What it does
Adds a render pass, not a renderer. Meshes, a perspective camera and a software rasteriser draw into the same framebuffer the 2D pass uses, so a scene can put a spinning model behind a sprite HUD without a second pipeline or a second buffer.
Geometry comes in as .obj. The maths is float throughout, like the rest of
the engine, which is why a board without a hardware FPU will run this but not
enjoy it.