- Navigation now operates on spread indices, not the non-contiguous page-position
scheme that mapped a forward step onto the same spread (so forward stalled and
triggered a no-op multi-flip). Forward/back move one spread; start/end and the
slider use spread indices. The page readout shows the odd page of the visible
pair (2*spread+1) or 0 at the title spread.
- Flipping forward could show the source page with its last word still masked: a
stale reveal mask left on the flip surface by a previous playback flip was not
cleared when the (finished) source page had no active reveal. Reset the flip
surface reveal shader in that case so the full page shows during the turn.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Establish book-playback-timeline as the sole playback owner driving the
scene through formal webgl-book:* events (not the BookLabDebug surface),
with a single reveal clock in the scene render loop and webgl-page-cache as
the only texture cache. Remove the legacy dual playback path and the
ownsPageFlipCommit gating.
Fixes:
- Flip page detached/folded at the spine: restore the raw page-cap line for
flip geometry (matches the prototype/pre-regression), removing
normalizeFlipLineToVisiblePage which moved the pivot off the spine arc.
- Flip textures: distance-based UVs (no horizontal compression),
direction-aware face material (source on the camera-facing side), source
meta derived from the visible spread (manual flips), prewarm shape fix.
- Reveal: flash removed on the static page and the flip back surface;
spanning blocks rebuild the reveal plan at activate and continue the
reveal on the next spread after the fill flip.
- Cache staleness is contentVersion-primary; nav clamps to spreadCount.
Docs updated to describe the intended single-owner architecture. Regression
checks updated to match.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Georg