jerome/wsg

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Jérôme Bousquié a3a7ff4a6b LOD: quadric edge collapse (Garland-Heckbert) replaces Rule A

Rule A (area-sorted triangle removal) left holes and open boundaries
on closed meshes (visible artifacts when zoomed far out). The decimator
is now a proper quadric edge collapse:

- Collapse: welded u32 topology, per-vertex quadrics (accumulated
  incident face planes), edge cost = quadric error at the optimal
  point (clamped to the segment) + edge length, BinaryHeap with a
  custom Ord (f32 is not Ord; inverted compare, NaN-safe).
- Standard GH semantics WITHOUT the new face: both incident pair faces
  degenerate and are removed; neighbouring faces remap and sweep over
  the region. Preserves the Euler characteristic and closedness (no
  holes, no books, no duplicate faces); interior collapse = -2 faces,
  boundary = -1. Guards: non-manifold edge (>2 faces) or a fold
  (duplicate sorted triple) rejects the collapse.
- welded(): fuzzy welding (1e-6 relative tolerance, grid + 27-
  neighbour broad phase, exact verify) - trig-generated seams differ
  by ~1e-16, exact-bit welding missed them.
- Root causes fixed along the way: dead face slots are never reused
  (stale edge/vface entries), vfaces updated on remap, degenerate
  faces dropped, best-effort target (granularity -2/-1 can land 1-2
  off; soft cap, deterministic).
- Docs: DRAFT D10, ROADMAP 4.3, ARCHI_CPU_GPU, gpu-driven, lib
  README, mesh/scene/demo comments - 'greedy decimation / Rule A'
  replaced by 'quadric edge collapse'.
- lod.rs test: deprecated glam perspective alias -> explicit
  glam::camera::rh::proj::opengl::perspective.

cargo test --workspace: 100 passed (94 lib + 3 wgsl + 3 integration),
0 failed; demo runs clean with LOD on.

2026-09-23 11:46:12 +02:00

cube.rs

update demos et docs

2026-09-21 12:01:28 +02:00

demo.rs

LOD: quadric edge collapse (Garland-Heckbert) replaces Rule A

2026-09-23 11:46:12 +02:00

manual.rs

update demos et docs

2026-09-21 12:01:28 +02:00

README.md

update demos et docs

2026-09-21 12:01:28 +02:00

shadow_test.rs

update demos et docs

2026-09-21 12:01:28 +02:00

simple.rs

update demos et docs

2026-09-21 12:01:28 +02:00

spot_test.rs

update demos et docs

2026-09-21 12:01:28 +02:00

README.md

Examples

Each .rs file in this directory is a standalone example auto-discovered by Cargo (cargo build -p wsg-lib --examples). To run an example:

cargo run -p wsg-lib --example <name>

Example	Command	Description
`demo`	`cargo run -p wsg-lib --example demo`	Showcase: one of each primitive, procedural textures, directional + point + spot lights, a shadow-casting light, and a live orbital camera (drag / wheel zoom / `R` reset / `1`-`3` presets).
`simple`	`cargo run -p wsg-lib --example simple`	Flat unlit quad (minimal declarative workflow, `AppBuilder` + auto scene).
`cube`	`cargo run -p wsg-lib --example cube`	Textured cube (procedural checker) lit by a directional + point + spot light.
`manual`	`cargo run -p wsg-lib --example manual`	Low-level workflow: `Context`, `Renderer`, `PipelineCache`, `Mesh` used directly (no `App` facade).
`spot_test`	`cargo run -p wsg-lib --example spot_test`	Spot-light isolation: only one spot is on (near-zero ambient), cube rotates on two axes so the oriented beam is clearly visible.
`shadow_test`	`cargo run -p wsg-lib --example shadow_test`	Shadow mapping: one directional light is the shadow caster (`set_shadow_caster(Some(0))`); a cube casts a PCF-softened shadow onto a thin ground slab.

Conventions

Examples are self-contained: no assets loaded from disk (procedural textures, hardcoded geometry).
They use the declarative workflow (AppBuilder + Scene) except manual, which bypasses the App facade.
When adding a new example: create a .rs file in this directory, document it here, and reference it in the root README if appropriate.