This tutorial will guide you through simulating mouse touch input in Godot Engine using a simple click. This is useful for creating features like click-and-drag interactions or for testing purposes where you want to simulate touch events without actually using a touch device. We'll cover several methods, progressing from basic to more advanced techniques.
Understanding the Difference: Mouse and Touch
Before diving in, it's crucial to understand that mouse and touch input are handled differently in Godot. Mouse events typically involve InputEventMouseButton, while touch events use InputEventScreenTouch. Our goal is to translate a mouse click into a simulated touch event.
Method 1: Direct InputEventScreenDrag Simulation
This is the most straightforward approach. We'll directly create and emit a InputEventScreenTouch within a InputEventMouseButton handler.
extends Node2D
func _input(event):
if event is InputEventMouseButton:
if event.button_index == MOUSE_BUTTON_LEFT and event.pressed:
var touch_event = InputEventScreenTouch.new()
touch_event.index = 0 # Usually index 0 for the first touch
touch_event.position = event.position
touch_event.pressed = true
get_tree().root.input_event(touch_event) # Emit the touch event
if event is InputEventMouseButton:
if event.button_index == MOUSE_BUTTON_LEFT and !event.pressed:
var touch_event = InputEventScreenTouch.new()
touch_event.index = 0 # Usually index 0 for the first touch
touch_event.position = event.position
touch_event.pressed = false
get_tree().root.input_event(touch_event) # Emit the touch event
This code listens for left mouse button clicks. When pressed, it creates a InputEventScreenTouch with the same position as the mouse click and marks it as pressed. The get_tree().root.input_event() function sends this event to the game's input system, simulating a touch. Similarly, when the mouse button is released, it sends a release touch event.
Advantages: Simple and easy to implement.
Disadvantages: Doesn't handle multi-touch and lacks more sophisticated touch event features (e.g., pressure, etc.)
Method 2: Using a Custom Input Action
This approach is cleaner and better organized, especially if you need to reuse this functionality elsewhere in your game.
First, create a new input action in the Project > Project Settings > Input Map. Name it something like "simulate_touch". Assign it to a mouse button (left click, for example).
extends Node2D
func _ready():
Input.action_set_event_callback("simulate_touch", self, "_on_simulate_touch")
func _on_simulate_touch(event):
if event is InputEventMouseButton:
if event.pressed:
# Simulate touch press
var touch_event = InputEventScreenTouch.new()
touch_event.index = 0
touch_event.position = event.position
touch_event.pressed = true
get_tree().root.input_event(touch_event)
else:
#Simulate touch release
var touch_event = InputEventScreenTouch.new()
touch_event.index = 0
touch_event.position = event.position
touch_event.pressed = false
get_tree().root.input_event(touch_event)
This code uses Godot's input action system. The _on_simulate_touch function is called whenever the "simulate_touch" action is triggered. The rest of the code is similar to Method 1.
Advantages: More organized, reusable, and avoids directly handling _input().
Disadvantages: Still lacks advanced touch features.
Advanced Considerations: Multi-touch and Drag
For more complex scenarios involving multi-touch or drag gestures, you'll need a more sophisticated solution. This might involve tracking multiple touch points, calculating velocity, and handling various touch phases (began, moved, ended). You might need to implement your own state machine to manage this.
Remember: Always test thoroughly. Make sure your simulated touch events behave as expected across different game elements and scenarios. This is a powerful technique for simplifying testing and prototyping touch-based interactions in Godot.
