How to implement cheat codes

Question

I don't want to go "console route" for inputting cheat codes. I'd like something like e.g. in first Doom where there is no visible or audible feedback until cheat is correctly entered. How would I go about that?

Answer 1

Yet another version.

Based on @mattssonon but I find this a bit easier to setup and use. Enjoy!

It makes use of UnityEvent to being able to pick any public function. And lets you pick any KeyCode instead of just plain strings.

 using UnityEngine;
 using UnityEngine.Events;
 
 public class CheatInput : MonoBehaviour
 {
     public KeyCode[] CheatCode;
     public UnityEvent CheatEvent;
     public float AllowedDelay = 1f;
 
     private float _delayTimer;
     private int _index = 0;
 
     void Update()
     {
         _delayTimer += Time.deltaTime;
         if (_delayTimer > AllowedDelay)
         {
             ResetCheatInput();
         }
 
         if (Input.anyKeyDown)
         {
             if (Input.GetKeyDown(CheatCode[_index]))
             {
                 _index++;
                 _delayTimer = 0f;
             }
             else
             {
                 ResetCheatInput();
             }
         }
 
         if (_index == CheatCode.Length)
         {
             ResetCheatInput();
             CheatEvent.Invoke();
         }
     }
 
     void ResetCheatInput()
     {
         _index = 0;
         _delayTimer = 0f;
     }
 
     public void Cheat()
     {
         Debug.Log("CHEAT ACTIVATED");
     }
 }

Answer 2

Answer by Shaolin-Dave · May 14, 2018 at 10:17 PM

I just threw this together so you might need to tweak it (i.e. I didn't confirm the keycodes). This example would start the game when the player presses "Enter" on the keyboard. Normally they have 3 lives, but if they enter the infamous "Konami Code", they get 30 lives:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class KonamiCode : MonoBehaviour {
 
     private String inputString;
 
     void Update ()  {
         if (Input.GetKeyDown(KeyCode.UpArrow)) {
             inputString += 'U';
         } else if (Input.GetKeyDown(KeyCode.LeftArrow)) {
             inputString += 'L';
         } else if (Input.GetKeyDown(KeyCode.DownArrow)) {
             inputString += 'D';
         } else if (Input.GetKeyDown(KeyCode.RightArrow)) {
             inputString += 'R';
         } else if (Input.GetKeyDown(KeyCode.A)) {
             inputString += 'A';
         } else if (Input.GetKeyDown(KeyCode.B)) {
             inputString += 'B';
         } else if (Input.GetKeyDown(KeyCode.Enter)) {
             if (inputString.endsWith('UUDDLRLRBA')) {
                 StartGameWithLives(30);
             } else {
                 StartGamesWithLives(3);
             }
         } 
     }
 }

Some perks to doing it this way, it'll allow for starting over because it only checks the end of the string. If they mess up the code three times but then get it right on the last one, it'll still work. Also, you can easily add codes. Just add a new "endsWith" condition inside the block where "Enter" is pressed. There's all sorts of tweaks you can make to this. I've also built off of this to create a "Street Fighter"-style special moves input script.

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Lagger625 · Sep 12, 2018 at 12:41 AM 0

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omg your approach is simple and clever compared to $$anonymous$$e...

The thing here is, if you keep playing and pressing keys the inputString will keep growing bigger and bigger, wich will cause a growing-over-time waste of memory and CPU resources (related to garbage collection and concatenation of strings using "+" operator).

You should use some other way of keeping track of the last pressed keys.

Shaolin-Dave · Sep 12, 2018 at 05:36 AM 0

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In this particular case, this code would only be relevant on the title screen. I don't think players would spend that much time there pushing random buttons. In my "Street Fighter"-style application, I had the method consider in the string ended with any special move key combination, execute the proper method if it did, execute a basic attack method if it didn't, and then clear out the string. It was never longer than whatever it gathered in-between punches/kicks. Depending on the application, you can have different methods of controlling the length. A new strategy I just thought of would be a looping coroutine (maybe every 10 seconds or so) that trims the string down to it's last 10 characters (or however many the longest cheat code is).

Answer 3

nothing wrong with matts answer i just wrote this for my game and i thought i would share. it limits the time between keystrokes so it has to be typed adjustably fast. just just reminded me of old school gaming. this code works with an x box controller too:

     float quickness;
     String cheater;
     int ii;
     void Update () {
         ii = 9;
         while(ii>0){ii--;
             if (Input.GetKeyDown ("joystick 1 button " + ii)) {
 
                 cheater=cheater+""+ii;
                 quickness=0.8f;
 
             }
             }
 
         if (Input.inputString != "") {
             cheater = cheater + Input.inputString;
             quickness = 0.8f;// <---time delay between buttons
                 }
 
         if (quickness >= 0) {
                         quickness += -Time.deltaTime;
                         if (quickness < 0) {
         print ("user is attempting cheat code: "+cheater);
         if (cheater == "boom") {print ("blow stuff up something here");}
         if (cheater == "allweapons") {print ("blow up everyone here");}
                 if (cheater == "funkychicken") {print ("i think you get the point");}
         if (cheater == "001133") {print ("i pushed A A B B Y Y on my controller");}
 
                     cheater="";}}}

How to implement cheat codes

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