well, not really. you load the data and pass it to the GPU. There's no real work to do on the CPU. I'm not saying it's trivial to write a viewer but to doesn't

well, not really. you load the data and pass it to the GPU. There's no real work to do on the CPU. I'm not saying it's trivial to write a viewer but to doesn't require performant code. I've written a GLTF viewer in JavaScript. You parse the JSON, pass the data to the GPU, apply shaders. It requires knowledge of how to render 3D and PBR but it's a day or 2 project to get working if you know the topic and no part of it requires any perf.