But let's cover the generic basics...
This post is intended to be a narrative to explain the links I've provided. Your answer is going to come from following the links and reading the information there.
How to track achievements
Achievements are usually implemented by the game tracking something happening once within game.
One common way is to track if a specific image has been shown to the player. If the player does the right things, then the image is shown, perhaps a popup "woohoo" is shown and the achievements gallery checks to see if the picture has been flagged by RenPy as being shown to the player.
You do this checking
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. RenPy tracks all images shown while the game is playing, so it's a good way of tracking achievements. The check is "persistent" - that is, it is not dependent on save files or an individual playthrough. If you replay a game with multiple paths/routes, each images seen during playthrough #1 are still unlocked while playing through playthrough #3. Which makes it a good solution for achievements, that tend to be game wide.
An alternative is
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. But this is much less common. Same idea, but using the name of
label: statements rather than the name of images.
Other developers choose to not to let RenPy do the heavy lifting and instead track things themselves. Again, RenPy has a persistent solution, in this case imaginatively called
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. You may or may not already be aware that "normal" variables within your game are kept within a data store called
store. It's usually invisible to you, but effectively RenPy doesn't save individual variables - instead just dumps the whole
store to your save files. Another data store is called
persistent. If you prefix your variable name with
persistent, then it will be stored there. Persistent variables like the "seen" data is independent of the current playthrough.
So you could have a line like
$ persistent.ach01_unlocked = True to set the achievement #1 and
if persistent.ach01_unlocked == True: as part of your gallery code to see if the achievement gallery can be shown or not.
RenPy even has an
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. Though honestly, I don't ever recall seeing it used. It is just a more structured way of using persistent data.
Showing a popup
I've done this, but can't find an example bit of code quickly while writing this.
The basics are that you show an image using some sort of
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or
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. Ideally with an accompanying
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at the same time. The animation could be as complex as you like or as simple. The most common solution I see is an image which is displayed in one of the corners of the screen for a few seconds before fading out. Though you could get more creative and have an image appear, then both scroll up off the screen while at the same time fading out or shrinking in size. Or anything else you can imagine.
The achievement gallery
The usual solution is to create a
You must be registered to see the links
which shows images. Though more complex versions can also make use of RenPy's
You must be registered to see the links
system to replay sections of your code/game.
Again, RenPy has a
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that some developers use and others avoid like the plague.
Another solution is a variation on
this gallery system.
... and may other variations on a theme.
"Borrow someone else's code"
By far the best way to implement this, if you are struggling, is to "borrow" someone else's code.
Pick a game (or ideally a couple of games) where you've seen achievement systems used and take a look how they did it. Cherry pick the best bits that suit your game and leave the rest behind.
Keep in mind that most AVN developers are not experts - their code is going to be badly written or very rarely, buggy. Don't just copy stuff wholesale - otherwise you won't understand how it to fix it if something goes wrong.
The starting point though is likely to be
UnRen. A tool which unpacks RenPy archives and rebuilds the source code files if they omitted from the game's distribution. Not all games need UnRen to see the
*.rpy source code files, but a lot do. Very rarely, you'll only be able to find
.rpyc files and not their source code. UnRen can rebuild the
.rpy files based on the data stored in the
.rpyc files.
Keep it simple
Finally, a note of caution.
A lot of new developers think they need to add complex solutions to their game in order to keep up with the more established games. They've seen something done in another game, liked it... and so what to do the same in their own game. Except... programming these solutions is complex and often very hard work for an inexperienced developer. The usual suspects are "an inventory system", "a gallery", "an open world game" and "
achievements". Theses are all "nice to have" within games, but not essential. If you never told your potential players that you were thinking of adding an achievement system - nobody would ever miss it.
Sometimes it's better to finished a simple game than abandon development of a more complex game.
Or put another way... players tend to play for the tits, ass and story. Achievement systems aren't even on their radar. Think about
keeping it simple.
