Save large chunks of data

What's the best way to save and retrieve large chunks of data in Unity/c#?

 

From memory, local storage, the internet or what?

 

Local store game data, save game... later to be loaded. Not internet...

 

Use the System.IO namespace to read from and write to Application.persistentDataPath.

 

The C# File class is the most generic thing to do. On mobile you'd want to be reading and writing data to Application.persistentDataPath; perhaps it's the same on non-mobile, but I'm not sure. How you format the files is up to you and would depend on your needs, e.g. raw binary or text.

 

Thanks RazorCut!

Do you have any code for this?

I've found:
http://docs.unity3d.com/ScriptReference/Application-persistentDataPath.html
http://forum.unity3d.com/threads/saving-and-loading-data-xmlserializer.85925/

I would want to store a large array of integers to a file then be able to fetch them again (save/load game for player data).

 

Is the data sensitive? When you save data locally, you want to make sure you encrypt it or do some sort of obfuscation to prevent "hackers" from getting to the data and changing values at will. Also, I recommend Application.dataPath, as it saves it internally where the application is saved at. Application.persistantDataPath is nice but if you are working in windows / unix clearing caches can also clear the game data. The only way the data can be cleared with Application.dataPath is by manually deleting with code or by removing the game itself.

 

If it's non-sensitive data you can use a BinaryReader and BinaryWriter class. They are nice and fast for saving and loading data

Code (CSharp):

1. using System.IO;
2.  
3. //Save and load player health, and ammo
4. int ammo = 0;
5. int health = 100;
6.  
7. void Save(){
8.      string savePath = Application.persistentDataPath + "/savefile.sav";
9.      using(var w = new BinaryWriter(File.OpenWrite(savePath))){
10.        w.Write(System.Convert.ToInt32(ammo)); //Write ammo as Int32 type
11.        w.Write(System.Convert.ToInt32(health)); //Write health as Int32 type
12.      }
13.      Debug.Log("Save complete");
14.    }
15.    void Load(){
16.      string loadPath = Application.persistentDataPath + "/savefile.sav";
17.      using(var r = new BinaryReader(File.OpenRead(loadPath))){
18.        //Load ammo and health
19.        ammo = r.ReadInt32();
20.        health = r.ReadInt32();
21.      }
22.      Debug.Log("Load complete");
23.    }
24.  
25. void Start(){
26.     health = 25;
27.     Save();
28.     health = 100;
29.     Load();
30.     Debug.Log("Health is " + health); //Will log 25
31. }

 

Thanks aaro4130! Much appreciated...

 

Some tips for reading and writing Binary data are :

-If you have a number that will NEVER be over 32767, you can use Int16. Or if it will never be > 255, you can use Byte
-If you have a boolean you can use ReadBoolean and Write(<bool value>)
-You can read and write strings directly too

Happy coding

 

Thanks again aaro4130, one more question what are the limits on the size of the array I can use?

For example say I want to deploy to Windows Tablet vs. iPhone, how can I determine max size of array for each device? Maybe when deploying to certain devices I then make my large data size a bit smaller (it's a tiled region of exploration in a game)...

 

Data on each device can be stored in this same way with usually the same size of data even. You shouldn't run into any issues even with large blocks . Just loading time will be longer on slower devices

 

2^n - 1, where n is the bit of the OS, 2^32 - 1 is the biggest int size for a 32 bit OS 2174483647 is the biggest int value. So, your array cannot exceed that size if it is a 32 bit OS.

 

See this plugin to download big files and save locally, It may help you.
https://assetstore.unity.com/packages/tools/network/large-file-downloader-cross-platform-92128

 

will this work for a 2d Minecraft word. I want to store 3 values. X,Y coordinates(Not sure if I spelled it right) and an int for the block type. The world is 1000x40 blocks long. Will this be quick because with other methods my pc crashes or takes like an hour.