Implement traffic lights using Ienumerator?

Questions & Answers
1

I want to implement a simple traffic light in unity . The traffic light game object will forever do just the below things.

  1. Red will turn on once game starts
  2. wait till 10 sec
  3. Yellow will turn on
  4. wait till 3 sec
  5. Green will turn on
  6. Wait for 10 sec before red turns on.

Please help me . As of now only red and yellow lights up but green wont turn on.

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

namespace open_world
{
public class traffic_light : MonoBehaviour
{
public Light red_traffic_light;
public Light yellow_traffic_light;
public Light green_traffic_light;

    void Start()
    {
        StartCoroutine(traffic());

    }

    IEnumerator traffic()
    {

while(true){
red_traffic_light.GetComponent().intensity = 30;
yield return new WaitForSeconds(10);
yellow_traffic_light.GetComponent().intensity = 30;
yield return new WaitForSeconds(3);
green_traffic_light.GetComponent().intensity = 30;
yield return new WaitForSeconds(10);
}

  }
}

}

2

Hello, I think the problem is the GetComponent() calls, which shouldn’t be needed. red_traffic_light is a reference to a Light component, so there’s no need to request a component before adjusting the light’s properties.

Calling GetComponent() without providing a type isn’t valid code anyway, you’d need to tell it what component you’re looking for, such as GetComponent<MeshFilter>(). But in this case you already have access to the Light component that you’re interested in, so don’t need to do that at all.

using UnityEngine;
using System.Collections;

public class TrafficLight : MonoBehaviour
{
  public Light Red;
  public Light Yellow;
  public Light Green;

  void Start()
  {
    StartCoroutine(Traffic());
  }

  IEnumerator Traffic()
  {
    while (true)
    {
      Red.intensity = 3f;
      Yellow.intensity = 0f;
      Green.intensity = 0f;
      
      yield return new WaitForSeconds(10f);

      Red.intensity = 0f;
      Yellow.intensity = 3f;
      Green.intensity = 0f;

      yield return new WaitForSeconds(3f);

      Red.intensity = 0f;
      Yellow.intensity = 0f;
      Green.intensity = 3f;

      yield return new WaitForSeconds(10f);
    }
  }
}

You might notice I set the intensity of all 3 lights for each phase. For some transitions that has no effect—the green light is already off when we enter the “yellow on” phase—but I think it makes the code’s purpose clearer. You may also want to consider turning the lights on and off by enabling/disabling the component rather than adjusting the intensity.