[TheWillard]

Fixes ODOL sections that failed to load, and adds what a renderer needs from P3D models and PAA textures: section face ranges, decoded UVs and BC blocks for GPUs. With this change all 6,682 models of Arma 3 load (v73), up from 6,648. The P3D viewer in arma.tools is built on it.

Format

• LodSection, version 67 and up: after the stages comes an i32 flag and, when it is set, 11 f32s, not a 4x3 matrix of 12. Reading 12 put the next section 4 bytes off: 34 models failed with "failed to fill whole buffer" in stages, all of them collimator sights and weapons carrying them (ACO, ARCO, ...). The flag was always 0 or 1. What the floats mean is not known.
• Section face ranges: face_lower_index and face_upper_index are byte offsets into the faces, with a face's vertex count and each of its vertex indices taking the size of an index: 4 bytes from version 69 (a triangle takes 16, a quad 20), 2 bytes before. Sections follow each other without gaps and cover all faces. Checked on every LOD of the test models (versions 40 to 75) and of Arma 3.

API

• Lod::section_faces(): per section, its faces as a range of Lod::faces.
• UVSet::uvs(): one [u, v] per vertex. Discretized sets (version 45 and up) map their i16s onto min..=max (in f64, the f32 result was off by 1e-4 on wide ranges), older ones are f32s, default-filled sets repeat their value.
• Paa::from_reader_blocks(): like from_reader, but DXT1 and DXT5 mipmaps stay BC1 and BC3 blocks (LZO decompressed) instead of being decoded to RGBA, to upload them to a GPU as they are. Other formats decode as before.
• Breaking: LodSection::unk_matrix_exists / unk_matrix: TransformMatrix are now has_unk_floats / unk_floats: Option<[f32; 11]>.
• read_lods no longer prints Lod Index: n for every LOD.

Test data

rv-test-data-part-4.7z holds the ACO sight (acco_aco_f.p3d, 70 KB packed), encrypted like the other parts. aff-test-data-setup now extracts parts 1 to 4. A checkout that already extracted the test data won't get the new file: the setup skips non-empty test data folders, so delete tests/real_virtuality/test-data or extract part 4 by hand.

Testing

All tests pass. New:

• section_faces: every LOD of every test model is covered by its sections without gaps.
• uvs: every UV set has a coordinate per vertex, inside its range for discretized sets. Both kinds occur in the test models.
• section_unk_floats: the ACO loads, has sections with the 11 floats, and its section ranges resolve.
• paa_test::blocks: the blocks of DXT1 and DXT5 PAAs have the BC size of each mipmap and decode to what from_reader returns. blocks_other_formats: ARGB4444 decodes as before.

Outside the tests, all 6,682 P3Ds of the Arma 3 Addons folder load and their section ranges resolve.

[codecov]

Codecov Report

❌ Patch coverage is 93.82716% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...rma-file-formats/src/real_virtuality/paa/mipmap.rs	73.33%	4 Missing ⚠️
arma-file-formats/src/real_virtuality/p3d/lod.rs	97.91%	1 Missing ⚠️

Files with missing lines	Coverage Δ
arma-file-formats/src/real_virtuality/p3d/odol.rs	48.78% <ø> (-0.62%)	⬇️
arma-file-formats/src/real_virtuality/paa/paa.rs	97.60% <100.00%> (+0.21%)	⬆️
arma-file-formats/src/real_virtuality/p3d/lod.rs	98.38% <97.91%> (-1.62%)	⬇️
...rma-file-formats/src/real_virtuality/paa/mipmap.rs	86.91% <73.33%> (-1.79%)	⬇️

... and 6 files with indirect coverage changes

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