--Function requires the same name as the file
local sound_entity = 963 --entity assigned to this lua file
local max_vol = 100 -- maximum sound volume
local trigger_zone = 1072 -- action zone radius
local zone_segments = 16 -- number of increments for a volume range of 84 to 100
local inzone = 0
local volume = 0
local dist = 0
local inc = 0
local volume_step = 0
function waterfall_volume_fade_init(sound_entity)
end
function waterfall_volume_fade_main(sound_entity)
  --calculate individual zone segment size based on the number of zone segments requested (16)
  inc = (math.floor(trigger_zone / zone_segments)) --will equal 65 using above variables
  dist = GetPlayerDistance(sound_entity) --find how far the player is from the center of zone
  volume_step = (math.floor(dist / inc)) --number of zone segments traveled becomes the steps in volume
  volume = max_vol - volume_step --volume level

  if dist < trigger_zone and inzone == 0 then --player is in the active zone
    PlaySoundIfSilent(sound_entity, 1)
    SetSoundVolume(volume)--this is where the volume changes based on the above calculation
    Prompt("volume =  " .. volume .." Distance =  " .. dist.." inc = " .. inc .." new_dist " .. volume_step)
  end
  if dist > trigger_zone and inzone == 0 then --player has left the active zone
	StopSound(sound_entity, 1)
    inzone = 1
  end
  inzone = 0
end