Pretty much the same. Both Vulkan and WebGL can use GLSL directly (well, GLSL -> SPIR-V for Vulkan). WebGPU technically can't if you run it in a browser, but native WebGPU implementations can take GLSL, you can transpile, and finally you could just write WGSL as it's basically the same as GLSL, just with more Rust-inspired syntax rather than C-inspired.