Imaging: implement TGA and DDS compatibility #39

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hugo · 2026-08-08T08:17:25Z

hugo commented

2026-08-08 08:17:25 +00:00

Objective

Implement TGA behavior and the Pfim-equivalent DDS/TGA paths using reviewed Rust crates or minimal native Rust parsing.

Deliverables

Preserve orientation, origin, pixel depth, channel order, alpha, RLE/uncompressed forms, and supported DDS container/format behavior.
Use golden image bytes and exact decoded pixel buffers.
Feature-gate optional format dependencies without leaking them.

Validation

All translated TGA/Pfim-related tests pass.
Malformed and oversized image fixtures return typed errors.
Round-trip output is deterministic where guaranteed.

Prerequisite

Types and StructuredData are implemented and the global API/test gates are complete.

Project constraints

Native Rust implementation only; optional third-party native codecs stay behind documented features.
Keep mapped signatures fixed and preserve translated geometry/pixel assertions exactly.
Enforce checked sizes and indices, then update docs and coverage status.

## Objective Implement TGA behavior and the Pfim-equivalent DDS/TGA paths using reviewed Rust crates or minimal native Rust parsing. ## Deliverables - Preserve orientation, origin, pixel depth, channel order, alpha, RLE/uncompressed forms, and supported DDS container/format behavior. - Use golden image bytes and exact decoded pixel buffers. - Feature-gate optional format dependencies without leaking them. ## Validation - All translated TGA/Pfim-related tests pass. - Malformed and oversized image fixtures return typed errors. - Round-trip output is deterministic where guaranteed. ## Prerequisite Types and StructuredData are implemented and the global API/test gates are complete. ## Project constraints - Native Rust implementation only; optional third-party native codecs stay behind documented features. - Keep mapped signatures fixed and preserve translated geometry/pixel assertions exactly. - Enforce checked sizes and indices, then update docs and coverage status.

hugo added this to the 06 - Imaging and PrimMesher implementation milestone 2026-08-08 08:17:25 +00:00

hugo added the enhancement label 2026-08-08 08:17:25 +00:00

hugo referenced this issue from a commit

2026-08-09 02:51:49 +00:00

Implement native TGA and DDS compatibility (#39)

hugo commented

2026-08-09 02:52:31 +00:00

Implemented and pushed as 5d1573f.

Implementation:

Replaced all 3 Targa shims with bounded native Rust file/stream decoding and reference-compatible deterministic encoding, including the C# alpha-only expansion behavior.
Added uncompressed/RLE true-color, grayscale, and indexed TGA decoding across all descriptor orientations, palette origins, 8/15/16/24/32-bit layouts, and alpha-bearing layouts.
Added legacy and DX10 DDS decoding for packed 8/16/24/32-bit layouts, BC1/2/3, signed/unsigned BC4/5, and feature-gated BC6H/BC7. The optional dds-bc67 dependency is safe pure Rust and does not leak into the mapped API.
Added checked dimensions, allocations, palettes, packets, masks, blocks, and bounded 64 MiB input with typed positioned parse errors; updated feature docs, lockfiles, API generation, and coverage.

Verification:

5/5 focused TGA/DDS tests pass with default features.
5/5 focused tests pass with no default features, including typed BC6H/BC7-disabled behavior.
Direct fixture audit against the pinned Pfim 0.11.4 published golden pixels passed for 32-bit DDS, DXT1/3/5, DX10 BC2/3/6H/7, signed and unsigned BC4/5, and 24/32-bit TGA.
Controlled compatibility audit: 198 pass, 1200 standardized expected failures, 0 ignored; five new support tests pass and the expected-failure set is unchanged.
API coverage and generation checks, test parity, surface generation, workspace check, locked API compile, workspace no-run, all-feature clippy, no-default clippy, docs, formatting, and diff checks all pass.

The only translated test mentioning head_color.tga stops at the still-generated Baker.LoadResourceLayer member. Tea assigns Baker behavior to milestone 09 issue #66, so it remains an expected failure and was intentionally not mixed into this milestone 06 issue.

Implemented and pushed as 5d1573f. Implementation: - Replaced all 3 Targa shims with bounded native Rust file/stream decoding and reference-compatible deterministic encoding, including the C# alpha-only expansion behavior. - Added uncompressed/RLE true-color, grayscale, and indexed TGA decoding across all descriptor orientations, palette origins, 8/15/16/24/32-bit layouts, and alpha-bearing layouts. - Added legacy and DX10 DDS decoding for packed 8/16/24/32-bit layouts, BC1/2/3, signed/unsigned BC4/5, and feature-gated BC6H/BC7. The optional dds-bc67 dependency is safe pure Rust and does not leak into the mapped API. - Added checked dimensions, allocations, palettes, packets, masks, blocks, and bounded 64 MiB input with typed positioned parse errors; updated feature docs, lockfiles, API generation, and coverage. Verification: - 5/5 focused TGA/DDS tests pass with default features. - 5/5 focused tests pass with no default features, including typed BC6H/BC7-disabled behavior. - Direct fixture audit against the pinned Pfim 0.11.4 published golden pixels passed for 32-bit DDS, DXT1/3/5, DX10 BC2/3/6H/7, signed and unsigned BC4/5, and 24/32-bit TGA. - Controlled compatibility audit: 198 pass, 1200 standardized expected failures, 0 ignored; five new support tests pass and the expected-failure set is unchanged. - API coverage and generation checks, test parity, surface generation, workspace check, locked API compile, workspace no-run, all-feature clippy, no-default clippy, docs, formatting, and diff checks all pass. The only translated test mentioning head_color.tga stops at the still-generated Baker.LoadResourceLayer member. Tea assigns Baker behavior to milestone 09 issue #66, so it remains an expected failure and was intentionally not mixed into this milestone 06 issue.

hugo closed this issue

2026-08-09 02:52:38 +00:00

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Reference: hugo/MetaCrate#39