OnCollisionEnter calls rapidly

Question

bool tntFall = true;

void Awake()
{
    tntFallTime = Time.deltaTime / 0.05f;
}

void OnCollisionEnter(Collision coll)
{
    if (CurrentScene != "ColorGame" && CurrentScene != "PaintingGame" && coll.gameObject.tag != "Player" && CurrentScene == "TNT Run" && tntFall)
    {
        Debug.Log(coll.gameObject.GetComponent<MeshRenderer>().material.name);
        if (coll.gameObject.GetComponent<MeshRenderer>().material.name == "TNT_0 (Instance)")
        {
            coll.gameObject.GetComponent<MeshRenderer>().material = TNT_Mat1;
            StartCoroutine(coroutine);
        }
        else if (coll.gameObject.GetComponent<MeshRenderer>().material.name == "TNT_1 (Instance)")
        {
            coll.gameObject.GetComponent<MeshRenderer>().material = TNT_Mat2;
            StartCoroutine(coroutine);
        }
        else if (coll.gameObject.GetComponent<MeshRenderer>().material.name == "TNT_2 (Instance)")
        {
            coll.gameObject.transform.position = Vector3.Lerp(coll.gameObject.transform.position, new Vector3(coll.gameObject.transform.position.x,-10,coll.gameObject.transform.position.z), tntFallTime);
            Destroy(coll.gameObject, 3);
        }
    }
}

IEnumerator TNTFallDelay(int WaitTime)
{
    tntFall = false;
    yield return new WaitForSeconds(WaitTime);
    tntFall = true;
}

This my code from Player script. If you look at my as you can see it's actually cubes holding together. All i want is;

1. When player touches one of the cubes For the first time it will change material
2. When player touches that cube Second time it will change material again
3. When player touches that cube Third time cube is going to fall down.

But in these case (with my code) when i touch one of the cubes it does all of the if-else statements in a second and cube falls down.

Answer 1

I'd move the responsibility for this from the player avatar to the tile they're sitting on, and correct some other errors while we're at it.

public class ColorChangingTile : MonoBehaviour 
{

    public Material[] materialSequence;

    Renderer renderer;
    float playerExitTime = float.NegativeInfinity;
    int state = 0;

    void Start()
    {
        renderer = gameObject.GetComponent<MeshRenderer>();
    }

    void OnCollisionEnter(Collision collision)
    {
        if (collision.gameObject.CompareTag("Player"))
        {
            // Add a little tolerance, so rapid vibration at the edge of collision
            // doesn't advance the state. We need to leave for some time then return.
            if (Time.time - playerExitTime > 0.1f)
                AdvanceState();
        }
    }

    void OnCollisionExit(Collision collision)
    {
        if (collision.gameObject.CompareTag("Player"))
        {
            playerExitTime = Time.time;
        }
    }

    void AdvanceState()
    {
        // If we're already falling, ignore further state changes.
        if (state == materialSequence.Length)
            return;

        renderer.sharedMaterial = materialSequence[state];
        state++;

        if (state == materialSequence.Length)
            StartCoroutine(FallThenDestroy(10f, 3f));
    }

    // This lets us animate out the fall before the destruction takes place.
    IEnumerator FallThenDestroy(float distance, float duration)
    {
        // 0.5f seconds later object will start to fall down.
        yield return new WaitForSeconds(0.5f);
        for (float t = 0; t < duration; t += Time.deltaTime)
        {
            // Fall some distance.
            transform.Translate(0, -distance * Time.deltaTime / duration, 0, Space.World);
            // Yield control to the engine to run for a frame, then resume here.
            yield return null;
        }

        // Destroy ourselves once the fall is over.
        Destroy(gameObject);
    }
}

Answer 2

How about using a simple boolean type to store when the player enters/exits in a cube area. My logic is simple... You have a 'colCounter' that increases each time the player collides with the cube. Then when the value is bigger/equal than '2' the cube falls. I used Physics to make the fall(which might be inefficient...). You can call the IEnumerator function @DMGregory instead.

I agree with @DMGregory on using collision check in a separate cube class. So all the cube should have that script and it would look for the player collision.

 public class CubeManager : MonoBehaviour
 {
   public Color[] colors;

   private bool playerEnter; // this helps to prevent continuous collision

   private int colCounter;

   private void OnCollisionEnter(Collision other)
   {
     if (playerEnter == false && other.transform.tag == "Player")
     {
        if (colCounter >= 2)
        {
            // code for falling. I Just used Physics.
            transform.GetComponent<Rigidbody>().isKinematic = false;
            return;
        }
        transform.GetComponent<Renderer>().material.color = colors[colCounter];
        colCounter++;
        playerEnter = true;

    }

  }

  private void OnCollisionExit(Collision other)
  {
    playerEnter = false;
  }
 }

Answer 3

public Material []materialSequence;
new public Renderer renderer;

float playerExitTime = float.NegativeInfinity;
int state = 0;

bool PlayerStays = false;

void Awake()
{
    renderer = gameObject.GetComponent<MeshRenderer>();
}

void OnCollisionEnter(Collision collision)
{
    if (collision.gameObject.CompareTag("Player"))
    {
        // Add a little tolerance, so rapid vibration at the edge of collision
        // doesn't advance the state. We need to leave for some time then return.
        if (Time.time - playerExitTime > 0.1f)
            AdvanceState();

    }
}

void OnCollisionStay(Collision collision)
{
    if (PlayerStays)
    {
        StartCoroutine(FallThenDestroy(5f, 9f));
        PlayerStays = false;
    }

    if (state == 1)
    {
        StartCoroutine(PlayerCheckStayStatus(1.5f));
    }
}

void OnCollisionExit(Collision collision)
{
    if (collision.gameObject.CompareTag("Player"))
    {
        playerExitTime = Time.time;
    }
}

void AdvanceState()
{
    // If we're already falling, ignore further state changes.
    if (state == materialSequence.Length)
        return;

    renderer.sharedMaterial = materialSequence[state];
    state++;

    if (state == materialSequence.Length)
        StartCoroutine(FallThenDestroy(10f, 3f));
}

// This lets us animate out the fall before the destruction takes place.
IEnumerator FallThenDestroy(float distance, float duration)
{
    PlayerStays = false;
    yield return new WaitForSeconds(0.5f);
    for (float t = 0; t < duration; t += Time.deltaTime)
    {
        // Fall some distance.
        transform.Translate(0, -distance * Time.deltaTime / duration, 0, Space.World);
        // Yield control to the engine to run for a frame, then resume here.
        yield return null;
    }

    // Destroy ourselves once the fall is over.
    Destroy(gameObject);
}

IEnumerator PlayerCheckStayStatus(float time)
{
    yield return new WaitForSeconds(time);
    PlayerStays = true;
    Debug.Log(PlayerStays);
}

Edited code like this, it works nice but i need to ask when cube falls, my character teleports to nearest cube around instead of falling with it. How can i fix it?