@tool
class_name TerrainInstance3D extends GeometryInstance3D

const _TERRAIN_MAX := 1024

var _mesh := PlaneMesh.new()

var _material := ShaderMaterial.new()

##
##
##
@export
var size: Vector2i = Vector2i.ZERO:
	get:
		return size

	set(value):
		var width := clampi(value.x, 0, _TERRAIN_MAX)
		var height := clampi(value.y, 0, _TERRAIN_MAX)

		if (width != size.x) or (height != size.y):
			if (width == 0) and (height == 0):
				RenderingServer.instance_set_base(self.get_instance(), RID())

			else:
				self._mesh.subdivide_width = width
				self._mesh.subdivide_depth = height
				self._mesh.size = value

				self._material.set_shader_parameter("SIZE", Vector2(value))
				RenderingServer.instance_set_base(self.get_instance(), self._mesh)

		size = Vector2i(width, height)

##
##
##
@export
var layer_1_albedo: Texture2D = null:
	get:
		return layer_1_albedo

	set(value):
		self._material.set_shader_parameter("LAYER_1_ALBEDO", value)

		layer_1_albedo = value

##
##
##
@export
var layer_1_normal_map: Texture2D = null:
	get:
		return layer_1_normal_map

	set(value):
		self._material.set_shader_parameter("LAYER_1_NORMAL_MAP", value)

		layer_1_normal_map = value

##
##
##
@export
var layer_2_albedo: Texture2D = null:
	get:
		return layer_2_albedo

	set(value):
		self._material.set_shader_parameter("LAYER_2_ALBEDO", value)

		layer_2_albedo = value

##
##
##
@export
var layer_2_normal_map: Texture2D = null:
	get:
		return layer_2_normal_map

	set(value):
		self._material.set_shader_parameter("LAYER_2_NORMAL_MAP", value)

		layer_2_normal_map = value

##
##
##
@export
var layer_3_albedo: Texture2D = null:
	get:
		return layer_3_albedo

	set(value):
		self._material.set_shader_parameter("LAYER_3_ALBEDO", value)

		layer_3_albedo = value

##
##
##
@export
var layer_3_normal_map: Texture2D = null:
	get:
		return layer_3_normal_map

	set(value):
		self._material.set_shader_parameter("LAYER_3_NORMAL_MAP", value)

		layer_3_normal_map = value

##
##
##
@export
var layer_4_albedo: Texture2D = null:
	get:
		return layer_4_albedo

	set(value):
		self._material.set_shader_parameter("LAYER_4_ALBEDO", value)

		layer_4_albedo = value

##
##
##
@export
var layer_4_normal_map: Texture2D = null:
	get:
		return layer_4_normal_map

	set(value):
		self._material.set_shader_parameter("LAYER_4_NORMAL_MAP", value)

		layer_4_normal_map = value

##
##
##
@export
var terrain_map: Texture2D = null:
	get:
		return terrain_map

	set(value):
		self._material.set_shader_parameter("TERRAIN_MAP", value)

		terrain_map = value

##
##
##
@export
var max_height := 100.0:
	get:
		return max_height

	set(value):
		self._material.set_shader_parameter("MAX_HEIGHT", value)

		max_height = max(value, 0.0)

func _init() -> void:
	self._material.shader = preload("res://terrain_shader.gdshader")

	self._mesh.surface_set_material(0, self._material)