Basis Doesn't Work on Wasm Target

[anlumo]

Bevy version

0.15.1

[Optional] Relevant system information

If you cannot get Bevy to build or run on your machine, please include:

• the Rust version you're using (you can get this by running cargo --version)

rustc 1.86.0-nightly (4a4309466 2025-02-02)

• the operating system or browser used, including its version
  • e.g. Windows 10, Ubuntu 18.04, iOS 14

Archlinux

What you did

Compile bevy with the feature basis-universal.

What went wrong

Works fine on native, but if I compile for the wasm32-unknown-unknown target, there are hundreds of error messages like this:

warning: basis-universal-sys@0.3.1: In file included from vendor/basis_universal/encoder/pvpngreader.cpp:14:
warning: basis-universal-sys@0.3.1: vendor/basis_universal/encoder/../transcoder/basisu.h:53:10: fatal error: 'stdlib.h' file not found
warning: basis-universal-sys@0.3.1:    53 | #include <stdlib.h>
warning: basis-universal-sys@0.3.1:       |          ^~~~~~~~~~
warning: basis-universal-sys@0.3.1: 1 error generated.
warning: basis-universal-sys@0.3.1: ToolExecError: Command LC_ALL="C" "clang++" "-O0" "-ffunction-sections" "-fdata-sections" "-fno-exceptions" "-g" "-fno-omit-frame-pointer" "--target=wasm32-unknown-unknown" "-Wall" "-Wextra" "-DBASISD_SUPPORT_KTX2_ZSTD=0" "-o" "/home/anlumo/Documents/dungeonfog/catalyst/target/wasm32-unknown-unknown/debug/build/basis-universal-sys-c1c2199e0df7ab26/out/dfe9b9f658ee268e-pvpngreader.o" "-c" "vendor/basis_universal/encoder/pvpngreader.cpp" with args clang++ did not execute successfully (status code exit status: 1).cargo:warning=In file included from vendor/basis_universal/encoder/jpgd.cpp:27:
warning: basis-universal-sys@0.3.1: vendor/basis_universal/encoder/jpgd.h:6:10: fatal error: 'stdlib.h' file not found
warning: basis-universal-sys@0.3.1:     6 | #include <stdlib.h>
warning: basis-universal-sys@0.3.1:       |          ^~~~~~~~~~
warning: basis-universal-sys@0.3.1: 1 error generated.
warning: basis-universal-sys@0.3.1: ToolExecError: Command LC_ALL="C" "clang++" "-O0" "-ffunction-sections" "-fdata-sections" "-fno-exceptions" "-g" "-fno-omit-frame-pointer" "--target=wasm32-unknown-unknown" "-Wall" "-Wextra" "-DBASISD_SUPPORT_KTX2_ZSTD=0" "-o" "/home/anlumo/Documents/dungeonfog/catalyst/target/wasm32-unknown-unknown/debug/build/basis-universal-sys-c1c2199e0df7ab26/out/dfe9b9f658ee268e-jpgd.o" "-c" "vendor/basis_universal/encoder/jpgd.cpp" with args clang++ did not execute successfully (status code exit status: 1).

Additional information

This is C++ code, that won't work on wasm due to incompatible ABIs. basis does have web support (I think by compiling the C++ code to wasm), but that needs special handling through the JavaScript library's interface.

I'm not sure if this is considered a bug or a feature request. It's a bug in that it's supposed to just work but doesn't, but fixing it will require a new implementation specifically for the web.