[LUA] NPC Channeling Question !

[~ Sh3ll]

Hey there OwnedCore community.
I would like to make two NPCs , one of em channel a spell on another one , But the script doesnt work for some reasons :
Actually the script works since the channeler npc yells a text as its intended but it just doesnt channel the spell :

here is the script :

local target = nil 
local Channeler = 100006 
local ChannelerTarget = 100007 

function Channel_NPC(pUnit, Event)
    pUnit:SendChatMessage(14, 0, "Test Text")
    pUnit:RegisterEvent("Check", 2500, 0)
end

function Check(pUnit, Event)
    if target ~= nil then
    pUnit:ChannelSpell(689, target)
    pUnit:RemoveEvents()
    end
end

RegisterUnitEvent(Channeler, 1, "Channel_NPC")

function target_on_load(pUnit, Event)
    target = pUnit
end

RegisterUnitEvent(ChannelerTarget, 18, "target_on_load") 

Any help will be appreciated.

Thanks.

[~ Sh3ll]

Bump !

Anyone ?

[stoneharry]

So what Lua engine are you using? I'm going to answer this post assuming Eluna. ArcEmu is far behind because it has been dead for years now and is unstable and full of bugs in core areas of game functionality.

There are not methods for this available in the Eluna engine, or at least not in the version I am on. I am quite out of date. You could implement some, or I made some utility Lua functions to help with this sort of thing.

File name: Utility.ext

function Creature:IsCasting()
	return self:HasUnitState(0x00008000)
end

function Player:IsCasting()
	return self:HasUnitState(0x00008000)
end

function Creature:ChannelSpell(target, id)
	self:SetUInt64Value(UNIT_FIELD_CHANNEL_OBJECT, target:GetGUID());
	self:SetUInt32Value(UNIT_CHANNEL_SPELL, id);
end

function Creature:StopChannel()
	self:SetUInt64Value(UNIT_FIELD_CHANNEL_OBJECT, 0);
	self:SetUInt32Value(UNIT_CHANNEL_SPELL, 0);
end

function Creature:GetCreature(range, id)
	return GetCreature(range, id, self)
end

function GetCreature(range, id, pUnit)
	local t = pUnit:GetCreaturesInRange(range, id)
	if not t or #t == 0 then
		return nil
	end
	if #t > 1 then
		for _,v in pairs(t) do
			if v:GetPhaseMask() == pUnit:GetPhaseMask() then
				return v
			end
		end
	end
	return t[1]
end

function Creature:IsFacing(target, compareAngle)
	local x = target:GetX() - self:GetX()
	local y = target:GetY() - self:GetY()
	
	local angle = math.atan2(y, x)
	if (angle < 0.0) then
		angle = 2.0 * math.pi + angle
	end
	angle = angle - self:GetO()
	
	while (angle > math.pi) do
		angle = angle - 2.0 * math.pi
	end
	while (angle < -math.pi) do
		angle = angle + 2.0 * math.pi
	end
	
	-- reduce or increase angle
	--local compareAngle = (60 * math.pi) / 180 --math.pi
	
	local left = -1.0 * (compareAngle / 2.0)
	local right = (compareAngle / 2.0)
	
	return (angle >= left) and (angle <= right)
end

function sendAddonMessage(plr, msg, packet)
	local splitLength = 240
	local splits = math.ceil(msg:len() / splitLength)
	local send
	local counter = 1
	for i=1, msg:len(), splitLength do
		send = string.format("%03d", packet)
		send = send .. string.format("%02d", counter)
		send = send .. string.format("%02d", splits)
		if ((i + splitLength) > msg:len()) then
			send = send .. msg:sub(i, msg:len())
		else
			send = send .. msg:sub(i, i + splitLength)
		end
		counter = counter + 1

		if _DEBUG then print("[SENT] " .. send) end
		plr:SendAddonMessage(send, "", 7, plr)
	end
end

function scen_split(str)
	local b = {}
	local c = 1
	local d = {}
	string.gsub(str, "[%w%s-]", function(a)
		if (a == "-") then
			c = c + 1
		else
			if (not b[c]) then
				b[c] = {}
			end
			table.insert(b[c], a)
		end
	end)
	for k, v in pairs (b) do
		table.insert(d, table.concat(v))
	end
	return d
end

Then in your other Lua scripts you can call:

local spellId = 11
local target = creature -- target can be self or any other unit reference
creature:ChannelSpell(target, spellId)
...
creature:StopChannel()

The script actually calls variables that need to be defined. I have a Constants.ext file but you can put it at the top of the same script if you want to.

OBJECT_END 						= 0x0006
UNIT_NPC_EMOTESTATE 			= OBJECT_END + 0x004D
UNIT_FIELD_BYTES_1 				= OBJECT_END + 0x0044
UNIT_FIELD_BYTES_2 				= OBJECT_END + 0x0074
UNIT_FIELD_FLAGS 				= OBJECT_END + 0x0035
UNIT_FIELD_FLAG_UNTARGETABLE	= 33554434
UNIT_FIELD_FLAG_UNATTACKABLE	= 2
UNIT_FIELD_FLAG_C_UNATTACKABLE	= 770
UNIT_FIELD_CHANNEL_OBJECT 		= OBJECT_END + 0x000E
UNIT_CHANNEL_SPELL 				= OBJECT_END + 0x0010
GAMEOBJECT_BYTES_1				= OBJECT_END + 0x000B

There are more flags than this in the game, these are just the ones I have used so far on something I am working on.

Oh and you cannot store references to objects in member variables like that. You have to obtain the reference when you need it and not pass it between functions. Eluna will now actually detect you doing this and warn you from doing it while disabling the functionality. Other game engines had the potential to crash.

One way would be to use a function from my utility script:

function Creature:GetCreature(range, id)

local creature = unit:GetCreature(40, 10811)

But I am, pretty sure there's a better way (like storing the GUID and then getting creature by GUID) but I cannot find the method from a quick scan.