Adding private variables

Adding private variables
Adding private variables to an existing Raft class is sometimes very necessary. There're many ways to add new variables. In this article we will consider the method provided by Whitebrim.
We will store variables in the newly created class and add an extension for original Raft class. You can read how C# extensions work here.
If your class has only one instance you can add static private variable. If not, you need to add Dictionary<class, variable> that will contain variables for each class instance.
In this example we will add new private bool isLocked variable to SteeringWheel class:
First, we need to create an extension class to store and handle variables:
public static class SteeringWheelExtension
{
    private static Dictionary<SteeringWheel, bool> isLocked = new Dictionary<SteeringWheel, bool>();
​
    public static bool IsLocked(this SteeringWheel steeringWheel)
    {
        if (!isLocked.ContainsKey(steeringWheel))
        {
            isLocked.Add(steeringWheel, false); // False is default value for isLocked bool in our case
        }
        return isLocked[steeringWheel];
    }
​
    public static void Lock(this SteeringWheel steeringWheel, bool value)
    {
        if (!isLocked.ContainsKey(steeringWheel))
        {
            isLocked.Add(steeringWheel, value);
            return;
        }
        isLocked[steeringWheel] = value;
    }
}
Then you need to patch original class. In our case we need to change displaying text depending on IsLocked state. We will patch OnIsRayed() methon inside SteeringWheel class:
[HarmonyPatch(typeof(SteeringWheel), "OnIsRayed")]
class SteeringWheelPatchOnIsRayed
{
    private static void Postfix(SteeringWheel __instance, ref DisplayTextManager ___displayText)
    {
        if (!__instance.IsLocked())
            ___displayText.ShowText("Press to LOCK rotation", MyInput.Keybinds["RMB"].MainKey, 2, 0, false);
        else
            ___displayText.ShowText("Press to UNLOCK rotation", MyInput.Keybinds["RMB"].MainKey, 2, 0, false);
​
        if (MyInput.GetButtonDown("RMB"))
            __instance.Lock(!__instance.IsLocked()); // Toggle bool
    }
}
You can read more about Harmony patching here.
Also you need to apply patch:
public class BetterSteeringWheel : Mod
{
    private HarmonyInstance harmonyInstance;
​
    public void Start()
    {
        harmonyInstance = HarmonyInstance.Create("com.whitebrim.bettersteeringwheel"); // It's custom patch name, you need to name your patch differently
        harmonyInstance.PatchAll(Assembly.GetExecutingAssembly());
    }
​
    public void OnModUnload()
    {
        harmonyInstance.UnpatchAll();
        Destroy(gameObject);
    }
}
You can access new variable using class instance. SteeringWheel.IsLocked(), SteeringWheel.Lock(bool newValue).
Example for float and string:
public static class CustomExtension
{
    private static Dictionary<YourClass, float> floatVarName = new Dictionary<YourClass, float>();
    private static Dictionary<YourClass, string> stringVarName = new Dictionary<YourClass, string>();
​
    public static float GetFloatVarName(this YourClass instance)
    {
        if (!floatVarName.ContainsKey(instance))
        {
            floatVarName.Add(instance, 0); // 0 is default value for floatVarName in our case
        }
        return floatVarName[instance];
    }
​
    public static void SetFloatVarName(this YourClass instance, float value)
    {
        if (!floatVarName.ContainsKey(instance))
        {
            floatVarName.Add(instance, value);
            return;
        }
        floatVarName[instance] = value;
    }
​
    public static string GetStringVarName(this YourClass instance)
    {
        if (!stringVarName.ContainsKey(instance))
        {
            stringVarName.Add(instance, string.Empty); // string.Empty is default value for stringVarName in our case
        }
        return stringVarName[instance];
    }
​
    public static void SetStringVarName(this YourClass instance, string value)
    {
        if (!stringVarName.ContainsKey(instance))
        {
            stringVarName.Add(instance, value);
            return;
        }
        stringVarName[instance] = value;
    }
}
Saving private variables
To save private variables you need to patch RDG_%RaftClassName% class and method that is invoked inside switch in SaveAndLoad class in RestoreRGDGame(RGD_Game game) method.
In this example we will use SteeringWheel class and save IsLocked variable (from Adding private variables section).
First, we have to add new link RGD Class -> our variable (Dictionary):
public static class SteeringWheelExtension
{
    public static Dictionary<RGD_SteeringWheel, bool> RGDisLocked = new Dictionary<RGD_SteeringWheel, bool>();
​
    public static void AddLockRGD(this RGD_SteeringWheel RGD_SteeringWheel, SteeringWheel steeringWheel) // For saving
    {
        RGD_SteeringWheel.AddLockRGD(steeringWheel.IsLocked());
    }
​
    public static void AddLockRGD(this RGD_SteeringWheel RGD_SteeringWheel, bool value) // For loading
    {
        RGDisLocked.Add(RGD_SteeringWheel, value);
    }
}
Second, we need to patch RGD_SteeringWheel class. There're two constructors (one for saving, another for loading) and GetObjectData method (to control flow of Serialization).
class RGD_SteeringWheelPatch
{
    [HarmonyPatch(typeof(RGD_SteeringWheel), MethodType.Constructor, new Type[]{ typeof(RGDType), typeof(SteeringWheel) })]
    class RGD_SteeringWheelConstructor1 // Constructor for saving
    {
        private static void Prefix(RGD_SteeringWheel __instance, ref SteeringWheel steeringWheel)
        {
            __instance.AddLockRGD(steeringWheel); // Linking this RGD object to variable value
        }
    }
​
    [HarmonyPatch(typeof(RGD_SteeringWheel), MethodType.Constructor, new Type[] { typeof(SerializationInfo), typeof(StreamingContext) })]
    class RGD_SteeringWheelConstructor2 // Constructor for loading
    {
        private static void Prefix(RGD_SteeringWheel __instance, ref SerializationInfo info)
        {
            foreach (SerializationEntry serializationEntry in info)
            {
                string name = serializationEntry.Name;
                if (name == "IsLocked") // If you'll open this save without mod installed - it'll not crash your game
                    __instance.AddLockRGD((bool)serializationEntry.Value); // Linking this RGD object to loaded value
            }
        }
    }
​
    [HarmonyPatch(typeof(RGD_SteeringWheel), "GetObjectData")]
    class GetObjectData // Interfering with the serialization flow and adding our custom data to the save
    {
        private static void Postfix(RGD_SteeringWheel __instance, ref SerializationInfo info)
        {
            bool value;
            if (SteeringWheelExtension.RGDisLocked.TryGetValue(__instance, out value))
                info.AddValue("IsLocked", value); // Getting variable value via link, using this RGD object as a key
        }
    }
}
Lastly, we need to find method that loads saved block data and patch it. This method is invoked inside switch in SaveAndLoad class in RestoreRGDGame(RGD_Game game) method:
switch (rgd.type)
    {
    case RGDType.Block:
    {
      //Some code
      break;
    }
    case RGDType.Block_Door:
    {
      //Some code
      break;
    }
    //etc...
Our case:
case RGDType.Block_SteeringWheel:
    {
      RGD_SteeringWheel rgd_SteeringWheel = rgd as RGD_SteeringWheel;
      Block block19 = this.RestoreBlock(network_Player.BlockCreator, rgd_SteeringWheel);
      if (block19 != null)
      {
          SteeringWheel componentInChildren3 = block19.GetComponentInChildren<SteeringWheel>();
          if (componentInChildren3 != null)
          {
              componentInChildren3.RestoreWheel(rgd_SteeringWheel); // <- This line
          }
      }
      break;
    }
In our case method is called RestoreWheel(RGD_SteeringWheel rgdWheel). This method contains instructions on how to deserialize RGD class to retrieve saved data. We will add our custom instructions:
[HarmonyPatch(typeof(SteeringWheel), "RestoreWheel")]
class SteeringWheelRestoreWheelPatch
{
    private static void Prefix(SteeringWheel __instance, RGD_SteeringWheel rgdWheel)
    {
        bool value;
        if (SteeringWheelExtension.RGDisLocked.TryGetValue(rgdWheel, out value)) // Using RGD class as a key to get isLocked value, check if save had data about isLocked state
            __instance.Lock(value);
    }
}
Congratulations, our custom data for Steering Wheel is saving and loading successfully.
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Modifying private variables
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Last updated 6 months ago