pub fn solid_z_extent(mip0: &MipUpload) -> Option<(u32, u32)>Expand description
CA perf — a chunk’s SOLID voxel z-extent (inclusive, in-chunk
0..CHUNK_Z) from its mip-0 solid bitmap, or None for an
all-air chunk. Feeds the per-grid vox_z_lo/hi marcher clamp in
crate::scene::GridStaticMeta. One pass over the bitmap words
(columns are z-major, so a word’s z window is
(word % words_per_col) * 32).