F6 is a clock question, not an effect question: the human confirms the light
animation itself looks like the game's and only starts earlier, and separately
that the port may be running it faster (flagged by them as an impression).
The port passed time_units straight to the leaf, which is an assumption -- offset
0, rate 1 -- that nobody measured and that the Decoder's capture contradicts:
the game's leaf t=0 is its first drawn frame, 40 frames after the title's first
element, at a rate measuring well below the title's.
ScreenView.leaf_clock(screen_units) applies an origin and a rate; both default to
-1.0 meaning unmeasured, in which case it is the identity and behaviour is
unchanged. Fed from authored/rendering.json leaf_clock per screen, currently null
with the provenance recorded.
No placeholder values, per F1: an invented constant here is indistinguishable
from a measured one later.
Verified inert: title rendered at t=2/3/4 s, 0 differing pixels against captures
taken before the change.
Also corrected in the process: my earlier 'the sweep enters the viewport at t=61'
used the UNROTATED sprite width. The leaf carries a 30 deg rest rotation, so its
AABB is 886 px against a 399 px sprite -- matching the Decoder's measured ~890 to
within 4 px. Port and game both put the quad on screen at leaf t~0, so the whole
discrepancy is the leaf clock's origin and rate.
4d533185e7