Root cause: the LA8 character-select screen's root background RenderSurface
(0x06007576, LayoutDesc 0x21000004 element 0x1000039A) is PFID_CUSTOM_RAW_JPEG
— a complete JFIF byte stream (confirmed live: 414,230 bytes, FFD8...FFD9,
Width=0/Height=0 on disk) that SurfaceDecoder.DecodeRenderSurface had no case
for, so it fell through the switch's `_ => DecodedTexture.Magenta` default arm
with nothing logged. Retail's RenderSurface::CreateFromSourceData
(named-retail decomp @0x004440a0) hands this exact byte stream to the Intel
JPEG Library (`_ijlInit`/`_ijlRead`/`_ijlFree`) at runtime and reads the real
pixel dimensions from the JPEG's own SOF header rather than this
RenderSurface's Width/Height fields, which are legitimately 0 for this
format — the same reason the decoder's generic non-positive-Width/Height
guard was also wrong to apply here.
A per-id media sweep of the installed DAT (new EveryDeclaredMediaId_
ResolvesToADecodableTexture test) showed this was the ONLY unresolved id
among the screen's 25 distinct media ids — the listbox (0x1000039D) and every
button face resolve fine. The listbox interior and the ENTER button's
circular fill are both transparent regions layered on top of the root, so
the one broken root background bled through everywhere nothing opaque
covered it, producing all three symptoms (full-screen background, listbox
interior, ENTER circle) from one cause.
Fix: SurfaceDecoder now special-cases PFID_CUSTOM_RAW_JPEG before the
Width/Height guard and decodes it with StbImageSharp (dual Unlicense/MIT,
pure managed, no native dependency — works on the Linux headless/graphical
targets Slice K/L commit to). JPEG is ITU T.81-standardized, so any
conforming decoder reproduces the pixels IJL would; round-tripped a
synthetic fixture through the real decode path to confirm. Verified against
the live DAT: 0x06007576 now decodes to 800x600, exactly the screen's
LayoutDesc-authored size.
Guard: per claude-memory/feedback_ui_resolve_zero_magenta.md, an unresolved
id reaching the draw path should be loud. That memory's existing guard
("guard on the id, not the handle") only covers a DIFFERENT trap — a
zero/absent id — and could not have caught this one, which has a real,
non-zero, DAT-resolved id. No guard existed for "id resolves but can't
decode" or "id doesn't exist in either dat" before this change, so both were
silent. SurfaceDecoder now logs once per surface id on every magenta-return
path (null data, JPEG decode failure, unsupported format, no-palette
paletted format, decode exception); TextureCache.GetOrUploadRenderSurface
logs once per id when a RenderSurface isn't found in Portal or HighRes at
all.
Tests: CharacterManagementLiveDatTests.EveryDeclaredMediaId_
ResolvesToADecodableTexture (installed-DAT gate, ACDREAM_PROBE_LIVE_MOUNT=1)
sweeps every StateMedia id in the char-select root + listbox row template
and asserts none decode to the magenta placeholder — this class of gap now
fails the gate instead of shipping silently. SurfaceDecoderTests adds
PFID_CUSTOM_RAW_JPEG coverage (real decode via a synthetic from-scratch
JPEG fixture — not retail art, generated with StbImageWriteSharp and
round-tripped before being pasted in as a literal; corrupt-data and
null-SourceData magenta paths) plus PFID_P8/PFID_INDEX16 no-palette cases
that now flow through the same logged path.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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