57 lines
1.8 KiB
C++
57 lines
1.8 KiB
C++
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#include "solvespace.h"
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void SSurface::IntersectAgainst(SSurface *b, SShell *into) {
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Vector amax, amin, bmax, bmin;
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GetAxisAlignedBounding(&amax, &amin);
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b->GetAxisAlignedBounding(&bmax, &bmin);
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if(Vector::BoundingBoxesDisjoint(amax, amin, bmax, bmin)) {
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// They cannot possibly intersect, no curves to generate
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return;
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}
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if(degm == 1 && degn == 1 && b->degm == 1 && b->degn == 1) {
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// Plane-plane intersection, easy; result is a line
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Vector pta = ctrl[0][0], ptb = b->ctrl[0][0];
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Vector na = NormalAt(0, 0), nb = b->NormalAt(0, 0);
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na = na.WithMagnitude(1);
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nb = nb.WithMagnitude(1);
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Vector d = (na.Cross(nb));
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if(d.Magnitude() < LENGTH_EPS) {
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// parallel planes, no intersection
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return;
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}
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Vector inter = Vector::AtIntersectionOfPlanes(na, na.Dot(pta),
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nb, nb.Dot(ptb));
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// The intersection curve can't be longer than the longest curve
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// that lies in both planes, which is the diagonal of the shorter;
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// so just pick one, and then give some slop, not critical.
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double maxl = ((ctrl[0][0]).Minus(ctrl[1][1])).Magnitude();
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Vector v;
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SCurve sc;
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ZERO(&sc);
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sc.surfA = h;
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sc.surfB = b->h;
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v = inter.Minus(d.WithMagnitude(2*maxl));
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sc.pts.Add(&v);
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v = inter.Plus(d.WithMagnitude(2*maxl));
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sc.pts.Add(&v);
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sc.interCurve = true;
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// Now split the line where it intersects our existing surfaces
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SCurve split = sc.MakeCopySplitAgainst(into);
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sc.Clear();
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into->curve.AddAndAssignId(&split);
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}
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// need to implement general numerical surface intersection for tough
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// cases, just giving up for now
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}
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