MiniGames/Assets/Scripts/ChaseOn/ChasePlatformSpawner.cs

using UnityEngine;
using System.Collections.Generic;

public class ChasePlatformSpawner : MonoBehaviour
{
    public GameObject platformPrefab;
    public int initialPlatforms = 5;
    public float platformLength = 10f;
    public Transform player;

    private float spawnZ = 0.0f;
    private float safeZone = 15.0f;
    private List<GameObject> activePlatforms = new List<GameObject>();
    int counter = 0;
    void Start()
    {
        for (int i = 0; i < initialPlatforms; i++)
            SpawnPlatform();
    }

    void Update()
    {
        if (player.position.z + safeZone < spawnZ)
        {
            SpawnPlatform();
            DeletePlatform();
        }
    }

    void SpawnPlatform()
    {
        //GameObject go = Instantiate(platformPrefab, new Vector3(0, 0, spawnZ), Quaternion.identity);
        GameObject go = Instantiate(platformPrefab, new Vector3(0, -counter*3.54f, spawnZ), platformPrefab.transform.rotation);
        activePlatforms.Add(go);
        spawnZ -= platformLength;
        counter++;
    }

    void DeletePlatform()
    {
        Destroy(activePlatforms[0]);
        activePlatforms.RemoveAt(0);
    }
}