assembly.h

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/*                    A S S E M B L Y . H
 * BRL-CAD
 *
 * Copyright (c) 2026 United States Government as represented by
 * the U.S. Army Research Laboratory.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * version 2.1 as published by the Free Software Foundation.
 */
/** @file brep/assembly.h
 *
 * Assemble independently constructed trimmed faces into shared OpenNURBS
 * topology.  These routines do not standardize or compact a B-Rep.
 */
 
#ifndef BREP_ASSEMBLY_H
#define BREP_ASSEMBLY_H
 
#include "common.h"
#include "brep/defines.h"
 
#ifdef __cplusplus
#  include <string>
#endif
 
__BEGIN_DECLS
 
#ifdef __cplusplus
extern "C++" {
 
enum brep_assembly_error {
    BREP_ASSEMBLY_OK = 0,
    BREP_ASSEMBLY_INVALID_TOLERANCE,
    BREP_ASSEMBLY_VERTEX_MERGE_FAILED,
    BREP_ASSEMBLY_EDGE_MERGE_FAILED,
    BREP_ASSEMBLY_CULL_FAILED,
    BREP_ASSEMBLY_ORIENTATION_FAILED,
    BREP_ASSEMBLY_VALIDATION_FAILED,
    BREP_ASSEMBLY_TOLERANCE_FAILED
};
 
struct brep_assembly_result {
    int input_naked_edges = 0;
    int merged_edges = 0;
    int ambiguous_edges = 0;
    int remaining_naked_edges = 0;
    int nonmanifold_edges = 0;
    bool oriented = false;
    bool valid = false;
    bool solid = false;
    enum brep_assembly_error error = BREP_ASSEMBLY_OK;
    std::string validation_log;
};
 
/** Bound whether two curves trace the same locus within @p tolerance.
 * Returns false when refinement cannot establish coincidence within its
 * work limit.  Point samples alone never establish a match. */
extern BREP_EXPORT bool
brep_curves_coincident(const ON_Curve &first, const ON_Curve &second,
        double tolerance, bool *reversed = NULL);
 
/**
 * Merge unambiguous pairs of coincident naked edges in place.
 *
 * Each retained edge acquires the trims from its duplicate.  Face pcurves are
 * not changed.  Returns the number of merged edges, or -1 on an OpenNURBS
 * topology error.  Ambiguous matches are deliberately left naked.
 */
extern BREP_EXPORT int
brep_stitch_naked_edges(ON_Brep &brep, double tolerance,
        brep_assembly_result *result = NULL);
 
/**
 * Derive edge tolerances required by authored vertex and trim endpoints.
 * Geometry is not changed; existing larger tolerances are preserved.
 */
extern BREP_EXPORT bool
brep_set_edge_endpoint_tolerances(ON_Brep &brep, double minimum_tolerance);
 
/** Make face orientations consistent in a closed two-manifold B-Rep. */
extern BREP_EXPORT bool
brep_orient_faces(ON_Brep &brep);
 
/**
 * Stitch, orient, derive tolerances and flags, and validate an assembled
 * B-Rep.  The return value reports whether the resulting B-Rep is valid;
 * solidity and incomplete topology are reported separately in @p result.
 */
extern BREP_EXPORT bool
brep_assemble(ON_Brep &brep, double tolerance,
        brep_assembly_result *result = NULL);
 
}
#endif
 
__END_DECLS
 
#endif /* BREP_ASSEMBLY_H */