formats: apply the keyframe fade alpha, and fix the resting rule it exposed

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blit modulated by tint only, which is 0xffffffff on essentially every keyframe,
so the fade word was decoded, stored and then discarded. Applying it as an ARGB
modulate takes the title composite's edge correlation against the framebuffer
capture of the running game from 0.4597 to 0.9538, both at zero shift. The white
wordmark with its blue outline, the trademark, the copyright and the orange
exploding planet all appear -- the planet because a full-screen blue effect that
rests at alpha 0 had been painting over it at full opacity.

ARGB is measured: across a fade-in the high byte walks 0x00 -> 0x80 -> 0xc0 ->
0xe0 -> 0xff while the low three stay ffffff, and the low 24 bits are 0xffffff on
5276 of the disc's 5453 resting keyframes.

A modulate can only remove pixels, so the risk is a blank screen. Measured: no-op
on 4060 of 5200 sprite elements, partial on 453, hides 687 -- transient HUD
indicators that should not be lit at rest -- and NO build is left with nothing
visible. A disc test asserts that, and that the no-op share stays high, which
also guards the resting rule against drifting onto ramp frames.

Both changes are in one commit because the second is invisible without the first.
Applying fade erased the word PAUSE, which the running-game capture plainly
shows: pgptitle.rat has three runs of two identical keyframes -- pre-roll, hold,
exit -- and the 'later run wins' tie-break grabbed the exit. A group carries the
screen's entry animation AND its exit, so a run ending on the last keyframe is
now excluded unless it is the only one. The title correlation is unchanged.

...

This commit is contained in:

Sylpheed RE agent

2026-08-19 06:56:38 +00:00

parent 2d2c281805

commit 7fbdcc078c

5 changed files with 157 additions and 16 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

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