AudioStreamPlayer.get_stream_playback() returns null

[blackears]

Godot version

v4.0.2.stable.official [7a0977c]

System information

Windows 10, Forward+

Issue description

Trying to get this project to run in Godot 4. I imported it and ran the conversion process to upgrade to Godot 4.

https://github.com/godotengine/godot-demo-projects/tree/3.5-9e68af3/audio/generator

When I try to run it, I get the error Attempt to call function 'get_frames_available' in base 'null instance' on a null instance.

Steps to reproduce

Run the attached project. When $Player.get_stream_playback() is called, it will return null which causes the rest of the demo to fail.

Minimal reproduction project

generator.zip

[KoBeWi]

You need to play the AudioStreamPlayer before getting the playback.

[blackears]

That worked.

[KoBeWi]

Reopening, because we should have it documented. I don't see it mentioned anywhere.

[blackears]

I'm also noticing AudioStreamPlayback's methods aren't documented.

[blackears]

Would you know why I'm able to access methods on AudioStreamPlayback like get_frames_available() and push_frame(), but not methods like seek() and get_playback_position()? None of these are listen in the documentation or the auto complete, but the first two can none the less be called.

I'm looking at audio_stream_generator.h in the source code to get an idea of what methods ought to be there.

[KoBeWi]

Methods beginning with _ are virtual. They are supposed to be overriden (to create custom playbacks), not called.
(they have virtual next to their name in the doc, you can hover it for more info)