1. Introduction

In this tutorial, you will learn how to handle touch inputs and gestures for mobile games. The importance of touch inputs in mobile games cannot be overstated as it is the primary way users interact with our games. By the end of the tutorial, you should be able to detect touch events, handle multi-touch inputs, and interpret common gestures like swipes and pinches.

What you will learn:

• How to detect touch events
• How to handle multi-touch inputs
• How to interpret common gestures

Prerequisites:

• Basic knowledge of programming
• Familiarity with a game development platform (like Unity or Unreal Engine)

2. Step-by-Step Guide

Detecting touch events

Most game development platforms have built-in functions for detecting touch events. For example, in Unity, we have the Input.touches property which returns a list of all the touches. The Touch struct has several properties like phase (describes the phase of the touch), position (coordinates of touch) etc.

Handling multi-touch inputs

We can use the Input.touches property in Unity to handle multi-touch inputs. Since it returns a list of all the touches, we can loop through this list to handle each touch.

Interpreting common gestures

For interpreting gestures like swipe or pinch, we need to track the movement of the touch. This can be done by storing the initial touch position and comparing it with the current touch position.

3. Code Examples

Detecting touch events

void Update() {
    if(Input.touchCount > 0) {
        Touch touch = Input.GetTouch(0);
        print("Touch detected at position " + touch.position);
    }
}

Handling multi-touch inputs

void Update() {
    for(int i = 0; i < Input.touchCount; i++) {
        Touch touch = Input.GetTouch(i);
        print("Touch " + i + " detected at position " + touch.position);
    }
}

Interpreting swipe gesture

Vector2 initialTouchPosition;
void Update() {
    if(Input.touchCount > 0) {
        Touch touch = Input.GetTouch(0);
        if(touch.phase == TouchPhase.Began) {
            initialTouchPosition = touch.position;
        } else if(touch.phase == TouchPhase.Ended) {
            Vector2 swipeVector = touch.position - initialTouchPosition;
            if(swipeVector.x > 0) {
                print("Swipe Right");
            } else {
                print("Swipe Left");
            }
        }
    }
}

4. Summary

In this tutorial, we learned how to detect touch events, handle multi-touch inputs, and interpret common gestures. We also saw how to use these techniques with Unity's built-in functions.

Next steps:

• Implement these techniques in a game
• Learn how to interpret more gestures like pinch and rotate

Additional resources:

• Unity's Touch documentation

5. Practice Exercises

Exercise 1: Create a simple game where the player has to tap on objects that appear on the screen. The objects should disappear on tap.

Exercise 2: Enhance the game from exercise 1 to support multi-touch. Multiple objects should be able to be tapped at the same time.

Exercise 3: Add a feature to the game where the player can swipe to clear all objects.

Solutions and tips:

• For exercise 1 and 2, you can use the techniques discussed in this tutorial. For detecting taps, you can use the TouchPhase.Began phase.
• For exercise 3, you can use the swipe gesture code from the examples. When a swipe is detected, loop through all the objects and remove them.

Remember to test your game thoroughly to ensure all touch events and gestures are working as expected.