Files
OneCAD-Draft/src/scene/tess_util.rs
T
Hakan SevenandClaude Opus 4.7 b413fe0efe refactor(tess): rename LegacyTess → FallbackTess
The trait isn't deprecating anything — it carries the path entities
take when they're not covered by the truck topology pipeline
(Viewport, Insert, Hatch outline, Ole2Frame). "Fallback" names the
purpose; "Legacy" implied retirement that isn't actually on the
roadmap.

Same rename for LegacyGeometry → FallbackGeometry,
legacy_geometry() → fallback_geometry().

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
2026-05-23 23:16:57 +03:00

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// Shared helpers used by per-entity tessellation impls in `crate::entities`
// and the dispatcher in `crate::scene::tessellate`.
//
// Anything cross-entity (colour resolution, arc sampling, chord tolerance)
// lives here. Entity-specific helpers (dim format strings, mleader path
// types, etc.) stay with their entity file.
use acadrust::types::Color as AcadColor;
use glam::Vec3;
use crate::scene::wire_model::{SnapHint, TangentGeom, WireModel};
/// Output of the fallback per-entity geometry path used by entities not
/// covered by the truck topology pipeline (Viewport, Insert, Hatch
/// outline, Ole2Frame). Tuple form preserved to avoid touching every
/// callsite when the dispatcher wraps these into a WireModel.
///
/// Layout: `(points, snap_pts, tangent_geoms, key_vertices)`.
pub type FallbackGeometry = (
Vec<[f32; 3]>,
Vec<(Vec3, SnapHint)>,
Vec<TangentGeom>,
Vec<[f32; 3]>,
);
// ── Arc tessellation helpers ─────────────────────────────────────────────
/// Convert hatch-boundary arc `(start, end, ccw)` into a
/// `(start, signed_span)` ready for the sampling loop. Matches the
/// legacy `(TAU - sa, TAU - ea)` flip used here for years — direction
/// semantics are preserved on real files. (Wrap-through-2π is a known
/// edge case in that convention; do not "fix" it without a wider audit
/// of how upstream writers emit CW boundary arcs.)
pub fn arc_signed_span(start: f64, end: f64, ccw: bool) -> (f64, f64) {
const TAU: f64 = std::f64::consts::TAU;
let (sa, ea) = if ccw { (start, end) } else { (TAU - start, TAU - end) };
(sa, ea - sa)
}
/// Segment count for an arc, targeting `chord_tol_world` chord-height
/// error in world units. Floor 8, cap 512.
///
/// Two production callers:
/// - hatch fill polygon (built at load / on edit) passes a radius-
/// relative tol via [`fill_chord_tol`] — ~0.1% radius, zoom-free so
/// the polygon stays sharp at extreme zoom-in without re-tessellation.
/// - hatch wire outline (re-tessellated every frame inside the render
/// scope) passes a zoom-adaptive tol via [`wire_chord_tol`] — pulls
/// from the per-frame override set by `Scene::wires_for_block` so
/// far-out arcs collapse to a handful of segments.
pub fn arc_segments(radius: f64, span_abs: f64, chord_tol_world: f64) -> u32 {
if span_abs < 1e-9 || radius < 1e-9 {
return 1;
}
let tol = chord_tol_world.max(1e-9).min(radius * 0.99);
// θ where r * (1 - cos(θ/2)) = tol → θ = 2 * acos(1 - tol/r).
let max_step = (2.0 * (1.0 - tol / radius).acos()).max(1e-6);
((span_abs / max_step).ceil() as u32).clamp(8, 512)
}
/// Chord tolerance for the load-time fill polygon: 0.1% of radius,
/// floor 1 µm so degenerate radii still produce a workable count.
pub fn fill_chord_tol(radius: f64) -> f64 {
(radius * 0.001).max(1e-6)
}
/// Chord tolerance for the per-frame wire outline: pulls the active
/// `truck_tess::set_curve_tol_override` value (Scene sets it to
/// `world_per_pixel × 0.5` so curves stay at ~half-pixel chord error at
/// the current zoom). When no override is active (snap / hit-test
/// passes, load-time builds), falls back to [`fill_chord_tol`] so we
/// never under-sample.
pub fn wire_chord_tol(radius: f64) -> f64 {
match crate::scene::truck_tess::active_curve_tol() {
Some(t) => t.min(fill_chord_tol(radius)).max(1e-9),
None => fill_chord_tol(radius),
}
}
// ── Colour helper ──────────────────────────────────────────────────────────
/// Convert an acadrust Color (ACI index or true-color) to a GPU RGBA value.
pub fn aci_to_rgba(color: &AcadColor) -> [f32; 4] {
if let Some((r, g, b)) = color.rgb() {
[r as f32 / 255.0, g as f32 / 255.0, b as f32 / 255.0, 1.0]
} else {
WireModel::WHITE
}
}