Slide

Lesson 4 of 20 in Coddy's Unity Game: Sky Lanes course.

Some obstacles hang too high to jump: the runner slides under them. A slide makes the runner half as tall for a moment.

Shrinking the object also shrinks its CharacterController, but it shrinks around the middle, so the feet would float half a unit above the road. Move the runner down by the same half unit. A controller must be off while you move it by hand, or its next Move undoes the change:

void Resize(float height)
{
    controller.enabled = false;
    transform.position += Vector3.up * (height - transform.localScale.y);
    transform.localScale = new Vector3(1f, height, 1f);
    controller.enabled = true;
}

A timer, slide, counts the slide down. When it runs out the runner stands up again with StopSlide:

void StopSlide()
{
    if (transform.localScale.y < 1f) Resize(1f);
    slide = 0f;
}

Challenge

Easy

Add public float slideTime = 0.7f; and private float slide;.
Add Resize and StopSlide as above.
When S or the down arrow is pressed on the ground, set slide = slideTime and call Resize(0.5f).
Each frame, if slide > 0f, take Time.deltaTime off it, and call StopSlide() once it reaches 0.
A jump ends a slide: call StopSlide() when the runner jumps.

Try it yourself

using UnityEngine;

public class Runner : MonoBehaviour
{
    public float laneWidth = 2.5f;
    public float laneSpeed = 16f;
    public float jumpHeight = 1.6f;
    public float gravity = -40f;

    public int lane;

    private CharacterController controller;
    private float fallSpeed;

    void Start()
    {
        controller = GetComponent<CharacterController>();
    }

    void Update()
    {
        if (Input.GetKeyDown(KeyCode.A) || Input.GetKeyDown(KeyCode.LeftArrow)) lane = Mathf.Max(-1, lane - 1);
        if (Input.GetKeyDown(KeyCode.D) || Input.GetKeyDown(KeyCode.RightArrow)) lane = Mathf.Min(1, lane + 1);
        bool jump = Input.GetKeyDown(KeyCode.W) || Input.GetKeyDown(KeyCode.UpArrow) || Input.GetKeyDown(KeyCode.Space);
        if (jump && controller.isGrounded)
        {
            fallSpeed = Mathf.Sqrt(jumpHeight * -2f * gravity);
        }

        if (controller.isGrounded && fallSpeed < 0f) fallSpeed = -2f;
        fallSpeed += gravity * Time.deltaTime;

        float targetX = lane * laneWidth;
        float x = Mathf.MoveTowards(transform.position.x, targetX, laneSpeed * Time.deltaTime);
        Vector3 move = new Vector3(x - transform.position.x, fallSpeed * Time.deltaTime, 0f);
        controller.Move(move);
    }
}