extends Node

var chunk_half_size setget _set_chunk_size
var chunk_size

func _set_chunk_size(val):
    chunk_half_size = val
    chunk_size = val * 2.0

onready var noise = OpenSimplexNoise.new()
onready var rng = RandomNumberGenerator.new()
var _seed

func _ready():
    randomize()
    self._seed = randi()
    self.noise.seed = self._seed
    self.noise.seed = 0
    self.noise.period = 16
    self.noise.persistence = 0
    self.rng.seed = self._seed

func rng_2dv(coords:Vector2):
    self.rng.seed = hash(coords)

func gen_chunk(chunk):
    var gen_tree = Spatial.new()
    gen_tree.name = "gen_tree"
    chunk.add_child(gen_tree)
    iterate_chunk(chunk, Vector2(10.0,10.0), funcref(self,"gen_rocks"))

func v2_coords(coords:Vector3):
    return Vector2(coords.x,coords.z)

func v3_coords(coords:Vector2):
    return Vector3(coords.x,0.0,coords.y)

func iterate_chunk(chunk,step:Vector2,cb:FuncRef):
    var chunk_size_rounded = Vector2(chunk_half_size,chunk_half_size).snapped(step)
    for x in range(-chunk_size_rounded.x,chunk_size_rounded.x,step.x):
        for y in range(-chunk_size_rounded.y,chunk_size_rounded.y,step.y):
            cb.call_func(chunk,Vector2(x,y))

onready var Rock = preload("res://world/obstacles/Rock.tscn")
const rock_size = 5.0
func make_rock(chunk,xform:Transform):
    var rock = Rock.instance()
    rock.transform = xform
    chunk.get_node("gen_tree").add_child(rock)

func gen_rocks(chunk,chunk_coords:Vector2):
    var coords = v3_coords(chunk_coords)
    var basis = Basis()
    var world_coords = chunk_coords + v2_coords(chunk.transform.origin)
    self.rng_2dv(world_coords)
    var rng_val = self.rng.randf_range(0.0,TAU)
    basis = Basis(Vector3.UP,rng_val) * basis
    var noise_val = self.noise.get_noise_2dv(world_coords * 0.125)
    if noise_val < 0.4:
        return
    noise_val = min(noise_val,0.6)
    noise_val -= 0.4
    noise_val /= 0.2
    noise_val = lerp(1.0,4.0,noise_val)
    basis = basis.scaled(Vector3.ONE*noise_val)
    coords.y += (noise_val*5.0)-5.0
    make_rock(chunk,Transform(basis,coords))