Aimbot ESP?

[MeepDarknessMeep]

Could someone please show me how to get the x, y of the screen compared to the x, y, z of the 3d world's player's head? Sorry I am bad at explaining :P

EDIT: The title was supposed to be head esp. It should make an X on the player's heads.

[MeepDarknessMeep]

I found something similar. Was wondering if someone could help me convert it for a single point. (x,y,z pair)

       local x1,y1,x2,y2 = coordinates(v)
        for _, value in pairs(traitornames) do
            if value == v then
                surface.SetDrawColor(255,0,0)
            else
                surface.SetDrawColor(0,255,0)
            end
        end
    
 
 
        surface.DrawLine( x1, y1, math.min( x1 + 5, x2 ), y1 )
        surface.DrawLine( x1, y1, x1, math.min( y1 + 5, y2 ) )
 
 
        surface.DrawLine( x2, y1, math.max( x2 - 5, x1 ), y1 )
        surface.DrawLine( x2, y1, x2, math.min( y1 + 5, y2 ) )
 
 
        surface.DrawLine( x1, y2, math.min( x1 + 5, x2 ), y2 )
        surface.DrawLine( x1, y2, x1, math.max( y2 - 5, y1 ) )
 
 
        surface.DrawLine( x2, y2, math.max( x2 - 5, x1 ), y2 )
        surface.DrawLine( x2, y2, x2, math.max( y2 - 5, y1 ) )

And coordinates() =

local function coordinates( ent )
local min, max = ent:OBBMins(), ent:OBBMaxs()
local corners = {
        Vector( min.x, min.y, min.z ),
        Vector( min.x, min.y, max.z ),
        Vector( min.x, max.y, min.z ),
        Vector( min.x, max.y, max.z ),
        Vector( max.x, min.y, min.z ),
        Vector( max.x, min.y, max.z ),
        Vector( max.x, max.y, min.z ),
        Vector( max.x, max.y, max.z )
}
 
local minX, minY, maxX, maxY = ScrW() * 2, ScrH() * 2, 0, 0
for _, corner in pairs( corners ) do
        local onScreen = ent:LocalToWorld( corner ):ToScreen()
        minX, minY = math.min( minX, onScreen.x ), math.min( minY, onScreen.y )
        maxX, maxY = math.max( maxX, onScreen.x ), math.max( maxY, onScreen.y )
end
 
return minX, minY, maxX, maxY
end