Possible Engine Bug? Numeric variables nil inside ContextActionService callback functions

Maelstorm_1973 · May 18, 2022, 11:31pm

Here’s a weird one. I’m working on the client script for a weapon that incorporates a variable zoom function. When I pickup the weapon, the zoom works. When I try to adjust the zoom, the variable that holds the current zoom is nil as the error message says. When I print the offending variable, and a few others, the numeric variables show as nil while the ones holding boolean values show their values as true or false.

local useZoom = false
local zoomToggle = false
local zoomFoV = 40
local zoomRD = 30
local zoomCurrent = 40
local zoomMin = 70
local zoomMax = 10
local zoomDebounce = false

Further down in the script…

-- Zooms the scope in and out.
local function zoomScope(actionName, inputState, inputObject)
	print(zoomCurrent, zoomToggle, zoomFoV, zoomDebounce, equipped)
	if actionName == "ScopeZoomIn" then
		if inputState == Enum.UserInputState.Begin then
			zoomCurrent -= 1
			if zoomCurrent <= zoomMax then
				zoomCurrent = zoomMax
			end
			workspace.CurrentCamera.FieldOfView = zoomCurrent
		elseif inputState == Enum.UserInputState.Change then
			if not zoomDebounce then
				zoomDebounce = true
				delay(0.25, function()
					zoomCurrent -= 1
					if zoomCurrent <= zoomMax then
						zoomCurrent = zoomMax
					end
					workspace.CurrentCamera.FieldOfView = zoomCurrent
				end)
			end
		end
	elseif actionName == "ScopeZoomOut" then
		if inputState == Enum.UserInputState.Begin then
			zoomCurrent += 1
			if zoomCurrent >= zoomMin then
				zoomCurrent = zoomMin
			end
			workspace.CurrentCamera.FieldOfView = zoomCurrent
		elseif inputState == Enum.UserInputState.Change then
			if not zoomDebounce then
				zoomDebounce = true
				delay(0.25, function()
					zoomCurrent += 1
					if zoomCurrent >= zoomMin then
						zoomCurrent = zoomMin
					end
					workspace.CurrentCamera.FieldOfView = zoomCurrent
					zoomDebounce = false
				end)
			end
		end
	end
end

I’m beginning to think this is an engine bug, as this is affecting ALL numeric variables, but Roblox says that I do not yet have the authority to report a bug. What do you guys think?

Katrist · May 18, 2022, 11:38pm

There’s a very small chance this is an engine bug. Do you change the values any time before calling the function?

Maelstorm_1973 · May 18, 2022, 11:55pm

In assignment, and when the client queries the server for the parameters of the weapon when it’s equipped. Here’s the entire script.

--
-- Local Weapon Script
--

-- ******** Requirements

-- Required Game Services and Facilities
local CAS = game:GetService("ContextActionService")
local playerService = game:GetService("Players")
local replicatedStorage = game:GetService("ReplicatedStorage")
local screenGui = game:GetService("GuiService")

-- Script Dependancies



-- ******** Local data

-- Housekeeping
local waitTimeout = 10
local localPlayer = playerService.LocalPlayer
local toolInstance = script.Parent
local mouseCursor
local equipped = false
local mouseButton1Down = false;

-- Ammo
local ammoMax = 0

-- Clip
local useClip = false
local clipReload = true
local clipSize = 0

-- AutoFire
local useAuto = false
local autoRate = 0

-- Zoom
local useZoom = false
local zoomToggle = false
local zoomFoV = 40
local zoomRD = 30
local zoomCurrent = 40
local zoomMin = 70
local zoomMax = 10
local zoomDebounce = false


-- ******** Functions/Methods

-- Debugging Tool
printTableRecursive = function(td, tab)
	local tableData = td
	if td == nil then
		warn("utilityMod.printTableRecursive: Parameter is nil.")
		return
	elseif type(td) ~= "table" then
		warn("utilityMod.printTableRecursive: Parameter is not a table:",
			type(tableData), " --> ", tableData)
		return
	end

	if tab == nil then
		tab = ""
	end
	for key, value in pairs(tableData) do
		if type(value) == "table" then
			print(string.format(tab) .. ">> Subtable: ", key)
			printTableRecursive(value, tab .. "\t")
		else
			print(string.format(tab), key, "=", value)
		end
	end
end

-- Enables the zoom GUI
local function enableZoomGui()
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local ZoomScope = WeaponsHUD:WaitForChild("ZoomScope", waitTimeout)
			if ZoomScope then
				ZoomScope.Visible = true
			end
		end
	end
end

-- Disables the zoom GUI
local function disableZoomGui()
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local ZoomScope = WeaponsHUD:WaitForChild("ZoomScope", waitTimeout)
			if ZoomScope then
				ZoomScope.Visible = false
			end
		end
	end
end

-- Zooms the scope in and out.
local function zoomScope(actionName, inputState, inputObject)
	print(zoomCurrent, zoomToggle, zoomFoV, zoomDebounce, equipped)
	if actionName == "ScopeZoomIn" then
		if inputState == Enum.UserInputState.Begin then
			zoomCurrent -= 1
			if zoomCurrent <= zoomMax then
				zoomCurrent = zoomMax
			end
			workspace.CurrentCamera.FieldOfView = zoomCurrent
		elseif inputState == Enum.UserInputState.Change then
			if not zoomDebounce then
				zoomDebounce = true
				delay(0.25, function()
					zoomCurrent -= 1
					if zoomCurrent <= zoomMax then
						zoomCurrent = zoomMax
					end
					workspace.CurrentCamera.FieldOfView = zoomCurrent
				end)
			end
		end
	elseif actionName == "ScopeZoomOut" then
		if inputState == Enum.UserInputState.Begin then
			zoomCurrent += 1
			if zoomCurrent >= zoomMin then
				zoomCurrent = zoomMin
			end
			workspace.CurrentCamera.FieldOfView = zoomCurrent
		elseif inputState == Enum.UserInputState.Change then
			if not zoomDebounce then
				zoomDebounce = true
				delay(0.25, function()
					zoomCurrent += 1
					if zoomCurrent >= zoomMin then
						zoomCurrent = zoomMin
					end
					workspace.CurrentCamera.FieldOfView = zoomCurrent
					zoomDebounce = false
				end)
			end
		end
	end
end

-- Zoom in the gun camera
local function zoomIn()
	localPlayer.CameraMode = Enum.CameraMode.LockFirstPerson
	workspace.CurrentCamera.FieldOfView = zoomFoV
	localPlayer.Character.Humanoid.CameraOffset = Vector3.new(0, 0, 4)
	enableZoomGui()
	zoomCurrent = zoomFoV
	
	-- Set hotkeys for variable zoom
	CAS:BindAction("ScopeZoomIn", zoomScope, true, Enum.KeyCode.RightBracket,
		Enum.KeyCode.ButtonL1)
	CAS:BindAction("ScopeZoomOut", zoomScope, true, Enum.KeyCode.LeftBracket,
		Enum.KeyCode.ButtonR1)
	print(zoomFoV, zoomCurrent)
end

-- Zoom out the gun camera
local function zoomOut()
	localPlayer.CameraMode = Enum.CameraMode.Classic
	workspace.CurrentCamera.FieldOfView = 70
	localPlayer.Character.Humanoid.CameraOffset = Vector3.new(0, 0, 0)
	localPlayer.CameraMinZoomDistance = zoomRD;
	disableZoomGui()
	wait()
	localPlayer.CameraMinZoomDistance = 0.5;
	CAS:UnbindAction("ScopeZoomIn")
	CAS:UnbindAction("ScopeZoomOut")
end

-- Called when the gun is equipped/unequipped. This helps to mitigate a problem
-- with the zoom getting stuck.
local function equipZoomOut()
	zoomOut()
	zoomToggle = false
end

-- Toggle zooms the gun camera in or out.
local function zoomCamera(actionName, inputState, inputObject)
	if not equipped then
		equipZoomOut()
		return
	end
	if actionName == "ZoomCameraScope" then
		if inputState == Enum.UserInputState.Begin then
			if zoomToggle then
				zoomToggle = false
				zoomOut(localPlayer, workspace.CurrentCamera)
			else
				zoomToggle = true
				zoomIn(localPlayer, workspace.CurrentCamera)
			end
		elseif inputState == Enum.UserInputState.End then
		end
	end
end

-- Initiates a manual clip reload.
local function reloadClipManual(actionName, inputState, inputObject)
	if not equipped then
		return
	end
	if actionName == "ManualClipReload" then
		if inputState == Enum.UserInputState.Begin then
			local folderEvents = toolInstance:WaitForChild("Events", waitTimeout)
			local eventReload = folderEvents:WaitForChild("Reload", waitTimeout)
			eventReload:FireServer()
		end
	end
end

-- Enables the Ammo Clip weapons HUD.
local function enableHUDClip()
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local ClipHUD = WeaponsHUD:WaitForChild("AmmoDisplayClip", waitTimeout)
			if ClipHUD then
				WeaponsHUD.Enabled = true
				ClipHUD.Visible = true
			end
		end
	end
end

-- Enables the No Ammo Clip weapons HUD.
local function enableHUDNoClip()
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local NoClipHUD = WeaponsHUD:WaitForChild("AmmoDisplayNoClip", waitTimeout)
			if NoClipHUD then
				WeaponsHUD.Enabled = true
				NoClipHUD.Visible = true
			end
		end
	end
end

-- Disables all HUDs
local function disableHUD()
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local FrameList = WeaponsHUD:GetChildren()
			if FrameList and FrameList ~= nil and #FrameList > 0 then
				for _, frame in pairs(FrameList) do
					frame.Visible = false
				end
			end
			WeaponsHUD.Enabled = false
		end
	end
end

-- Sets text colors based on a percentage
local function textColors(value, str)
	local text
	if value > 0.75 then
		text = str
	elseif value > 0.50 then
		-- Blue
		text = "<font color=\"#4482B4\">" .. str .. "</font>"
	elseif value > 0.33 then
		-- Green
		text = "<font color=\"#00DD00\">" .. str .. "</font>"
	elseif value > 0.25 then
		-- Gold/Yellow
		text = "<font color=\"#FFD700\">" .. str .. "</font>"
	elseif value > 0.10 then
		-- Orange
		text = "<font color=\"#FFA500\">" .. str .. "</font>"
	elseif value <= 0.10 then
		-- Red
		text = "<font color=\"#FF0000\">" .. str .. "</font>"
	end
	return text
end

-- Write to the Clip version of the weapons HUD.
local function writeHudClip(clip, spare)
	local fracClip = clip / clipSize
	local fracSpare = spare / ammoMax
	local textClip = "<b>" .. tostring(clip) .. "</b>"
	local textSpare = "<b>" .. tostring(spare) .. "</b>"
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local ClipHUD = WeaponsHUD:WaitForChild("AmmoDisplayClip", waitTimeout)
			if ClipHUD then
				WeaponsHUD.Enabled = true
				ClipHUD.Visible = true
				local displayClip = ClipHUD:WaitForChild("Clip", waitTimeout)
				local displaySpare = ClipHUD:WaitForChild("Spare", waitTimeout)
				displayClip.Text = textColors(fracClip, textClip)
				displaySpare.Text = textColors(fracSpare, textSpare)
			end
		end
	end
end

-- Write to the No Clip version of the weapons HUD.
local function writeHudNoClip(ammo)
	local frac = ammo / ammoMax
	local text = "<b>" .. ammo .. "</b>"
	local PlayerGUI = localPlayer:WaitForChild("PlayerGui", waitTimeout)
	if PlayerGUI then
		local WeaponsHUD = PlayerGUI:WaitForChild("WeaponsHud",waitTimeout)
		if WeaponsHUD then
			local NoClipHUD = WeaponsHUD:WaitForChild("AmmoDisplayNoClip", waitTimeout)
			if NoClipHUD then
				WeaponsHUD.Enabled = true
				NoClipHUD.Visible = true
				local displayAmmo = NoClipHUD:WaitForChild("Ammo", waitTimeout)
				displayAmmo.Text = textColors(frac, text)
			end
		end
	end
end

-- Called when the weapon is equipped.
script.Parent.Equipped:connect(function(mouse)
	equipped = true
	mouseCursor = replicatedStorage.Images.Normal.Texture
	local folderEvents = toolInstance:WaitForChild("Events", waitTimeout)
	local eventClick = folderEvents:WaitForChild("Click", waitTimeout)
	local eventAmmo = folderEvents:WaitForChild("Ammo", waitTimeout)
	local eventParam = folderEvents:WaitForChild("Parameter", waitTimeout)
	local eventCursor = folderEvents:WaitForChild("Cursor", waitTimeout)

	-- Targeting Cursor
	mouse.Icon = mouseCursor

	-- Fire
	mouse.Button1Down:connect(function()
		mouseButton1Down = true
		eventClick:FireServer(mouse.Hit.p)
		mouse.Icon = mouseCursor
		if useAuto then
			-- Autofire for automatic weapons.
			-- We delay 0.2 seconds before beginning so
			-- the player has enough time to release the
			-- button if they wanted only one shot.
			-- The fire rate comes from server parameters
			-- and cannot be changed on the server side by
			-- the player.  So the server will never accept
			-- an input faster than the firing rate.
			task.wait(0.2)
			while mouseButton1Down do
				eventClick:FireServer(mouse.Hit.p)
				mouse.Icon = mouseCursor
				task.wait(autoRate)
			end
		end
	end)

	-- Resets the mouse button 1 down flag to false when
	-- the player releases the mouse button.	
	mouse.Button1Up:Connect(function()
		mouseButton1Down = false
	end)

	-- Cursor change based on weapon state
	eventCursor.OnClientEvent:Connect(function(cursor)
		if cursor == 0 then
			mouseCursor = replicatedStorage.Images.Normal.Texture
		elseif cursor == 1 then
			mouseCursor = replicatedStorage.Images.Reload.Texture
		elseif cursor == 2 then
			mouseCursor = replicatedStorage.Images.NoAmmo.Texture
		else
			mouseCursor = replicatedStorage.Images.NeedReload.Texture
		end
		mouse.Icon = mouseCursor
	end)

	-- When the tool is equipped, the server sends a few parameters.
	eventParam.OnClientEvent:Connect(function(params)
		-- Set Parameters
		ammoMax = params.ammoMax

		-- Camera Zoom Function
		if params.useZoom then
			useZoom = true
			zoomToggle = false
			zoomFoV = params.zoomFoV
			zoomRD = params.zoomRD
			zoomCurrent = params.zoomFoV
			equipZoomOut()
			CAS:BindAction("ZoomCameraScope", zoomCamera, true,
				Enum.KeyCode.Z, Enum.KeyCode.ButtonB)
		end

		-- Auto-Fire Function
		if params.useAuto then
			useAuto = true
			autoRate = params.rate
		end

		-- Ammo Clip Function
		if params.useClip then
			useClip = true
			clipSize = params.clipSize
			clipReload = params.clipLoad
			CAS:BindAction("ManualClipReload", reloadClipManual,
				true, Enum.KeyCode.R, Enum.KeyCode.ButtonY)
			writeHudClip(params.clipAmmo, params.ammo)
			enableHUDClip()
		else
			useClip = false
			writeHudNoClip(params.ammo)
			enableHUDNoClip()
		end
	end)

	-- Updates the ammunition count display
	eventAmmo.OnClientEvent:Connect(function(ammo1, ammo2)
		if useClip then
			writeHudClip(ammo1, ammo2)
		else
			writeHudNoClip(ammo2)
		end
	end)

	-- Request the parameters
	eventParam:FireServer()

end)

-- Called when the weapon is unequipped.
toolInstance.Unequipped:Connect(function(mouse)
	equipped = false
	if useZoom then
		zoomToggle = false
		equipZoomOut()
		CAS:UnbindAction("ZoomCameraScope")
	end
	if useClip then
		CAS:UnbindAction("ManualClipReload")
	end
	disableHUD()
end)

Maelstorm_1973 · May 21, 2022, 3:10am

This is an engine bug. But, I was able to work around it. It seems that tables are also seen inside of ContextActionService callback functions, so I put the values in a table and it’s working correctly now.