Module gmegabuf 

Thread-local persistent scratch buffer for MD2 gmegabuf / megabuf.

evalexpr Function closures can’t capture mutable state, so the backing array lives in a thread-local RefCell<Vec<f64>> cleared from MilkEvaluator::new() (via gmegabuf::reset). Reads at indices past the high-water mark return 0.0 (uninitialised); writes grow the vector lazily up to [MAX_SLOTS] so a loop(1024*1024, gmegabuf(i)=0) preset doesn’t allocate 8 MB up-front for evaluators that never touch the buffer.

Constants

BUFFER 🔒

MAX_SLOTS

MD2’s documented cap (1 048 576 slots = 8 MB at f64). Indices outside this range silently no-op so a malformed preset can’t OOM the eval.

Functions

read

Read slot idx (clamped to [0, MAX_SLOTS)); returns 0.0 if out of range or past the current high-water mark.

reset

Clear the buffer. Called by MilkEvaluator::new() so each evaluator starts with fresh state on the current thread. (Within a single thread, evaluators can stomp on each other’s buffer mid-frame; in practice each preset is loaded → eval’d → dropped sequentially.)

write

Write val to slot idx. Grows the buffer if needed; out-of-range indices are silently ignored.