Lamp doesn't parent to head

[Chunk3ym4n]

I decided to just try attaching an flashlight to an NPC myself. I decided to use the NPC camera code since I don't know how to use LUA, i'll ask for permission later since I haven't released it. I tried parenting an env_projectedtexture to the head but it isn't parented, it follows the general position of the NPC but it doesn't parent the env_projectedtexture to the head or more specificly eyes. Also how would I parent an point_spotlight with the env_projectedtexture as well? It also doesn't cast dynamic shadows which I had for in mind. I also can't parent it to the hand or more specifically anim_attachment_LH. Help?
[lua]
TOOL.Category = "Render"
TOOL.Name = "#NPCVision"
TOOL.Command = nil
TOOL.ConfigName = ""

TOOL.ClientConVar[ "key" ] = "0"
TOOL.ClientConVar[ "toggle" ] = "1"

GAMEMODE.CameraList = GAMEMODE.CameraList or {}

if ( CLIENT ) then
language.Add( "NPCVision", "NPC Camera" )
language.Add( "Tool_npcvision_name", "NPC Camera Tool" )
language.Add( "Tool_npcvision_desc", "Creates a camera inside of a NPC's head." )
language.Add( "Tool_npcvision_0", "Left click on a NPC to create a camera. Right click to remove it from the NPC's head." )
language.Add( "Tool_npcvision_key", "Key:" )
language.Add( "Tool_npcvision_toggle", "Toggle:" )
language.Add( "Undone_NPC Camera", "Undone NPC Camera" )
end

function TOOL:LeftClick( trace )

local key = self:GetClientNumber( "key" )
if (key == -1) then return false end

if ( !trace.Entity ) then return end
if ( !trace.Entity:IsValid( ) ) then return end
if ( !trace.Entity:IsNPC( ) ) then return end

if ( CLIENT ) then return true end

local ply = self:GetOwner()
local pid = ply:UniqueID()
local toggle = self:GetClientNumber( "toggle" )
GAMEMODE.CameraList[ pid ] = GAMEMODE.CameraList[ pid ] or {}
local CameraList = GAMEMODE.CameraList[ pid ]

local attname = "eyes"

local head = trace.Entity:LookupAttachment( "eyes" )
if ( head == 0 ) then
attname = "Eye"
head = trace.Entity:LookupAttachment( "Eye" )
if ( head == 0 ) then -- No eyes :(
return
end
end

-- Already have a camera ? Remove it
local cam
cam = trace.Entity.NPC_ViewCam

if ( cam && cam:IsValid() ) then
cam:Remove()
end

-- If the camera already exists then remove it
if (CameraList[ key ] && CameraList[ key ] != NULL ) then
local ent = CameraList[ key ]
ent:Remove()
end

-- Create the camera
local cam = ents.Create( "env_projectedtexture" )
cam:SetParent( trace.Entity )

-- Position and rotate the camera correctly
local attachment = trace.Entity:GetAttachment( head )

local ang = attachment.Ang
local pos = attachment.Pos
cam:SetPos( pos )
cam:SetAngles( ang )

cam:Spawn( )

cam:SetNotSolid( true )
cam:GetTable():SetKey( key )
cam:GetTable():SetPlayer( ply )
cam:GetTable().toggle = toggle

cam:GetTable():SetTracking( NULL, Vector(0) )

if toggle == 1 then
numpad.OnDown( ply, key, "Camera_Toggle", cam )
else
numpad.OnDown( ply, key, "Camera_On", cam )
numpad.OnUp( ply, key, "Camera_Off", cam )
end

undo.Create("NPC Camera")
undo.AddEntity( cam )
undo.SetPlayer( ply )
undo.Finish()

ply:AddCleanup( "cameras", cam )

CameraList[ key ] = cam

-- Attach it to the head so it moves and rotate with it
cam:Fire( "setparentattachmentmaintainoffset" , attname , 0 )

trace.Entity.NPC_ViewCam = cam

return true
end

function TOOL:RightClick( trace )

if ( !trace.Entity ) then return end
if ( !trace.Entity:IsValid( ) ) then return end
if ( !trace.Entity:IsNPC( ) ) then return end

if ( CLIENT ) then return true end

if ( trace.Entity.NPC_ViewCam and trace.Entity.NPC_ViewCam:IsValid() ) then
trace.Entity.NPC_ViewCam:Remove()
trace.Entity.NPC_ViewCam = nil
return true
end

end

function TOOL:Think()

end

function TOOL.BuildCPanel(panel)
panel:AddControl("Header", { Text = "#Tool_npcvision_name", Description = "#Tool_npcvision_desc" })

panel:AddControl("Numpad", { Label = "#Tool_npcvision_key", Command = "npcvision_key", Buttonsize = "22" } )
panel:AddControl("CheckBox", {Label = "#Tool_npcvision_toggle",Command = "npcvision_toggle"})
end[/lua]

[media]http://www.youtube.com/watch?v=MIwxS5_i2N8[/media]

[Averice]

pos,ang = npc:GetBonePosition("ValveBiped.Bip01_L_Hand");

Could use that to get it on the left hand.

[Chunk3ym4n]

[QUOTE=Averice;20098645]pos,ang = npc:GetBonePosition("ValveBiped.Bip01_L_Hand");

Could use that to get it on the left hand.[/QUOTE]

So where would I copy paste that?

I made it overwrite:
local ang = attachment.Ang
local pos = attachment.Pos
but it comes up

weapons\gmod_tool\stools/npcvision.lua:70: attempt to index global 'npc' (a nil value)

[-TB-]

Well you should set the lamp's position and angle before you parent the lamp. You might also want to parent it after its spawned to.

[Chunk3ym4n]

Is there any good examples of parenting stuff to NPCs?

[Averice]

replace npc with tr.Entity:

and use pos/ang, you may need to do it in some sort of think/draw hook to make sure it stays updated with the client.

[Chunk3ym4n]

[QUOTE=Averice;20114880]replace npc with tr.Entity:

and use pos/ang, you may need to do it in some sort of think/draw hook to make sure it stays updated with the client.[/QUOTE]

Still comes up with attempt to index nil value