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solvespace/srf/boolean.cpp

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#include "solvespace.h"
int I, N, FLAG;
void SShell::MakeFromUnionOf(SShell *a, SShell *b) {
MakeFromBoolean(a, b, AS_UNION);
}
void SShell::MakeFromDifferenceOf(SShell *a, SShell *b) {
MakeFromBoolean(a, b, AS_DIFFERENCE);
}
//-----------------------------------------------------------------------------
// Take our original pwl curve. Wherever an edge intersects a surface within
// either agnstA or agnstB, split the piecewise linear element. Then refine
// the intersection so that it lies on all three relevant surfaces: the
// intersecting surface, srfA, and srfB. (So the pwl curve should lie at
// the intersection of srfA and srfB.) Return a new pwl curve with everything
// split.
//-----------------------------------------------------------------------------
static Vector LineStart, LineDirection;
static int ByTAlongLine(const void *av, const void *bv)
{
SInter *a = (SInter *)av,
*b = (SInter *)bv;
double ta = (a->p.Minus(LineStart)).DivPivoting(LineDirection),
tb = (b->p.Minus(LineStart)).DivPivoting(LineDirection);
return (ta > tb) ? 1 : -1;
}
SCurve SCurve::MakeCopySplitAgainst(SShell *agnstA, SShell *agnstB,
SSurface *srfA, SSurface *srfB)
{
SCurve ret;
ret = *this;
ZERO(&(ret.pts));
SCurvePt *p = pts.First();
if(!p) oops();
SCurvePt prev = *p;
ret.pts.Add(p);
p = pts.NextAfter(p);
for(; p; p = pts.NextAfter(p)) {
List<SInter> il;
ZERO(&il);
// Find all the intersections with the two passed shells
if(agnstA)
agnstA->AllPointsIntersecting(prev.p, p->p, &il, true, false, true);
if(agnstB)
agnstB->AllPointsIntersecting(prev.p, p->p, &il, true, false, true);
if(il.n > 0) {
// The intersections were generated by intersecting the pwl
// edge against a surface; so they must be refined to lie
// exactly on the original curve.
il.ClearTags();
SInter *pi;
for(pi = il.First(); pi; pi = il.NextAfter(pi)) {
if(pi->srf == srfA || pi->srf == srfB) {
// The edge certainly intersects the surfaces that it
// trims (at its endpoints), but those ones don't count.
// They are culled later, but no sense calculating them
// and they will cause numerical problems (since two
// of the three surfaces they're refined to lie on will
// be identical, so the matrix will be singular).
pi->tag = 1;
continue;
}
Point2d puv;
(pi->srf)->ClosestPointTo(pi->p, &puv, false);
// Split the edge if the intersection lies within the surface's
// trim curves, or within the chord tol of the trim curve; want
// some slop if points are close to edge and pwl is too coarse,
// and it doesn't hurt to split unnecessarily.
Point2d dummy = { 0, 0 };
int c = pi->srf->bsp->ClassifyPoint(puv, dummy, pi->srf);
if(c == SBspUv::OUTSIDE) {
double d;
d = pi->srf->bsp->MinimumDistanceToEdge(puv, pi->srf);
if(d > SS.ChordTolMm()) {
pi->tag = 1;
continue;
}
}
// We're keeping the intersection, so actually refine it.
(pi->srf)->PointOnSurfaces(srfA, srfB, &(puv.x), &(puv.y));
pi->p = (pi->srf)->PointAt(puv);
}
il.RemoveTagged();
// And now sort them in order along the line. Note that we must
// do that after refining, in case the refining would make two
// points switch places.
LineStart = prev.p;
LineDirection = (p->p).Minus(prev.p);
qsort(il.elem, il.n, sizeof(il.elem[0]), ByTAlongLine);
// And now uses the intersections to generate our split pwl edge(s)
Vector prev = Vector::From(VERY_POSITIVE, 0, 0);
for(pi = il.First(); pi; pi = il.NextAfter(pi)) {
double t = (pi->p.Minus(LineStart)).DivPivoting(LineDirection);
// On-edge intersection will generate same split point for
// both surfaces, so don't create zero-length edge.
if(!prev.Equals(pi->p)) {
SCurvePt scpt;
scpt.tag = 0;
scpt.p = pi->p;
scpt.vertex = true;
ret.pts.Add(&scpt);
}
prev = pi->p;
}
}
il.Clear();
ret.pts.Add(p);
prev = *p;
}
return ret;
}
void SShell::CopyCurvesSplitAgainst(bool opA, SShell *agnst, SShell *into) {
SCurve *sc;
for(sc = curve.First(); sc; sc = curve.NextAfter(sc)) {
SCurve scn = sc->MakeCopySplitAgainst(agnst, NULL,
surface.FindById(sc->surfA),
surface.FindById(sc->surfB));
scn.source = opA ? SCurve::FROM_A : SCurve::FROM_B;
hSCurve hsc = into->curve.AddAndAssignId(&scn);
// And note the new ID so that we can rewrite the trims appropriately
sc->newH = hsc;
}
}
void SSurface::TrimFromEdgeList(SEdgeList *el, bool asUv) {
el->l.ClearTags();
STrimBy stb;
ZERO(&stb);
for(;;) {
// Find an edge, any edge; we'll start from there.
SEdge *se;
for(se = el->l.First(); se; se = el->l.NextAfter(se)) {
if(se->tag) continue;
break;
}
if(!se) break;
se->tag = 1;
stb.start = se->a;
stb.finish = se->b;
stb.curve.v = se->auxA;
stb.backwards = se->auxB ? true : false;
// Find adjoining edges from the same curve; those should be
// merged into a single trim.
bool merged;
do {
merged = false;
for(se = el->l.First(); se; se = el->l.NextAfter(se)) {
if(se->tag) continue;
if(se->auxA != stb.curve.v) continue;
if(( se->auxB && !stb.backwards) ||
(!se->auxB && stb.backwards)) continue;
if((se->a).Equals(stb.finish)) {
stb.finish = se->b;
se->tag = 1;
merged = true;
} else if((se->b).Equals(stb.start)) {
stb.start = se->a;
se->tag = 1;
merged = true;
}
}
} while(merged);
if(asUv) {
stb.start = PointAt(stb.start.x, stb.start.y);
stb.finish = PointAt(stb.finish.x, stb.finish.y);
}
// And add the merged trim, with xyz (not uv like the polygon) pts
trim.Add(&stb);
}
}
static bool KeepRegion(int type, bool opA, int shell, int orig)
{
bool inShell = (shell == SShell::INSIDE),
inSame = (shell == SShell::COINC_SAME),
inOpp = (shell == SShell::COINC_OPP),
inOrig = (orig == SShell::INSIDE);
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 indir_shell, int outdir_shell,
int indir_orig, int outdir_orig)
{
bool keepIn = KeepRegion(type, opA, indir_shell, indir_orig),
keepOut = KeepRegion(type, opA, outdir_shell, outdir_orig);
// 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 void TagByClassifiedEdge(int bspclass, int *indir, int *outdir)
{
switch(bspclass) {
case SBspUv::INSIDE:
*indir = SShell::INSIDE;
*outdir = SShell::INSIDE;
break;
case SBspUv::OUTSIDE:
*indir = SShell::OUTSIDE;
*outdir = SShell::OUTSIDE;
break;
case SBspUv::EDGE_PARALLEL:
*indir = SShell::INSIDE;
*outdir = SShell::OUTSIDE;
break;
case SBspUv::EDGE_ANTIPARALLEL:
*indir = SShell::OUTSIDE;
*outdir = SShell::INSIDE;
break;
default:
dbp("TagByClassifiedEdge: fail!");
*indir = SShell::OUTSIDE;
*outdir = SShell::OUTSIDE;
break;
}
}
void DEBUGEDGELIST(SEdgeList *sel, SSurface *surf) {
dbp("print %d edges", sel->l.n);
SEdge *se;
for(se = sel->l.First(); se; se = sel->l.NextAfter(se)) {
Vector mid = (se->a).Plus(se->b).ScaledBy(0.5);
Vector arrow = (se->b).Minus(se->a);
SWAP(double, arrow.x, arrow.y);
arrow.x *= -1;
arrow = arrow.WithMagnitude(0.01);
arrow = arrow.Plus(mid);
SS.nakedEdges.AddEdge(surf->PointAt(se->a.x, se->a.y),
surf->PointAt(se->b.x, se->b.y));
SS.nakedEdges.AddEdge(surf->PointAt(mid.x, mid.y),
surf->PointAt(arrow.x, arrow.y));
}
}
static char *REGION(int d) {
switch(d) {
case SShell::INSIDE: return "inside";
case SShell::OUTSIDE: return "outside";
case SShell::COINC_SAME: return "same";
case SShell::COINC_OPP: return "opp";
default: return "xxx";
}
}
//-----------------------------------------------------------------------------
// We are given src, with at least one edge, and avoid, a list of points to
// avoid. We return a chain of edges (that share endpoints), such that no
// point within the avoid list ever occurs in the middle of a chain. And we
// delete the edges in that chain from our source list.
//-----------------------------------------------------------------------------
void SSurface::FindChainAvoiding(SEdgeList *src, SEdgeList *dest,
SPointList *avoid)
{
if(src->l.n < 1) oops();
// Start with an arbitrary edge.
dest->l.Add(&(src->l.elem[0]));
src->l.ClearTags();
src->l.elem[0].tag = 1;
bool added;
do {
added = false;
// The start and finish of the current edge chain
Vector s = dest->l.elem[0].a,
f = dest->l.elem[dest->l.n - 1].b;
// We can attach a new edge at the start or finish, as long as that
// start or finish point isn't in the list of points to avoid.
bool startOkay = !avoid->ContainsPoint(s),
finishOkay = !avoid->ContainsPoint(f);
// Now look for an unused edge that joins at the start or finish of
// our chain (if permitted by the avoid list).
SEdge *se;
for(se = src->l.First(); se; se = src->l.NextAfter(se)) {
if(se->tag) continue;
if(startOkay && s.Equals(se->b)) {
dest->l.AddToBeginning(se);
s = se->a;
se->tag = 1;
startOkay = !avoid->ContainsPoint(s);
} else if(finishOkay && f.Equals(se->a)) {
dest->l.Add(se);
f = se->b;
se->tag = 1;
finishOkay = !avoid->ContainsPoint(f);
} else {
continue;
}
added = true;
}
} while(added);
src->l.RemoveTagged();
}
void SSurface::EdgeNormalsWithinSurface(Point2d auv, Point2d buv,
Vector *pt,
Vector *enin, Vector *enout,
Vector *surfn,
DWORD auxA,
SShell *shell, SShell *sha, SShell *shb)
{
// the midpoint of the edge
Point2d muv = (auv.Plus(buv)).ScaledBy(0.5);
// a vector parallel to the edge
Point2d abuv = buv.Minus(auv).WithMagnitude(0.01);
*pt = PointAt(muv);
// If this edge just approximates a curve, then refine our midpoint so
// so that it actually lies on that curve too. Otherwise stuff like
// point-on-face tests will fail, since the point won't actually lie
// on the other face.
hSCurve hc = { auxA };
SCurve *sc = shell->curve.FindById(hc);
if(sc->isExact && sc->exact.deg != 1) {
double t;
sc->exact.ClosestPointTo(*pt, &t, false);
*pt = sc->exact.PointAt(t);
ClosestPointTo(*pt, &muv);
} else if(!sc->isExact) {
SSurface *trimmedA = sc->GetSurfaceA(sha, shb),
*trimmedB = sc->GetSurfaceB(sha, shb);
*pt = trimmedA->ClosestPointOnThisAndSurface(trimmedB, *pt);
ClosestPointTo(*pt, &muv);
}
*surfn = NormalAt(muv.x, muv.y);
// Compute the edge's inner normal in xyz space.
Vector ab = (PointAt(auv)).Minus(PointAt(buv)),
enxyz = (ab.Cross(*surfn)).WithMagnitude(SS.ChordTolMm());
// And based on that, compute the edge's inner normal in uv space. This
// vector is perpendicular to the edge in xyz, but not necessarily in uv.
Vector tu, tv;
TangentsAt(muv.x, muv.y, &tu, &tv);
Point2d enuv;
enuv.x = enxyz.Dot(tu) / tu.MagSquared();
enuv.y = enxyz.Dot(tv) / tv.MagSquared();
// Compute the inner and outer normals of this edge (within the srf),
// in xyz space. These are not necessarily antiparallel, if the
// surface is curved.
Vector pin = PointAt(muv.Minus(enuv)),
pout = PointAt(muv.Plus(enuv));
*enin = pin.Minus(*pt),
*enout = pout.Minus(*pt);
}
//-----------------------------------------------------------------------------
// 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
// also need a pointer to the shell that contains our own surface, since that
// contains our original trim curves.
//-----------------------------------------------------------------------------
SSurface SSurface::MakeCopyTrimAgainst(SShell *parent,
SShell *sha, SShell *shb,
SShell *into,
int type)
{
bool opA = (parent == sha);
SShell *agnst = opA ? shb : sha;
SSurface ret;
// The returned surface is identical, just the trim curves change
ret = *this;
ZERO(&(ret.trim));
// First, build a list of the existing trim curves; update them to use
// the split curves.
STrimBy *stb;
for(stb = trim.First(); stb; stb = trim.NextAfter(stb)) {
STrimBy stn = *stb;
stn.curve = (parent->curve.FindById(stn.curve))->newH;
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; remember the coordinates could
// be changed if we just flipped the surface normal, and we are using
// the split curves (not the original curves).
SEdgeList orig;
ZERO(&orig);
ret.MakeEdgesInto(into, &orig, AS_UV);
ret.trim.Clear();
// which means that we can't necessarily use the old BSP...
SBspUv *origBsp = SBspUv::From(&orig, &ret);
// And now intersect the other shell against us
SEdgeList inter;
ZERO(&inter);
SSurface *ss;
for(ss = agnst->surface.First(); ss; ss = agnst->surface.NextAfter(ss)) {
SCurve *sc;
for(sc = into->curve.First(); sc; sc = into->curve.NextAfter(sc)) {
if(sc->source != SCurve::FROM_INTERSECTION) continue;
if(opA) {
if(sc->surfA.v != h.v || sc->surfB.v != ss->h.v) continue;
} else {
if(sc->surfB.v != h.v || sc->surfA.v != ss->h.v) continue;
}
int i;
for(i = 1; i < sc->pts.n; i++) {
Vector a = sc->pts.elem[i-1].p,
b = sc->pts.elem[i].p;
Point2d auv, buv;
ss->ClosestPointTo(a, &(auv.x), &(auv.y));
ss->ClosestPointTo(b, &(buv.x), &(buv.y));
int c = ss->bsp->ClassifyEdge(auv, buv, ss);
if(c != SBspUv::OUTSIDE) {
Vector ta = Vector::From(0, 0, 0);
Vector tb = Vector::From(0, 0, 0);
ret.ClosestPointTo(a, &(ta.x), &(ta.y));
ret.ClosestPointTo(b, &(tb.x), &(tb.y));
Vector tn = ret.NormalAt(ta.x, ta.y);
Vector sn = ss->NormalAt(auv.x, auv.y);
// We are subtracting the portion of our surface that
// lies in the shell, so the in-plane edge normal should
// point opposite to the surface normal.
bool bkwds = true;
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);
}
}
}
}
}
// Record all the points where more than two edges join, which I will call
// the choosing points. If two edges join at a non-choosing point, then
// they must either both be kept or both be discarded (since that would
// otherwise create an open contour).
SPointList choosing;
ZERO(&choosing);
SEdge *se;
for(se = orig.l.First(); se; se = orig.l.NextAfter(se)) {
choosing.IncrementTagFor(se->a);
choosing.IncrementTagFor(se->b);
}
for(se = inter.l.First(); se; se = inter.l.NextAfter(se)) {
choosing.IncrementTagFor(se->a);
choosing.IncrementTagFor(se->b);
}
SPoint *sp;
for(sp = choosing.l.First(); sp; sp = choosing.l.NextAfter(sp)) {
if(sp->tag == 2) {
sp->tag = 1;
} else {
sp->tag = 0;
}
}
choosing.l.RemoveTagged();
// The list of edges to trim our new surface, a combination of edges from
// our original and intersecting edge lists.
SEdgeList final;
ZERO(&final);
while(orig.l.n > 0) {
SEdgeList chain;
ZERO(&chain);
FindChainAvoiding(&orig, &chain, &choosing);
// Arbitrarily choose an edge within the chain to classify; they
// should all be the same, though.
se = &(chain.l.elem[chain.l.n/2]);
Point2d auv = (se->a).ProjectXy(),
buv = (se->b).ProjectXy();
Vector pt, enin, enout, surfn;
ret.EdgeNormalsWithinSurface(auv, buv, &pt, &enin, &enout, &surfn,
se->auxA, into, sha, shb);
int indir_shell, outdir_shell, indir_orig, outdir_orig;
indir_orig = SShell::INSIDE;
outdir_orig = SShell::OUTSIDE;
agnst->ClassifyEdge(&indir_shell, &outdir_shell,
ret.PointAt(auv), ret.PointAt(buv), pt,
enin, enout, surfn);
if(KeepEdge(type, opA, indir_shell, outdir_shell,
indir_orig, outdir_orig))
{
for(se = chain.l.First(); se; se = chain.l.NextAfter(se)) {
final.AddEdge(se->a, se->b, se->auxA, se->auxB);
}
}
chain.Clear();
}
while(inter.l.n > 0) {
SEdgeList chain;
ZERO(&chain);
FindChainAvoiding(&inter, &chain, &choosing);
// Any edge in the chain, same as above.
se = &(chain.l.elem[chain.l.n/2]);
Point2d auv = (se->a).ProjectXy(),
buv = (se->b).ProjectXy();
Vector pt, enin, enout, surfn;
ret.EdgeNormalsWithinSurface(auv, buv, &pt, &enin, &enout, &surfn,
se->auxA, into, sha, shb);
int indir_shell, outdir_shell, indir_orig, outdir_orig;
int c_this = origBsp->ClassifyEdge(auv, buv, &ret);
TagByClassifiedEdge(c_this, &indir_orig, &outdir_orig);
agnst->ClassifyEdge(&indir_shell, &outdir_shell,
ret.PointAt(auv), ret.PointAt(buv), pt,
enin, enout, surfn);
if(KeepEdge(type, opA, indir_shell, outdir_shell,
indir_orig, outdir_orig))
{
for(se = chain.l.First(); se; se = chain.l.NextAfter(se)) {
final.AddEdge(se->a, se->b, se->auxA, se->auxB);
}
}
chain.Clear();
}
// Cull extraneous edges; duplicates or anti-parallel pairs. In particular,
// we can get duplicate edges if our surface intersects the other shell
// at an edge, so that both surfaces intersect coincident (and both
// generate an intersection edge).
final.CullExtraneousEdges();
// Use our reassembled edges to trim the new surface.
ret.TrimFromEdgeList(&final, true);
SPolygon poly;
ZERO(&poly);
final.l.ClearTags();
if(!final.AssemblePolygon(&poly, NULL, true)) {
into->booleanFailed = true;
dbp("failed: I=%d, avoid=%d", I, choosing.l.n);
DEBUGEDGELIST(&final, &ret);
}
poly.Clear();
choosing.Clear();
final.Clear();
inter.Clear();
orig.Clear();
return ret;
}
void SShell::CopySurfacesTrimAgainst(SShell *sha, SShell *shb, SShell *into,
int type)
{
SSurface *ss;
for(ss = surface.First(); ss; ss = surface.NextAfter(ss)) {
SSurface ssn;
ssn = ss->MakeCopyTrimAgainst(this, sha, shb, into, type);
ss->newH = into->surface.AddAndAssignId(&ssn);
I++;
}
}
void SShell::MakeIntersectionCurvesAgainst(SShell *agnst, SShell *into) {
SSurface *sa;
for(sa = surface.First(); sa; sa = surface.NextAfter(sa)) {
SSurface *sb;
for(sb = agnst->surface.First(); sb; sb = agnst->surface.NextAfter(sb)){
// Intersect every surface from our shell against every surface
// from agnst; this will add zero or more curves to the curve
// list for into.
sa->IntersectAgainst(sb, this, agnst, into);
}
}
}
void SShell::CleanupAfterBoolean(void) {
SSurface *ss;
for(ss = surface.First(); ss; ss = surface.NextAfter(ss)) {
ss->edges.Clear();
}
}
//-----------------------------------------------------------------------------
// All curves contain handles to the two surfaces that they trim. After a
// Boolean or assembly, we must rewrite those handles to refer to the curves
// by their new IDs.
//-----------------------------------------------------------------------------
void SShell::RewriteSurfaceHandlesForCurves(SShell *a, SShell *b) {
SCurve *sc;
for(sc = curve.First(); sc; sc = curve.NextAfter(sc)) {
sc->surfA = sc->GetSurfaceA(a, b)->newH,
sc->surfB = sc->GetSurfaceB(a, b)->newH;
}
}
//-----------------------------------------------------------------------------
// Copy all the surfaces and curves from two different shells into a single
// shell. The only difficulty is to rewrite all of their handles; we don't
// look for any surface intersections, so if two objects interfere then the
// result is just self-intersecting. This is used for assembly, since it's
// much faster than merging as union.
//-----------------------------------------------------------------------------
void SShell::MakeFromAssemblyOf(SShell *a, SShell *b) {
booleanFailed = false;
Vector t = Vector::From(0, 0, 0);
Quaternion q = Quaternion::IDENTITY;
int i = 0;
SShell *ab;
// First, copy over all the curves. Note which shell (a or b) each curve
// came from, but assign it a new ID.
SCurve *c, cn;
for(i = 0; i < 2; i++) {
ab = (i == 0) ? a : b;
for(c = ab->curve.First(); c; c = ab->curve.NextAfter(c)) {
cn = SCurve::FromTransformationOf(c, t, q, false);
cn.source = (i == 0) ? SCurve::FROM_A : SCurve::FROM_B;
// surfA and surfB are wrong now, and we can't fix them until
// we've assigned IDs to the surfaces. So we'll get that later.
c->newH = curve.AddAndAssignId(&cn);
}
}
// Likewise copy over all the surfaces.
SSurface *s, sn;
for(i = 0; i < 2; i++) {
ab = (i == 0) ? a : b;
for(s = ab->surface.First(); s; s = ab->surface.NextAfter(s)) {
sn = SSurface::FromTransformationOf(s, t, q, false, true);
// All the trim curve IDs get rewritten; we know the new handles
// to the curves since we recorded them in the previous step.
STrimBy *stb;
for(stb = sn.trim.First(); stb; stb = sn.trim.NextAfter(stb)) {
stb->curve = ab->curve.FindById(stb->curve)->newH;
}
s->newH = surface.AddAndAssignId(&sn);
}
}
// Finally, rewrite the surfaces associated with each curve to use the
// new handles.
RewriteSurfaceHandlesForCurves(a, b);
}
void SShell::MakeFromBoolean(SShell *a, SShell *b, int type) {
booleanFailed = false;
a->MakeClassifyingBsps(NULL);
b->MakeClassifyingBsps(NULL);
// Copy over all the original curves, splitting them so that a
// piecwise linear segment never crosses a surface from the other
// shell.
a->CopyCurvesSplitAgainst(true, b, this);
b->CopyCurvesSplitAgainst(false, a, this);
// Generate the intersection curves for each surface in A against all
// the surfaces in B (which is all of the intersection curves).
a->MakeIntersectionCurvesAgainst(b, this);
SCurve *sc;
for(sc = curve.First(); sc; sc = curve.NextAfter(sc)) {
SSurface *srfA = sc->GetSurfaceA(a, b),
*srfB = sc->GetSurfaceB(a, b);
sc->RemoveShortSegments(srfA, srfB);
}
// And clean up the piecewise linear things we made as a calculation aid
a->CleanupAfterBoolean();
b->CleanupAfterBoolean();
// Remake the classifying BSPs with the split (and short-segment-removed)
// curves
a->MakeClassifyingBsps(this);
b->MakeClassifyingBsps(this);
if(b->surface.n == 0 || a->surface.n == 0) {
I = 1000000;
} else {
I = 0;
}
// Then trim and copy the surfaces
a->CopySurfacesTrimAgainst(a, b, this, type);
b->CopySurfacesTrimAgainst(a, b, this, type);
// Now that we've copied the surfaces, we know their new hSurfaces, so
// rewrite the curves to refer to the surfaces by their handles in the
// result.
RewriteSurfaceHandlesForCurves(a, b);
// And clean up the piecewise linear things we made as a calculation aid
a->CleanupAfterBoolean();
b->CleanupAfterBoolean();
}
//-----------------------------------------------------------------------------
// All of the BSP routines that we use to perform and accelerate polygon ops.
//-----------------------------------------------------------------------------
void SShell::MakeClassifyingBsps(SShell *useCurvesFrom) {
SSurface *ss;
for(ss = surface.First(); ss; ss = surface.NextAfter(ss)) {
ss->MakeClassifyingBsp(this, useCurvesFrom);
}
}
void SSurface::MakeClassifyingBsp(SShell *shell, SShell *useCurvesFrom) {
SEdgeList el;
ZERO(&el);
MakeEdgesInto(shell, &el, AS_UV, useCurvesFrom);
bsp = SBspUv::From(&el, this);
el.Clear();
ZERO(&edges);
MakeEdgesInto(shell, &edges, AS_XYZ, useCurvesFrom);
}
SBspUv *SBspUv::Alloc(void) {
return (SBspUv *)AllocTemporary(sizeof(SBspUv));
}
static int ByLength(const void *av, const void *bv)
{
SEdge *a = (SEdge *)av,
*b = (SEdge *)bv;
double la = (a->a).Minus(a->b).Magnitude(),
lb = (b->a).Minus(b->b).Magnitude();
// Sort in descending order, longest first. This improves numerical
// stability for the normals.
return (la < lb) ? 1 : -1;
}
SBspUv *SBspUv::From(SEdgeList *el, SSurface *srf) {
SEdgeList work;
ZERO(&work);
SEdge *se;
for(se = el->l.First(); se; se = el->l.NextAfter(se)) {
work.AddEdge(se->a, se->b, se->auxA, se->auxB);
}
qsort(work.l.elem, work.l.n, sizeof(work.l.elem[0]), ByLength);
SBspUv *bsp = NULL;
for(se = work.l.First(); se; se = work.l.NextAfter(se)) {
bsp = bsp->InsertEdge((se->a).ProjectXy(), (se->b).ProjectXy(), srf);
}
work.Clear();
return bsp;
}
//-----------------------------------------------------------------------------
// The points in this BSP are in uv space, but we want to apply our tolerances
// consistently in xyz (i.e., we want to say a point is on-edge if its xyz
// distance to that edge is less than LENGTH_EPS, irrespective of its distance
// in uv). So we linearize the surface about the point we're considering and
// then do the test. That preserves point-on-line relationships, and the only
// time we care about exact correctness is when we're very close to the line,
// which is when the linearization is accurate.
//-----------------------------------------------------------------------------
void SBspUv::ScalePoints(Point2d *pt, Point2d *a, Point2d *b, SSurface *srf) {
Vector tu, tv;
srf->TangentsAt(pt->x, pt->y, &tu, &tv);
double mu = tu.Magnitude(), mv = tv.Magnitude();
pt->x *= mu; pt->y *= mv;
a ->x *= mu; a ->y *= mv;
b ->x *= mu; b ->y *= mv;
}
double SBspUv::ScaledSignedDistanceToLine(Point2d pt, Point2d a, Point2d b,
SSurface *srf)
{
ScalePoints(&pt, &a, &b, srf);
Point2d n = ((b.Minus(a)).Normal()).WithMagnitude(1);
double d = a.Dot(n);
return pt.Dot(n) - d;
}
double SBspUv::ScaledDistanceToLine(Point2d pt, Point2d a, Point2d b, bool seg,
SSurface *srf)
{
ScalePoints(&pt, &a, &b, srf);
return pt.DistanceToLine(a, b, seg);
}
SBspUv *SBspUv::InsertEdge(Point2d ea, Point2d eb, SSurface *srf) {
if(!this) {
SBspUv *ret = Alloc();
ret->a = ea;
ret->b = eb;
return ret;
}
double dea = ScaledSignedDistanceToLine(ea, a, b, srf),
deb = ScaledSignedDistanceToLine(eb, a, b, srf);
if(fabs(dea) < LENGTH_EPS && fabs(deb) < LENGTH_EPS) {
// Line segment is coincident with this one, store in same node
SBspUv *m = Alloc();
m->a = ea;
m->b = eb;
m->more = more;
more = m;
} else if(fabs(dea) < LENGTH_EPS) {
// Point A lies on this lie, but point B does not
if(deb > 0) {
pos = pos->InsertEdge(ea, eb, srf);
} else {
neg = neg->InsertEdge(ea, eb, srf);
}
} else if(fabs(deb) < LENGTH_EPS) {
// Point B lies on this lie, but point A does not
if(dea > 0) {
pos = pos->InsertEdge(ea, eb, srf);
} else {
neg = neg->InsertEdge(ea, eb, srf);
}
} else if(dea > 0 && deb > 0) {
pos = pos->InsertEdge(ea, eb, srf);
} else if(dea < 0 && deb < 0) {
neg = neg->InsertEdge(ea, eb, srf);
} else {
// New edge crosses this one; we need to split.
Point2d n = ((b.Minus(a)).Normal()).WithMagnitude(1);
double d = a.Dot(n);
double t = (d - n.Dot(ea)) / (n.Dot(eb.Minus(ea)));
Point2d pi = ea.Plus((eb.Minus(ea)).ScaledBy(t));
if(dea > 0) {
pos = pos->InsertEdge(ea, pi, srf);
neg = neg->InsertEdge(pi, eb, srf);
} else {
neg = neg->InsertEdge(ea, pi, srf);
pos = pos->InsertEdge(pi, eb, srf);
}
}
return this;
}
int SBspUv::ClassifyPoint(Point2d p, Point2d eb, SSurface *srf) {
if(!this) return OUTSIDE;
double dp = ScaledSignedDistanceToLine(p, a, b, srf);
if(fabs(dp) < LENGTH_EPS) {
SBspUv *f = this;
while(f) {
Point2d ba = (f->b).Minus(f->a);
if(ScaledDistanceToLine(p, f->a, ba, true, srf) < LENGTH_EPS) {
if(ScaledDistanceToLine(eb, f->a, ba, false, srf) < LENGTH_EPS){
if(ba.Dot(eb.Minus(p)) > 0) {
return EDGE_PARALLEL;
} else {
return EDGE_ANTIPARALLEL;
}
} else {
return EDGE_OTHER;
}
}
f = f->more;
}
// Pick arbitrarily which side to send it down, doesn't matter
int c1 = neg ? neg->ClassifyPoint(p, eb, srf) : OUTSIDE;
int c2 = pos ? pos->ClassifyPoint(p, eb, srf) : INSIDE;
if(c1 != c2) {
dbp("MISMATCH: %d %d %08x %08x", c1, c2, neg, pos);
}
return c1;
} else if(dp > 0) {
return pos ? pos->ClassifyPoint(p, eb, srf) : INSIDE;
} else {
return neg ? neg->ClassifyPoint(p, eb, srf) : OUTSIDE;
}
}
int SBspUv::ClassifyEdge(Point2d ea, Point2d eb, SSurface *srf) {
int ret = ClassifyPoint((ea.Plus(eb)).ScaledBy(0.5), eb, srf);
if(ret == EDGE_OTHER) {
// Perhaps the edge is tangent at its midpoint (and we screwed up
// somewhere earlier and failed to split it); try a different
// point on the edge.
ret = ClassifyPoint(ea.Plus((eb.Minus(ea)).ScaledBy(0.294)), eb, srf);
}
return ret;
}
double SBspUv::MinimumDistanceToEdge(Point2d p, SSurface *srf) {
if(!this) return VERY_POSITIVE;
double dn = neg->MinimumDistanceToEdge(p, srf),
dp = pos->MinimumDistanceToEdge(p, srf);
Point2d as = a, bs = b;
ScalePoints(&p, &as, &bs, srf);
double d = p.DistanceToLine(as, bs.Minus(as), true);
return min(d, min(dn, dp));
}
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