Build the Road

Lesson 5 of 20 in Coddy's Unity Game: Sky Lanes course.

Until now the runner stood on a plain block named Ground. From here the Road script builds the road, and the block is gone.

The road is made of pieces 20 units long, laid one after another. A piece is an empty GameObject named Chunk, and everything on that piece is its child: the floor, the dashes between the lanes and the two edges. Moving the piece will move all of it.

Transform chunk = new GameObject("Chunk").transform;
chunk.position = new Vector3(0f, 0f, i * chunkLength);
Instantiate(floorPrefab, chunk.position + new Vector3(0f, -0.25f, 0f), Quaternion.identity, chunk);

The last argument of Instantiate is the parent. The floor is half a unit thick, so its middle sits a quarter below the road's surface at y 0.

Each lane line is four dashes, 3 long, one every 5 units, at x -laneWidth / 2f and laneWidth / 2f. The edges sit at x -4.1 and 4.1, y 0.05.

Challenge

Easy

In Road add the prefab fields floorPrefab, stripePrefab and edgePrefab (all public GameObject), and chunkCount = 7, chunkLength = 20f, laneWidth = 2.5f. The Inspector fills the prefabs.
In Start, make chunkCount pieces, piece i at z i * chunkLength, each with its floor.
On each piece, for d from 0 to 3, place two dashes at z -7.5f + d * 5f, y 0.01, one on each lane line.
Place the two edges.

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 float slideTime = 0.7f;

    public int lane;

    private CharacterController controller;
    private float fallSpeed;
    private float slide;

    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);
            StopSlide();
        }
        if ((Input.GetKeyDown(KeyCode.S) || Input.GetKeyDown(KeyCode.DownArrow)) && controller.isGrounded)
        {
            slide = slideTime;
            Resize(0.5f);
        }

        if (slide > 0f)
        {
            slide -= Time.deltaTime;
            if (slide <= 0f) StopSlide();
        }

        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);
    }

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

    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;
    }
}