MetaCrate/crates/libremetaverse-rendering-simple/README.md

LibreMetaverse simple renderer

libremetaverse-rendering-simple is the small, deterministic reference pipeline for geometry that is already represented by a Primitive or a decoded sculpt map. It has no windowing, GPU, Skia, voice, RLV, or LSL dependency. The only geometry backend is the workspace's checked native libremetaverse-prim-mesher crate.

Supported inputs and output

SimpleRenderer implements both its concrete C#-mapped methods and the shared IRendering trait. It supports:

• linear and flexible paths, plus circular prim paths;
• square, circular, half-circle, and all three triangular profiles;
• profile/path cuts, hollow profiles, shear, taper, twist, skew, radius offset, and revolutions at all four DetailLevel values;
• plane, cylinder, sphere, and torus sculpt maps supplied as ManagedImage;
• faceted output grouped by prim face, and flattened simple output that keeps each face's independent vertex/normal/UV domain;
• per-face texture-entry inheritance, including texture, legacy material, and render-material UUIDs; and
• default and planar texture transforms with repeat, offset, rotation, and primitive scale.

Positions are emitted in prim-local coordinates. Every face contains finite positions, normals, and UVs, in-range triangle indices, its local bounds and center, and its effective texture-entry face. Identical inputs produce byte-for-byte-identical floating-point and index sequences; the compatibility suite pins a golden high-detail box.

Bounds and errors

Each face and flattened mesh is limited to the 16-bit index domain (65,536 vertices), and aggregate vertex/index growth uses checked arithmetic before allocation or conversion. Non-finite construction data, malformed mesher domains, invalid indices, unsupported topology, and budget overflow return Error::Rendering. That error includes the source primitive UUID and a static operation context so callers can identify the object that failed. Invalid standalone texture-transform arguments return Error::Argument because that API has no primitive parameter from which to derive source context.

Deliberate boundary

A sculpt whose type is Mesh names an encoded mesh asset rather than a sculpt height map. SimpleRenderer does not fetch or decode assets, so that input returns a typed mesh sculpt requires a decoded mesh asset error. Mesh-asset decoding, skin weights, secondary UVs, and rigged-mesh metadata belong to the separate MeshFoundry renderer. The simple renderer also performs no world transform, scene traversal, material shading, texture download, or drawing.

Run the focused implementation gates with:

python3 tools/check_milestone_10_issue_76.py
CARGO_BUILD_JOBS=1 cargo test -p libremetaverse-compat-tests --test rendering_shims --locked -j1
CARGO_BUILD_JOBS=1 cargo test -p libremetaverse-rendering-simple --locked -j1