gesture.md

Gestures

Use the Gesture module to detect gestures such as swipes, long press and double tap. It also supports two finger gestures. You can use the Gesture module either via the gesture.script or directly via gesture.lua.

Using gesture.script

Attach the gesture.script to the game object that should detect gestures. Configure the script properties if necessary. When a gesture is detected the script will generate an on_gesture message and send that to the game object.

function on_message(self, message_id, message, sender)
	if message_id == hash("on_gesture") then
		if message.swipe_right then
			print(message.swipe.from, message.swipe.to)
		elseif message.tap then
			print(message.tap.position)
		elseif message.double_tap then
			print(message.double_tap.position)
		elseif message.long_press then
			print(g.long_press.position, message.long_press.time)
		end
	end
end

Configuration of the Gesture module when using the gesture.script is done via the exposed script properties. Select the script when it's attached to a game object and modify the settings from the Properties panel of the editor. See Configuration.

Using gesture.lua

Using the gesture module directly gives you full control but requires a couple of lines of code to get started with:

local gesture = require "in.gesture"

function init(self)
	msg.post(".", "acquire_input_focus")
	gesture.SETTINGS.double_tap_interval = 1
end

function on_input(self, action_id, action)
	local g = gesture.on_input(self, action_id, action)
	if g then
		if g.swipe_right then
			print(g.swipe.from, g.swipe.to)
		elseif g.tap then
			print(g.tap.position)
		elseif g.double_tap then
			print(g.double_tap.position)
		elseif g.long_press then
			print(g.long_press.position, g.long_press.time)
		elseif g.repeated then
			print("Repeated")
		elseif g.two_finger.tap then
			print("Two finger tap!")
		elseif g.two_finger.pinch then
			print(g.two_finger.pinch.ratio, g.two_finger.center)
		end
	end
end

It's possible to create multiple gesture detectors where each instance has unique settings:

local gesture = require "in.gesture"

function init(self)
	self.gesture = gesture.create({
		action_id = hash("interact"),
		double_tap_interval = 1,
		long_press_time = 2,
		swipe_threshold = 100,
	})
end

function on_input(self, action_id, action)
	local g = self.gesture.on_input(self, action_id, action)
	if g then
		-- handle gestures here
	end
end

Configuration is done via the gesture.SETTINGS.* table or via a settings table passed into gesture.create(settings). In both cases the accepted configuration values can be seen in the Configuration section.

Configuration

The Gesture module has the following configuration options:

• action_id - (hash) The action_id to use when detecting gestures (default: "touch")
• double_tap_interval - (number) Maximum time in seconds between two taps to consider it as a double tap (default: 0.5)
• long_press_time - (number) Minimum time in seconds before a tap is considered a long press (default: 0.5)
• swipe_threshold - (number) Minimum distance in pixels before considering it a swipe (default: 100)
• tap_threshold - (number) Maximum distance in pixels between a press and release action to consider it a tap (default: 20)
• multi_touch - (boolean) If multi touch gestures should be handled or not (default: true)