2D Endless Runner - Problem with generating new Platforms

Unity Engine
1

Hello Guys,

i work on my platformer and i followed a tutorial for an endless runner with generating platforms when the player is nearby specific endpoints which are set for the platform prefabs.

In that script there are two functions for spawning levels, first to spawn at start of the level and this can set to 1 or 10 or 100 without problems.

The problem is that if the character reaches the end of the last preloaded Platform, no new one gets loaded.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class LevelGenerator : MonoBehaviour
{

private const float PLAYER_DISTANCE_SPAWN_LEVEL_PART = 200f;


[SerializeField] private Transform LevelPart_Start;
[SerializeField] private List<Transform> LevelList;
[SerializeField] private GameObject Player;

private Vector3 lastEndPosition;

private void Awake() {
  lastEndPosition = LevelPart_Start.Find("EndPosition").position;

int startingSpawnLevelParts = 2;
for (int i = 0; i < startingSpawnLevelParts; i++)
{
SpawnLevelPart();
}
}

private void Update() {
if (Vector3.Distance(Player.transform.position, lastEndPosition) < PLAYER_DISTANCE_SPAWN_LEVEL_PART)
{
SpawnLevelPart();
}
}

private void SpawnLevelPart() {

Transform chosenLevelPart = LevelList[Random.Range(0, LevelList.Count)];
Transform lastLevelPartTransform = SpawnLevelPart(chosenLevelPart, lastEndPosition);
lastEndPosition = lastLevelPartTransform.Find("Endposition").position;
}

private Transform SpawnLevelPart(Transform levelPart, Vector3 spawnPosition)
{
Transform levelPartTransform = Instantiate(levelPart, spawnPosition, Quaternion.identity);
return levelPartTransform;
}

}

I also get an warning message about Null, but i have set all items into the inspector. (Player GameObject, Starting Level and the List is filled with the platforms)

NullReferenceException: Object reference not set to an instance of an object
LevelGenerator.SpawnLevelPart () (at Assets/Scripts/LevelGenerator.cs:38)
LevelGenerator.Awake () (at Assets/Scripts/LevelGenerator.cs:23)

As iam really new to coding and struggle already a few days with that issue, i thought maybe asking for advice in the community.

Hope we can find a solution for it and thanks already for your help.

2

LevelGenerator.Awake () (at Assets/Scripts/LevelGenerator.cs:23)
LevelGenerator.Awake calls SpawnLevelPart()
LevelGenerator.SpawnLevelPart () (at Assets/Scripts/LevelGenerator.cs:38)
SpawnLevelPart() has an error on line 38
NullReferenceException: Object reference not set to an instance of an object
lastEndPosition is trying to equal something that does not exist.

3

Hello adehm,

thanks for your reply. I double checked everything again and found that i wrote at line 38 “Endposition” and not “EndPosition”. This resolved that the “null” warning is not given anymore but the initial problem of:

“The problem is that if the character reaches the end of the last preloaded Platform, no new one gets loaded.”

still persists.

The issue is, i dont see a reason for it not working and in the tutorial i followed it worked.
Youtube:

I hope its okay to put a video link in here if not please let me know.

Maybe more infos are needed besides the code regarding EndPosition.

I created multiple preFabs of Platforms and in these preFabs there is always one GameObject which is called EndPosition at the end of the platform, so that way the platforms should spawn after each other.

Maybe you or someone else has another reason why no platforms get generated? I get no errors anymore when starting the game.

Thanks for help already.

4

I found the issue within the starting level which had wrong parameters for the Z Axis as well as their children. Reset all positions multiple times, solved the issue. :slight_smile: