Saving, Loading, and Rollback link

Ren'Py has support for saving game state, loading game state, and rolling back to a previous game state. Although implemented in a slightly different fashion, rollback can be thought of as saving the game at the start of each statement that interacts with the user, and loading saves when the user rolls back.


While we usually attempt to keep save compatibility between releases, this compatibility is not guaranteed. We may decide to break save-compatibility if doing so provides a sufficiently large benefit.

What is Saved link

Ren'Py attempts to save the game state. This includes both internal state and Python state.

The internal state consists of all aspects of Ren'Py that are intented to change once the game has started, and includes:

  • The current statement, and all statements that can be returned to.
  • The images and displayables that are being shown.
  • The screens being shown, and the values of variables within those screens.
  • The music that Ren'Py is playing.
  • The list of nvl-mode text blocks.

The Python state consists of the variables in the store that have changed since the game began, and all objects reachable from those variables. Note that it's the change to the variables that matters – changes to fields in objects will not cause those objects to be saved.

Variables set using the default statement will always be saved.

In this example:

define a = 1
define o = object()
default c = 17

label start:
     $ b = 1
     $ o.value = 42

only b and c will be saved. A will not be saved because it does not change once the game begins. O is not saved because it does not change – the object it refers to changes, but the variable itself does not.

What isn't Saved link

Python variables that are not changed after the game begins will not be saved. This can be a major problem if a variable that is saved and one that is refer to the same object. (Alias the object.) In this example:

init python:
    a = object()
    a.f = 1

label start:
    $ b = a
    $ b.f = 2

    "a.f=[a.f] b.f=[b.f]"

a and b are aliased. Saving and loading may break this aliasing, causing a and b to refer to different objects. Since this can be very confusing, it's best to avoid aliasing saved and unsaved variables. (This is rare to encounter directly, but might come up when an unsaved variable and saved field alias.)

There are several other kinds of state that isn't saved:

control flow path
Ren'Py only saves the current statement, and the statement it needs to return to. It doesn't remember how it got there. Importantly, statements (including variable assignments) that are added to the game won't run.
mappings of image names to displayables
Since this mapping is not saved, the image may change to a new image when the game loads again. This allows an image to change to a new file as the game evolves.
configuration variables, styles, and style properties
Configuration variables and styles aren't saved as part of the game. Therefore, they should only be changed in init blocks, and left alone once the game has started.

Where Ren'Py Saves link

Saves occur at the start of a Ren'Py statement in the outermost interaction context.

What's important here is to note that saving occurs at the start of a statement. If a load or rollback occurs in the middle of a statement that interacts multiple times, the state will be the state that was active when the statement began.

This can be a problem in Python-defined statements. In:


     i = 0

     while i < 10:

          i += 1

          narrator("The count is now [i].")

if the user saves and loads in the middle, the loop will begin anew. Using Ren'Py script – rather than Python – to loop avoids this problem.:

$ i = 0

while i < 10:

     $ i += 1

     "The count is now [i]."

What Ren'Py can Save link

Ren'Py uses the Python pickle system to save game state. This module can save:

  • Basic types, such as True, False, None, int, str, float, complex, str, and Unicode objects.
  • Compound types, like lists, tuples, sets, and dicts.
  • Creator-defined objects, classes, functions, methods, and bound methods. For pickling these functions to succeed, they must remain available under their original names.
  • Character, Displayable, Transform, and Transition objects.

There are certain types that cannot be pickled:

  • Render objects.
  • Iterator objects.
  • File-like objects.
  • Inner functions and lambdas.

By default, Ren'Py uses the cPickle module to save the game. Setting config.use_cpickle to False will make Ren'Py use the pickle module instead. This makes the game slower, but is better at reporting save errors under Python 2.x. Note that this setting has no effect on Python 3, as the system chooses the implementation transparently in that case.

Save Functions and Variables link

There is one variable that is used by the high-level save system:

save_name = ... link

This is a string that is stored with each save. It can be used to give a name to the save, to help users tell them apart.

There are a number of high-level save actions and functions defined in the screen actions. In addition, there are the following low-level save and load actions.

renpy.take_screenshot(scale=None, background=False) link

Causes a screenshot to be taken. This screenshot will be saved as part of a save game.

Retaining Data After Load link

When a game is loaded, the state of the game is reset (using the rollback system described below) to the state of the game when the current statement began executing.

In some cases, this may not be desirable. For example, when a screen allows editing of a value, we may want to retain that value when the game is loaded. When renpy.retain_after_load is called, data will not be reverted when a game is saved and loaded before the end of the next checkpointed interaction.

Note that while data is not changed, control is reset to the start of the current statement. That statement will execute again, with the new data in place at the start of the statement.

For example:

screen edit_value:
        text "[value]"
        textbutton "+" action SetVariable("value", value + 1)
        textbutton "-" action SetVariable("value", value - 1)
        textbutton "+" action Return(True)

label start:
    $ value = 0
    $ renpy.retain_after_load()
    call screen edit_value
renpy.retain_after_load() link

Causes data modified between the current statement and the statement containing the next checkpoint to be retained when a load occurs.

Rollback link

Rollback allows the user to revert the game to an earlier state in much the same way as undo/redo systems that are available in most modern applications. While the system takes care of maintaining the visuals and game variables during rollback events, there are several things that should be considered while creating a game.

Supporting Rollback and Roll Forward link

Most Ren'Py statements automatically support rollback and roll forward. If you call ui.interact() directly, you'll need to add support for rollback and roll-forward yourself. This can be done using the following structure:

# This is None if we're not rolling back, or else the value that was
# passed to checkpoint last time if we're rolling forward.
roll_forward = renpy.roll_forward_info()

# Set up the screen here...

# Interact with the user.
rv = ui.interact(roll_forward=roll_forward)

# Store the result of the interaction.

It's important that your game does not interact with the user after renpy.checkpoint has been called. (If you do, the user may not be able to rollback.)

renpy.can_rollback() link

Returns true if we can rollback.

renpy.checkpoint(data=None) link

Makes the current statement a checkpoint that the user can rollback to. Once this function has been called, there should be no more interaction with the user in the current statement.

This will also clear the current screenshot used by saved games.

This data is returned by renpy.roll_forward_info() when the game is being rolled back.
renpy.get_identifier_checkpoints(identifier) link

Given a rollback_identifier from a HistoryEntry object, returns the number of checkpoints that need to be passed to renpy.rollback() to reach that identifier. Returns None of the identifier is not in the rollback history.

renpy.in_rollback() link

Returns true if the game has been rolled back.

renpy.roll_forward_info() link

When in rollback, returns the data that was supplied to renpy.checkpoint() the last time this statement executed. Outside of rollback, returns None.

renpy.rollback(force=False, checkpoints=1, defer=False, greedy=True, label=None, abnormal=True) link

Rolls the state of the game back to the last checkpoint.

If true, the rollback will occur in all circumstances. Otherwise, the rollback will only occur if rollback is enabled in the store, context, and config.
Ren'Py will roll back through this many calls to renpy.checkpoint. It will roll back as far as it can, subject to this condition.
If true, the call will be deferred until control returns to the main context.
If true, rollback will finish just after the previous checkpoint. If false, rollback finish just before the current checkpoint.
If not None, a label that is called when rollback completes.
If true, the default, script executed after the transition is run in an abnormal mode that skips transitions that would have otherwise occured. Abnormal mode ends when an interaction begins.
renpy.suspend_rollback(flag) link

Rollback will skip sections of the game where rollback has been suspended.

When flag is true, rollback is suspended. When false, rollback is resumed.

Blocking Rollback link


Blocking rollback is a user-unfriendly thing to do. If a user mistakenly clicks on an unintended choice, he or she will be unable to correct their mistake. Since rollback is equivalent to saving and loading, your users will be forced to save more often, breaking game engagement.

It is possible to disable rollback in part or in full. If rollback is not wanted at all, it can simply be turned off through the config.rollback_enabled option.

More common is a partial block of rollback. This can be achieved by the renpy.block_rollback() function. When called, it will instruct Ren'Py not to roll back before that point. For example:

label final_answer:
    "Is that your final answer?"

        jump no_return
        "We have ways of making you talk."
        "You should contemplate them."
        "I'll ask you one more time..."
        jump final_answer

label no_return:
    $ renpy.block_rollback()

    "So be it. There's no turning back now."

When the label no_return is reached, Ren'Py won't allow a rollback back to the menu.

Fixing Rollback link

Fixing rollback provides for an intermediate choice between unconstrained rollback and blocking rollback entirely. Rollback is allowed, but the user is not allowed to make changes to their decisions. Fixing rollback is done with the renpy.fix_rollback() function, as shown in the following example:

label final_answer:
    "Is that your final answer?"
        jump no_return
        "We have ways of making you talk."
        "You should contemplate them."
        "I'll ask you one more time..."
        jump final_answer

label no_return:
    $ renpy.fix_rollback()

    "So be it. There's no turning back now."

Now, after the fix_rollback function is called, it will still be possible for the user to roll back to the menu. However, it will not be possible to make a different choice.

There are some caveats to consider when designing a game for fix_rollback. Ren'Py will automatically take care of locking any data that is given to checkpoint(). However, due to the generic nature of Ren'Py, it is possible to write Python that bypasses this and changes things in ways that may have unpredictable results. It is up to the game designer to block rollback at problematic locations or write additional Python to deal with it.

The internal user interaction options for menus, renpy.input() and renpy.imagemap() are designed to fully work with fix_rollback.

Styling Fixed Rollback link

Because fix_rollback changes the functionality of menus and imagemaps, it is advisable to reflect this in the appearance. To do this, it is important to understand how the widget states of the menu buttons are changed. There are two modes that can be selected through the config.fix_rollback_without_choice option.

The default option will set the chosen option to "selected", thereby activating the style properties with the "selected_" prefix. All other buttons will be made insensitive and show using the properties with the "insensitive_" prefix. Effectively this leaves the menu with a single selectable choice.

When the config.fix_rollback_without_choice option is set to False, all buttons are made insensitive. This means that the chosen option will use the "selected_insensitive_" prefix for the style properties while the other buttons use properties with the "insensitive_" prefix.

Fixed Rollback and Custom Screens link

When writing custom Python routines that must play nice with the fix_rollback system there are a few simple things to know. First of all the renpy.in_fixed_rollback() function can be used to determine whether the game is currently in fixed rollback state. Second, when in fixed rollback state, ui.interact() will always return the supplied roll_forward data regardless of what action was performed. This effectively means that when the ui.interact()/renpy.checkpoint() functions are used, most of the work is done.

To simplify the creation of custom screens, two actions are provided to help with the most common uses. The ui.ChoiceReturn() action returns the value when the button it is attached to is clicked. The ui.ChoiceJump() action can be used to jump to a script label. However, this action only works properly when the screen is called trough a call screen statement.


screen demo_imagemap:
        ground "imagemap_ground.jpg"
        hover "imagemap_hover.jpg"
        selected_idle "imagemap_selected_idle.jpg"
        selected_hover "imagemap_hover.jpg"

        hotspot (8, 200, 78, 78) action ui.ChoiceJump("swimming", "go_swimming", block_all=False)
        hotspot (204, 50, 78, 78) action ui.ChoiceJump("science", "go_science_club", block_all=False)
        hotspot (452, 79, 78, 78) action ui.ChoiceJump("art", "go_art_lessons", block_all=False)
        hotspot (602, 316, 78, 78) action uiChoiceJump("home", "go_home", block_all=False)


    roll_forward = renpy.roll_forward_info()
    if roll_forward not in ("Rock", "Paper", "Scissors"):
        roll_forward = None

    ui.imagebutton("rock.png", "rock_hover.png", selected_insensitive="rock_hover.png", clicked=ui.ChoiceReturn("rock", "Rock", block_all=True))
    ui.imagebutton("paper.png", "paper_hover.png", selected_insensitive="paper_hover.png", clicked=ui.ChoiceReturn("paper", "Paper", block_all=True))
    ui.imagebutton("scissors.png", "scissors_hover.png", selected_insensitive="scissors_hover.png", clicked=ui.ChoiceReturn("scissors", "Scissors", block_all=True))

    if renpy.in_fixed_rollback():

    choice = ui.interact(roll_forward=roll_forward)

$ renpy.fix_rollback()
m "[choice]!"

Rollback-blocking and -fixing Functions link

renpy.block_rollback() link

Prevents the game from rolling back to before the current statement.

renpy.fix_rollback() link

Prevents the user from changing decisions made before the current statement.

renpy.in_fixed_rollback() link

Returns true if rollback is currently occurring and the current context is before an executed renpy.fix_rollback() statement.

NoRollback link

class NoRollback link

Instances of classes inheriting from this class do not participate in rollback. Objects reachable through an instance of a NoRollback class only participate in rollback if they are reachable through other paths.

For example:

init python:

    class MyClass(NoRollback):
        def __init__(self):
            self.value = 0

label start:
    $ o = MyClass()


    $ o.value += 1

    "o.value is [o.value]. It will increase each time you rolllback and then click ahead."