create/src/Mod/Part/App/FCBRepAlgoAPI_BooleanOperation.cpp

// SPDX-License-Identifier: LGPL-2.1-or-later

/***************************************************************************
 *   Copyright (c) 2024 Eric Price (CorvusCorax)                           *
 *                      <eric.price[at]tuebingen.mpg.de>                   *
 *                                                                         *
 *   This file is part of FreeCAD.                                         *
 *                                                                         *
 *   FreeCAD is free software: you can redistribute it and/or modify it    *
 *   under the terms of the GNU Lesser General Public License as           *
 *   published by the Free Software Foundation, either version 2.1 of the  *
 *   License, or (at your option) any later version.                       *
 *                                                                         *
 *   FreeCAD is distributed in the hope that it will be useful, but        *
 *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with FreeCAD. If not, see                               *
 *   <https://www.gnu.org/licenses/>.                                      *
 *                                                                         *
 **************************************************************************/

/**
  * FCBRepAlgoAPI provides a wrapper for various OCCT functions.
  */

#include <FCBRepAlgoAPI_BooleanOperation.h>
#include <BRepBndLib.hxx>
#include <Bnd_Box.hxx>
#include <BRepCheck_Analyzer.hxx>
#include <BRep_Builder.hxx>
#include <TopoDS_Shape.hxx>
#include <TopoDS_Iterator.hxx>
#include <Precision.hxx>
#include <FuzzyHelper.h>

FCBRepAlgoAPI_BooleanOperation::FCBRepAlgoAPI_BooleanOperation()
{
    SetRunParallel(Standard_True);
    SetNonDestructive(Standard_True);
}


FCBRepAlgoAPI_BooleanOperation::FCBRepAlgoAPI_BooleanOperation(const TopoDS_Shape& theS1,
                                               const TopoDS_Shape& theS2,
                                               const BOPAlgo_Operation theOperation)
: BRepAlgoAPI_BooleanOperation(theS1, theS2, theOperation)
{
    if (!BRepCheck_Analyzer(theS1).IsValid()){
        Standard_ConstructionError::Raise("Base shape is not valid for boolean operation");
    }
    if (! BRepCheck_Analyzer(theS2).IsValid()){
        Standard_ConstructionError::Raise("Tool shape is not valid for boolean operation");
    }
    setAutoFuzzy();
    SetRunParallel(Standard_True);
    SetNonDestructive(Standard_True);
}

void FCBRepAlgoAPI_BooleanOperation::setAutoFuzzy()
{
    FCBRepAlgoAPIHelper::setAutoFuzzy(this);
}


void FCBRepAlgoAPIHelper::setAutoFuzzy(BRepAlgoAPI_BooleanOperation* op) {
    Bnd_Box bounds;
    for (TopTools_ListOfShape::Iterator it(op->Arguments()); it.More(); it.Next())
        BRepBndLib::Add(it.Value(), bounds);
    for (TopTools_ListOfShape::Iterator it(op->Tools()); it.More(); it.Next())
        BRepBndLib::Add(it.Value(), bounds);
    op->SetFuzzyValue(Part::FuzzyHelper::getBooleanFuzzy() * sqrt(bounds.SquareExtent()) * Precision::Confusion());
}

void FCBRepAlgoAPIHelper::setAutoFuzzy(BRepAlgoAPI_BuilderAlgo* op) {
    Bnd_Box bounds;
    for (TopTools_ListOfShape::Iterator it(op->Arguments()); it.More(); it.Next())
        BRepBndLib::Add(it.Value(), bounds);
    op->SetFuzzyValue(Part::FuzzyHelper::getBooleanFuzzy() * sqrt(bounds.SquareExtent()) * Precision::Confusion());
}

void FCBRepAlgoAPI_BooleanOperation::Build() {

    if (myOperation == BOPAlgo_CUT && myArguments.Size() == 1 && myTools.Size() == 1 && myTools.First().ShapeType() == TopAbs_COMPOUND) {
        // cut argument and compound tool
        TopTools_ListOfShape myOriginalArguments = myArguments;
        TopTools_ListOfShape myOriginalTools = myTools;
        RecursiveCutFusedTools(myOriginalArguments, myOriginalTools.First());
        myArguments = myOriginalArguments;
        myTools = myOriginalTools;
        
    } else if (myOperation==BOPAlgo_CUT && myArguments.Size()==1 && myArguments.First().ShapeType() == TopAbs_COMPOUND) {
        // cut compound argument
        TopTools_ListOfShape myOriginalArguments = myArguments;
        RecursiveCutCompound(myOriginalArguments.First());
        myArguments = myOriginalArguments;
        
    } else {
        BRepAlgoAPI_BooleanOperation::Build();
    }
}

void FCBRepAlgoAPI_BooleanOperation::RecursiveAddTools(const TopoDS_Shape& theTool) {
    TopoDS_Iterator it(theTool);
    for (; it.More(); it.Next()) {
        if (it.Value().ShapeType() == TopAbs_COMPOUND) {
            RecursiveAddTools(it.Value());
        } else {
            myTools.Append(it.Value());
        }
    }
}

void FCBRepAlgoAPI_BooleanOperation::RecursiveCutFusedTools(const TopTools_ListOfShape& theOriginalArguments, const TopoDS_Shape& theTool)
{
    // get a list of shapes in the tool compound
    myTools.Clear();
    RecursiveAddTools(theTool);
    
    // if tool consists of two or more shapes, fuse them together
    if (myTools.Size() >= 2) {
        myArguments.Clear();
        myArguments.Append(myTools.First());
        myTools.RemoveFirst();
        myOperation = BOPAlgo_FUSE;
        Build();
        
        // restore original state
        myOperation = BOPAlgo_CUT;
        myArguments = theOriginalArguments;
        
        if (!IsDone()) {
            myShape = {};
            return;
        }
        
        // use fused shape as new tool
        // if the original tools didn't all touch, the fused shape will be a compound
        // which we convert into a list of shapes so we don't attempt to fuse them again
        myTools.Clear();
        RecursiveAddTools(myShape);
    }
    
    // do the cut
    Build();
}

void FCBRepAlgoAPI_BooleanOperation::RecursiveCutCompound(const TopoDS_Shape& theArgument) {
    BRep_Builder builder;
    TopoDS_Compound comp;
    builder.MakeCompound(comp);
    
    // iterate through shapes in argument compound and cut each one with the tool
    TopoDS_Iterator it(theArgument);
    for (; it.More(); it.Next()) {
        myArguments.Clear();
        myArguments.Append(it.Value());
        Build();
        
        if (!IsDone()) {
            myShape = {};
            return;
        }
        
        builder.Add(comp, myShape);
    }
    
    // result is a compound of individual cuts
    myShape = comp;
}