pushfoo / py_game_coroutines

game_coro

Framework-agnostic coroutines for games in Python.

Features:

• Write logic as a python generator, then tick it every frame.
• Use yield to pause till the next frame
• Pause for a given number of frames or seconds by using helpers

Usage

Warning: This library is currently experimental!

There are no tests and limited few docs. For usage, check out example/example.py. You can run it by doing the following:

1. Clone this repository
2. cd py_game_coroutines
3. pip install -e .
4. pip install arcade==3.0.0dev23 to install the 3.0 development preview of the Arcade library
5. python -m example.example to run the example

Design, Behavior

Note: this section is still somewhat unorganized. Treat it as unfinished notes!

Coroutines should not expect raised exceptions to be swallowed.
Just like any other call, exceptions will crash the game.

Coroutines can wrap themselves in try-finally to implement cleanup logic.

Coroutines should use yield from to delegate to another generator function.

When a coroutine is stopped, generator .close() is called. This follows standard python rules, where a GeneratorExit is raised within the generator.

When coroutine A yields to coroutine B, the return value of B is passed to A. Any raised exception from B is raised in A. Just like a normal call stack.

When implementing a state machine, back-and-forth yield from other_state() will eventually fill up the call stack, crashing the game. Instead, return other_state(). return will close the current generator function, and the coroutine manager will detect that you've returned another generator and start iterating it. This only works when returning from your top-level generator. If in a nested generator call, use trampoline(): yield from trampoline(other_state())

Tips and Tricks

return (yield from self.other())

Allows self.other() to return a value, which will be returned through Can trampoline from it.