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Same capture, counts only. Title's first drawn element is frame 706; the sweep is first submitted at 746 and first ON SCREEN at 747, so +41 frames. For scale, the plate's declared t=236 is frame ~942 at 1 unit/present -- 195 frames after the sweep is already visible geometrically. Named rather than folded in: that comparison assumes the title's first drawn frame is its t=0 and that its clock runs at 1 unit/present. The 41 is a raw frame count and carries neither. What it settles: POSITION does not gate the sweep late. So if a human sees it start when the plate appears, the gate cannot be where the quad is -- it has to be how opaque it is. That puts the whole of F6 on unit 2, which is amber: does the parent's alpha multiply into the leaf? The parent ramps 0->255 across t=70..100, so if it multiplies the sweep is invisible until ~70 and dim to 100 (a real early gate); if it does not, the sweep is fully lit from +41 frames and the human's report has no mechanism yet. The disagreement has narrowed usefully: before this unit "starts when the plate appears" had two candidate mechanisms, position or alpha. Position is now excluded by measurement. Refutes my own unit 1 framing. I wrote that a quad can be "fully opaque and entirely off-screen" and offered the travel as the likely explanation. It is not -- the sweep is on screen at +41 frames, nowhere near the plate. The travel explanation is dead, and I record it because I proposed it and it steered the port's reading of their own renderer. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Jc4pciRArGHfxGGhEbwp5t
72 lines
3.1 KiB
Markdown
72 lines
3.1 KiB
Markdown
# F6 unit 4 — the sweep is **on screen 41 frames after the title starts**, long before the plate
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**Status: ✅ measured ⟨capture⟩ ×1.** 2026-09-02.
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**Question:** how many frames after the title starts drawing does the sweep first
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appear on screen?
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**Look at:** the frame its leading edge crosses into the viewport, minus the frame
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the title's first element draws.
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**Not covered:** alpha gating (unit 2, 🟡); the title's own clock origin.
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---
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## The measurement
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Same capture as units 2 and 3. Counts only — no clock conversion.
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```
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title's first drawn element frame 706
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sweep first SUBMITTED frame 746 (+40 frames)
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sweep first ON SCREEN frame 747 (+41 frames) NDC x span [−2.380, −0.990]
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```
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> **The sweep's leading edge is inside the viewport 41 frames after the title
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> begins drawing.**
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**For scale:** the plate reaches full alpha at declared `t = 236`. At the
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1 unit/present the splash work established, that is frame ≈ 942 — **195 frames
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after the sweep is already on screen.**
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⚠️ **That last comparison carries two assumptions and I am naming them rather
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than folding them in:** that the title's first drawn frame is its `t = 0`, and
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that its clock runs at 1 unit/present. The **41** is a raw frame count and carries
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neither.
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## 🔴 What this settles, and what it hands to unit 2
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**Position does not gate the sweep late.** It is geometrically visible from very
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early in the title, not at the plate. So if a human sees it start when the plate
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appears, **the gate cannot be where the quad is** — it has to be how opaque it is.
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That puts the whole of F6 on **unit 2**, which is 🟡: does the parent's alpha
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multiply into the leaf? The parent ramps `0→255` across `t = 70→100`, so:
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| if parent alpha multiplies in | the sweep is invisible until ≈ t 70 and dim to 100 — **a real early gate** |
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|---|---|
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| **if it does not** | the sweep is fully lit from the moment it enters at +41 frames — **and the human's report has no mechanism yet** |
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**Neither is established.** Unit 2's evidence was 14 sub-floor samples of 1754 and
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was rightly downgraded.
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📌 **But note the shape of the disagreement has narrowed usefully.** Before this
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unit, "starts when the plate appears" had two candidate mechanisms — position or
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alpha. Position is now excluded by measurement. One candidate left, and it is the
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one already under test.
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## Refutation attempt
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**Target:** my own unit 1 framing, that the human might be watching the leaf
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travel on screen rather than an alpha gate.
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**Result: REFUTED.** I wrote that a quad can be *"fully opaque and entirely
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off-screen"* and offered that as the likely explanation. It is not: the sweep is
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on screen at +41 frames, nowhere near the plate. **The travel explanation is
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dead**, and I am recording it because I proposed it two units ago and it steered
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the port's reading of their own renderer.
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## Reach
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⟨capture⟩ ×1, one boot, `pteff03` only. The `+41` is a frame count between two
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events in one stream and needs no clock. The comparison to the plate does need
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one, and is labelled. `pteff03a` does not appear in this capture.
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