Unity Input System 🕹️ ¶

There are 3 ways of handling user input in Unity Games:

• Manually
• Using the new input system
• Using the old input system

⚠️ Todo: using input to move a character is not a good practice?

Delta Time ¶

As per what is explained about the Game Loop, the time between updates is inconsistent. To ensure something moves at 10 m/s, we use Time.deltaTime in the update method:

// defaultSpeed is an attribute with the value "10"
var speed = defaultSpeed * Time.deltaTime; 

Input System Configuration ¶

Navigate to Edit > Project Settings > Input Manager. Expand Axes.

You will define each "control" of the game. For instance, you can define that "Jump" is done by pressing the left-click of the mouse. From the code, only the control name is referenced, so the key can be changed relatively easily over time.

• Horizontal: you can see that there is left/right to move, while A and D are marked as alternative keys.
• Vertical: you can see that there is down/up to move, while S and W are marked as alternative keys.
• Jump: the default key is space

To add more keys, increase the size of the array.

➡️ The "dead" property is a range where if a value is within that range, then it's considered as "null"/0.

➡️ The "negative" means the value will be negative in "GetAxis".

➡️ The "sensitivity" is the response time (low=smooth, great=fast)

Raw Input ¶

When using non-raw input, for instance, when moving a character, the character will still move a bit after the key is released. If this behavior is not acceptable, we can use:

float axisX = Input.GetAxisRaw("Horizontal");

Discontinuous Input ¶

User presses a key and releases it.

// <0 (left) or 0 (none) or 0> (right)
float axisX = Input.GetAxis("Horizontal");
// <0 (down) or 0 (none) or 0> (up)
float axisY = Input.GetAxis("Vertical");

if (Input.GetButton("Jump")) // if "Jump" triggered
{
    // do action
}

Continuous Input ¶

User holds a key.

if (Input.GetButtonDown("Jump"))
{
    _isJumpPressed = true; // change the state
}
if (Input.GetButtonUp("Jump"))
{
    _isJumpPressed = false; // revert the state
}

For testing purposes, as it's a bad practice. Use an input system.

Keyboard Input ¶

bool pressed = Input.GetKey(KeyCode.Space);
bool down = Input.GetKeyDown(KeyCode.Space);
bool up = Input.GetKeyUp(KeyCode.Space);

Mouse Input ¶

// b is 0 = Left-Click, 1 = Right-Click, 2 = Middle-Click
Input.GetMouseButton(b);
Input.GetMouseButtonDown(b);
Input.GetMouseButtonUp(b);

Mouse Events ¶

Each game object has these methods that you can override:

private void OnMouseUp() {}
private void OnMouseDown() {}
private void OnMouseOver() {}
private void OnMouseEnter() {}
private void OnMouseExit() {}

Hold Events ¶

You may use the following interfaces:

using UnityEngine.EventSystems;

public class XXX : 
    IPointerUpHandler, IPointerDownHandler {}

Drag Events ¶

You may use the following interfaces:

using UnityEngine.EventSystems;

public class XXX : 
    IDragHandler, IBeginHandler, IEndDragHandler,
    IPointerEnterHandler IPointerExitHandler {}

EventSystem.current.IsMouseOverGameObject()