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Additional poking at Booleans. At least this is a halfway rational 

way to think about the cases; I'm classifying the regions to the
left and right of each edge, and keeping the edges if those regions
(2d, surfaces) classify different.

Still screws up with edge-on-edge intersections; but if I make the
surface intersection stuff handle that, then might be more
straightforward to use that info.

[git-p4: depot-paths = "//depot/solvespace/": change = 1914]
solver
Jonathan Westhues 2009-02-16 04:05:08 -08:00
parent 90842131ff
commit c6b429b9ce
3 changed files with 196 additions and 68 deletions
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202
srf/boolean.cpp
View File

@ -126,6 +126,94 @@ void SSurface::TrimFromEdgeList(SEdgeList *el) {
}
}
// For each edge, we record the membership of the regions to its left and
// right, which we call the "in direction" and "out direction" (wrt its
// outer normal)
#define INDIR (0)
#define OUTDIR (8)
// Regions of interest are the other shell itself, the coincident faces of the
// shell (same or opposite normal) and the original surface.
#define SHELL (0)
#define COINCIDENT_SAME (1)
#define COINCIDENT_OPPOSITE (2)
#define ORIG (3)
// Macro for building bit to test
#define INSIDE(reg, dir) (1 << ((reg)+(dir)))
static bool KeepRegion(int type, bool opA, int tag, int dir)
{
bool inShell = (tag & INSIDE(SHELL, dir)) != 0,
inSame = (tag & INSIDE(COINCIDENT_SAME, dir)) != 0,
inOpp = (tag & INSIDE(COINCIDENT_OPPOSITE, dir)) != 0,
inOrig = (tag & INSIDE(ORIG, dir)) != 0;
bool inFace = inSame || inOpp;
// If these are correct, then they should be independent of inShell
// if inFace is true.
if(!inOrig) return false;
switch(type) {
case SShell::AS_UNION:
if(opA) {
return (!inShell && !inFace);
} else {
return (!inShell && !inFace) || inSame;
}
break;
case SShell::AS_DIFFERENCE:
if(opA) {
return (!inShell && !inFace);
} else {
return (inShell && !inFace) || inSame;
}
break;
default: oops();
}
}
static bool KeepEdge(int type, bool opA, int tag)
{
bool keepIn = KeepRegion(type, opA, tag, INDIR),
keepOut = KeepRegion(type, opA, tag, OUTDIR);
// If the regions to the left and right of this edge are both in or both
// out, then this edge is not useful and should be discarded.
if(keepIn && !keepOut) return true;
return false;
}
static int TagByClassifiedEdge(int bspclass, int reg)
{
switch(bspclass) {
case SBspUv::INSIDE:
return INSIDE(reg, OUTDIR) | INSIDE(reg, INDIR);
case SBspUv::OUTSIDE:
return 0;
case SBspUv::EDGE_PARALLEL:
return INSIDE(reg, OUTDIR);
case SBspUv::EDGE_ANTIPARALLEL:
return INSIDE(reg, INDIR);
default: oops();
}
}
void DBPEDGE(int tag) {
dbp("edge: indir %s %s %s %s ; outdir %s %s %s %s",
(tag & INSIDE(SHELL, INDIR)) ? "shell" : "",
(tag & INSIDE(COINCIDENT_SAME, INDIR)) ? "coinc-same" : "",
(tag & INSIDE(COINCIDENT_OPPOSITE, INDIR)) ? "coinc-opp" : "",
(tag & INSIDE(ORIG, INDIR)) ? "orig" : "",
(tag & INSIDE(SHELL, OUTDIR)) ? "shell" : "",
(tag & INSIDE(COINCIDENT_SAME, OUTDIR)) ? "coinc-same" : "",
(tag & INSIDE(COINCIDENT_OPPOSITE, OUTDIR)) ? "coinc-opp" : "",
(tag & INSIDE(ORIG, OUTDIR)) ? "orig" : "");
}
//-----------------------------------------------------------------------------
// Trim this surface against the specified shell, in the way that's appropriate
// for the specified Boolean operation type (and which operand we are). We
@ -150,6 +238,11 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
ret.trim.Add(&stn);
}
if(type == SShell::AS_DIFFERENCE && !opA) {
// The second operand of a Boolean difference gets turned inside out
ret.Reverse();
}
// Build up our original trim polygon
SEdgeList orig;
ZERO(&orig);
@ -162,8 +255,8 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
SEdgeList sameNormal, oppositeNormal;
ZERO(&sameNormal);
ZERO(&oppositeNormal);
agnst->MakeCoincidentEdgesInto(this, true, &sameNormal);
agnst->MakeCoincidentEdgesInto(this, false, &oppositeNormal);
agnst->MakeCoincidentEdgesInto(&ret, true, &sameNormal);
agnst->MakeCoincidentEdgesInto(&ret, false, &oppositeNormal);
// and build the trees for quick in-polygon testing
SBspUv *sameBsp = SBspUv::From(&sameNormal);
SBspUv *oppositeBsp = SBspUv::From(&oppositeNormal);
@ -196,16 +289,19 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
if(c != SBspUv::OUTSIDE) {
Vector ta = Vector::From(0, 0, 0);
Vector tb = Vector::From(0, 0, 0);
ClosestPointTo(a, &(ta.x), &(ta.y));
ClosestPointTo(b, &(tb.x), &(tb.y));
ret.ClosestPointTo(a, &(ta.x), &(ta.y));
ret.ClosestPointTo(b, &(tb.x), &(tb.y));
Vector tn = NormalAt(ta.x, ta.y);
Vector tn = ret.NormalAt(ta.x, ta.y);
Vector sn = ss->NormalAt(auv.x, auv.y);
if((tn.Cross(b.Minus(a))).Dot(sn) > 0) {
inter.AddEdge(ta, tb, sc->h.v, 0);
} else {
bool bkwds = false;
if((tn.Cross(b.Minus(a))).Dot(sn) < 0) bkwds = !bkwds;
if(type == SShell::AS_DIFFERENCE && !opA) bkwds = !bkwds;
if(bkwds) {
inter.AddEdge(tb, ta, sc->h.v, 1);
} else {
inter.AddEdge(ta, tb, sc->h.v, 0);
}
}
}
@ -225,36 +321,31 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
// Get the midpoint of this edge
Point2d am = (auv.Plus(buv)).ScaledBy(0.5);
Vector pt = PointAt(am.x, am.y);
Vector pt = ret.PointAt(am.x, am.y);
// and the outer normal from the trim polygon (within the surface)
Vector n = NormalAt(am.x, am.y);
Vector ea = PointAt(auv.x, auv.y),
eb = PointAt(buv.x, buv.y);
Vector n = ret.NormalAt(am.x, am.y);
Vector ea = ret.PointAt(auv.x, auv.y),
eb = ret.PointAt(buv.x, buv.y);
Vector ptout = n.Cross((eb.Minus(ea)));
int c_shell = agnst->ClassifyPoint(pt, ptout);
bool keep;
if(c_opp != SBspUv::OUTSIDE) {
// Edge lies on coincident (opposite normals) surface of agnst
keep = (c_opp == SBspUv::OUTSIDE ) ||
(c_opp == SBspUv::EDGE_ANTIPARALLEL );
int tag = 0;
tag |= INSIDE(ORIG, INDIR);
tag |= TagByClassifiedEdge(c_same, COINCIDENT_SAME);
tag |= TagByClassifiedEdge(c_opp, COINCIDENT_OPPOSITE);
} else if(c_same != SBspUv::OUTSIDE) {
// Edge lies on coincident (same normals) surface of agnst
if(opA) {
keep = true;
} else {
keep = false;
if(c_shell == SShell::INSIDE) {
tag |= INSIDE(SHELL, INDIR) | INSIDE(SHELL, OUTDIR);
} else if(c_shell == SShell::OUTSIDE) {
tag |= 0;
} else if(c_shell == SShell::ON_PARALLEL) {
tag |= INSIDE(SHELL, INDIR);
} else if(c_shell == SShell::ON_ANTIPARALLEL) {
tag |= INSIDE(SHELL, OUTDIR);
}
} else {
// Edge does not lie on a coincident surface
keep = (c_shell == SShell::OUTSIDE ) ||
(c_shell == SShell::ON_ANTIPARALLEL );
}
if(keep) {
if(KeepEdge(type, opA, tag)) {
final.AddEdge(se->a, se->b, se->auxA, se->auxB);
}
}
@ -267,25 +358,38 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
int c_same = sameBsp->ClassifyEdge(auv, buv);
int c_opp = oppositeBsp->ClassifyEdge(auv, buv);
bool keep;
if(c_opp != SBspUv::OUTSIDE) {
keep = (c_this == SBspUv::INSIDE);
} else if(c_same != SBspUv::OUTSIDE) {
if(opA) {
keep = false;
int tag = 0;
tag |= TagByClassifiedEdge(c_this, ORIG);
tag |= TagByClassifiedEdge(c_same, COINCIDENT_SAME);
tag |= TagByClassifiedEdge(c_opp, COINCIDENT_OPPOSITE);
if(type == SShell::AS_DIFFERENCE && !opA) {
// The second operand of a difference gets turned inside out
tag |= INSIDE(SHELL, INDIR);
} else {
keep = (c_this == SBspUv::INSIDE);
}
} else {
keep = (c_this == SBspUv::INSIDE);
tag |= INSIDE(SHELL, OUTDIR);
}
if(keep) {
if(I == 0) DBPEDGE(tag);
if(KeepEdge(type, opA, tag)) {
final.AddEdge(se->b, se->a, se->auxA, !se->auxB);
}
}
for(se = final.l.First(); se; se = final.l.NextAfter(se)) {
// If our surface intersects an edge, then it will intersect two surfaces
// from the shell at that edge, so we'll get a duplicate. Cull those.
final.l.ClearTags();
int i, j;
for(i = 0; i < final.l.n; i++) {
se = &(final.l.elem[i]);
for(j = i+1; j < final.l.n; j++) {
SEdge *set = &(final.l.elem[j]);
if((set->a).Equals(se->a) && (set->b).Equals(se->b)) {
set->tag = 1;
}
}
if(I == 0) {
Vector mid = (se->a).Plus(se->b).ScaledBy(0.5);
Vector arrow = (se->b).Minus(se->a);
@ -294,13 +398,15 @@ SSurface SSurface::MakeCopyTrimAgainst(SShell *agnst, SShell *parent,
arrow = arrow.WithMagnitude(0.03);
arrow = arrow.Plus(mid);
SS.nakedEdges.AddEdge(PointAt(se->a.x, se->a.y),
PointAt(se->b.x, se->b.y));
SS.nakedEdges.AddEdge(PointAt(mid.x, mid.y),
PointAt(arrow.x, arrow.y));
SS.nakedEdges.AddEdge(ret.PointAt(se->a.x, se->a.y),
ret.PointAt(se->b.x, se->b.y));
SS.nakedEdges.AddEdge(ret.PointAt(mid.x, mid.y),
ret.PointAt(arrow.x, arrow.y));
}
}
final.l.RemoveTagged();
// Use our reassembled edges to trim the new surface.
ret.TrimFromEdgeList(&final);
sameNormal.Clear();
@ -356,9 +462,9 @@ void SShell::MakeFromBoolean(SShell *a, SShell *b, int type) {
// the surfaces in B (which is all of the intersection curves).
a->MakeIntersectionCurvesAgainst(b, this);
if(a->surface.n == 0 || b->surface.n == 0) {
// Then trim and copy the surfaces
I = 100;
if(b->surface.n == 0 || a->surface.n == 0) {
// Then trim and copy the surfaces
a->CopySurfacesTrimAgainst(b, this, type, true);
b->CopySurfacesTrimAgainst(a, this, type, false);
} else {

29
srf/ratpoly.cpp
View File

@ -617,10 +617,7 @@ void SSurface::TriangulateInto(SShell *shell, SMesh *sm) {
SPolygon poly;
ZERO(&poly);
if(!el.AssemblePolygon(&poly, NULL, true)) {
dbp("failed to assemble polygon to trim nurbs surface in uv space");
}
if(el.AssemblePolygon(&poly, NULL, true)) {
int i, start = sm->l.n;
poly.UvTriangulateInto(sm);
@ -638,11 +635,35 @@ void SSurface::TriangulateInto(SShell *shell, SMesh *sm) {
// the triangle direction, sigh.
st->FlipNormal();
}
} else {
dbp("failed to assemble polygon to trim nurbs surface in uv space");
}
el.Clear();
poly.Clear();
}
//-----------------------------------------------------------------------------
// Reverse the parametrisation of one of our dimensions, which flips the
// normal. We therefore must reverse all our trim curves too. The uv
// coordinates change, but trim curves are stored as xyz so nothing happens
//-----------------------------------------------------------------------------
void SSurface::Reverse(void) {
int i, j;
for(i = 0; i < (degm+1)/2; i++) {
for(j = 0; j <= degn; j++) {
SWAP(Vector, ctrl[i][j], ctrl[degm-i][j]);
SWAP(double, weight[i][j], weight[degm-i][j]);
}
}
STrimBy *stb;
for(stb = trim.First(); stb; stb = trim.NextAfter(stb)) {
stb->backwards = !stb->backwards;
SWAP(Vector, stb->start, stb->finish);
}
}
void SSurface::Clear(void) {
trim.Clear();
}

1
srf/surface.h
View File

@ -195,6 +195,7 @@ public:
void MakeEdgesInto(SShell *shell, SEdgeList *sel, bool asUv);
void MakeClassifyingBsp(SShell *shell);
void Reverse(void);
void Clear(void);
};