Map Storage

by Foomer
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ID:110844
 
The purpose of this library is to save and load maps for use in such things as level-based puzzle games. Currently it will save and load the entire map, and has no support for chunks, although that may change in the future. The library is setup so that if maps are tampered with, the game can detect this and optionally reject the tampered map file. Maps can also be password protected so that only the author of the map (or the creator of the game) can work with them in an editor.

LIMITATIONS:
  • Bad things tend to happen if you try to have two objects of the same type on the same turf when you save. Its nothing destructive, but you'll end up with saved variables being tossed around between objects.

  • Currently the library only saves and loads the entire game world at once. Chunks aren't implemented right now.

  • Before a map is loaded, it will run a function called ClearMap that will attempt to remove all turfs and objects from the map, and any cliented mobs will be moved to null. Make sure you move players back onto the map after loading it, otherwise you'll be stuck in null.

INSTRUCTIONS:
STEP 1)
You need to create a map storage datum to use this library. If you just want to use the basic saving and loading functions and you don't need to override any procs, then you can create a global map storage object like this:

var/map_storage/map_storage = new(game_id, backdoor, ignore)

If you want more control over what's happening in certain functions, then you'll need to create your own version of the map storage datum:

var/map_storage/my_saving/my_saving = new()

map_storage/my_saving
    game_id = "FoomerMaps"
    backdoor_password = "CutiePie"
    ignore_types = list(/mob)

Either way, you'll need to specify some additional options:
  • The GAME_ID variable is used to identify your game and separate it from any other games that may be using this library. A map saved with one game_id can not be loaded by a game using a different ID.

  • The BACKDOOR is an secondary password that allows access to maps which are password protected. This is necessary in order for a game to be able to load password-locked maps freely using the backdoor password, while a level editor requires users to enter the map's password in order to edit it. The backdoor can also be entered at the password prompt in order for the developer to access password-locked maps for debugging purposes.

    NOTE: Backdoor passwords will only work if a game_id is specified.

  • The IGNORE LIST is an optional list which specifies which object types you do NOT want to be saved with the map, such as /mob, which will prevent any mobs from being saved on the map.

STEP 2)
You need to specify which objects will have which variables saved. You can do this using the variable called map_storage_saved_vars. This variables accepts a params string containing the names of the variables that you want to save with the map when this object is saved.

For example, if you have a door and you want to save whether the door has been opened or not, you could do it like this"

turf/door
    density = 1
    opacity = 0
    var/opened = 0

    map_storage_saved_vars = "density;opacity;opened"

Then the "density", "opacity" and "opened" variables will be saved with the gate object, but only if those variables have been modified from their original values. If they haven't been changed, they won't be saved, to conserve map space.

STEP 3)
You can SAVE maps using the map_storage.Save() function, like this:

var/savefile/map = new("map.sav")
map_storage.Save(map, password, extra)

The map argument is a savefile which needs to be created before trying to save any information to it (See _example.dm). If you want the file to be password-locked, then specify the password here.

NOTE: Passwords are case-sensetive.

You can also add in a list (or params) containing any extra values that you want to be stored with the file. These values will be returned by the Load() function in /list format when a map is loaded.

The function will return true if the map was loaded successfully.

STEP 4)
You can load maps using the map_storage.Load() function, like this:

var/savefile/map = new("map.sav")
var/list/extra = map_storage.Load(map, password)

The map argument is the savefile containing the saved map data. If the map is password-locked, you will need to specify the correct password or a backdoor password in order to open the map.

When a map is loading, before it actually loads anything it will run a function called ClearMap that will attempt to clear all turfs and objects off the map, and will move any cliented mobs to null. You'll need to remember to move any players back onto the map after it loads.

Once a map is successfully loaded, it will return a /list containing any extra variables that were added to the savefile in Save().

There are also some additional functions that you can use to get info about the map before you decide to load it.
  • map_storage.IsValid(savefile) can be used to find out if this is a valid map file, and if it was created using the same game_id. If not, then it will return false. Otherwise it returns true.

  • map_storage.Verify(savefile) lets you find out if the map has been changed at all since it was last saved through this library. If the map has been changed, then verification will return false.

  • map_storage.PasswordLocked(savefile) lets you find out of the map has a password lock or not. Returns true if it does.
You can use the map_storage.GetExtra() function to extract any extra variables stored in the savefile anytime you'd like, like this:

map_storage.GetExtra(map)

That will return a /list containing all the extra variables stored in the savefile, along with their associated values. Or:

map_storage.GetExtra(map, variable)

This will return the value associated with the requested variable.

OTHER STUFF:
If you create your own version of the map storage datum, you can override some functions in order to change their behavior. For instance, the _example.dm shows you how to override the SaveOutput(percent) and LoadOutput(percent) procs to have them update a label to display the current saving or loading progress:

var/map_storage/map_save/map_save = new()
map_storage/map_save
    game_id = "FoomerMaps"
    backdoor_password = "CutiePie"
    ignore_types = list(/mob)

    SaveOutput(percent)
        if(prob(10) || percent == 100)
            winset(usr, "status", "text=\"[percent]% done.\"")
            sleep(1)
        return

    LoadOutput(percent)
        if(prob(10) || percent == 100)
            winset(usr, "status", "text=\"[percent]% done\"")
            sleep(1)
        return

You can also override the library's ClearMap() function in order to change how the library handles clearing the map before it loads a new one:

     ClearMap()
        for(var/turf/T in world)
            for(var/atom/movable/A in T)
                if(ismob(A))
                    var/mob/M = A
                    if(M.client)
                        M.loc = null
                        continue
                del(A)
            del(T)
        return
Very helpful and exactly what I was looking for.