Web build support

[Anut-py]

Set up h-raylib to work with emscripten and support building to WebAssembly.

[Anut-py]

This will be possible when the ghc WebAssembly backend adds support for JS FFI. Then the C code can be compiled with emscripten and the Haskell can be compiled to wasm.

[Ashe]

Do we know if GHC has made any progress on this? I feel like h-raylib could handle this this could become a really simple and universal method of getting into haskell gamedev. I feel like it'd be a huge challenge to get this working and I wouldn't know where to begin, but if you think it's possible then there's hope maybe? :)

[Anut-py]

Web building with GHC is still a somewhat complex process (this has the instructions. It seems a lot simpler than it was when I created this issue though).

What I had in mind for this was to compile the Raylib C code using emscripten (as described here), which would output JS equivalents to the raylib functions. Then the Haskell code would be compiled using GHC's web build support. The main problem is finding a way to link the two together (i.e. call the JS functions from Haskell). I found this article about it (the article is about Asterius, which has since been merged into GHC), so it should be possible.

[Anut-py]

Update: I was able to make a simple example using haskell to call JS functions. Once it's cleaned up a bit I'll create a repository for it.

[Anut-py]

Here's the proof-of-concept repository: https://github.com/Anut-py/ghc-web-test

As I said, the Haskell-to-WASM compilation process is a bit of a hassle, but it's relatively simple with Nix. Now that this is done I have to figure out how to call the raylib functions through WASM.

[Anut-py]

I integrated raylib into the repository above. I'll add this to h-raylib as soon as possible.

[Anut-py]

I have (in the web branch) added experimental web support and converted the basic-window example into a web-compatible example. Unfortunately, ghc's wasm backend does not yet support Template Haskell, which is required for the changes I made*, so we'll have to wait a bit. TH support for the wasm backend is being worked on, and you can track the progress here.

* The changes to support the web actually don't require TH; I made a TH function to make writing h-raylib/web programs easier, which is why Template Haskell support is necessary. See Raylib.Util.raylibApplication and the basic-window example for more (in the web branch, of course).

[realbogart]

First of all, you are doing great work here! I'm very excited about the possibility of running a Haskell/raylib game in the browser.

The changes to support the web actually don't require TH; I made a TH function to make writing h-raylib/web programs easier, which is why Template Haskell support is necessary. See Raylib.Util.raylibApplication and the basic-window example for more (in the web branch, of course).

Does this mean that it's possible to skip raylibApplication to get web working without template haskell? I'm eager to get the web support 😄

Thanks!

[Anut-py]

It’s been a while since I made that comment. At the moment, h-raylib uses a lot of template haskell internally, so I don’t think it is possible to get it to work. Afaik we’ll just have to wait for ghc wasm support for template haskell.

[Anut-py]

The ghc merge request looks like it will be merged soon