A better enum for working with directions and faces in Roblox.

Facing.lua

--!strict

--[[
	Facing
	A better enum for working with directions and faces.
	-----
	© Elttob 2022 - Available under MIT license
]]

type Facing = {
	normalID: Enum.NormalId,
	facingID: number,
	direction: Vector3,
	axis: Vector3,
	opposite: Facing
}

local fromNormalID: {[Enum.NormalId]: Facing} = {}
local fromFacingID: {[number]: Facing} = {}
local allFacings: {Facing} = {}

local function newFacing(normalID: Enum.NormalId, facingID: number): Facing
	local self = {}
	self.normalID = normalID
	self.facingID = facingID

	local direction = Vector3.FromNormalId(normalID)
	self.direction = direction
	self.axis = Vector3.new(math.abs(direction.X), math.abs(direction.Y), math.abs(direction.Z))
	self.opposite = self -- we'll remap this later

	fromNormalID[normalID] = self
	fromFacingID[facingID] = self
	table.insert(allFacings, self)

	return self
end

local Facing = {}
Facing.fromNormalID = fromNormalID
Facing.fromFacingID = fromFacingID
Facing.allFacings = allFacings

Facing.TOP = newFacing(Enum.NormalId.Top, 1)
Facing.BOTTOM = newFacing(Enum.NormalId.Bottom, 2)
Facing.FRONT = newFacing(Enum.NormalId.Front, 4)
Facing.BACK = newFacing(Enum.NormalId.Back, 8)
Facing.LEFT = newFacing(Enum.NormalId.Left, 16)
Facing.RIGHT = newFacing(Enum.NormalId.Right, 32)

-- aliases
Facing.UP = Facing.TOP
Facing.DOWN = Facing.BOTTOM

Facing.X_POSITIVE = Facing.RIGHT
Facing.X_NEGATIVE = Facing.LEFT
Facing.Y_POSITIVE = Facing.UP
Facing.Y_NEGATIVE = Facing.DOWN
Facing.Z_POSITIVE = Facing.BACK
Facing.Z_NEGATIVE = Facing.FRONT

Facing.X_AXIS = Facing.X_POSITIVE
Facing.Y_AXIS = Facing.Y_POSITIVE
Facing.Z_AXIS = Facing.Z_POSITIVE

-- map opposites
Facing.TOP.opposite = Facing.BOTTOM
Facing.BOTTOM.opposite = Facing.TOP
Facing.FRONT.opposite = Facing.BACK
Facing.BACK.opposite = Facing.FRONT
Facing.LEFT.opposite = Facing.RIGHT
Facing.RIGHT.opposite = Facing.LEFT

return Facing