What is missing is a way for one's wasm code to make WebGL or 2D canvas calls (or even write directly into a bitmap canvas), without writing a bunch of Javascri

What is missing is a way for one's wasm code to make WebGL or 2D canvas calls (or even write directly into a bitmap canvas), without writing a bunch of Javascript trampoline / thunk / whatever code. If I'm mistaken, a pointer to some C / C++ / Rust code that compiles down to wasm that actually touches a canvas that's being displayed in the browser would be most appreciated.