15 replies to this topic

[hypersniper]

Comparisons
I decided to make some simple comparison scripts to show the old way of scripting vs the new way of scripting. I will make multiple scenarios where the new way of scripting helps out, and will describe the problem and solution in each one.

1. Monstrosity - Privatising Variables
OLD WAY

local killcount = 0
local entry = 555

function Monstrosity_OnKill(pUnit, event)
   killcount = killcount + 1
   if (killcount > 2) then
      pUnit:SendChatMessage(14, 0, "RAWR! I have killed many people!")
   end
end

RegisterUnitEvent(entry, 3, "Monstrosity_OnKill")

Problems:

• The killcount variable is shared among all units who use this script, therefore the script will malfunction if you have more than one of mob '555' spawned.
  
• The functions are all globals which is unorganised and lowers performance.
  
• local entry is fine because it is never changed. It is constant.

NEW WAY

MONSTROSITY = {}
local entry = 555

function MONSTROSITY.OnKill(pUnit, event)
   local sUnit = tostring(pUnit)
   if (MONSTROSITY[sUnit] == nil) then --this is initialising sub-tables
      MONSTROSITY[sUnit] = {}
      MONSTROSITY[sUnit].killsCount = 0
   end
   MONSTROSITY[sUnit].killsCount = MONSTROSITY[sUnit].killsCount + 1
   if (MONSTROSITY[sUnit].killsCount > 2) then
      pUnit:SendChatMessage(14, 0, "RAWR! I have killed many people!")
   end
end

RegisterUnitEvent(entry, 3, "MONSTROSITY.OnKill")

Solutions:

• We created a global table "MONSTROSITY" to hold all of our functions, which is more organised and makes the functions within the MONSTROSITY table instead of floating around as globals
  
• We ensure that the MONSTROSITY table isn't full of nils by initialising the sub-tables. Since we only need to initialise once, we check that the sub-table is nil first.
  
• We have privatised the killsCount variable, so instead of being shared by all mobs with entry '555', it is not shared, and is kept private to each pUnit.

2. Mages - 2 interactive units
OLD WAY

local mage1
local mage2

function Mage1_OnSpawn(pUnit, event)
   mage1 = pUnit
end

function Mage2_OnSpawn(pUnit, event)
   mage2 = pUnit
end

function Mage1_OnCombat(pUnit, event)
   pUnit:RegisterEvent("Mage1_Check_Mage2_HP", 1000, 0)
end

function Mage1_Check_Mage2_HP(pUnit, event)
   if (mage2:GetHealthPct() < 20) then
      pUnit:SendChatMessage(14, 0, "No! My brother is in danger!")
   end
end

RegisterUnitEvent(750, 18, "Mage1_OnSpawn")
RegisterUnitEvent(750, 1,  "Mage1_OnCombat")
RegisterUnitEvent(751, 18, "Mage2_OnSpawn")

Problems:

• The mage1 and mage2 variables are being shared around with all units with entry id '750' or '751', so having more than 1 group of these mages will not work.
  
• The functions are all globals which is unorganised and lowers performance.

NEW WAY

MAGES = {}

function MAGES.Mage1_OnSpawn(pUnit, event)
   local sUnit = tostring(pUnit)
   if (MAGES[sUnit] == nil) then
      MAGES[sUnit] = {}
   end
   local mage2 = pUnit:GetCreatureNearestCoords(pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 751)
   MAGES[sUnit].partner = mage2
end

function MAGES.Mage2_OnSpawn(pUnit, event)
   local sUnit = tostring(pUnit)
   if (MAGES[sUnit] == nil) then
      MAGES[sUnit] = {}
   end
   local mage1 = pUnit:GetCreatureNearestCoords(pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 750)
   MAGES[sUnit].partner = mage1
end

function MAGES.Mage1_OnCombat(pUnit, event)
   pUnit:RegisterEvent("MAGES.Mage1_Check_Mage2_HP", 1000, 0)
end

function MAGES.Mage1_Check_Mage2_HP(pUnit, event)
   local sUnit = tostring(pUnit)
   if (MAGES[sUnit].partner:GetHealthPct() < 20) then
      pUnit:SendChatMessage(14, 0, "No! My brother is in danger!")
   end
end

RegisterUnitEvent(750, 18, "MAGES.Mage1_OnSpawn")
RegisterUnitEvent(750, 1,  "MAGES.Mage1_OnCombat")
RegisterUnitEvent(751, 18, "MAGES.Mage2_OnSpawn")

Solutions:

• We created a global table "MAGES" to hold all of our functions, which is more organised and makes the functions within the MAGES table instead of floating around as globals
  
• OnSpawn we make sure that our table isn't nil by initialising sub-tables.
  
• Each mage finds their partner using the GetCreatureNearestCoords function, and stores it in a private table so they can access it later, eliminating the global variables!

3. Instance - Waves of Adds
OLD WAY

local wave = 0
local mob1, mob2, mob3

function MadScientist_SpawnWave(pUnit, event)
   if (wave == 1) then
      pUnit:SendChatMessage(14, 0, "Go, my front line minions!")
      pUnit:SpawnCreature(320, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
      pUnit:SpawnCreature(321, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
   elseif (wave == 2) then
      pUnit:SendChatMessage(14, 0, "Go, my lieutenant!")
      pUnit:SpawnCreature(322, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
   end
   pUnit:RegisterEvent("MadScientist_CheckDead", 1000, 0)
end

function MadScientist_CheckDead(pUnit, event)
   if (wave == 1)
      if (mob1:IsDead() == true and mob2:IsDead() == true) then
         wave = wave+1
         pUnit:RegisterEvent("MadScientist_SpawnWave", 5000, 1)
      end
   elseif (wave == 2)
      if (mob3:IsDead() == true) then
         wave = wave+1
         pUnit:SendChatMessage(14, 0, "How could you defeat my waves of monsters!?")
      end
   end
end

function Minion1_OnSpawn(pUnit, event)
   mob1 = pUnit
end

function Minion2_OnSpawn(pUnit, event)
   mob2 = pUnit
end

function Minion1_OnSpawn(pUnit, event)
   mob3 = pUnit
end

RegisterUnitEvent(319, 1, "MadScientist_SpawnWave")
RegisterUnitEvent(320, 18, "Minion1_OnSpawn")
RegisterUnitEvent(321, 18, "Minion2_OnSpawn")
RegisterUnitEvent(322, 18, "Minion3_OnSpawn")

Problems:

• Since the variables (mob1, mob2, mob3, wave) are all shared, when two different groups enter the instance, the script will malfunction.
  
• The functions are all globals which is unorganised and lowers performance.

NEW WAY

INSTANCE_ASYLUM = {}

function INSTANCE_ASYLUM.MadScientist_SpawnWave(pUnit, event)
   local iid = pUnit:GetInstanceID()
   if (INSTANCE_ASYLUM[iid] == nil) then
      INSTANCE_ASYLUM[iid] = {}
      INSTANCE_ASYLUM[iid].wave = 1
   end
   if (INSTANCE_ASYLUM[iid].wave == 1) then
      pUnit:SendChatMessage(14, 0, "Go, my front line minions!")
      INSTANCE_ASYLUM[iid].mob1 = pUnit:SpawnCreature(320, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
      INSTANCE_ASYLUM[iid].mob2 = pUnit:SpawnCreature(321, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
   elseif (INSTANCE_ASYLUM[iid].wave == 2) then
      pUnit:SendChatMessage(14, 0, "Go, my lieutenant!")
      INSTANCE_ASYLUM[iid].mob3 = pUnit:SpawnCreature(322, pUnit:GetX(), pUnit:GetY(), pUnit:GetZ(), 0, 14, 0)
   end
   pUnit:RegisterEvent("INSTANCE_ASYLUM.MadScientist_CheckDead", 1000, 0)
end

function INSTANCE_ASYLUM.MadScientist_CheckDead(pUnit, event)
   local iid = pUnit:GetInstanceID()
   if (INSTANCE_ASYLUM[iid].wave == 1)
      if (INSTANCE_ASYLUM[iid].mob1:IsDead() == true and INSTANCE_ASYLUM[iid].mob2:IsDead() == true) then
         INSTANCE_ASYLUM[iid].wave = INSTANCE_ASYLUM[iid].wave+1
         pUnit:RegisterEvent("INSTANCE_ASYLUM.MadScientist_SpawnWave", 5000, 1)
      end
   elseif (INSTANCE_ASYLUM[iid].wave == 2)
      if (INSTANCE_ASYLUM[iid].mob3:IsDead() == true) then
         INSTANCE_ASYLUM[iid].wave = INSTANCE_ASYLUM[iid].wave+1
         pUnit:SendChatMessage(14, 0, "How could you defeat my waves of monsters!?")
      end
   end
end

RegisterUnitEvent(319, 1, "INSTANCE_ASYLUM.MadScientist_SpawnWave")

Solutions:

• We created a global table "INSTANCE_ASYLUM" to hold all of our functions, which is more organised and we added the functions to the table instead of making them floating around as globals
  
• Since we need units within a specific instance to share variables, we use their instance ID as the key. This is unique per-instance, so it's ideal for the sharing of wave, mob1/2/3.
  
• We eliminate the global variables by storing the spawns in the instance's table. SpawnCreature actually returns the spawned creature, which comes in handy here.

[hypersniper]

Reserved if I need more space

[Blacktide]

I think I actually finally grasped the last bit of information I needed to understand this new way of scripting.  Thanks, Hyper ;)

[BlackBoy0]

The only part I completely understood:

MONSTROSITY = {}
local entry = 555

function MONSTROSITY.OnKill(pUnit, event)

The rest was just

BLAH BLAH.blah
BLAH BLAH. blah

etc...

The hell is a tostring?

[hypersniper]

IT's part of regular Lua so anyone can use it, and It turns anything to a string eg.

tostring(5) is "5"
tostring(nil) is "nil"

For a good example, try doing print(nil). You get an error  :-X But, if you do print(tostring(nil)) you won't :D

We use it here because we can't really use pUnit as a key, it doesn't work. So we turn it into a simple string which Lua can handle as a table key :)

[BlackBoy0]

...

Out of all that, all I understood was

Quote

IT's part of regular Lua so anyone can use it

:-X

LuA's way too fucking complex right now :-\

[SmashnCrash]

BB0, ease your mind with metatables ^_^

[Halestorm]

Quote

LuA's way too fucking complex right now :-\

[color=green]It's not that it is complex, you can still do the old way, this is just the more efficient way.

[Darren]

Quote

...

Out of all that, all I understood was

Quote

IT's part of regular Lua so anyone can use it

:-X

LuA's way too fucking complex right now :-\

Lua*
<3

[Goodbye-Hunter]

Quote

BB0, ease your mind with metatables ^_^

SnC, I dont want to explain. But that statement makes me want to jump on you and rip your eyes out.

Anyways, Bb0, I guess your no longer an Lua pro. A lot of our newer members understand it <3

I'll update my guide to explain tostrings better.

[SmashnCrash]

Oh, please explain.. O:

[amin2000]

Amazing ...

But please explain this part ... i didn`t understand it :

local sUnit = tostring(pUnit)
if (MONSTROSITY[sUnit] == nil) then --this is initialising sub-tables
  MONSTROSITY[sUnit] = {}
  MONSTROSITY[sUnit].killsCount = 0
end

[Rochet2]

pUnit is an object.
He is making a local string out of the object and then using it as a table key to recognize the NPC in the table and assign the killcount to that spesific NPC.

[kenuvis]

Hyper,...
function MONSTROSITY.OnKill(pUnit, event)
The given unit (pUnit) is a metatable, or? thats should be the reason, why tostring works on it. Its quite cool. ^^

Otherwise, maybe for all other, who dont understand it.
sUnit = tostring(pUnit) is the same like sUnit = pUnit:GetName(), or sUnit = pUnit:GetGUID() (I dont know, if tostring(Unit) give me the name or the Guid ^^)

[Sympathy™]

Quote

Hyper,...
function MONSTROSITY.OnKill(pUnit, event)
The given unit (pUnit) is a metatable, or? thats should be the reason, why tostring works on it. Its quite cool. ^^

Otherwise, maybe for all other, who dont understand it.
sUnit = tostring(pUnit) is the same like sUnit = pUnit:GetName(), or sUnit = pUnit:GetGUID() (I dont know, if tostring(Unit) give me the name or the Guid ^^)

[color=cyan]In the binding method (That's basically C++ class to Lua object) that LuaHypArc uses, all units are given a metatable which is filled with methods and metamethods;

Basically, yeah :P It's really interesting how it works.

		static void Register(lua_State* L)
		{
			lua_newtable(L);
			int methods = lua_gettop(L);

			luaL_newmetatable(L, GetTName<T>());
			int metatable = lua_gettop(L);

			// store method table in globals so that
			// scripts can add functions in Lua
			lua_pushvalue(L, methods);
			lua_setglobal(L, GetTName<T>());

			// hide metatable
			lua_pushvalue(L, methods);
			lua_setfield(L, metatable, "__metatable");

			lua_pushvalue(L, methods);
			lua_setfield(L, metatable, "__index");

			lua_pushcfunction(L, tostringT);
			lua_setfield(L, metatable, "__tostring");

			lua_pushcfunction(L, gcT);
			lua_setfield(L, metatable, "__gc");

			lua_newtable(L);
			lua_setmetatable(L, methods);

			lua_pop(L, 2);
		}

		static int tostringT(lua_State* L)
		{
			char buff[32];
			T** ptrHold = (T**)lua_touserdata(L, 1);
			T* obj = *ptrHold;
			sprintf(buff, "%p", obj);
			lua_pushfstring(L, "%s (%s)", GetTName<T>(), buff);
			return 1;
		}

[amin2000]

Quote

pUnit is an object.
He is making a local string out of the object and then using it as a table key to recognize the NPC in the table and assign the killcount to that spesific NPC.

Realized it , thanks :P