如何在Unity 3D OnCollisionEnter中提高得分

Question

I'm stuck with ac# code that should be easy to solve at first instance but I'm not able to get it work. I'm making a videogame in Unity3D and I want to make a function that increases the score once the object Collides with a wall.

I have 2 script for that:

1. Puntuacion.cs // All the functions to increase and set the MAX and ACTUAL Score Values
2. Collisions.cs // Script that detects whenever is a Collision on the game

CODE:

Puntuacion.cs

using UnityEngine;
using System.Collections;

public class Puntuacion : MonoBehaviour 
{
    public  int puntuacionActual=0;
    public  int maximaPuntuacion = 14;

    public  Transform gamePointsTextActual;            // Texto Marcador Actual
    public  Transform gamePointsTextMaxima;            // Texto Marcador Maxima  

    void Start () 
    {
        gamePointsTextActual=GameObject.Find("Texto 3D - ScoreActual").transform;
        gamePointsTextMaxima=GameObject.Find("Texto 3D - ScoreMaxima").transform;
    }


    void Update () 
    {
        gamePointsTextActual.GetComponent<TextMesh>().text=this.puntuacionActual.ToString("D3");
        gamePointsTextMaxima.GetComponent<TextMesh>().text=this.maximaPuntuacion.ToString("D3");

        if(puntuacionActual>maximaPuntuacion)
        {
            maximaPuntuacion = puntuacionActual;
            gamePointsTextActual.GetComponent<TextMesh>().text=this.maximaPuntuacion.ToString("D3");
        }
    }

    public void incrementarPuntuacion()
    {
        puntuacionActual = puntuacionActual+1; 

        Debug.Log("Puntuacion Actual :"+puntuacionActual);
        if(puntuacionActual>maximaPuntuacion)
        {
            maximaPuntuacion = puntuacionActual; 
        }
    }
}

Collisions.cs

using UnityEngine;
using System.Collections;


public class Collisions : MonoBehaviour 
{       
    public Puntuacion puntuacion = new Puntuacion();

    public void OnCollisionEnter(Collision obj_collision  )   
    {

            if(obj_collision.gameObject.name == "HitScore")
            {
                Debug.Log("Collision");
                puntuacion.incrementarPuntuacion();
                Destroy(gameObject,2.0F);
            }

            if(obj_collision.gameObject.name == "Plane")
            {
                Debug.Log("Collision Plano");
                Destroy(gameObject,1.0F);
            }

    }
}

Both Script are attached to the same GameObject but I get this error:

NullReferenceException: Object reference not set to an instance of an object
Collisions.OnCollisionEnter (UnityEngine.Collision obj_collision

On the other hand, the code does not increase the score, always increases 1 and the actual score stays in 1. I guess that is because everytime there is a Collision on the game, I create a new instance of Puntuacion.cs including the values puntuacionActual=0 and maximaPuntuacion = 14; and increases the value from that puntuacionActual from 0 to 1 in each collision.

What I would like to achieve is to increase the score value (+1) whenever there is a collision on the system the wall, just that.I would like to save that value for the next collision.

I will be very grateful to whoever helps me with this doubt

Best regards

Answer 1

Yes I think you are indeed right, your score always gets reset because you create an instance of new Punctuation in Collisions script. Try using GetComponent instead:

Punctuation punctuationScript= gameObject.getComponent<Punctuation>();

Then you can access the public variables or methods just like this:

punctuationScript.incrementarPunctuation();

This way no new script will be created, instead it will just get the script from that gameObject.

EDIT:
I just copied your code into my project and I get the same error as you when I used your code:

Collisions.cs

public Puntuacion puntuacion = new Puntuacion();

public void OnCollisionEnter(Collision obj_collision)   
{   
    if(obj_collision.gameObject.name == "HitScore")
    {
        Debug.Log("Collision");
        puntuacion.incrementarPuntuacion();
        Destroy(gameObject,2.0F);
    }
}

However after I tried using the code I gave you, everything went fine and the score even got incremented correctly:

public void OnCollisionEnter(Collision obj_collision)   
{
    if(obj_collision.gameObject.name == "HitScore")
    {
        Debug.Log("Collision");
        Puntuacion puntuacionScript = gameObject.GetComponent<Puntuacion>();
        puntuacionScript.incrementarPuntuacion();
        Destroy(gameObject,2.0F);
    }
}

Are you sure you have made it like this?