HTML5/web export

[nii236]

I’ve been avoiding using this library as I wait for HTML5 export support.

The readme states there there are “ideas” on how to achieve this but I can not find what these ideas are, how feasible it is, when these ideas can be tested, where they’re being discussed etc.

For now I’ve gone ahead with implementing game state in Go and will push it through to vanilla Godot via websockets, but would be keen to get an idea on the above.

[Splizard]

The idea is use a wasm build and bridge to Godot via some sort of Javascript layer. Unfortunately there aren't any official Javascript interfaces for GDextension, so this would need to be be developed.

I've been looking at https://github.com/godotjs/Javascript, which could be a path towards this, however it's not based on GDextension, so this doesn't look to be very straightforward.

The last time I investigated this, Emscripten had some limitations that meant it wasn't possible to access Javascript from a side module. Which I initially hoped could be a good was to expose the GDExtension API to the browser. Well I've just checked and it doesn't look like the issue has had any movement emscripten-core/emscripten#21491

The other option would be to try to develop the Javascript interface into Godot itself. If I had something to start from, I could probably chip away at it but I'm not familiar enough with Emscripten with C++ to set this up properly. Hence getting something merged into Godot would probably take some time.

[Splizard]

I've had another investigation on this, I've got an initial bootstrap of the GDExtension API in Javascript, I will continue on this path and see if I can make some progress here, I'm not confident that this would get merged by Godot so we will probably maintain our own web export template for graphics.gd.

[nii236]

Woah, appreciate you getting back to me on it. Keen to read more as you progress.

Anything I can do to help? I'm primarily a Go developer only.

[Splizard]

Notes

I've forked Godot with the changes needed to start exposing GDExtension via Javascript.
https://github.com/grow-graphics/godot

The web export template can be built with scons platform=web target=template_debug

When this is all ready and working, this export template will need to be hosted somewhere and periodically rebuilt so the gd command can download it as needed. In the meantime, it has to be configured in the editor export settings.

I've also pushed the graphics.gd changes in 998e42d, if you GOOS=js GOACH=wasm gd run a project, the gd command will build the export project, place it inside of graphics/.godot/public and serve it on port 8080.

The Go wasm will load before Godot and register an initialization function at window.GDExtension["res://library.gdextension"], the Godot fork will load everything under window.GDExtension when it starts up. After this point, it is much like the C version of gdextension except we call into javascript functions defined in the patched version of Godot. They are quite low level and designed to expose the low level wasm memory directly without allocations.

https://github.com/grow-graphics/godot/blob/master/platform/web/gdextension_web.cpp

This file is incomplete, the GDExtension API is so large, so it's rather grueling to go through and wrap each function, I will need to come back to this. Then there is the same thing in reverse on the graphics.gd side, I've only added a single function for now.

https://github.com/grow-graphics/gd/blob/master/startup/startup_js.go

There are some changes required to make sure graphics.gd is 32bit compatible, as the project currently relies on the internal 64bit memory representation for Godot variants. Some of the pointer types will also need to be adjusted for 32bit.

Anyhow the good news is at least there is a bit of a bootstrap here that can be iterated upon. Much of the annoying setup to get things connected and starting up together is at least in place.

[Splizard]

Might be worth trying some code gen here.