How would i change a semi gun into an automatic?

[12345koip]

You could use the UserInputService to detect if the mouse button is pressed.

something like:

local uis = game:GetService("UserInputService")

tool.Activated:Connect(function()
    repeat
        --shooting code
        wait(0.1) --shooting cooldown
        if not uis:IsMouseButtonPressed(Enum.UserInputType.MouseButton1) then break end
    until
        not uis:IsMouseButtonPressed(Enum.UserInputType.MouseButton1) --this line will check if the given mouse button, MouseButton1, is being held or not.
end)

I have used a similar system before, and it has worked for me.

[Mob1leN0OB (MLK)]

yes i used the realistic gun thingy but its really old, the script im using right now is alot more modified.

[DasKairo (Cairo)]

Looping outside of the functions.
Creating a new loop for everytime you fire the gun will just cause lag.

local IsShooting = false; -- to determine whether you can fire or not

Tool.Activated:Connect(function() -- fire when the weapon is activated
    IsShooting = true;
end)

Tool.Deactivated:Connect(function() -- fire when the weapon is deactivated
    -- this will not fire until you let go of your button
    IsShooting = false;
end)

while true do
    if IsShooting then
        -- fire if you are shooting
    else
        -- stops shooting
    end
    task.wait(Firerate) -- yield time for each activation
end

I believe there is more efficient way to doing this, so you dont have to create a loop for every weapon, however I still need to figure that out.

[Content_Corrupted019 (StifledSaucepan)]

Spawn a separate thread that handles the firing when the tool is activated and cancel the thread when deactivated.

local fireThread = nil

local function CanFire()
	-- Returns true if we can shoot right now, e.g. we have enough ammo
end

mouse.Button1Down:Connect(function()
	fireThread = task.spawn(function()
		while task.wait(FIRERATE) do
			
			if not CanFire() then
				-- Skip this fire attempt and wait for the next one
				continue
			end
			
			-- Fire server, reduce ammo, etc.
		end
	end)
end)

mouse.Button1Up:Connect(function()
	if fireThread then -- Check if we're firing
		task.cancel(fireThread) -- Stops the while loop
		fireThread = nil
	end
end)

[goldbullet82 (CloudNinja)]

Here’s some code I use in my FPS Projects structured for your reference.
Try dropping it directly into an empty tool and mess around with it before putting it to use.

-- // Services
local RunService = game:GetService("RunService")

-- // References
local Tool = script.Parent

-- // Settings
local mag_ammo, reserve_ammo = (30), (30 * 100)
local fire_rate = 800 -- RPM (Rounds Per Minute)

-- // Variables
local trigger_down = false

local next_fire_time = 0

local fire_delay = 1 / (fire_rate / 60)

local fire_mode = "FULL_AUTO"

-- // Functions
local function Fire()
	mag_ammo -= 1
	
	print("Pew!")
	print(mag_ammo.." / "..reserve_ammo)
end

local function OnToolActivated()
	trigger_down = true
end

local function OnToolDeactivated()
	trigger_down = false
end

local function OnCameraUpdate()
	
	-- // Shoot Code
	if (trigger_down and mag_ammo > 0 and time() > next_fire_time) then
		next_fire_time = time() + fire_delay

		if (fire_mode == "SEMI_AUTO") then
			Fire()
			trigger_down = false

		elseif (fire_mode == "FULL_AUTO") then
			Fire()

		elseif (fire_mode == "BURST_AUTO") then
			next_fire_time = time() + fire_delay + .3
			for i = 1, 3, 1 do
				if (mag_ammo < 1) then break end
				Fire()
				task.wait(fire_delay)
			end
			trigger_down = false

		end
	end
	----------------
	
end

-- // Events
Tool.Activated:Connect(OnToolActivated)
Tool.Deactivated:Connect(OnToolDeactivated)

RunService:BindToRenderStep("camera_update", Enum.RenderPriority.Camera.Value, OnCameraUpdate)

It Supports SEMI, FULL, and BURST. Hope this helps!