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Add plane-plane intersection as a special case (to generate the

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trimmed line), and plane-line intersection. Terminate the Bezier
surface subdivision on a chord tolerance, and that seems okay now.
And print info about the graphics adapter in the text window, could
be useful.

Also have a cylinder-detection routine that works; should special
case those surfaces in closed form since they are common, but not
doing it yet.

[git-p4: depot-paths = "//depot/solvespace/": change = 1928]
This commit is contained in:
Jonathan Westhues 2009-03-14 12:01:20 -08:00
parent 8c648af4de
commit adc910185c
11 changed files with 246 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile
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@ -53,7 +53,7 @@ LIBS = user32.lib gdi32.lib comctl32.lib advapi32.lib shell32.lib opengl32.lib g
all: $(OBJDIR)/solvespace.exe
@cp $(OBJDIR)/solvespace.exe .
solvespace t.slvs
solvespace tttt.slvs
clean:
rm -f obj/*

4
draw.cpp
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@ -1024,10 +1024,10 @@ void GraphicsWindow::Paint(int w, int h) {
// And the naked edges, if the user did Analyze -> Show Naked Edges.
glLineWidth(7);
glEnable(GL_LINE_STIPPLE);
glLineStipple(4, 0x5555);
glLineStipple(1, 0x5555);
glColor3d(1, 0, 0);
glxDrawEdges(&(SS.nakedEdges));
glLineStipple(4, 0xaaaa);
glLineStipple(1, 0xaaaa);
glColor3d(0, 0, 0);
glxDrawEdges(&(SS.nakedEdges));
glDisable(GL_LINE_STIPPLE);

2
dsc.h
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@ -95,6 +95,8 @@ class Point2d {
public:
double x, y;
static Point2d From(double x, double y);
Point2d Plus(Point2d b);
Point2d Minus(Point2d b);
Point2d ScaledBy(double s);

1
srf/boolean.cpp
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@ -73,7 +73,6 @@ SCurve SCurve::MakeCopySplitAgainst(SShell *agnstA, SShell *agnstB,
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);
dbp("t=%.3f", t);
// On-edge intersection will generate same split point for
// both surfaces, so don't create zero-length edge.
if(!prev.Equals(pi->p)) {

72
srf/ratpoly.cpp
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@ -50,7 +50,42 @@ static double Bernstein(int k, int deg, double t)
double BernsteinDerivative(int k, int deg, double t)
{
return deg*(Bernstein(k-1, deg-1, t) - Bernstein(k, deg-1, t));
switch(deg) {
case 0:
return 0;
break;
case 1:
if(k == 0) {
return -1;
} else if(k = 1) {
return 1;
}
break;
case 2:
if(k == 0) {
return -2 + 2*t;
} else if(k == 1) {
return 2 - 4*t;
} else if(k == 2) {
return 2*t;
}
break;
case 3:
if(k == 0) {
return -3 + 6*t - 3*t*t;
} else if(k == 1) {
return 3 - 12*t + 9*t*t;
} else if(k == 2) {
return 6*t - 9*t*t;
} else if(k == 3) {
return 3*t*t;
}
break;
}
oops();
}
SBezier SBezier::From(Vector p0, Vector p1) {
@ -418,6 +453,41 @@ bool SSurface::IsExtrusion(SBezier *of, Vector *alongp) {
return true;
}
bool SSurface::IsCylinder(Vector *center, Vector *axis, double *r,
double *dtheta)
{
SBezier sb;
if(!IsExtrusion(&sb, axis)) return false;
if(sb.deg != 2) return false;
Vector t0 = (sb.ctrl[0]).Minus(sb.ctrl[1]),
t2 = (sb.ctrl[2]).Minus(sb.ctrl[1]),
r0 = axis->Cross(t0),
r2 = axis->Cross(t2);
*center = Vector::AtIntersectionOfLines(sb.ctrl[0], (sb.ctrl[0]).Plus(r0),
sb.ctrl[2], (sb.ctrl[2]).Plus(r2),
NULL, NULL, NULL);
double rd0 = center->Minus(sb.ctrl[0]).Magnitude(),
rd2 = center->Minus(sb.ctrl[2]).Magnitude();
if(fabs(rd0 - rd2) > LENGTH_EPS) return false;
Vector u = r0.WithMagnitude(1),
v = (axis->Cross(u)).WithMagnitude(1);
Point2d c2 = center->Project2d(u, v),
pa2 = (sb.ctrl[0]).Project2d(u, v).Minus(c2),
pb2 = (sb.ctrl[2]).Project2d(u, v).Minus(c2);
double thetaa = atan2(pa2.y, pa2.x), // in fact always zero due to csys
thetab = atan2(pb2.y, pb2.x);
*dtheta = WRAP_NOT_0(thetab - thetaa, 2*PI);
if(fabs(sb.weight[1] - cos(*dtheta/2)) > LENGTH_EPS) return false;
return true;
}
SSurface SSurface::FromPlane(Vector pt, Vector u, Vector v) {
SSurface ret;
ZERO(&ret);

2
srf/surface.h
View File

@ -203,6 +203,7 @@ public:
void CopyRowOrCol(bool row, int this_ij, SSurface *src, int src_ij);
void BlendRowOrCol(bool row, int this_ij, SSurface *a, int a_ij,
SSurface *b, int b_ij);
double DepartureFromCoplanar(void);
void SplitInHalf(bool byU, SSurface *sa, SSurface *sb);
void AllPointsIntersecting(Vector a, Vector b,
List<SInter> *l, bool seg, bool trimmed);
@ -221,6 +222,7 @@ public:
bool CoincidentWithPlane(Vector n, double d);
bool CoincidentWith(SSurface *ss, bool sameNormal);
bool IsExtrusion(SBezier *of, Vector *along);
bool IsCylinder(Vector *center, Vector *axis, double *r, double *dtheta);
void TriangulateInto(SShell *shell, SMesh *sm);
void MakeEdgesInto(SShell *shell, SEdgeList *sel, bool asUv);

161
srf/surfinter.cpp
View File

@ -15,8 +15,7 @@ void SSurface::AddExactIntersectionCurve(SBezier *sb, SSurface *srfB,
SCurve split = sc.MakeCopySplitAgainst(agnstA, agnstB, this, srfB);
sc.Clear();
/*
if(sb->deg == 1) {
if(0 && sb->deg == 1) {
dbp(" ");
Vector *prev = NULL, *v;
dbp("split.pts.n =%d", split.pts.n);
@ -26,7 +25,7 @@ void SSurface::AddExactIntersectionCurve(SBezier *sb, SSurface *srfB,
}
prev = v;
}
} */
}
split.source = SCurve::FROM_INTERSECTION;
into->curve.AddAndAssignId(&split);
@ -44,7 +43,67 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
return;
}
if((degm == 1 && degn == 1 && b->IsExtrusion(NULL, NULL)) ||
if(degm == 1 && degn == 1 && b->degm == 1 && b->degn == 1) {
// Line-line intersection; it's a plane or nothing.
Vector na = NormalAt(0, 0).WithMagnitude(1),
nb = b->NormalAt(0, 0).WithMagnitude(1);
double da = na.Dot(PointAt(0, 0)),
db = nb.Dot(b->PointAt(0, 0));
Vector dl = na.Cross(nb);
if(dl.Magnitude() < LENGTH_EPS) return; // parallel planes
dl = dl.WithMagnitude(1);
Vector p = Vector::AtIntersectionOfPlanes(na, da, nb, db);
// Trim it to the region 0 <= {u,v} <= 1 for each plane; not strictly
// necessary, since line will be split and excess edges culled, but
// this improves speed and robustness.
int i;
double tmax = VERY_POSITIVE, tmin = VERY_NEGATIVE;
for(i = 0; i < 2; i++) {
SSurface *s = (i == 0) ? this : b;
Vector tu, tv;
s->TangentsAt(0, 0, &tu, &tv);
double up, vp, ud, vd;
s->ClosestPointTo(p, &up, &vp);
ud = (dl.Dot(tu)) / tu.MagSquared();
vd = (dl.Dot(tv)) / tv.MagSquared();
// so u = up + t*ud
// v = vp + t*vd
if(ud > LENGTH_EPS) {
tmin = max(tmin, -up/ud);
tmax = min(tmax, (1 - up)/ud);
} else if(ud < -LENGTH_EPS) {
tmax = min(tmax, -up/ud);
tmin = max(tmin, (1 - up)/ud);
} else {
if(up < -LENGTH_EPS || up > 1 + LENGTH_EPS) {
// u is constant, and outside [0, 1]
tmax = VERY_NEGATIVE;
}
}
if(vd > LENGTH_EPS) {
tmin = max(tmin, -vp/vd);
tmax = min(tmax, (1 - vp)/vd);
} else if(vd < -LENGTH_EPS) {
tmax = min(tmax, -vp/vd);
tmin = max(tmin, (1 - vp)/vd);
} else {
if(vp < -LENGTH_EPS || vp > 1 + LENGTH_EPS) {
// v is constant, and outside [0, 1]
tmax = VERY_NEGATIVE;
}
}
}
if(tmax > tmin) {
SBezier bezier = SBezier::From(p.Plus(dl.ScaledBy(tmin)),
p.Plus(dl.ScaledBy(tmax)));
AddExactIntersectionCurve(&bezier, b, agnstA, agnstB, into);
}
} else if((degm == 1 && degn == 1 && b->IsExtrusion(NULL, NULL)) ||
(b->degm == 1 && b->degn == 1 && this->IsExtrusion(NULL, NULL)))
{
// The intersection between a plane and a surface of extrusion
@ -95,10 +154,6 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
} else {
// Direction of extrusion is not parallel to plane; so
// intersection is projection of extruded curve into our plane.
// If both curves are planes, then we could do it either way;
// so choose the one that generates the shorter curve.
// XXX TODO
int i;
for(i = 0; i <= bezier.deg; i++) {
Vector p0 = bezier.ctrl[i],
@ -116,6 +171,64 @@ void SSurface::IntersectAgainst(SSurface *b, SShell *agnstA, SShell *agnstB,
// cases, just giving up for now
}
double SSurface::DepartureFromCoplanar(void) {
int i, j;
int ia, ja, ib, jb, ic, jc;
double best;
// Grab three points to define a plane; first choose (0, 0) arbitrarily.
ia = ja = 0;
// Then the point farthest from pt a.
best = VERY_NEGATIVE;
for(i = 0; i <= degm; i++) {
for(j = 0; j <= degn; j++) {
if(i == ia && j == ja) continue;
double dist = (ctrl[i][j]).Minus(ctrl[ia][ja]).Magnitude();
if(dist > best) {
best = dist;
ib = i;
jb = j;
}
}
}
// Then biggest magnitude of ab cross ac.
best = VERY_NEGATIVE;
for(i = 0; i <= degm; i++) {
for(j = 0; j <= degn; j++) {
if(i == ia && j == ja) continue;
if(i == ib && j == jb) continue;
double mag =
((ctrl[ia][ja].Minus(ctrl[ib][jb]))).Cross(
(ctrl[ia][ja].Minus(ctrl[i ][j ]))).Magnitude();
if(mag > best) {
best = mag;
ic = i;
jc = j;
}
}
}
Vector n = ((ctrl[ia][ja].Minus(ctrl[ib][jb]))).Cross(
(ctrl[ia][ja].Minus(ctrl[ic][jc])));
n = n.WithMagnitude(1);
double d = (ctrl[ia][ja]).Dot(n);
// Finally, calculate the deviation from each point to the plane.
double farthest = VERY_NEGATIVE;
for(i = 0; i <= degm; i++) {
for(j = 0; j <= degn; j++) {
double dist = fabs(n.Dot(ctrl[i][j]) - d);
if(dist > farthest) {
farthest = dist;
}
}
}
return farthest;
}
void SSurface::WeightControlPoints(void) {
int i, j;
for(i = 0; i <= degm; i++) {
@ -250,16 +363,14 @@ void SSurface::AllPointsIntersectingUntrimmed(Vector a, Vector b,
if(*cnt > 2000) {
dbp("!!! too many subdivisions (level=%d)!", *level);
dbp("degm = %d degn = %d", degm, degn);
return;
}
(*cnt)++;
// If we might intersect, and the surface is small, then switch to Newton
// iterations.
double h = max(amax.x - amin.x,
max(amax.y - amin.y,
amax.z - amin.z));
if(fabs(h) < SS.ChordTolMm()) {
if(DepartureFromCoplanar() < 0.2*SS.ChordTolMm()) {
Vector p = (amax.Plus(amin)).ScaledBy(0.5);
Inter inter;
sorig->ClosestPointTo(p, &(inter.p.x), &(inter.p.y), false);
@ -302,10 +413,32 @@ void SSurface::AllPointsIntersecting(Vector a, Vector b,
List<Inter> inters;
ZERO(&inters);
// First, get all the intersections between the infinite ray and the
// untrimmed surface.
// All the intersections between the line and the surface; either special
// cases that we can quickly solve in closed form, or general numerical.
Vector center, axis;
double radius, dtheta;
if(degm == 1 && degn == 1) {
// Against a plane, easy.
Vector n = NormalAt(0, 0).WithMagnitude(1);
double d = n.Dot(PointAt(0, 0));
// Trim to line segment now if requested, don't generate points that
// would just get discarded later.
if(!seg ||
(n.Dot(a) > d + LENGTH_EPS && n.Dot(b) < d - LENGTH_EPS) ||
(n.Dot(b) > d + LENGTH_EPS && n.Dot(a) < d - LENGTH_EPS))
{
Vector p = Vector::AtIntersectionOfPlaneAndLine(n, d, a, b, NULL);
Inter inter;
ClosestPointTo(p, &(inter.p.x), &(inter.p.y));
inters.Add(&inter);
}
} else if(IsCylinder(&center, &axis, &radius, &dtheta) && 0) {
// XXX, cylinder is easy in closed form
} else {
// General numerical solution by subdivision, fallback
int cnt = 0, level = 0;
AllPointsIntersectingUntrimmed(a, b, &cnt, &level, &inters, seg, this);
}
// Remove duplicate intersection points
inters.ClearTags();

5
textscreens.cpp
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@ -672,6 +672,11 @@ void TextWindow::ShowConfiguration(void) {
(SS.drawBackFaces ? "" : "yes"), (SS.drawBackFaces ? "yes" : ""),
&ScreenChangeBackFaces,
(!SS.drawBackFaces ? "" : "no"), (!SS.drawBackFaces ? "no" : ""));
Printf(false, "");
Printf(false, " %Ftgl vendor %E%s", glGetString(GL_VENDOR));
Printf(false, " %Ft renderer %E%s", glGetString(GL_RENDERER));
Printf(false, " %Ft version %E%s", glGetString(GL_VERSION));
}
//-----------------------------------------------------------------------------

6
util.cpp
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@ -716,6 +716,12 @@ Vector Vector::AtIntersectionOfPlanes(Vector na, double da,
return Vector::From(detx/det, dety/det, detz/det);
}
Point2d Point2d::From(double x, double y) {
Point2d r;
r.x = x; r.y = y;
return r;
}
Point2d Point2d::Plus(Point2d b) {
Point2d r;
r.x = x + b.x;

5
win32/w32main.cpp
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@ -54,9 +54,10 @@ void dbp(char *str, ...)
va_list f;
static char buf[1024*50];
va_start(f, str);
vsprintf(buf, str, f);
OutputDebugString(buf);
_vsnprintf(buf, sizeof(buf), str, f);
va_end(f);
OutputDebugString(buf);
}

4
wishlist.txt
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@ -1,10 +1,10 @@
marching algorithm for surface intersection
surfaces of revolution (lathed)
fix surface-line intersection
cylinder-line and plane-line special cases
cylinder-line special cases
exact boundaries when near pwl trim
step and repeat rotate/translate
tangent intersections
short pwl edge avoidance
faces
take consistent pwl with coincident faces