Input.GetAxis

Description

Returns the value of the virtual axis identified by axisName.

The value will be in the range -1...1 for keyboard and joystick input devices.

The meaning of this value depends on the type of input control, for example with a joystick's horizontal axis a value of 1 means the stick is pushed all the way to the right and a value of -1 means it's all the way to the left; a value of 0 means the joystick is in its neutral position.

If the axis is mapped to the mouse, the value is different and will not be in the range of -1...1. Instead it'll be the current mouse delta multiplied by the axis sensitivity. Typically a positive value means the mouse is moving right/down and a negative value means the mouse is moving left/up.

This is frame-rate independent; you do not need to be concerned about varying frame-rates when using this value.

To set up your input or view the options for axisName, go to Edit > Project Settings > Input Manager. This brings up the Input Manager. Expand Axis to see the list of your current inputs. You can use one of these as the axisName. To rename the input or change the positive button etc., expand one of the options, and change the name in the Name field or Positive Button field. Also, change the Type to Joystick Axis. To add a new input, add 1 to the number in the Size field.

using UnityEngine;
using System.Collections;

// A very simplistic car driving on the x-z plane.

public class ExampleClass : MonoBehaviour
{
    public float speed = 10.0f;
    public float rotationSpeed = 100.0f;

    void Update()
    {
        // Get the horizontal and vertical axis.
        // By default they are mapped to the arrow keys.
        // The value is in the range -1 to 1
        float translation = Input.GetAxis("Vertical") * speed;
        float rotation = Input.GetAxis("Horizontal") * rotationSpeed;

        // Make it move 10 meters per second instead of 10 meters per frame...
        translation *= Time.deltaTime;
        rotation *= Time.deltaTime;

        // Move translation along the object's z-axis
        transform.Translate(0, 0, translation);

        // Rotate around our y-axis
        transform.Rotate(0, rotation, 0);
    }
}

using UnityEngine;
using System.Collections;

// Performs a mouse look.

public class ExampleClass : MonoBehaviour
{
    float horizontalSpeed = 2.0f;
    float verticalSpeed = 2.0f;

    void Update()
    {
        // Get the mouse delta. This is not in the range -1...1
        float h = horizontalSpeed * Input.GetAxis("Mouse X");
        float v = verticalSpeed * Input.GetAxis("Mouse Y");

        transform.Rotate(v, h, 0);
    }
}

Note: The Horizontal and Vertical ranges change from 0 to +1 or -1 with increase/decrease in 0.05f steps. GetAxisRaw has changes from 0 to 1 or -1 immediately, so with no steps.