Input handling

The two ways: Input Manager

• Manual: Input
• There are two ways to get input in Unity
• The legacy Input Manager
  • uses the Input class
  • uses Directinput
  • works almost always
  • (but sometimes controller axes are screwed up)
  • easier to setup -> this is the one we’ll be using

The two ways: Input system

• The new Input System
  • Read more on these slides
  • Needs to be installed as a separate package
  • Needs more work to get it running than Input Manager
  • Uses XInput
  • “action-based”
  • We’ll stick to the legacy input manager for now…

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• Here’s a button press event visualized across multiple frames.
• The colored boxes show which are the frames when the corresponding function returns true.

Keyboard input

• uses Keycodes
• Input.GetKeyDown(KeyCode.Space)
  • returns true for one frame when pressed down
  • Good for jumps, navigating the UI, other discrete actions
• Input.GetKey(KeyCode.Space)
  • returns true for the duration of pressage
  • Good for movement or other continuous actions
• Input.GetKeyUp(KeyCode.Space)
  • return true for one frame when we stop pressing a button
  • Good for a charge weapon: hold down for charge, release button to shoot
  • Needed less often than the previous ones

More general input

• What if you want to be able to change game controls?
• Or check both keyboard and game controller input?
• Use the GetButton functions instead
  • Input.GetButtonDown("Jump")
  • Input.GetButton("Jump")
  • Input.GetButtonUp("Jump")
• But what IS the “Jump” button?
  • The keyboard and controller button mappings for “Jump” and other buttons are defined in the Input table

Input table

• Edit > Project Settings > Input Manager
• You can change the names, and the buttons that correspond to the names
  • “Fire1” could be changed to “Crouch”, for instance!
• Positive button refers to a button being pressed
• Negative button is only needed for directional input
• You can assign an Alt Button for an alternate input method
• Note: Keyboard and controller bindings are in their separate entries!
• Add new entries by increasing the Size property
  • It will duplicate the last entry in the list. Oh wow
• Use this link to see which button numbers correspond to which controller buttons
  • For example, joystick button 0 is the Xbox button A
  • See button naming convention in Docs: Input manager

Analog input

• Script Reference: Input.GetAxis
• how to account for analog sticks? They aren’t buttons you press
  • rather a two-dimensional field of many possible coordinates
  • -> separate input to two axes, vertical and horizontal
  • Sliding scale between -1 and 1
• Input.GetAxis(axisName)
  • Smoothing with Gravity and Sensitivity
  • Deadzone applied (no input registered if only move the analog stick a bit)
  • float h = Input.GetAxis("Horizontal");

GetAxisRaw

• Input.GetAxisRaw(axisName)
  • float h = Input.GetAxisRaw("Horizontal");
  • just the raw input data as-is
  • no deadzone, no smoothing

Exercise 1. Player input

Create a top-down player character with a sprite renderer that can

• change color with the Fire1 button
• move with the analog stick

Extra: Mouse input

• Input.GetMouseButton(0)
  • Down & Up methods work similarly to previous examples as well
• get mouse position:
  • Vector2 mousePos = Input.mousePosition;
• you can also create a dedicated method for checking if the mouse cursor is on a GameObject (requires a collider!):

  OnMouseDown()
  {
      // do stuff
  }
  

Mouse input example

• Script Reference: Input.GetMouseButton (GetMouseButtonDown, GetMouseButtonUp)
• Script Reference: Input.mousePosition

    private Rigidbody rb;
  
    void Awake()
    {
        rb = GetComponent<Rigidbody>();
    }
    void OnMouseDown()
    {
        if (Input.GetMouseButton(0))
        {
            rb.AddForce(- transform.forward * 500f);
            rb.useGravity = true;
        }
    }
  

Extra: Touch input

• Script Reference: Input.GetTouch
• Script Reference: Input.touches
• Script Reference: Camera.ScreenToWorldPoint

  if (Input.touchCount > 0)
    {
      Touch touch = Input.GetTouch(0);
      // Move thing if the screen has the finger moving.
      if (touch.phase == TouchPhase.Moved)
      {
        Vector3 position = new Vector3(
          touch.position.x,
          touch.position.y,
          Camera.Main.nearClipPlane
        );
        transform.position = Camera.Main.ScreenToWorldPoint(position);
      }
    }
  }
  

Extra: Multiplayer input

• With the input table, you can assign the joystick index for every input with Joy Num
  • $\Rightarrow$ For multiplayer games, you need to create new entries for other players
  • ALSO: you need to set the positive button to “joystick 2 button 0” etc
• The new Input System handles this a bit more elegantly, see this tutorial:
  • Madwomb: Unity Local Multi-player