docs: mark stage 15 complete in DRAFT/ROADMAP/README

Check off 15.A/15.B/15.C + factors + fmt in DRAFT; mark ROADMAP 2.2 and 2.3
done (gamepad noted [~] deferred, DRAFT D7); add README roadmap items 13-15.
Runtime check of the demo remains (user-driven).

README.md

@@ -189,3 +189,6 @@ The architecture docs live in `docs/tech/` and are written in **French**. Each d
 10. ✅ **Multi-lighting (Étape 12, Phase 4.2)** — the scene now carries a global light list (directional + point) with a white ambient, uploaded into the per-frame `FrameUniforms` array each frame. `Scene::add_directional_light` / `add_point_light` / `set_ambient` / `clear_lights` configure it; `FrameUniforms::default()` (one white directional along +Z + white ambient) reproduces the pre-multi-light look exactly. The `standard` fragment accumulates ambient + all lights; the `cube` example adds a warm point light on top of the default directional. (Done 2026-09-18.)
 11. ✅ **Spot lights (Étape 13, Phase 4.2)** — spot lights (oriented cone + half-angle) added on top of the multi-lighting system. `Scene::add_spot_light(pos, dir, color, intensity, radius, half_angle)` registers a spot light; the `standard` fragment accumulates a spot term with a smoothed penumbra (half-angle ± 0.1 rad) and linear attenuation. `Light` grew from 48 to 64 bytes (added `dir_angle`); `FrameUniforms` from 576 to 704 bytes (added `num_spot`). Non-regression: default scene unchanged. The `cube` example adds a green spot light aimed at the cube. (Done 2026-09-18.)
 12. ✅ **Shadows — shadow mapping (Étape 14, Phase 4.2, optionnel)** — classic two-pass shadow mapping on a **single** light (directional or spot), selected by `Scene::set_shadow_caster(index)`. A depth-only pass (`shadow_shader.wgsl` + dedicated `shadow_pipeline`) renders the scene into a 1024² `Depth32Float` shadow map (`Renderer`-owned, slope-scaled depth bias); the `standard` fragment re-projects each fragment into light space and applies a **PCF 3×3** comparison-sampler test (bind group **@3**, shared). `FrameUniforms` grew from 704 to 784 bytes (`shadow_light_index`, `light_view_proj`, `shadow_params`). Shadows are **off by default** (`shadow_caster = None`) so `simple`/`cube`/`manual`/`spot_test` are unchanged. The `shadow_test` example casts a soft shadow from a cube onto a ground slab. (Done 2026-09-19.)
+13. ✅ **Procedural primitive meshes (Étape 15.A)** — `math::primitives` provides drop-in `Geometry` generators (`cube`, `plane`, `uv_sphere`, `icosphere`, `cylinder`, `cone`, `torus`) with positions + per-face/smooth normals + UVs + indices. Re-exported at `math::*`. The `cube` and `spot_test` examples now reuse `math::cube(1.0)` (the `cube_geometry` helper was factored away; `shadow_test` keeps its generic `box_geometry`). (Done 2026-09-20; 6 unit tests.)
+14. ✅ **Unified input (Étape 15.B)** — `core::input::InputState` gives cross-frame **pressed/held/released** semantics for keyboard (physical `KeyCode`) and mouse (buttons, position, per-frame delta, wheel scroll), rotated by `begin_frame`/`end_frame` around `AppHandler::update`. `App` exposes it as a public `input` field, fed from winit `WindowEvent`s and reset each frame. Gamepad is reserved/deferred (DRAFT D7). (Done 2026-09-20; 5 unit tests; winit event handling is host-driven on the CPU, not WGSL.)
+15. ✅ **Orbital camera + final demo (Étape 15.C)** — `resources::CameraController` (yaw/pitch/distance/target, `apply_to` writes into a `Camera`, drag-orbit + wheel-zoom + clamps) drives the new `demo` example: one of each primitive, procedural textures, standard Phong material, a shadow-casting directional light + point + spot, and live mouse-orbit / wheel-zoom / `R` reset / `1`/`2`/`3` view presets. Run with `cargo run -p wsg-lib --example demo`. (Done 2026-09-20; runtime check pending.)