Jump to content

  • Log In with Google      Sign In   
  • Create Account

Passing information between gamestates


Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.

  • You cannot reply to this topic
7 replies to this topic

#1 SonicD007   Members   -  Reputation: 464

Like
0Likes
Like

Posted 31 January 2013 - 05:46 PM

Hi,  I'm using the gamestate sample from: http://gamedevgeek.com/tutorials/managing-game-states-in-c/  and I want to pass information from one gamestate to another gamestate.  In particular, I'm thinking of creating a LogIn state in which it will connect to a server, verify/login, then grab the character data.  I then want to pass the character data to the next gamestate (PlayGameState or something) and use that data to do whatever game logic I need done.  What would be the best way to do this?  Would I need to change the Init class to have another parameter in which I can pass a generic object of some sort similar to how C# forms use the Tag property to exchange data with other forms?  How would you do this?



Sponsor:

#2 CC Ricers   Members   -  Reputation: 733

Like
0Likes
Like

Posted 31 January 2013 - 05:54 PM

I would pass the data as a structure parameter in the state's Instance function. If you design your game well, you should not need to pass a lot of structures between states. If you were to successfully login, it could pass the character data to a loading screen state. The data could contain information on where the character was last in the game, and based on that information, load that part of the world for the game for the state following the loading screen.

Also consider what data you want to be persistent throughout the run of the program, not just when you're actually playing the game.


My development blog: Electronic Meteor

#3 SiCrane   Moderators   -  Reputation: 9668

Like
0Likes
Like

Posted 31 January 2013 - 06:04 PM

There's no reason not to think of game state classes as very different from any other class. Like any other class, if there's information you want to pass to an object as you create it, then you can make it a parameter of the constructor.

#4 L. Spiro   Crossbones+   -  Reputation: 14248

Like
5Likes
Like

Posted 31 January 2013 - 08:06 PM

Passing data between game states got ya down?

Well turn that frown up-side down!

I wrote about this here.

 

 

L. Spiro


It is amazing how often people try to be unique, and yet they are always trying to make others be like them. - L. Spiro 2011
I spent most of my life learning the courage it takes to go out and get what I want. Now that I have it, I am not sure exactly what it is that I want. - L. Spiro 2013
I went to my local Subway once to find some guy yelling at the staff. When someone finally came to take my order and asked, “May I help you?”, I replied, “Yeah, I’ll have one asshole to go.”
L. Spiro Engine: http://lspiroengine.com
L. Spiro Engine Forums: http://lspiroengine.com/forums

#5 Goran Milovanovic   Members   -  Reputation: 1104

Like
0Likes
Like

Posted 31 January 2013 - 08:47 PM

I don't see why you have to pass character data from one state to the next (in this case), because "logging in" and "getting character data" are two distinct activities, which can be executed in two distinct states: In your log-in state, you're trying to authenticate, and if you do, you transition into the "load" state, where you can get the relevant data from the network.

 

Some general comments relating to state machines: There are many cases where you don't really need to have a convoluted class hierarchy, and where setting a function pointer will work just fine.

 

I actually wrote a small Tetris game in C, where states, and state transitions, are just as simple as that.

 

You can see the code on my github, specifically in this file: states.c.


+---------------------------------------------------------------------+

| Game Dev video tutorials  ->   http://www.youtube.com/goranmilovano |
+---------------------------------------------------------------------+

#6 SonicD007   Members   -  Reputation: 464

Like
0Likes
Like

Posted 01 February 2013 - 06:27 AM

I don't see why you have to pass character data from one state to the next (in this case), because "logging in" and "getting character data" are two distinct activities, which can be executed in two distinct states: In your log-in state, you're trying to authenticate, and if you do, you transition into the "load" state, where you can get the relevant data from the network.

 

Even if I do it that way, wouldn't I only be pushing the transfer of data between states to the load state?  



#7 NightCreature83   Crossbones+   -  Reputation: 3032

Like
0Likes
Like

Posted 01 February 2013 - 07:41 AM

As a side not on the original state system I would ditch the singleton behaviour from all the states, you can have different instances of the same state in a game. Some information shouldn't be stored in the states itself they only indicate in which state the game is. We stored player information for example in a player profile which was globally accesseable through a resource class that was passed in the constructor of a state. You then had multiple states to check whether the player had signed into a profile on the console, and then other states to check other things in the profile when needed.


Worked on titles: CMR:DiRT2, DiRT 3, DiRT: Showdown, GRID 2, Mad Max

#8 Goran Milovanovic   Members   -  Reputation: 1104

Like
0Likes
Like

Posted 01 February 2013 - 12:05 PM

Even if I do it that way, wouldn't I only be pushing the transfer of data between states to the load state?  

 

You would no longer need to have a system for transferring data between states, because each state would be responsible for getting the data it actually requires.

 

If other states need to access this data somewhere along the line, they should be able to get it from some globally visible data structure.


+---------------------------------------------------------------------+

| Game Dev video tutorials  ->   http://www.youtube.com/goranmilovano |
+---------------------------------------------------------------------+




Old topic!
Guest, the last post of this topic is over 60 days old and at this point you may not reply in this topic. If you wish to continue this conversation start a new topic.



PARTNERS