-- comment key  [P] denotes a performance improvement (however small)
--              [L] denotes a 'Lua'ism, i.e, a language feature

function PlayerLookingAt (e, dist, fov)
	-- localise the global list entry for this entity [P]
	local Ent = g_Entity[e]
	
	if Ent == nil then return false end

	-- how to provide default inputs [L]
	dist = dist or 3000
	fov  = fov  or 1

	-- alternate way of doing <list>['value'] [L]
	local Dx = Ent.x - g_PlayerPosX
	local Dz = Ent.z - g_PlayerPosZ
	
	-- high performance distance calculation, avoids need for square root
	-- only continue function if horizontal distance to entity less than
	-- specified limit (or default is one wasn't specified)  [P]
	if (Dx*Dx + Dz*Dz) > dist*dist then return false end
	
	-- define functions on the fly!  [L]
	local function limitAngle (Angle)
		if Angle <= 0 then
		    Angle = 360 + Angle 
	    elseif Angle > 360 then
		    Angle = Angle - 360
		end
		return Angle
	end

	-- define local variable holding value of horizontal angle from
	-- player to entity
	local angle = limitAngle(math.atan2(Dx, Dz) * (180.0 / math.pi))
	
	-- localise the global holding Player Angle [P]
	local pAng  = g_PlayerAngY

	-- In some versions of GameGuru the player angle isn't limited
	-- to 360 degrees so this fixes it if needed.
	while pAng < 0 or pAng > 360 do
		if pAng <= 0 then
			pAng = 360 + pAng
		elseif pAng > 360 then
			pAng = pAng - 360
		end
	end

	-- Calculate left and right angles from user specified field of view
	-- value (or default is one wasn't specified)
	local L = limitAngle(angle - fov / 2)
	local R = limitAngle(angle + fov / 2)
	
	-- Is player angle within left and right limits?
	-- (if you find this bit confusing grab some paper and a pencil and
	--  draw it)
	if L < R and (pAng > L and pAng < R) or
	   L > R and (pAng > L or  pAng < R) then
		return true
	else
		return false
	end
end