flappy bevy example

[af-games]

Objective

• Include a fun new example game

Solution

• Built flappy bird clone where there are many birds. Aimed for idiomatic and minimal code.

[alice-i-cecile]

I don't think that Chaos, Gravity or DriftToCenter components have value; the behavior can be configured based on adding and removing the systems.

[bjorn3]

You can't remove systems from a schedule, right? At most have a run criterion to disable them. Also these components are not global, but specific to the properties of specific entities it seems, so globally adding or removing systems wouldn't work.

[af-games]

These systems could all operate on Bird. I've been using a Component for each distinct behavior if possible for clarity.

[alice-i-cecile]

Yep, the main thing here is that when designing which components I use, I try and think about this in terms of future extensibility.

I think that Gravity is plausible to extend, but the others probably aren't? That said, I think there's an argument for keeping this as minimal as possible to improve the clarity as a learning example.

[af-games]

I would argue for keeping these micro-components separate as they can be copy-pasted into new users' projects.

[alice-i-cecile]

#2504 would help make this example much cleaner.

[alice-i-cecile]

My opinion is that this example is appealing and valuable: it more clearly demonstrates some of the fundamental notions of ECS (operating on groups of entities) than the Breakout example. I'd like to include this, and later work towards a more scalable example presentation schema than large nested folders.

[af-games]

Is there anything else I need to do to move this along?

[alice-i-cecile]

This just needs another couple of reviews :) I want more discussion and feedback on whether we should add this as another game example, but I'm happy with the code itself now.

The main drawback is that this is more code to maintain, and doesn't necessarily showcase new concepts. My personal opinion is that it's worth it on the balance, but we still need a better solution to manage the growing collection of examples.

If you want to be proactive about it, starting a thread on Discord about this PR is the best way to stimulate that sort of discussion IME.

[mockersf]

this game could use a "restart" or "you lost" screen. as is, if you start the example and don't do anything, the birds fall down and out of the screen and you end up not being able to do anything but quitting

[af-games]

this game could use a "restart" or "you lost" screen. as is, if you start the example and don't do anything, the birds fall down and out of the screen and you end up not being able to do anything but quitting

I have some ideas to make the game more player-friendly, but I've implemented none of them in a bid to keep the example minimal.

1. Auto flap: a system periodically flaps until space is pressed, at which point the auto flap system is disabled. A good implementation of this would decouple the input from the flap using an event which is also sent by auto flap.
2. Respawn: when the last bird dies, spawn another after a short time.
3. Explainer text: large text top center saying 'PRESS SPACE TO FLAP' until space is pressed

1 & 2 are implemented in the following commit, which also fixes the 'birds falling out of the sky' issue by putting the flap system in PostUpdate. It increases the length of the example from 280 to 380 lines. Is it worth it?

[alice-i-cecile]

From a pure game design perspective, I like 2 but not 1. Player agency is good! I don't think 3 is needed.

Overall I would prefer restarting the game using states and a Game Over screen rather than startup systems. It demonstrates how to handle this pattern much more realistically, and is worth the added length.

[bas-ie]

Backlog cleanup: had a crack at this one myself! But see linked PR for discussion, probably consign this to history with thanks to the original contributor.