Decode_A8_ExpandsSingleByteToRgbaWithAlphaInAllChannels renamed to
Decode_A8_NonAdditive_ProducesWhitePlusAlpha with updated expectations
(R=G=B=255, A=val) matching the new default isAdditive:false WB semantics.
Decode_CustomLscapeAlpha_TreatedIdenticallyToA8 updated to the same
non-additive expectation (255,255,255,val).
New test Decode_A8_Additive_ReplicatesByteToAllChannels documents the
isAdditive:true path (R=G=B=A=val) used by TerrainAtlas alpha maps.
8 pre-existing failures unchanged. 883 pass.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Entities using 8-bit palette-indexed textures (PFID_P8), uncompressed 24-bit
RGB surfaces (PFID_R8G8B8), and 32-bit packed-BGR surfaces (PFID_X8R8G8B8)
were all rendering as solid magenta. PFID_P8 uses the same palette-lookup and
isClipMap (indices 0..7 → fully transparent) convention as the existing
INDEX16 decoder, reading one byte per pixel instead of two. PFID_R8G8B8 and
PFID_X8R8G8B8 decode on-disk B,G,R[,X] byte order to R,G,B,255 RGBA8 output
for OpenGL PixelFormat.Rgba upload; the X padding byte in X8R8G8B8 is
discarded rather than forwarded as alpha.
168 tests green (85 AcDream.Core.Tests + 83 AcDream.Core.Net.Tests), including
9 new SurfaceDecoder tests covering correct channel mapping, clipmap
transparency, truncated-data fallback, and palette-missing fallback for P8.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Loads AC's terrain blending alpha masks into a second GL_TEXTURE_2D_ARRAY
alongside the existing terrain atlas. The alpha atlas is built but not
yet sampled by any shader — that wiring lands in Phase 3c.4.
SurfaceDecoder additions:
- Handles PFID_A8 (generic single-byte-alpha) by replicating each
alpha byte into all four RGBA channels
- Same branch handles PFID_CUSTOM_LSCAPE_ALPHA (0xF4), AC's landscape-
specific alpha format — the bit layout is identical, just a different
format ID to distinguish the asset class in the dats. I only found
this by adding a diagnostic in the first iteration (initial attempt
returned Magenta for every alpha map because I only wired PFID_A8)
- 3 new tests: 2x2 A8 round-trip, short-source fallback, and a
CUSTOM_LSCAPE_ALPHA test verifying it's routed through the same path
TerrainAtlas additions:
- New GlAlphaTexture property plus CornerAlphaLayers / SideAlphaLayers
/ RoadAlphaLayers index lists so the coming BuildSurface port can
cite atlas layers by source category
- BuildAlphaAtlas walks TexMerge.CornerTerrainMaps, SideTerrainMaps,
RoadMaps and uploads each decoded mask as a layer in insertion
order; categories carry their atlas-layer index in the respective
list
- Fallback handling (single-layer white) when TexMerge is missing or
every map fails to decode
- Alpha atlas uses ClampToEdge wrap so repeating tile sampling at
mask boundaries doesn't produce seams
- Dispose() now cleans up both textures
On Holtburg's region the log prints:
TerrainAtlas: 33 terrain layers at 512x512
AlphaAtlas: 8 layers at 512x512 (corners=4, sides=1, roads=3)
Tests: 61/61 passing. No visual change expected this commit (shader
still ignores Data0..3 and the alpha sampler).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Three root causes found via systematic debugging after the user reported
that the dc60405 texture fix and 4763b97 height table fix had no visible
effect on Holtburg.
## Heightmap transpose (LandblockMesh.Build)
Phase 1's LandblockMesh.Build indexed block.Height as y*9+x but AC packs
per-vertex heights in x-major order (x*9+y, matching ACViewer's
LandblockStruct: Height[x * VertexDim + y]). The bug was invisible on
flat landblocks (Phase 1 smoke test) but left buildings buried by 10-13
world-Z units on Holtburg, because building Frame.Origin positions
reference the un-transposed ground truth.
Diagnostic evidence (before fix, Holtburg 0xA9B4FFFF):
entity 0x020000A5 at ( 84.6,126.0) entityZ= 66.03 terrainZ= 78.15 delta=-12.13
entity 0x02000118 at ( 74.2,139.9) entityZ= 66.03 terrainZ= 78.92 delta=-12.89
After fix: deltas are 0.03 to 2.18 — buildings now sit on the ground
with small positive offsets for foundations.
Regression test added: Build_HeightmapPackedAsXMajor_NotYMajor asserts
asymmetric heights land at the correct world positions.
## Solid-color surfaces with Translucency=1.0 (SurfaceDecoder.DecodeSolidColor)
The "bright pink doors and windows" the user saw were 11 Holtburg
surfaces with OrigTextureId==0 — these carry a ColorValue instead of
a texture chain. Phase 2a's TextureCache dropped them into the magenta
fallback. All 11 turned out to be Base1Solid|Translucent with
Translucency=1.00, meaning "fully transparent placeholder surface"
(debug ColorValue is gray/green/red/blue/black, never displayed).
DecodeSolidColor now takes a translucency parameter and multiplies
alpha by (1 - translucency), so Translucency=1.0 → alpha=0, and the
mesh shader's existing alpha discard (< 0.5) makes the pixel invisible.
TextureCache honors Surface.Type.HasFlag(Base1Solid) and passes
surface.Translucency through.
Regression tests added: DecodeSolidColor_Opaque_PreservesAlpha and
DecodeSolidColor_FullyTranslucent_AlphaGoesToZero.
## Clipmap alpha-key (DecodeIndex16)
AC convention (per ACViewer TextureCache.IndexToColor): on surfaces
marked Base1ClipMap, palette indices 0..7 are treated as fully
transparent regardless of their actual palette color. Without this,
low-index pixels on clipmap surfaces (typically doorway cutouts and
foliage) render as opaque using whatever sentinel color is at those
palette slots.
DecodeRenderSurface now takes an isClipMap parameter. TextureCache
passes Surface.Type.HasFlag(Base1ClipMap). DecodeIndex16 forces
rgba=(0,0,0,0) when isClipMap && idx < 8.
Regression test added: DecodeIndex16_ClipMap_ZerosAlphaForLowIndices.
## Notes
- dc60405's PFID_INDEX16 palette decoder remains correct — no change.
- 4763b97's LandHeightTable wiring remains correct — real-table lookup
still runs, it just happens to be linear at Holtburg's height range.
The fix is forward-compatible with mountains elsewhere.
- All three bugs were invisible to the original unit tests. The new
regression tests pin them down.
## State
- dotnet build: 0 warnings, 0 errors
- dotnet test: 42 passing (was 38 + 4 new)
- Runtime: 126 entities hydrated on Holtburg, no exceptions, no
magenta fallback (counter was 11, now 0 via diagnostic confirmation)
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
