prec_put / prec_get / prec_size (Physics' spec): PREC_FULL, 12 bytes, for trees, boulders and stones
(u16 x, z in 1/65536 of the chunk; u16 y in cm above y_base; u8 scale over the kind's lo..hi, yaw, seed,
wind), and PREC_PACKED, 7 bytes, for the stream kinds (56 bits, least significant first: x 12, z 12,
y 12 in cm, scale 6, yaw 6, seed 4, wind 4). An encode takes the cell a value falls in, a decode its
centre, so a round trip is stable; a record is read from a []byte at an offset, never a pointer.
stream_emit_baked and layer_chunk_put take (recs, at, fmt) and decode through it; the earlier sb7_*
pair is gone.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
sb7_pack / sb7_field are the one pack and unpack of the stream kinds' record (56 bits, least significant
first: x 12, z 12, y 12 over the chunk's y span, scale 6, yaw 6, seed 4, wind 4, read as a low and a high
word), which the bake and the game both import; stream_emit_baked decodes a prefix of it.
layer_chunks_begin / layer_chunk_put / layer_chunk_drop keep a fixed layer (trees, boulders, stones:
12-byte records) as a slab per resident chunk in its instance list, an n x n index made at load, the
list re-uploaded at most once a frame. Nothing calls them yet: behaviour unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
