ac1371cda3
The sweep starts early because ScreenView drew a leaf WITHOUT multiplying its
parent's alpha in. ptloop01/ptloop02 declare 0:0 70:0 100:255 238:255 250:0, so
the sweep is invisible until t=70 and full at t=100. The port has had that ramp
in its export the whole time and was throwing it away at the draw call.
Three changes:
1. Parent alpha multiplies into the leaf's. This file asserted the opposite,
arguing from the sweeps being drawn while their parent had expired -- but that
could not separate 'the leaf wins' from 'the parent is ignored because it
draws nothing', and its own comment said so and named the interval that would
settle it. Measured there: dividing the leaf's declared curve out of the drawn
alpha pins the implied parent at 255.0 (+/-1.5) over hundreds of frames while
the drawn alpha swings 242 -> 132 -> 145.
2. rate 0.5, calibrated against a DECLARED interval (ptloop01's own 30-unit ramp)
rather than captured frames: two runs differing 2x in frames give 0.4795 and
0.4667, 2.7% apart. This number was 0.514, withdrawn, now reinstated at 0.5 --
what failed the first time was quoting a rate in presents, and the ratio was
discarded along with the frames.
3. The 107-unit authored offset is DELETED, with its guard tool. It came from a
ratio measured against an element identified only by screen position; the
declared ramp needs no such identification. Deleting an authored value because
the data already says it is the outcome PORT-MISSION asks for.
Also reverted, same day I made it: removing the transparent-parent skip. I read
'the game submits the sweep ~950 frames past its parent's expiry' as the leaf
outliving the parent. It does not follow -- a draw submitted at alpha 0 is still
a draw, and submitted is not visible. With the multiply, skipping on a
transparent parent IS multiplying by zero.
VERIFIED, pre-registered before running, via --probe-leaf:
u= 60 -> no draw at all (predicted: parent alpha 0.00, gated off)
u=100 -> leaf_t 50.0, x -439 (predicted 50.0, -439)
u=236 -> leaf_t 118.0, x -167 (predicted 118.0, -167)
verify-capture: every row unchanged.
⚠️ BUILD-SENSITIVE: builds 5 and 6 of GP_TITLE declare these records as a single
flat a=255 with no ramp. This export reads the ramped build; if that changes the
gate disappears silently.
Authored decisions
Everything here is a decision we made, not something the disc said. It is
hand-written, committed, and survives a re-export — unlike export/, which is
regenerated wholesale and must never be hand-edited.
Every entry carries a why. When the RE agent decodes the real answer, delete
the entry and let the exporter emit it; that deletion is the measure of
progress.
See docs/FORMAT.md for the schemas and docs/BLOCKED.md for which HANDOFF
question each placeholder is standing in for.