Waiting for a key press in the Update method

Hi,
I'm working on a game in which I want the game to wait in the update function inside an if statement until the player presses a specific key. Is there any specific way I can do that?
Thanks.

 

Input.GetKeyDown

 

nope, blocking the Update method will block the game.

You should be testing on a per frame basis and reacting.

If you have a long routine that must stop mid way and wait for a duration until some event occurs in game, that's what 'Coroutines' are for. You can start up a Coroutine, resolve some code, then in an while/foreach loop keep yield returning null until some event occurs.

Like so:

Code (csharp):

1.  
2. IEnumerator SomeRoutine()
3. {
4.  
5.     //do stuff
6.  
7.     //wait for space to be pressed
8.     while(!Input.GetKeyDown(KeyCode.Space))
9.     {
10.         yield return null;
11.     }
12.  
13.     //do stuff once space is pressed
14.  
15. }
16.  

This though is more for setting up sequences of actions over a duration of time. Rather than reacting to user input repeatedly.

If you're doing something where you want to jump on spacebar pressed, a routine is not how you'd go about it. Update is. And the update code would just check each frame if the key was pressed.

'Update' is like a while loop, its code operating repeatedly, once per frame.

Code (csharp):

1.  
2. void Update()
3. {
4.     if(Input.GetKeyDown(KeyCode.Space))
5.     {
6.         //do jump
7.     }
8. }
9.  

 

Ok. What do you recommend I do for a turn-based rpg battle system where I want the game to wait for you to press a button (to finish reading the text) before ending your turn.

 

That'd be a coroutine.

You'd start a coroutine, the coroutine would display the message, then it'd wait for a keypress. Just like in my coroutine example above.

 

In this case, you need to setup a manager to handle turns. Then give 'turn' access to the next player where they can input w/e you need.

 

A simple way to set this up would be to have a GameObject that handles whose turn it is, and have other objects refer to that. For example:

Create a GameObject with a script called GameManager.cs with the following:

Code (CSharp):

1. public class GameManager : MonoBehaviour
2. {
3.     public int currentPlayer = 0;
4.     public int totalPlayers = 2;
5.  
6.     public void NextPlayer()
7.     {
8.         // Update the current player, use the modulo operator to wrap around
9.         currentPlayer = (currentPlayer + 1) % totalPlayers;
10.     }
11. }

Then your individual game pieces could check to see if they need to act:

Code (CSharp):

1. public class GamePiece : MonoBehaviour
2. {
3.     public int myPlayerNumber = 0;
4.     public GameManager gameManager;
5.  
6.    void Update()
7.     {
8.         if(gameManager.currentPlayer == myPlayerNumber)
9.         {
10.             // It is my turn, do my logic
11.  
12.             if(Input.GetKeyDown(KeyCode.Space))
13.             {
14.                 gameManager.GoToNextPlayer();
15.             }
16.         }
17.     }
18. }

 

I think better solution for coroutine is like:

Code (CSharp):

1. IEnumerator SomeRoutine()
2. {
3.  
4.     //do stuff
5.  
6.     //wait for space to be pressed
7.     yield return new WaitUntil(() => Input.GetKeyDown(KeyCode.Space));
8.  
9.     //do stuff when space is pressed
10.  
11. }

This is another solution without while loop.. You can see also lambdas article right here: https://docs.microsoft.com/en-us/do...ents-expressions-operators/lambda-expressions