Struct AquiferColumnCache 

struct AquiferColumnCache {
    world_x: i32,
    world_z: i32,
    y_anchor: i32,
    cell_loc_y: [i32; 16],
    cell_xz_dist_sq: [i32; 16],
    cell_idx: [u32; 12],
}

Column-scan state for the 12 aquifer-neighborhood cells, stored SoA so the per-Y distance computation can be SIMD-batched as 3× i32x4.

compute_substance is called many times with the same (world_x, world_z) and decreasing world_y (innermost loop in noise_chunk::fill). Within a stable y_anchor window (Y_SPACING blocks tall) the 12 cells of the neighborhood don’t change, and dx*dx + dz*dz only depends on x/z — only dy = loc_y - world_y varies per call.

y_anchor = i32::MIN marks the cache as invalid (forces a refill).

Fields

world_x: i32

world_z: i32

y_anchor: i32

cell_loc_y: [i32; 16]

Per-cell unpacked Y of the aquifer-cell center (constant while cached). Padded to 16 entries so the 12 valid cells fit cleanly into 3× i32x4 SIMD batches; trailing slots stay at default 0.

cell_xz_dist_sq: [i32; 16]

Per-cell (dx + fx)² + (dz + fz)² (Y-independent component of distance).

cell_idx: [u32; 12]

Per-cell index into location_cache / status_cache.

Trait Implementations

impl Default for AquiferColumnCache

fn default() -> Self

Returns the “default value” for a type.