class_name ForestEdgeResourceCluster
extends TerrainResourceCluster

const FERN_OFFSETS := [
	Vector3(-5.4, 0.0, 1.8),
	Vector3(-3.2, 0.0, -1.7),
	Vector3(-1.3, 0.0, 2.9),
	Vector3(1.1, 0.0, -2.8),
	Vector3(2.8, 0.0, 1.4),
	Vector3(4.8, 0.0, -3.1),
	Vector3(6.2, 0.0, 2.5),
	Vector3(8.5, 0.0, -1.2),
	Vector3(10.6, 0.0, 1.0),
	Vector3(-7.4, 0.0, -2.9),
]
const MUSHROOM_OFFSETS := [
	Vector3(-4.4, 0.0, -0.2),
	Vector3(-2.1, 0.0, 1.2),
	Vector3(0.3, 0.0, -3.5),
	Vector3(2.2, 0.0, 3.2),
	Vector3(5.0, 0.0, 0.2),
	Vector3(7.1, 0.0, -2.8),
	Vector3(9.3, 0.0, 2.6),
	Vector3(-6.5, 0.0, 2.9),
]
const STONE_OFFSETS := [
	Vector3(-6.8, 0.0, 0.2),
	Vector3(-2.7, 0.0, -3.4),
	Vector3(0.7, 0.0, 0.4),
	Vector3(4.0, 0.0, 3.5),
	Vector3(7.8, 0.0, 0.8),
	Vector3(10.8, 0.0, -2.2),
]


func _build_understory() -> void:
	var fern_material := StandardMaterial3D.new()
	fern_material.albedo_color = Color("#2f5935")
	fern_material.roughness = 0.95
	fern_material.cull_mode = BaseMaterial3D.CULL_DISABLED
	_assign_multimesh(
		$DecorativeInstances/Understory/FernClumps,
		_create_fern_mesh(fern_material),
		FERN_OFFSETS,
		Vector3(0.86, 0.86, 0.86),
		0.03
	)

	_assign_multimesh(
		$DecorativeInstances/Understory/MushroomClumps,
		_create_mushroom_mesh(),
		MUSHROOM_OFFSETS,
		Vector3(1.0, 1.0, 1.0),
		0.02
	)

	var stone_mesh := SphereMesh.new()
	stone_mesh.radius = 1.0
	stone_mesh.height = 2.0
	stone_mesh.radial_segments = 8
	stone_mesh.rings = 4
	var stone_material := StandardMaterial3D.new()
	stone_material.albedo_color = Color("#68695d")
	stone_material.roughness = 0.97
	stone_mesh.material = stone_material
	_assign_multimesh(
		$DecorativeInstances/Understory/ForestStones,
		stone_mesh,
		STONE_OFFSETS,
		Vector3(0.55, 0.22, 0.4),
		0.2
	)


func _create_mushroom_mesh() -> ArrayMesh:
	var vertices := PackedVector3Array()
	var normals := PackedVector3Array()
	var colors := PackedColorArray()
	var segment_count := 8
	var stem_color := Color("#e8d8ae")
	var cap_color := Color("#d98142")
	var cap_under_color := Color("#b85f35")
	for segment in segment_count:
		var angle_a := float(segment) / segment_count * TAU
		var angle_b := float(segment + 1) / segment_count * TAU
		var normal_a := Vector3(cos(angle_a), 0.0, sin(angle_a))
		var normal_b := Vector3(cos(angle_b), 0.0, sin(angle_b))
		var stem_bottom_a := normal_a * 0.065
		var stem_bottom_b := normal_b * 0.065
		var stem_top_a := normal_a * 0.045 + Vector3.UP * 0.3
		var stem_top_b := normal_b * 0.045 + Vector3.UP * 0.3
		(
			vertices
			. append_array(
				[
					stem_bottom_a,
					stem_bottom_b,
					stem_top_b,
					stem_bottom_a,
					stem_top_b,
					stem_top_a,
				]
			)
		)
		normals.append_array([normal_a, normal_b, normal_b, normal_a, normal_b, normal_a])
		for _vertex in 6:
			colors.append(stem_color)

		var cap_ring_a := normal_a * 0.24 + Vector3.UP * 0.3
		var cap_ring_b := normal_b * 0.24 + Vector3.UP * 0.3
		var cap_top := Vector3.UP * 0.48
		var cap_normal := (
			Vector3(
				cos((angle_a + angle_b) * 0.5) * 0.55, 0.82, sin((angle_a + angle_b) * 0.5) * 0.55
			)
			. normalized()
		)
		vertices.append_array([cap_top, cap_ring_b, cap_ring_a])
		normals.append_array([cap_normal, cap_normal, cap_normal])
		colors.append_array([cap_color, cap_color, cap_color])

		vertices.append_array([Vector3.UP * 0.29, cap_ring_a, cap_ring_b])
		normals.append_array([Vector3.DOWN, Vector3.DOWN, Vector3.DOWN])
		colors.append_array([cap_under_color, cap_under_color, cap_under_color])

	var arrays := []
	arrays.resize(Mesh.ARRAY_MAX)
	arrays[Mesh.ARRAY_VERTEX] = vertices
	arrays[Mesh.ARRAY_NORMAL] = normals
	arrays[Mesh.ARRAY_COLOR] = colors
	var material := StandardMaterial3D.new()
	material.albedo_color = Color.WHITE
	material.vertex_color_use_as_albedo = true
	material.roughness = 0.88
	var mesh := ArrayMesh.new()
	mesh.add_surface_from_arrays(Mesh.PRIMITIVE_TRIANGLES, arrays)
	mesh.surface_set_material(0, material)
	return mesh