[flohofwoe]

WebGL is slower than native mainly because of the additional security-validations compared to a native GL driver, e.g. it cannot simply forward calls into the underlying 3D-API but instead WebGL needs to take everything apart, look at each single piece to make sure it's correct, reassamble everything and then call the underlying 3D-API (roughly speaking).

The calling overhead between WASM and JS is quite negligable compared to that (at least since around 2018: https://hacks.mozilla.org/2018/10/calls-between-javascript-a...).

Another problem is that WebGL relies on garbage collected Javascript objects, but this problem can't really be solved on the WASM side, even with the "anyref" proposal (this would just allow to remove the mapping layer between integer ids and Javascript objects that's currently needed).