@tool
class_name TerrainInstance3D extends GeometryInstance3D

const _DETAIL := 2

var _mesh := PlaneMesh.new()

var _material := ShaderMaterial.new()

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

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

		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 * _DETAIL
				self._mesh.subdivide_depth = height * _DETAIL
				self._mesh.size = value

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

		size = value

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

	set(value):
		self._material.set_shader_parameter("ALBEDO_MAP_0", value)

		albedo_map = value

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

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

		albedo_map_b = value

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

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

		albedo_map_g = value

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

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

		albedo_map_r = value

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

	set(value):
		self._material.set_shader_parameter("NORMAL_MAP_0", value)

		normal_map = value

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

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

		normal_map_b = value

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

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

		normal_map_g = value

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

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

		normal_map_r = 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)