Assets\Scripts\Player system\PlayerOxygen.cs(10,33): error CS0236: A field initializer cannot refere

I am making a water system for my game... And for drowning to properly work, I need to reference a "health" variable and a death function from another script. The function was referenced successfully, but the variable is giving me this error.

*Assets\Scripts\Player system\PlayerOxygen.cs(10,33): error CS0236: A field initializer cannot reference the non-static field, method, or property 'PlayerOxygen.data'*

Code (CSharp):

1.  using System.Collections;
2.     using System.Collections.Generic;
3.     using UnityEngine;
4.     using UnityEngine.UI;
5.     using UnityEngine.SceneManagement;
6.     public class PlayerOxygen : MonoBehaviour
7.     {
8.         public PlayerDamage data;
9.         public float playerHealth = data.health;
10.         public float damage = 0.1f;
11.         public float oxygen = 100f;
12.         public Text O2Text;
13.         public bool outOfO2 = false;
14.         public bool underWater = false;
15.         void Update(){
16.             if (underWater == true) {
17.                 oxygen = oxygen - 0.02f;
18.             } else {
19.                 oxygen++;
20.             }
21.             if (oxygen > 100f) {
22.                 oxygen = 100f;
23.             }
24.             if (oxygen < 0f) {
25.                 oxygen = 0f;
26.             }
27.             if (oxygen == 0f && underWater == true) {
28.                 playerHealth = playerHealth - damage;
29.             }
30.             if (playerHealth == 0f) {
31.                 data.Die();
32.             }
33.         }
34.         public void OnTriggerEnter(Collision waterCollision) {
35.             if (waterCollision.collider.tag=="Water"){
36.                 underWater = true;
37.             } else {
38.                 underWater = false;
39.             }
40.         }
41.     }

Does anyone know how to fix this?

 

What I don't understand is what the error means. I have referenced variables from seperate scripts before, but here it doesn't work.

When I remove "data.health" from line 9, there are no errors. I have checked the file name and namespace of the other script, so I don't believe that causes the issue...

 

Just to settle the case. Have a look at this line:

Code (CSharp):

1. public float playerHealth = data.health;

This is a field:

Code (CSharp):

1. public float playerHealth;

and this is the field initializer:

Code (CSharp):

1.  = data.health;

it is executed even before the constructor of the class is called when your class instance is created. So your "data" value can not possibly contain any meaningful data at this point. The compiler knows this and does not allow such an assignment inside a field initializer. You should remove the field initializer and move the initialization to Start or Awake.

Code (CSharp):

1. public float playerHealth;
2. void Start()
3. {
4.     playerHealth = data.health;
5. }
6.  

When Start is executed the whole class has already been created, initialized and the serialized data has been deserialized.

Note that your whole oxygen logic is currently frame rate dependent. So on a faster PC you would loose ocxgen much faster. Also once you run out you would take damage much quicker. You should multiply your delta values by Time.deltaTime to make them time dependent (and framerate independent)

Code (CSharp):

1.             if (underWater == true) {
2.                 oxygen = oxygen - 1f * Time.deltaTime;
3.             } else {
4.                 oxygen += 50f * Time.deltaTime;
5.             }
6.             if (oxygen > 100f) {
7.                 oxygen = 100f;
8.             }
9.             if (oxygen < 0f) {
10.                 oxygen = 0f;
11.             }
12.             if (oxygen == 0f && underWater == true) {
13.                 playerHealth = playerHealth - damage * Time.deltaTime;
14.             }
15.             if (playerHealth <= 0f) {
16.                 playerHealth = 0f;
17.                 data.Die();
18.             }

Note I've adjusted your hardcoded values by a factor of about "50" so you should get roughly the same result as before assuming a framerate of about 50 - 60 fps. You have to adjust your "damage" value yourself. I would recommend besides the "damage" value to define an "oxygenDrain" and "oxygenRegen" field as well so that you can configure them in the inspector instead of the "1f" and "50f". When multiplied by deltaTime the meaning of the value changes. Instead of the "amount per frame" it becomes the "amount per second".

So a "damage" value of 10 would take away 10 hp per second. At a framerate of 60 fps that would be about 0.1666 HP per frame. However at a framerate of 500fps it would only subtract 0.02HP per frame so that after 500 frames you have subtracted 10HP. Likewise if the framerate drops to 10fps (which we do not hope) it would subtract 1 HP per frame