects.effects[name] = {}
+   end
+
+   save_effects()
+
+   player_effects.apply_effect(player, "lowgravity")
+end
+
+local function on_leaveplayer(player)
+   save_effects()
+end
+
+local function on_dieplayer(player)
+   player_effects.clear_effects(player)
+end
+
+minetest.register_globalstep(step)
+minetest.register_on_joinplayer(on_joinplayer)
+minetest.register_on_leaveplayer(on_leaveplayer)
+minetest.register_on_dieplayer(on_dieplayer)
+
+minetest.register_chatcommand(
+   "player_effects",
+   {
+      description = "Show current player effects",
+      func = function(name, param)
+		local s = "Current player effects:\n"
+		local ea = 0
+
+		for ename, endtime in pairs(player_effects.effects[name]) do
+		   if endtime < 0 then
+		      s = s .. "  " .. player_effects.registered_effects[ename].title .. ": unlimited\n"
+		   else
+		      s = s .. "  " .. player_effects.registered_effects[ename].title .. ": " .. (endtime - minetest.get_gametime()) .. " seconds remaining\n"
+		   end
+
+		   ea = ea + 1
+		end
+
+		if ea > 0 then
+		   minetest.chat_send_player(name, s)
+		else
+		   minetest.chat_send_player(name, "You currently have no effects")
+		end
+	     end
+   })
+
+default.log("mod:player_effects", "loaded")