Godot Web Export in gdextension mode

[eefano]

Hello, this project is very interesting and intriguing, you're awesome!

I'd like to build a prototype chiptune player with Godot+Amy and I'd like to sync the feeding of the note events with the buffer filling routine.

In the native version I have already hooked a signal that fires a callback on every buffer refill and it works great on lnux, but it fails flat on web export version.

I think because web export does not use the AudioStreamGenerator node. So there's no way at the moment to sync the browser AudioWorklet with a gdscript callback function. Or is it possible?

Is there a particular reason why you went for a custom web module instead of building the gdextension with emscripten?
Like, building godot-cpp with scons platform=web , and compile the rest with emscripten compiler and linker?

Thank you

[eefano]

I have delved a bit into the sources and managed to build a working wasm gdextension without thread requirements and without the need of custom shell. I can provide a pull request if someone is interested.

It's a matter of substituting the preprocessor checks in the right places
from

#ifdef __EMSCRIPTEN__

to

#if defined(__EMSCRIPTEN__) && !defined(GDEXTENSION)

or a combination of those.

in order to build the wasm file i have done these steps (from the project root):

cd godot
export AMY_SRC_PATH=../src/
export GODOT_CPP_PATH=../../godot-cpp/
scons api_version=4.3 target=template_release platform=web threads=no

the resulting file is copied in the addon/amy/bin folder and modified amy.gdextension by adding:

web.debug.wasm32 = "res://addons/amy/bin/libamy.web.template_release.wasm32.nothreads.wasm"
web.release.wasm32 = "res://addons/amy/bin/libamy.web.template_release.wasm32.nothreads.wasm"

I have patched amy.gd in order to force native behavior:

func _ready() -> void:
	_is_web = false
...

During the export i have checked "Extension Support"

Exported from Godot Editor 4.6.3 stable in a Linux environment.
Tested on Linux Firefox and Chromium.

[eefano]

Adding on that, the sequencer is not supported in the "nothreads" version, but the events can be programmed later in time, and by leveraging Godot signals I can calculate the correct delay and send the events before the buffer gets filled (in a synchronous approach).

[bwhitman]

This is great, thanks. I'll check up on this in a week or so and try to make a patch with your changes and test. Thanks for the contribution!