Add Ghosts

[emmenko]

Acceptance criteria

• Ghosts move like Pacman
• Ghosts are controlled by the game system and move in a semi-random fashion (e.g. if they are close to you they tend to follow your movements)
• Encountering a ghost will make you loose a life
• Player starts with 3 life, then it's game over

[feychou]

I'd like to give this a try, will report if failure ensues :robot: :ghost:

[emmenko]

Awesome ❤️

So good to see so many people interested in a post-hackathon project! 🙌

[ncthbrt]

@feychou Would recommend checking out a write up of ghost behaviour. It is more deterministic than you'd think. The different ghosts also have different "personalities"

[feychou]

@ncthbrt I know

[ncthbrt]

Fair enough :) Sorry if I'm being prescriptive. Just remember this stuff from our game dev module. Pac Man was one of our projects

[feychou]

No worries; I just thought of it as a given, to model the ghost behaviours according to the ones in the original game.

That's the reason why it could be wise to introduce one ghost at once, but that depends on how much the algorithm differs - which I am not sure about yet.

[feychou]

The acceptance criteria should probably reflect that too.

[emmenko]

Feel free to update the AC however you like, I just put there some points that I could think of.

[feychou]

Read up on the ghosts behaviour mostly here and I will summarize the takeaways.

There are three modes in the game that effect all ghosts more or less equally:

• scatter, when the ghosts are reaching for their own corner on the board (each of them has a designed one);
• chase, when ghosts try to catch Pacman;
• frightened, when the ghosts turn blue after an energising pill.

The algorithms by which the ghosts try to catch Pacman are very different; for instance Akabei just takes the next tile that will bring it closer to Pacman, but Aosuke takes into account also Akabei position to determine its next tile.

The ghosts all start from the same position, in an area of the game where just the inactive ghosts can be held - basically their house. Also in the original game the maze is strictly defined, which means the ghosts have to make decisions just at the intersections. Also important to notice, every small white dot slows Pacman down a bit and makes the ghosts faster in comparison.

This bears the question, do we want to make a clone of Pacman or something similar that kind of works? In any case, I think this issue can be broken down in smaller ones considering its complexity.

Implementing a ghost house that is not crossable by active agents could be one. Chase/Akabei combo implementation could be another and so forth.

[emmenko]

Thanks a lot for the write up Fede!

While it would be obviously nice to have a game resembling the original version as much as possible, given the complexity of those different pieces it would make sense to start with something more tangible to achieve.

So let‘s try to build the simplest behavior and improve upon it.

How would you like to proceed here? Do you want to break this down into smaller and more concrete tasks?

[feychou]

@emmenko Ok, then I'd propose we could first have one single ghost that starts in the middle of the boad and no ghost house. The ghost would always be in chase mode and behave like Akabei, that is, its target tile (coordinates) is always Pacman.

I would avoid having 4 ghosts behaving the same way at any point in time because that could make the game very stressful ^^

[emmenko]

Makes sense 👌

[emmenko]

Would you like to give this a shot?

[feychou]

Yup!

[feychou]

On Ubuntu 17, been trying to work around this problem on yarn build without success :disappointed:

[emmenko]

Hmm, is this happening on latest master? You did manage to run it before right? Did something change recently that is causing this? 🤔

[bsansouci]

@feychou This was just fixed in a reprocessing dep. Try nuking any lock file and installing again.