What is the formula for acceleratedDirection?

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#1

I’m currently making a quake movement or bhop system from this article for my game and I’m trying to find what exactly the acceleratedDirection is. My first attempt that acceleratedDirection would be Humanoid.MoveDirection but the result is inaccurate which I didn’t move my camera:


Here’s my code:

--!strict

local RunService = game:GetService("RunService")
local Players = game:GetService("Players")

type Controls = {
	GetMoveVector: (self: Controls) -> Vector3,
}

type PlayerModule = {
	GetControls: (self: PlayerModule) -> Controls,
}

local LocalPlayer = Players.LocalPlayer
local PlayerScripts = LocalPlayer:WaitForChild("PlayerScripts") :: PlayerScripts
local PlayerModule: PlayerModule =
	require(PlayerScripts:WaitForChild("PlayerModule")) :: any

local MAX_VELOCITY_GROUND = 1000
local MAX_VELOCITY_AIR = 1000

local GROUND_ACCELERATE = 10
local AIR_ACCELERATE = 32
local FRICTION = 5

local function findChild<T>(
	parent: Instance,
	name: string,
	predicate: (child: Instance) -> T
): T?
	for _, child in ipairs(parent:GetChildren()) do
		if child.Name ~= name then
			continue
		end
		local result = predicate(child)
		if result then
			return result
		end
	end
	return nil
end

local parent: Instance? = script.Parent
if not parent then
	error(string.format("%s script has no parent!", script.Name))
end

local character = if parent:IsA("Model") then parent else nil
if not character then
	error(string.format("Parent of %s must be a Model!", script.Name))
end

local humanoid = character:FindFirstChildOfClass("Humanoid")
if not humanoid then
	error(
		string.format(
			"No Humanoid found for the %s script to use!",
			script.Name
		)
	)
end

local rootPart = humanoid.RootPart
if not rootPart then
	error(
		string.format(
			"No RootPart found for the %s script to use!",
			script.Name
		)
	)
end

local rootAttachment = findChild(rootPart, "RootAttachment", function(child)
	return if child:IsA("Attachment") then child else nil
end)
if not rootAttachment then
	error(
		string.format(
			"No RootAttachment found for the %s script to use!",
			script.Name
		)
	)
end

local function accelerate(
	acceleratedDirection: Vector3,
	previousVelocity: Vector3,
	acceleration: number,
	maxVelocity: number,
	deltaTime: number
): Vector3
	local projectionVelocity = previousVelocity:Dot(acceleratedDirection)
	local acceleratedVelocity = acceleration * deltaTime

	if projectionVelocity + acceleratedVelocity > maxVelocity then
		acceleratedVelocity = maxVelocity - projectionVelocity
	end

	return previousVelocity + acceleratedDirection * acceleratedVelocity
end

local function moveGround(
	acceleratedDirection: Vector3,
	previousVelocity: Vector3,
	deltaTime: number
): Vector3
	local speed = previousVelocity.Magnitude
	if speed ~= 0 then
		local drop = speed * FRICTION * deltaTime
		previousVelocity *= math.max(speed - drop, 0) / speed
	end
	return accelerate(
		acceleratedDirection,
		previousVelocity,
		GROUND_ACCELERATE,
		MAX_VELOCITY_GROUND,
		deltaTime
	)
end

local function moveAir(
	acceleratedDirection: Vector3,
	previousVelocity: Vector3,
	deltaTime: number
): Vector3
	return accelerate(
		acceleratedDirection,
		previousVelocity,
		AIR_ACCELERATE,
		MAX_VELOCITY_AIR,
		deltaTime
	)
end

local previousVelocity = Vector3.zero
RunService.Stepped:Connect(function(_, deltaTime)
	local camera = workspace.CurrentCamera
	local currentVelocity = Vector3.zero

	local moveVector = PlayerModule:GetControls():GetMoveVector()
	local moveDirection = camera
		:GetRenderCFrame()
		:VectorToWorldSpace(moveVector) * Vector3.new(1, 0, 1)

	if humanoid.FloorMaterial ~= Enum.Material.Air and not humanoid.Jump then
		currentVelocity = moveGround(moveDirection, previousVelocity, deltaTime)
	else
		currentVelocity = moveAir(moveDirection, previousVelocity, deltaTime)
	end
	previousVelocity = currentVelocity
	rootPart.AssemblyLinearVelocity = Vector3.new(
		currentVelocity.X,
		rootPart.AssemblyLinearVelocity.Y,
		currentVelocity.Z
	)
end)
#2

According to the article you linked, acceleratedDirection is the “normalized direction that the player has requested to move (taking into account the movement keys and look direction)”

Unsure whether I’m correct but taking into account both factors, this is what acceleratedDirection should be

local VEC_XZ = Vector3.new(1, 0, 1)
local Humanoid = character:FindFirstChildWhichIsA("Humanoid")

local function getMoveDirection()
	local direction = Vector3.zero
	if Humanoid.MoveDirection.Magnitude > 0 then
		direction = (Humanoid.MoveDirection * VEC_XZ).Unit
	end
	return direction
end

local function getLookDirection()
	local currentCamera = workspace.CurrentCamera
	return (currentCamera.LookVector * VEC_XZ).Unit
end

local function getAccelDir()
	return (getMoveDirection() + getLookDirection()).Unit
end
#3

I tried your method. It didn’t work like I can still bhop without moving my camera
Edit: I think the issue relies on previousVelocity