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Construct surfaces of revolution from lathe groups, although we're 

not triangulating them correctly yet.

[git-p4: depot-paths = "//depot/solvespace/": change = 1950]
solver
Jonathan Westhues 2009-04-28 18:42:44 -08:00
parent ff6eae884e
commit 3581d9b9ec
5 changed files with 155 additions and 2 deletions
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1
dsc.h
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@ -21,6 +21,7 @@ public:
static Quaternion From(double w, double vx, double vy, double vz);
static Quaternion From(hParam w, hParam vx, hParam vy, hParam vz);
static Quaternion From(Vector u, Vector v);
static Quaternion From(Vector axis, double dtheta);
Quaternion Plus(Quaternion b);
Quaternion Minus(Quaternion b);

5
groupmesh.cpp
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@ -185,10 +185,11 @@ void Group::GenerateShellAndMesh(void) {
} else if(type == LATHE) {
Group *src = SK.GetGroup(opA);
Vector orig = SK.GetEntity(predef.origin)->PointGetNum();
Vector axis = SK.GetEntity(predef.entityB)->VectorGetNum();
Vector pt = SK.GetEntity(predef.origin)->PointGetNum(),
axis = SK.GetEntity(predef.entityB)->VectorGetNum();
axis = axis.WithMagnitude(1);
thisShell.MakeFromRevolutionOf(&(src->bezierLoopSet), pt, axis, color);
} else if(type == IMPORTED) {
// Triangles are just copied over, with the appropriate transformation
// applied.

136
srf/surface.cpp
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@ -62,6 +62,48 @@ bool SSurface::IsCylinder(Vector *axis, Vector *center, double *r,
return true;
}
SSurface SSurface::FromRevolutionOf(SBezier *sb, Vector pt, Vector axis,
double thetas, double thetaf)
{
SSurface ret;
ZERO(&ret);
ret.degm = sb->deg;
ret.degn = 2;
double dtheta = fabs(WRAP_SYMMETRIC(thetaf - thetas, 2*PI));
// We now wish to revolve the curve about the z axis
int i;
for(i = 0; i <= ret.degm; i++) {
Vector p = sb->ctrl[i];
Vector ps = p.RotatedAbout(pt, axis, thetas),
pf = p.RotatedAbout(pt, axis, thetaf);
Vector c = ps.ClosestPointOnLine(pt, axis);
Vector rs = ps.Minus(c),
rf = pf.Minus(c);
Vector ts = axis.Cross(rs),
tf = axis.Cross(rf);
Vector ct = Vector::AtIntersectionOfLines(ps, ps.Plus(ts),
pf, pf.Plus(tf),
NULL, NULL, NULL);
ret.ctrl[i][0] = ps;
ret.ctrl[i][1] = ct;
ret.ctrl[i][2] = pf;
ret.weight[i][0] = sb->weight[i];
ret.weight[i][1] = sb->weight[i]*cos(dtheta/2);
ret.weight[i][2] = sb->weight[i];
}
return ret;
}
SSurface SSurface::FromPlane(Vector pt, Vector u, Vector v) {
SSurface ret;
ZERO(&ret);
@ -430,6 +472,100 @@ void SShell::MakeFromExtrusionOf(SBezierLoopSet *sbls, Vector t0, Vector t1,
}
}
void SShell::MakeFromRevolutionOf(SBezierLoopSet *sbls, Vector pt, Vector axis,
int color)
{
ZERO(this);
// Normalize the axis direction so that the direction of revolution
// ends up parallel to the normal of the sketch, on the side of the
// axis where the sketch is.
Vector pto = sbls->point,
ptc = pto.ClosestPointOnLine(pt, axis),
up = (pto.Minus(ptc)).WithMagnitude(1),
vp = (sbls->normal).Cross(up);
if(vp.Dot(axis) < 0) {
axis = axis.ScaledBy(-1);
}
SBezierLoop *sbl;
for(sbl = sbls->l.First(); sbl; sbl = sbls->l.NextAfter(sbl)) {
int i, j;
SBezier *sb, *prev;
typedef struct {
hSSurface d[4];
} Revolved;
List<Revolved> hsl;
ZERO(&hsl);
for(sb = sbl->l.First(); sb; sb = sbl->l.NextAfter(sb)) {
Revolved revs;
for(j = 0; j < 4; j++) {
SSurface ss = SSurface::FromRevolutionOf(sb, pt, axis,
(PI/2)*j,
(PI/2)*(j+1));
ss.color = color;
revs.d[j] = surface.AddAndAssignId(&ss);
}
hsl.Add(&revs);
}
for(i = 0; i < sbl->l.n; i++) {
Revolved revs = hsl.elem[i],
revsp = hsl.elem[WRAP(i-1, sbl->l.n)];
sb = &(sbl->l.elem[i]);
prev = &(sbl->l.elem[WRAP(i-1, sbl->l.n)]);
for(j = 0; j < 4; j++) {
Quaternion qs = Quaternion::From(axis, (PI/2)*j);
// we want Q*(x - p) + p = Q*x + (p - Q*p)
Vector ts = pt.Minus(qs.Rotate(pt));
SCurve sc;
ZERO(&sc);
sc.isExact = true;
sc.exact = sb->TransformedBy(ts, qs);
(sc.exact).MakePwlInto(&(sc.pts));
sc.surfA = revs.d[j];
sc.surfB = revs.d[WRAP(j-1, 4)];
hSCurve hcb = curve.AddAndAssignId(&sc);
STrimBy stb;
stb = STrimBy::EntireCurve(this, hcb, true);
(surface.FindById(sc.surfA))->trim.Add(&stb);
stb = STrimBy::EntireCurve(this, hcb, false);
(surface.FindById(sc.surfB))->trim.Add(&stb);
SSurface *ss = surface.FindById(sc.surfA);
ZERO(&sc);
sc.isExact = true;
sc.exact = SBezier::From(ss->ctrl[0][0],
ss->ctrl[0][1],
ss->ctrl[0][2]);
sc.exact.weight[1] = ss->weight[0][1];
(sc.exact).MakePwlInto(&(sc.pts));
sc.surfA = revs.d[j];
sc.surfB = revsp.d[j];
hSCurve hcc = curve.AddAndAssignId(&sc);
stb = STrimBy::EntireCurve(this, hcc, false);
(surface.FindById(sc.surfA))->trim.Add(&stb);
stb = STrimBy::EntireCurve(this, hcc, true);
(surface.FindById(sc.surfB))->trim.Add(&stb);
}
}
hsl.Clear();
}
}
void SShell::MakeFromCopyOf(SShell *a) {
MakeFromTransformationOf(a, Vector::From(0, 0, 0), Quaternion::IDENTITY);
}

4
srf/surface.h
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@ -201,6 +201,8 @@ public:
SBspUv *bsp;
static SSurface FromExtrusionOf(SBezier *spc, Vector t0, Vector t1);
static SSurface FromRevolutionOf(SBezier *sb, Vector pt, Vector axis,
double thetas, double thetaf);
static SSurface FromPlane(Vector pt, Vector u, Vector v);
static SSurface FromTransformationOf(SSurface *a, Vector t, Quaternion q,
bool includingTrims);
@ -265,6 +267,8 @@ public:
void MakeFromExtrusionOf(SBezierLoopSet *sbls, Vector t0, Vector t1,
int color);
void MakeFromRevolutionOf(SBezierLoopSet *sbls, Vector pt, Vector axis,
int color);
void MakeFromUnionOf(SShell *a, SShell *b);
void MakeFromDifferenceOf(SShell *a, SShell *b);

11
util.cpp
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@ -120,6 +120,17 @@ Quaternion Quaternion::From(hParam w, hParam vx, hParam vy, hParam vz) {
return q;
}
Quaternion Quaternion::From(Vector axis, double dtheta) {
Quaternion q;
double c = cos(dtheta / 2), s = sin(dtheta / 2);
axis = axis.WithMagnitude(s);
q.w = c;
q.vx = axis.x;
q.vy = axis.y;
q.vz = axis.z;
return q;
}
Quaternion Quaternion::From(Vector u, Vector v)
{
Vector n = u.Cross(v);