The cube indices were deliberately clockwise, on the reasoning that the projection's Y negation reverses a triangle's orientation, so a counter-clockwise face in the world would arrive clockwise on screen and be culled. That misses the second flip: Vulkan maps NDC onto a framebuffer whose Y runs down, and `frontFace` is judged in framebuffer space. The two flips cancel, so counter-clockwise world winding was already the front face and only the inner faces of every cube and the plane were drawn.
The plane shares the cube mesh through `attach_cube_renderer`, so the same change fixes it.
`cube_mesh` now emits 0,1,2 and 0,2,3, the misleading winding comment is gone, and the `perspective` comment states why Y is negated. The winding test is renamed `the_cube_winds_counter_clockwise_seen_from_outside` and asserts outward-facing triangles.
`just test` passes all 63 tests.
Co-authored-by: Alic Szecsei <aszecsei@gmail.com>
Reviewed-on: #107
crowmaki
8e5e703fa9