Problem: pressing play on frames that still had to render left the playhead
standing still for seconds. The cache bar showed a gap of a few frames right
after the playhead while frames further ahead turned green, and playback
started only once the whole prefetch window was cached. The earlier #595
change (prefetch order, eviction) started the right frames first, but they
still finished last. Cache Frames When Idle left the same late-filling gaps.
Cause: prefetch frames render side by side on one rayon pool, and each
frame's own parallel loops run on that pool too. An idle thread steals a
piece of a frame that is rendering; when that piece waits on a nested
parallel loop, the thread picks up a queued frame job instead and renders
queued frames until the queue is empty. Only then does it return to the
piece it stole, so the frame that piece belongs to cannot finish while
frames keep being queued. The frames started first are the ones just ahead
of the playhead.
Fix: the frames of a playing preview and of Cache Frames When Idle render on
lanes: one single-thread pool per frame thread, one frame at a time each. A
lane's thread only ever works on its own frame, so no frame waits under
another. The shared pool keeps the viewer's frame, which still uses every
thread, and the few frames prefetched around it while paused. Queued frames
change hands when a preview starts or stops, or when the viewer shows one.
Idle caching takes every lane instead of half the pool's threads.
Tests: frames_started_first_are_done_first (a playing preview, idle
caching) and queued_frames_render_when_a_preview_starts_or_stops.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
The merge of main put craft_quit::on_close_request inside
EffectcraftApp::tick, so the control channel, autosave, screenshots and the
desktop host's file dialogs still ran after it in the same logic callback.
The tick keeps the unsaved-changes check; each desktop host's logic now calls
panels::unsaved::quit_on_close last, after the device-loss close as well.
bflatastic