You can still do your own stuff in PlayCanvas (write your own shaders, procedurally create geometry, etc etc). But there's extra stuff you get: physically based

You can still do your own stuff in PlayCanvas (write your own shaders, procedurally create geometry, etc etc). But there's extra stuff you get: physically based renderer, powerful chunk based shader system, point light shadows, entity-component system, and lots more besides. Definitely worth checking out. :) Sounds like you're not interested in higher level tools, but the PlayCanvas Editor is really cool too (that's on https://playcanvas.com https://playcanvas.com - and it's optional). It's essentially Unity in the browser.