extends Node


var datafile = "user://sldem2015_512_00n_30n_000_045_float.img"
var samplesPerLine = 23040
var lines = 15360
var offset = 1737.4
var scaleFact = 1
var resolution = 512

var latMin = 0
var latMax = 30
var lonMin = 0
var lonMax = 45

var cache = {}
var file: File

# Called when the node enters the scene tree for the first time.
func open():
	file = File.new()
	file.open(datafile, File.READ)
	
func close():
	file.close()
	queue_free()
	
func cacheArea(latMinIN, latMaxIN, lonMinIN, lonMaxIN):
	if not _validate(latMinIN,lonMinIN) and not _validate(latMaxIN,lonMaxIN) :
		print("out of scope!")
		return
		
	var lat = latMinIN
	while lat <= latMaxIN:
		cache[lat]={}
		file.seek(lat*resolution*samplesPerLine*4 + lonMinIN*resolution*4)
		var lon = lonMinIN
		while lon <= lonMaxIN:
			cache[lat][lon] = file.get_float()
			lon += 1.0/float(resolution)
		lat += 1.0/float(resolution)
	return
	
func read(lat,lon):
	if _validate(lat,lon):
		return cache[lat][lon]
	else:
		print("out of scope!")

func _validate(lat,lon):
	if lat <= latMax and lat >= latMin and lon <= lonMax and lon >= lonMin:
		return true
	return false

# Called every frame. 'delta' is the elapsed time since the previous frame.
#func _process(delta):
#	pass