-- CODE BY !nullptr (aka SisterMatic) - please credit - not fussed - just don't call it your code :)

-- SPECIAL NOTE: This script was NOT designed for a massive forest type map where shade is provided by every tree.
-- It was designed for my Australian outback project where trees are often in clumps along water courses.
-- The onus is on you to manage and contain "active shade" trees sensibly.

-- BENEFITS
-- A script that auto detects "shade" trees added to a map as long as the script is assigned. (See usage for best way)
-- Shade benefits per tree increase as you get closer. 
-- Tree group shade is accounted for. Each tree in a group casts it's own shade and is accumulative.
-- ie: Tree 1 might give 100% of it's shade and Tree 2 might also be giving 50% of it's shade etc..

-- USAGE
-- Add a tree to your map. Assign tree_shade.lua, static = no and IMPORTANT, set health to the shade value of the tree.
-- eg: a BIG tree might offer 10 shade, a small tree might offer 3.
-- Copy and paste, even paint your trees in. Script will do the count etc. for you.

-- Access "shade" as a global variable. (or change script to return shade)

-- KNOWN ISSUES
-- Nil that I could find except performance on high tree count.

-- PERFORMANCE NOTES: 
-- This was tested with over 500 "shade" trees and 1000+ non-shade (script not-assigned on map edges etc.)
-- Performance hit was neglible AS LONG AS a timer is set to at least 1 second intervals.
-- Does NOT take into account which "side" of a tree the sun is on. That would cripple you. Being "under" a tree is more than adequate.
-- Array population occurs only once. Step through occurs every call but is no issue *with* interval.
-- Don't use animated trees - although I haven't tried, no point really and is just pushing your luck.

-- EDITS
-- Safe to make changes to the area of shade but it's pretty accurate imho. It was designed around "Aussie" trees
-- Increase timer at poll_timer to reduce overhead but shade update will be slower.

-- In this example I have added my "hour" timing to stop calculations if it's dark. For obvious reasons :)
-- You can adjust the timer value to increase interval and have either constant or periodical shade updates.



shade = 0 -- access this var for total shade value

local tree_array = {}
local start_time_tree=math.ceil(g_Time/1000)
local tupdate = 0

function tree_shade_init(e)
  have_entity = 0
  iterations=0  --  debug timer check -- can be removed
end

function tree_shade_main(e)
  -- no need to keep count of trees you add with the tree.lua script attached. This is full auto.
  if have_entity == 0 then
    tcount=table.count(tree_array)
    -- do we have this tree already?
    have_entity=table.search(tcount,tree_array,e) -- pass tcount so we don't do it twice
    if have_entity==0 then
      tree_array[tcount+1] = e
    end -- if  
  end -- table populate  

  -- let's slow down the processing by restricting this to every second (could be increased even more if tree shade benefit is periodical) 
  -- tested with 500+ trees - almost zero performance loss
  
  local triggerT = poll_timer(1) -- 1 second - could be increased
  
  if triggerT > 0 then --  use this line if you are not doing day/night etc. below is an example if you are
  
  --if triggerT > 0 and tt_Hour > 5 and tt_Hour < 20 then -- if it's completely dark, not much point doing "shade" :)
    shade=0
    for i=1, tcount, 1 do
       treeDist = math.ceil(GetPlayerDistance(tree_array[i]))
       if treeDist < 150 then shade = shade + g_Entity[tree_array[i]]['health']*1.5
       elseif treeDist < 200 then shade = shade + g_Entity[tree_array[i]]['health']/2
       elseif treeDist < 300 then shade = shade + g_Entity[tree_array[i]]['health']/3
     end
     
       -- debug / visual rep -- these 2 lines can be removed, commented out.
       iterations=iterations+1 -- can be removed
       PromptDuration(tcount.." trees on map :: Current shade value: "..shade,1000) -- can be removed
    end -- for   
  end -- timer
end -- function

-- ***************************************
function table.count(tbl)
   local c=0
   for k in pairs(tbl) do c=c+1 end
   return c
end

-- ***************************************
function table.search(tbllen,tbl,tblval)
  local z = 1
  tblmatch = 0
  for z=1, tbllen, 1 do 
    if tbl[z]==tblval then
      tblmatch = 1
    end  
  end   
  return tblmatch
end

-- ***************************************
function poll_timer(finish)
  local stop_timex=math.ceil(g_Time/1000)
  local t_elapsedx=start_time_tree-stop_timex
  
  if t_elapsedx == 0 then
    start_time_tree=stop_timex+1
    tupdate=tupdate+1
  else  
    start_time_tree=stop_timex+1
  end  

  if tupdate == finish then
    tupdate=0 -- reset for next use
    return 1
  else 
    return 0
  end  
  
 end -- poll timer