The goal is to start storing multiple meshes in the same vertex buffer/index buffer. (I already have a decent chunk of this code written in a branch.) This reduces binding overhead, but moreover it allows us to start using multidraw indirect where supported, which should reduce drawcall counts dramatically. I measured a 97% drawcall count reduction for the opaque pass on the Bistro test scene, for example. The benefits are even higher for shadow maps, because they use a single shader and so the drawcall count should drop to the single digits in most cases.

I've said it before, but if drawcall count is a problem in your game, you should complain to the engine vendor. On modern GPUs, there's no reason people should be manually optimizing for drawcall count in 2024. Game engines have the tools to make it a non-issue; they just need to use them.