Hm, does this count? https://github.com/DusteDdk/bounceball/blob/master/main.cpp

Kinda. SDL_renderer is a level on top of the raw GPU API, which is what WebGPU is targeted at. Feel free to use Canvas2DRenderingContext or any other rendering libraries (e.g. Phaser, Pixi.js) to achieve a similar line count to what you're seeing with SDL_renderer.

Also, you might struggle to implement glTF and PBR materials with the same line count with SDL_renderer.

no, no rendering code is shown. The code is calling into some class called Ball whuch itself is using a library. if you're going to rely on a library then there are plenty of js libraries that will abstract to few lines or you could even use canvas 2d