ActionCancel - Instantly cancel active actions, even if fully client-sided, and communicate between scripts

[GoulStorm (Cassie)]

ActionCancel

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ActionCancel is a module for instantly cancelling actions. It’s very common nowadays in combat systems to have pretty… unreliable action cancelling methods, such as stopping all animations loaded in the target’s Animator, which is not really the ideal method.

One of the main problems with using timing based cancelling methods (such as checking if the character is stunned when the animation hits a specific event marker) is that:

1. Sometimes, stuns may last shortly, and specially in long animations, at the point you check if the character has been stunned, the stun may have disappeared already.
2. Stuns will not necessarily mean you want that character to cancel its actions. For developers who use non-specific character state structures (for example, no “Stunned” state, but instead a “CantMove” state, which will only make the character unable to move, not necessarily unable to use skills, which gives us better control over states), using an event-based action cancelling method is much better and more solid.
3. You may not want to cancel actions necessarily when the character is applied a state, such at instant hits that don’t apply any long stun but just deals damage. This is only possible with a method like the one this module offers.

Additionally, ActionCancel can be used for script intercommunication, such as stopping a Dash action when another action is about to be performed.

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Information

Module Overview

• CancelActions(target: Model, cancelInfo: {[any]: any}?) - Will fire the action cancelled event, cancelling actions currently listening to the event on both the server and the client. This method can only be called in the server.
• Connect(character: Model, func: (cancelInfo: {[any]: any}) -> ()) - Starts listening for when the action cancelled event is fired for the respective character. Can be used on both the client and the server.

Connection class functions:

• :Disconnect() - Disconnects the connection for the action cancelled event.

Server Example

-- After hitting a target with a skill:
actionCancel.CancelActions(target)

-- Cancelling a skill listening to the event:
    local connections: {RBXScriptConnection} = {}

	local function Stop(cancelInfo)
		for _, connection in ipairs(connections) do
			if connection.Connected then
				connection:Disconnect()
			end
		end

		if animTrack.IsPlaying then
			animTrack:Stop()
		end

		-- Set cooldown
	end

	table.insert(connections, actionCancel.Connect(character, Stop))
	table.insert(connections, animTrack.Stopped:Once(Stop))

	table.insert(connections, animTrack:GetMarkerReachedSignal("Swing"):Once(function()
        -- Action
    end))

Client Example

For a dash action, common in most combat systems. Keep in mind this is a LocalScript.

	local connections: {RBXScriptConnection} = {}
	
	local function Cancel(cancelInfo)
		for _, connection in ipairs(connections) do
			if connection.Connected then
				connection:Disconnect()
			end
		end
		
		if track.IsPlaying then
			track:Stop()
		end
		
		bodyVelocity:Destroy()
		updateVelocity:Disconnect()
		dashingState:Remove()
		-- Thanks to this module, we're able to destroy the velocity correctly when the dashing action is cancelled,
		-- avoiding bugs where you are ragdolled/stunned/knockbacked, but the dashing velocity remains acting
	end

	table.insert(connections, actionCancel.Connect(character, Cancel))
	table.insert(connections, track.Stopped:Once(Cancel))

cancelInfo Parameter Example

In the context of a skill being parried, you want the parry to stop, but need to know whether the parry was successful or not in order to apply a cooldown to it or not.

-- When a skill is successfully parried:
actionCancel.CancelActions(target, {Parried = true})

-- In the parry skill script
actionCancel.Connect(character, function(cancelInfo)
    if cancelInfo.Parried then
        -- do not apply cooldown
        return
    end

    -- apply cooldown
end)

Another use case in the server is the common feiting feature in close ranged combats. Simply fire CancelActions with {Feint = true} as the cancelInfo, then check in the script if the player used feint.

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Any suggestions, please comment!

[GoulStorm (Cassie)]

Made small changes to the module, using dot for the default funcions and colon only for the necessary (Disconnect). Changed slightly the type checking as well to a better structure.

[GoulStorm (Cassie)]

v1.0.2

• Had a small update to the event creation. Now the module creates it upon server require instead.
• Added some comments.
• Added a version indicator.

Also updated the post.