Nameplate tracking SPELL_CAST_START destination unit

[Ketho]

Recently there was this question which I was wondering for years.

The SPELL_CAST_START CLEU event doesn't include a destination.
http://wow.gamepedia.com/COMBAT_LOG_EVENT

But now with the Legion nameplate unit ids we can kind of still get that information.

With the added footnote that it won't work for most cases, like

• mouseover casting
• @unit macros
• AoE casts
• most boss abilities
• when the nameplates are toggled off

Rough example where unit(s) are casting a spell and they are "targeting" the player; by comparing nameplateNtarget

local np = C_NamePlate
local f = CreateFrame("Frame")
 
function f:OnEvent(event, timestamp, subevent, _, sourceGUID, sourceName, _, _, destGUID, destName, _, _, spellID, spellName)
    if subevent == "SPELL_CAST_START" then
        for _, v in pairs(np.GetNamePlates()) do
            if np.GetNamePlateForUnit(v.namePlateUnitToken.."target") == np.GetNamePlateForUnit("player") then
                print(format("%s is casting %s on me", sourceName, GetSpellLink(spellID)))
            end
        end
    end
end
 
f:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
f:SetScript("OnEvent", f.OnEvent)

So I'm wondering if this is already sort of implemented in WeakAuras or Boss Mods? It would probably be handy if not.

[Banknorris]

Err, wouldn't your code print all name plates who have you as a target and not only the one casting on you?

[Ketho]

Originally Posted by Banknorris Err, wouldn't your code print all name plates who have you as a target and not only the one casting on you?

Yeah it would, nice find! It's a barebones proof of concept example I took from that other post

[SDPhantom]

Something like this would work much better without involving the NamePlate API. NamePlates may still need to be enabled, but it'll run more efficient and allows you to add more units. You also can prioritize which groups of units are checked first by rearranging their order.

local UnitTable={};
for i=1,4 do table.insert(UnitTable,"boss"..i); end
for i=1,5 do table.insert(UnitTable,"arena"..i); end
for i=1,30 do table.insert(UnitTable,"nameplate"..i); end
 
local EventFrame=CreateFrame("Frame");
EventFrame:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED");
EventFrame:SetScript("OnEvent",function(self,event,_,subevent,_,guid,name,_,_,_,_,_,_,spellid)
    if subevent=="SPELL_CAST_START" then
        for _,unit in ipairs(UnitTable) do
            if UnitIsUnit(unit.."target","player") then
                if UnitIsEnemy("player",unit) then
                    print(("%s is casting %s on me"):format(name,GetSpellLink(spellid)));
                end
                break;
            end
        end
    end
end

[Lombra]

Well, you've still got exactly the same limitations as before, only more likely that a uni token for the target exists. I certainly wouldn't rely on it for any sort of PvP purposes. Could probably work as a complement for boss mods, since they already use every conceivable channel for gathering of information, but on its own, much too unreliable.

[SDPhantom]

I didn't exactly say that it fixes the caveats of macros and mouseovers. It's just a more direct way of detection than previously posted. This is done by building a list of UnitIDs and using UnitIsUnit() to check if they're targeting us rather than loading up a list of NamePlates, grabbing their NamePlate UnitID, attempting to grab the NamePlate for their target, and check if it's the same as the NamePlate grabbed for the player.

Though in PvP, it would be more useful to skip the target filtering and trigger a warning if an enemy starts casting a CC ability. No matter who it's cast on, it's the same result. You or a team member is out of the fight for a few seconds.

[Ketho]

UnitIsUnit seems indeed more efficient, I'd personally do it like this. I don't really understand when a nameplate id is active or not :s

for _, v in pairs(C_NamePlate.GetNamePlates()) do
    if UnitIsUnit(v.namePlateUnitToken.."target", "player") then
        -- do stuff
    end
end

Originally Posted by SDPhantom Though in PvP, it would be more useful to skip the target filtering and trigger a warning if an enemy starts casting a CC ability. No matter who it's cast on, it's the same result. You or a team member is out of the fight for a few seconds.

Yeah, it's mostly not really important who it's casting on in PvP/Arena, while it's prone to error to get the actual destination unit.
Just that it could be useful in some cases.

[SDPhantom]

If the NamePlate UnitID isn't active, the unit simply doesn't exist and would return false anyway. Though UnitIsUnit() may have problems if both units don't exist, this issue won't happen since player always points to yourself.

PS: You should still filter enemy casts unless you want to be spammed about party members healing you. Also consider breaking the loop when you find a match or ideally check the unit's casting info to see if they're casting the same spell. Otherwise it'll spam you with every unit targeting you, even those not casting.

[Ketho]

Originally Posted by SDPhantom PS: You should still filter enemy casts unless you want to be spammed about party members healing you. Also consider breaking the loop when you find a match or ideally check the unit's casting info to see if they're casting the same spell. Otherwise it'll spam you with every unit targeting you, even those not casting.

Yes, this is how I would filter it

local f = CreateFrame("Frame")
 
function f:OnEvent(event, timestamp, subevent, _, sourceGUID, sourceName, sourceFlags, _, destGUID, destName, _, _, spellID, spellName)
    if subevent == "SPELL_CAST_START" then
        for _, v in pairs(C_NamePlate.GetNamePlates()) do
            if UnitGUID(v.namePlateUnitToken) == sourceGUID then
                -- source is targeting player, source is hostile
                if UnitIsUnit(v.namePlateUnitToken.."target", "player") and bit.band(sourceFlags, COMBATLOG_OBJECT_REACTION_HOSTILE) > 0 then
                    print( format("%s is casting %s on me", sourceName, GetSpellLink(spellID)) )
                end
                break
            end
        end
    end
end
 
f:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")
f:SetScript("OnEvent", f.OnEvent)

Originally Posted by SDPhantom Something like this would work much better without involving the NamePlate API. NamePlates may still need to be enabled, but it'll run more efficient and allows you to add more units. You also can prioritize which groups of units are checked first by rearranging their order.

That works too, but I'm not sure how much more efficient it is
Since nameplates get recycled/removed you have to check all 40 nameplate unit ids, instead of getting the actives ones through the NamePlate API

/run for i = 1, 40 do print("nameplate"..i, UnitName("nameplate"..i)) end

"nameplate1", "Blamedatank", "Outland"
"nameplate2", "Pluex", "Outland"
"nameplate3", "Thomas Miller", nil
"nameplate4", "Maawi", "Outland"
"nameplate5", "Stormwind City Guard", nil
"nameplate6", "Edna Mullby", nil
"nameplate7", nil, nil
"nameplate8", "Dankzter", "Outland"
"nameplate9", nil, nil
"nameplate10", nil, nil
"nameplate11", "Renato Gallina", nil
"nameplate12", nil, nil
"nameplate13", "Stephanie Turner", nil
"nameplate14", nil, nil
"nameplate15", "Stormwind City Patroller", nil
"nameplate16", nil, nil
"nameplate17", nil, nil
"nameplate18", "Blackfirez", "DunModr"
"nameplate19", nil, nil
"nameplate20", "Stormwind City Guard", nil
"nameplate21", "\195\146\195\164k", "Outland"
"nameplate22", nil, nil
"nameplate23", "Thurman Mullby", nil
"nameplate24", nil, nil
"nameplate25", "Varcher", "Stormscale"
"nameplate26", nil, nil
"nameplate27", nil, nil
"nameplate28", nil, nil
"nameplate29", "Bay\195\184n\195\170ta", "Outland"
"nameplate30", nil, nil
"nameplate31", nil, nil
"nameplate32", nil, nil
"nameplate33", nil, nil
"nameplate34", nil, nil
"nameplate35", nil, nil
"nameplate36", "Elling Trias", nil
"nameplate37", nil, nil
"nameplate38", "Jusraalin", "Outland"
"nameplate39", nil, nil
"nameplate40", "Golden King", nil

[Banknorris]

Just another aproach, not using any loops.

local f = CreateFrame("Frame")
local unit_from_plate = {}
local plate_from_unit = {}
 
f:SetScript("OnEvent",function(self,event,...)
    if event=="NAME_PLATE_UNIT_ADDED" then
        local plate = "NamePlate"..string.match(...,"%a+(%d+)")
        local unit = GetUnitName(plate,true)
        if unit then
            plate_from_unit[unit] = plate
            unit_from_plate[plate] = unit
        end
    elseif event=="NAME_PLATE_UNIT_REMOVED" then
        local plate = ...
        if plate then
            local unit = unit_from_plate[plate]
            if unit then
                plate_from_unit[unit] = nil
            end
            unit_from_plate[plate] = nil
        end
    elseif event=="COMBAT_LOG_EVENT_UNFILTERED" then
        local timestamp,sub_event,_,_,source_name,_,_,_,_,_,_,spell_id = ...
        if sub_event=="SPELL_CAST_START" then
            local plate = plate_from_unit[source_name]
            if plate and UnitIsEnemy("player",plate) and UnitIsUnit(plate.."target","player") then
                print(("%s is casting %s on me"):format(sourceName,GetSpellLink(spell_id)))
            end
        end     
    end
end)
f:RegisterEvent("NAME_PLATE_UNIT_ADDED")
f:RegisterEvent("NAME_PLATE_UNIT_REMOVED")
f:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")

[Ketho]

Originally Posted by Banknorris Just another aproach, not using any loops.

That approach is even better, I'll steal that
It looks like UnitGUID still returns valid information when nameplates get removed

local guids = {}
local f = CreateFrame("Frame")
 
function f:NAME_PLATE_UNIT_ADDED(unit)
    guids[UnitGUID(unit)] = unit
end
 
function f:NAME_PLATE_UNIT_REMOVED(unit)
    guids[UnitGUID(unit)] = nil
end
 
function f:COMBAT_LOG_EVENT_UNFILTERED(timestamp, subevent, _, sourceGUID, sourceName, sourceFlags, _, destGUID, destName, _, _, spellID, spellName)
    if subevent == "SPELL_CAST_START" then
        local unit = guids[sourceGUID]
        if unit and UnitIsUnit(unit.."target", "player") and bit.band(sourceFlags, COMBATLOG_OBJECT_REACTION_HOSTILE) > 0 then
            print( format("%s is casting %s on me", sourceName, GetSpellLink(spellID)) )
        end
    end
end
 
f:SetScript("OnEvent", function(self, event, ...)
    f[event](self, ...)
end)
 
f:RegisterEvent("NAME_PLATE_UNIT_ADDED")
f:RegisterEvent("NAME_PLATE_UNIT_REMOVED")
f:RegisterEvent("COMBAT_LOG_EVENT_UNFILTERED")