meshsubmap.h File Reference

#include <QPolygonF>
#include <QString>
#include "mesh/meshpatch.h"

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Namespaces
namespace	mesh

Functions
bool	mesh::ringIsRectilinear (const QPolygonF &ring, double tolDeg, double *frameAngleDeg)
	True when every edge of the (normalised) ring is parallel to one of two perpendicular axes within tolDeg. frameAngleDeg receives the frame rotation when non-null.
PatchMesh	mesh::makeSubmappedPatch (const QPolygonF &ring, double h, const QString &tag, QString *err=nullptr, double tolDeg=2.0)
	Build the submapped patch. On failure returns an empty PatchMesh and sets *err ("not rectilinear", "spacing must be > 0", "degenerate ring").

Detailed Description

Author

Caleb Buahin caleb.nosp@m..bua.nosp@m.hin@g.nosp@m.mail.nosp@m..com

Date

2026

License\n GPL-3.0-or-later

Grid-based submapping of an exactly rectilinear ring (workplans/QUAD_MESHING_REDESIGN_PLAN_2026-09-06.md §4.3, reduced scope — Whiteley et al. 1996 without the integer-programming interval assignment):

1. the dominant edge direction defines a local frame (rotation by the length-weighted mean edge angle folded to [0, 90°));
2. every edge must be parallel to a frame axis within tolDeg, else the ring is rejected ("not rectilinear") — the caller falls back to Free;
3. vertices are snapped so the edges are exactly axis-parallel in the frame (each edge's constant coordinate = mean of its endpoints; the move is bounded by tan(tolDeg)·len/2);
4. the distinct local x (and y) coordinates of the vertices define grid bands; each band [x_i, x_i+1] is split into max(1, round(Δ/h)) equal intervals — so every rectangle of the decomposition shares grid lines and the mesh is conforming by construction, with exact user geometry;
5. a grid cell is emitted when its centre is inside the ring (rectilinear → cells are fully inside or outside).

Output quads are rectangles (CCW), vertices in the original frame; the boundary segments are the ring edges split at the grid nodes, so the caller can stitch the patch exactly like a transfinite one (MeshGenerator::addPatch).