From b4d53b758d70858ff0aa0598c6d61e1543c7ae2a Mon Sep 17 00:00:00 2001 From: Sylpheed port agent Date: Wed, 2 Sep 2026 18:20:38 +0000 Subject: [PATCH] port: F6 unit a -- where the sweep IS when the plate arrives, and a window that settles two questions Answers the Decoder's direct question: the port positions the leaf from the LEAF's own clock, it does not draw the parent's pose and ignore the translation. Computed from the leaf translation: pteff03 enters the frame at t=61 and is mid-screen (x=305) when the plate reaches full alpha at t=236 -- visible and travelling for ~175 units before the plate. And screen_view.gd's own flagged limit -- 'a capture during t=100..238 would separate' leaf-wins from parent-ignored-because-it-draws-nothing -- is the SAME interval F6 is about. Applying the parent would hide the sweep until t=70 and dim it to t=100, which accounts for ~40 units of the earliness but not the other ~175. One capture in that window settles both questions. --- docs/port/f6-what-starts-the-sweep.md | 34 +++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) diff --git a/docs/port/f6-what-starts-the-sweep.md b/docs/port/f6-what-starts-the-sweep.md index c39109d7..f8d10e2e 100644 --- a/docs/port/f6-what-starts-the-sweep.md +++ b/docs/port/f6-what-starts-the-sweep.md @@ -57,6 +57,40 @@ with `pteff03` having already crossed the measured band and with the coarse resize washing a thin glow out. **The film neither adds to nor contradicts the declaration; the declaration is the evidence here.** +## Where the sweep actually is, computed from the leaf's own translation + +The port positions the leaf **from the leaf's own clock** — it does not draw the +parent's pose and ignore the translation. Sprite 399 wide on a 1280 screen: + +| t | 0 | **61** | 70 | 100 | 150 | **236** | 250 | +|---|---|---|---|---|---|---|---| +| `pteff03` x | −639 | **−395** | −359 | −239 | −39 | **305** | 361 | +| `pteff03a` x | 1721 | 1477 | 1436 | 1314 | 1111 | 762 | 705 | + +**`pteff03` enters the frame at t=61 and is mid-screen at t=305 when the plate +reaches full alpha at t=236** — visible and travelling for ~175 units ≈ 2.9 s +before the plate. `pteff03a` enters much later. + +## 🔴 The open question in this file sits exactly inside F6's window + +`screen_view.gd` flags its own limit on the leaf-vs-parent alpha decode: + +> *"Every observation behind this has parent alpha 0, so 'the leaf wins' and 'the +> parent is ignored because it draws nothing' are NOT separated. **A capture +> during t=100…238 would separate them.**"* + +The parent is non-zero exactly on `t=100…238`, and the plate arrives at 236. So +that unresolved ambiguity is **the same interval F6 is about**, and it is +load-bearing for the first stretch: the parent ramps 70→100, so applying it would +hide the sweep until t=70 and dim it to t=100, while the port shows it at full +alpha from t=61. + +That accounts for ~40 units of the earliness. **It does not account for the other +~175**, which is the leaf clock starting at title t=0 with no offset. + +📌 **One capture in `t=100…238` would settle both** — F6's start time and the +leaf/parent alpha rule — rather than two. + ## What changes when the answer lands A start time is an **offset**, and `leaf_time_units` is an absolute override —