Reze Engine: A Hand-Rolled WebGPU Renderer for MMD Characters

If you've fallen down the MMD rabbit hole, you know the aesthetic: anime characters with ink-crisp outlines, milky rim light, hair that whips around with too much enthusiasm. Reze Engine drops that whole look into the browser through WebGPU. Hand it a .pmx model and a .vmd motion clip, and a shaded, IK-solved character drops into your canvas with Bullet running her joints. Double-click and the GPU picks the bone you're hovering.

What makes it worth a closer look is what's not in the dependency tree. It's a hand-rolled TypeScript renderer with exactly one runtime dependency (Ammo.js, for the physics). Every other layer is Amyang's own: Blinn-Phong, rim lighting, MSAA 4x, PCF shadow mapping, the outline pass, even a VMD round-trip serializer that re-encodes bone names back to Shift-JIS so the output still loads in MMD desktop tools from 2008. There's also a long-form tutorial that starts at Hello Triangle and ends at a rigged, dancing character. It's one of the cleaner ways to read WebGPU without a framework's fingerprints all over it.

reze.one itself is a quiet one-liner pointing at the repo, so don't stop there. Reze Studio for browser-native animation curve editing, MiKaPo for webcam motion capture, and PoPo, which lets an LLM pose your model in a custom DSL. Worth a follow.