How to show different background for day/night cycles in Renpy

 Here is a quick explanation for how I keep track of day/night cycles in my Renpy games, including how to show different background images depending on the time and day.

Adding a DayTracker class

Here is the python code I use which creates a dayTracker class. This class is used to keep track of the day of the week and time of day. There are a few other functions in there too.

class dayTracker:

        _tod = 1

        _dow = 0

        _game_day = 0

        weekdays = (

            'Mon',

            'Tue',

            'Wed',

            'Thu',

            'Fri',

            'Sat',

            'Sun',

            )

        weekdays_long = (

            'Monday',

            'Tuesday',

            'Wednesday',

            'Thursday',

            'Friday',

            'Saturday',

            'Sunday',

            )

       

        def is_morning(self):

            return self._tod == 1

       

        def is_afternoon(self):

            return self._tod == 2

       

        def is_evening(self):

            return self._tod == 3

        def is_night(self):

            return self._tod == 4

        def is_dark(self):

            return self._tod >= 3

        def set_tod(self,tod):

            self._tod = tod

        def set_dow(self,dow):

            self._dow = dow

       

        def image(self, name, layer = "master"):

            import re

            tmp = name

            if not re.search('\{}', name):

                name = name + '{}'

            if  not self.is_morning() and not self.is_afternoon():

                name = name.replace("_day", "")

                if self.is_evening():

                    tmp = name.format("_evening")

                    if renpy.exists("images/"+tmp):

                        return tmp

                else:

                    tmp = name.format("_night")

                    if renpy.exists("images/"+tmp):

                        return tmp

                if renpy.exists("images/"+tmp):

                        return tmp

                return name.format("_night")

            else:

                return name.format("")

       

        def is_weekend(self):

            return self._dow == 5 or self._dow ==6

       

        def dayOfWeek(self,full=False):

            if full:

                return self.weekdays_long[self._dow]

            else:

                return self.weekdays[self._dow]

       

        def gameDay(self):

            return self._game_day

       

        def tick(self,tod=None):

            if tod:

                self._tod = tod

            elif self._tod < 4:

                self._tod += 1

        
        def sleep(self):

            self._tod = 1

            self._dow = (self._dow +1) % 7

            self._game_day += 1

            renpy.force_autosave()

Time of day (tod) is split into 4 day parts (Morning = 1, Afternoon = 2, Evening = 3 , Night= 4)

To move time forward, I use dayTracker.tick(), which increments tod by 1 until it is night.

Once it is night, I use a dayTracker.sleep(), which resets the tod and increments the day of the week.

Setting a different background image for different day parts

First, set up your images correctly. I use the following naming conventions for my backgrounds.

Morning = IMAGENAME.jpg

Afternoon = IMAGENAME.jpg

Evening = IMAGENAME_evening.jpg

Night = IMAGENAME_night.jpg

Then I usage dayTracker.image() to handle updating the background image.

For example, let's say I have a background of a library called campus_library.jpg.

I'd also have campus_library_evening.jpg for the evening scene and campus_library_night.jpg for the night scene.

In Renpy, I'd write:

scene expression dayTracker.image("backgrounds/campus_library{}.jpg")

This will check the time of day, and then replace the {} with either _evening or _night, depending on the tod.

Hope this helps! Leave a comment if you have any issues.