1. apireference
2. scripting
3. runservice

BindToRenderStep

local RunService = game:GetService("RunService")
    
local function functionToBind() end
    
-- Bind the function above to the binding named "tempBinding"
RunService:BindToRenderStep("tempBinding", 1, functionToBind)
-- Unbind the function bound to "tempBinding"
RunService:UnbindFromRenderStep("tempBinding")

local RunService = game:GetService("RunService")
    
local function beforeCamera(delta)
	-- Code in here will run before the default Roblox camera script
end
    
RunService:BindToRenderStep("Before camera", Enum.RenderPriority.Camera.Value - 1, beforeCamera)

Parameters

Returns

Code Samples

Frame Moving in Circle

This code sample moves a GuiObject in a circle within its parent object using RunService’s BindToRenderStep. It defines a parametric equation in a function to help with positioning the GuiObject.

To try this code out, put a ScreenGui in the StarterGui. Inside the ScreenGui, insert a Frame with a LocalScript. Paste this code into the LocalScript, then play the game. Watch the Frame travel counterclockwise within.

local RunService = game:GetService("RunService")

-- How fast the frame ought to move
local SPEED = 2

local frame = script.Parent
frame.AnchorPoint = Vector2.new(.5, .5)

-- A simple parametric equation of a circle
-- centered at (0.5, 0.5) with radius (0.5)
local function circle(t)
	return .5 + math.cos(t) * .5,
	       .5 + math.sin(t) * .5
end

-- Keep track of the current time
local currentTime = 0
local function onRenderStep(deltaTime)
	-- Update the current time
	currentTime = currentTime + deltaTime * SPEED
	-- ...and our frame's position
	local x, y = circle(currentTime)
	frame.Position = UDim2.new(x, 0, y, 0)
end

-- This is just a visual effect, so use the "Last" priority
RunService:BindToRenderStep("FrameCircle", Enum.RenderPriority.Last.Value, onRenderStep)
--RunService.RenderStepped:Connect(onRenderStep) -- Also works, but not recommended

RunService Custom Function

This example shows how to bind a simple function to the render step. All this function does is print how much time passed between the last render step and the current one. Note that this code will need to be in a LocalScript to run.

-- Make variables for Roblox services
local RunService = game:GetService("RunService")

-- Function that will be bound to the render step
local function checkDelta(deltaTime)
	-- Print the time since the last render step
	print("Time since last render step:", deltaTime)
end

-- Bind the function
RunService:BindToRenderStep("Check delta", Enum.RenderPriority.First.Value, checkDelta)

Bind and Unbind a Function

This example uses the RunService to bind and unbind a function named printHello. First, we bind the function to the RenderStep so that fires every step. Then, after we wait 5 seconds (wait(5)), we unbind the function.

Please note that we take caution to surround the function unbind in a pcall to prevent the code from breaking due to an error being thrown if the function name passed does not match the name of an already bound function. While we know that the function used in this example is bound when we try to unbind it, doing this is good coding practice.

local RunService = game:GetService("RunService")

-- Step 1: Declare the function and a name
local name = "Print Hello"
function printHello()
	print("Hello")
end

-- Step 3: Bind the function
RunService:BindToRenderStep(name, Enum.RenderPriority.First.Value, printHello)

-- Step 3: Unbind the function
local success, message = pcall(function() RunService:UnbindFromRenderStep(name) end)
if success then
	print("Success: Function unbound!")
else 
	print("An error occurred: " .. message)
end