re: the skewed draw is not the swoosh -- refuting the identification five

iterations of work were built on

I flagged last iteration that "draw 2 is the swoosh" was an inference I
had never checked. Checking it took one line, and it is wrong.

Converting the quads from NDC to screen space: quad A spans y -209 to
925, quad B spans y -292 to 1012. Both cover the full screen height and
run well off it. The swoosh, ptlogo_back2, rests at (71,126) and is a
234-pixel band at y 126 to 360. Draw 2 is not it.

A candidate offered as one: the two ptloop sweeps. pteff03a is 399x180
with element scale (100,800), so 399x1440, and pteff03 carries (100,600)
-- two long thin sprites, two quads, and the drawn vertex alphas 0xC3 and
0xB6 sit inside the 0x80 to 0xff ramp those records declare. Not
confirmed; no texture or position match was made.

If that is right it matters, and I have written it conditionally rather
than acting on it: our renderer parks those sweeps at their final
keyframe, both off screen, and draws nothing, while the game draws them
across the screen. That would mean the capture caught them mid-sweep
inside their t=150 to 600 window, and that the "groups hold" reading
needs re-examining for those two elements.

What this cost is worth stating plainly. Five iterations -- the additive
blend test, the pivot analysis, the vertex-colour capture -- were built
on an identification made by elimination on one screen and never checked
against the draw's own coordinates. The eliminations themselves stand,
because each was measured against the capture rather than against the
identification. The chain that pointed them at ptlogo_back2 did not.
METHOD takes the general form.
This commit is contained in:
Sylpheed RE agent
2026-08-28 22:21:42 +00:00
parent 5115b4894a
commit 130ad8d1b3
4 changed files with 53 additions and 1 deletions

View File

@@ -35,6 +35,10 @@ neighbourhood, not just the line.
## Screens, classes and RTTI
* "the rotated draw in the title's capture is the `Z` swoosh
(`ptlogo_back2*`)" → **mine, and refuted.** Its quads span y 209…925 and
292…1012 in screen space; the swoosh is a band at y 126…360.
[`ui-title-build-map.md`](ui-title-build-map.md)
* "the keyframe words at `+4`/`+8`/`+12` are always zero" → they are non-zero in
4.81 %, 4.56 % and 15.82 % of 72 287 blocks disc-wide, reading as **degrees**
(±180, ±90, 120). The original note was a sample artefact.