int ON_Intersect( // returns 0 = no intersections,
// 1 = one intersection,
// 2 = 2 intersections
// If 0 is returned, first point is point
// on line closest to sphere and 2nd point is the point
// on the sphere closest to the line.
// If 1 is returned, first point is obtained by evaluating
// the line and the second point is obtained by evaluating
// the sphere.
const ON_Line& line, const ON_Sphere& sphere,
ON_3dPoint& A, ON_3dPoint& B // intersection point(s) returned here
)
{
int rc = 0;
const ON_3dPoint sphere_center = sphere.plane.origin;
const double sphere_radius = fabs(sphere.radius);
double tol = sphere_radius*ON_SQRT_EPSILON;
if ( tol < ON_ZERO_TOLERANCE )
tol = ON_ZERO_TOLERANCE;
ON_3dPoint line_center = line.ClosestPointTo(sphere_center);
double d = line_center.DistanceTo(sphere_center);
if ( d >= sphere_radius-tol ) {
rc = ( d <= sphere_radius-tol ) ? 1 : 0;
A = line_center;
B = sphere.ClosestPointTo(line_center);
}
else {
d /= sphere_radius;
double h = sphere_radius*sqrt(1.0 - d*d);
ON_3dVector V = line.Direction();
V.Unitize();
A = sphere.ClosestPointTo(line_center - h*V);
B = sphere.ClosestPointTo(line_center + h*V);
d = A.DistanceTo(B);
if ( d <= ON_ZERO_TOLERANCE ) {
A = line_center;
B = sphere.ClosestPointTo(line_center);
rc = 1;
}
else
rc = 2;
}
return rc;
}
double ON_Line::MinimumDistanceTo( const ON_Line& L ) const
{
ON_3dPoint A, B;
double a, b, t, x, d;
bool bCheckA, bCheckB;
bool bGoodX = ON_Intersect(*this,L,&a,&b);
bCheckA = true;
if ( a < 0.0) a = 0.0; else if (a > 1.0) a = 1.0; else bCheckA=!bGoodX;
bCheckB = true;
if ( b < 0.0) b = 0.0; else if (b > 1.0) b = 1.0; else bCheckB=!bGoodX;
A = PointAt(a);
B = L.PointAt(b);
d = A.DistanceTo(B);
if ( bCheckA )
{
L.ClosestPointTo(A,&t);
if (t<0.0) t = 0.0; else if (t > 1.0) t = 1.0;
x = L.PointAt(t).DistanceTo(A);
if ( x < d )
d = x;
}
if ( bCheckB )
{
ClosestPointTo(B,&t);
if (t<0.0) t = 0.0; else if (t > 1.0) t = 1.0;
x = PointAt(t).DistanceTo(B);
if (x < d )
d = x;
}
return d;
}
int ON_Intersect(
const ON_Line& line,
const ON_Arc& arc,
double* line_t0,
ON_3dPoint& arc_point0,
double* line_t1,
ON_3dPoint& arc_point1
)
{
ON_Circle c = arc;
ON_3dPoint p[2];
double t[2], a[2], s;
ON_BOOL32 b[2] = {false,false};
int i, xcnt = ON_Intersect( line, c, &t[0], p[0], &t[1], p[1] );
if ( xcnt > 0 )
{
// make sure points are on the arc;
ON_Interval arc_domain = arc.DomainRadians();
for ( i = 0; i < xcnt; i++ )
{
b[i] = c.ClosestPointTo(p[i], &a[i]);
if ( b[i] )
{
s = arc_domain.NormalizedParameterAt(a[i]);
if ( s < 0.0 )
{
if ( s >= -ON_SQRT_EPSILON )
{
a[i] = arc_domain[0];
p[i] = c.PointAt(a[i]);
b[i] = line.ClosestPointTo( p[i], &t[i] );
}
else
b[i] = false;
}
else if ( s > 1.0 )
{
if ( s <= 1.0+ON_SQRT_EPSILON )
{
a[i] = arc_domain[1];
p[i] = c.PointAt(a[i]);
b[i] = line.ClosestPointTo( p[i], &t[i] );
}
else
b[i] = false;
}
}
}
if ( !b[0] && !b[1] )
xcnt = 0;
if ( xcnt == 2 )
{
if ( !b[1] )
xcnt = 1;
if ( !b[0] )
{
xcnt = 1;
b[0] = b[1];
t[0] = t[1];
a[0] = a[1];
p[0] = p[1];
b[1] = 0;
}
if ( xcnt == 2 && t[0] == t[1] )
{
xcnt = 1;
b[1] = 0;
ON_3dPoint q = line.PointAt(t[0]);
if ( p[0].DistanceTo(q) > p[1].DistanceTo(q) )
{
a[0] = a[1];
t[0] = t[1];
p[0] = p[1];
}
}
}
if ( xcnt == 1 && !b[0] )
xcnt = 0;
if ( xcnt >= 1 )
{
if ( line_t0 )
*line_t0 = t[0];
arc_point0 = p[0];
}
if ( xcnt == 2 )
{
if ( line_t1 )
*line_t1 = t[1];
arc_point1 = p[1];
}
}
return xcnt;
}
int ON_Intersect(
const ON_Line& line,
const ON_Circle& circle,
double* line_t0,
ON_3dPoint& circle_point0,
double* line_t1,
ON_3dPoint& circle_point1
)
{
// transform to coordinate system where equation of circle
// is x^2 + y^2 = R^2 and solve for line parameter(s).
ON_Xform xform;
xform.ChangeBasis( circle.plane, ON_xy_plane );
xform.ChangeBasis( ON_xy_plane, circle.plane );
ON_Line L = line;
L.Transform(xform);
double r = fabs(circle.radius);
double tol = r*ON_SQRT_EPSILON;
if ( tol < ON_ZERO_TOLERANCE )
tol = ON_ZERO_TOLERANCE;
int xcnt;
if ( fabs(L.from.x - L.to.x) <= tol
&& fabs(L.from.y - L.to.y) <= tol
&& fabs(L.from.z - L.to.z) > tol )
{
xcnt = 0;
}
else
{
xcnt = Intersect2dLineCircle( L.from, L.to, r, tol, line_t0, line_t1 );
if ( xcnt == 3 )
xcnt = 1;
}
if ( xcnt == 0 )
{
if ( L.ClosestPointTo( circle.Center(), line_t0 ) )
{
xcnt = 1;
*line_t1 = *line_t0;
}
}
ON_3dPoint line_point1, line_point0 = line.PointAt(*line_t0);
circle_point0 = circle.ClosestPointTo(line_point0);
double d1, d0 = line_point0.DistanceTo(circle_point0);
if ( xcnt == 2 )
{
line_point1 = line.PointAt(*line_t1);
circle_point1 = circle.ClosestPointTo(line_point1);
d1 = line_point1.DistanceTo(circle_point1);
}
else
{
line_point1 = line_point0;
circle_point1 = circle_point0;
d1 = d0;
}
if ( xcnt==2 && (d0 > tol && d1 > tol) )
{
xcnt = 1;
if ( d0 <= d1 )
{
*line_t1 = *line_t0;
line_point1 = line_point0;
circle_point1 = circle_point0;
d1 = d0;
}
else
{
*line_t0 = *line_t1;
line_point0 = line_point1;
circle_point0 = circle_point1;
d0 = d1;
}
}
if ( xcnt == 1 && d0 > tol )
{
// TODO: iterate to closest point
}
return xcnt;
}
int ON_Intersect( // returns 0 = no intersections,
// 1 = one intersection,
// 2 = 2 intersections
// 3 = line lies on cylinder
// If 0 is returned, first point is point
// on line closest to cylinder and 2nd point is the point
// on the sphere closest to the line.
// If 1 is returned, first point is obtained by evaluating
// the line and the second point is obtained by evaluating
// the cylinder.
const ON_Line& line,
const ON_Cylinder& cylinder, // if cylinder.height[0]==cylinder.height[1],
// then infinite cyl is used. Otherwise
// finite cyl is used.
ON_3dPoint& A, ON_3dPoint& B // intersection point(s) returned here
)
{
ON_BOOL32 bFiniteCyl = true;
int rc = 0;
const double cylinder_radius = fabs(cylinder.circle.radius);
double tol = cylinder_radius*ON_SQRT_EPSILON;
if ( tol < ON_ZERO_TOLERANCE )
tol = ON_ZERO_TOLERANCE;
ON_Line axis;
axis.from = cylinder.circle.plane.origin + cylinder.height[0]*cylinder.circle.plane.zaxis;
axis.to = cylinder.circle.plane.origin + cylinder.height[1]*cylinder.circle.plane.zaxis;
if ( axis.Length() <= tol ) {
axis.to = cylinder.circle.plane.origin + cylinder.circle.plane.zaxis;
bFiniteCyl = false;
}
//ON_BOOL32 bIsParallel = false;
double line_t, axis_t;
if ( !ON_Intersect(line,axis,&line_t,&axis_t) ) {
axis.ClosestPointTo( cylinder.circle.plane.origin, &axis_t );
line.ClosestPointTo( cylinder.circle.plane.origin, &line_t );
}
ON_3dPoint line_point = line.PointAt(line_t);
ON_3dPoint axis_point = axis.PointAt(axis_t);
double d = line_point.DistanceTo(axis_point);
if ( bFiniteCyl ) {
if ( axis_t < 0.0 )
axis_t = 0.0;
else if ( axis_t > 1.0 )
axis_t = 1.0;
axis_point = axis.PointAt(axis_t);
}
if ( d >= cylinder_radius-tol) {
rc = ( d <= cylinder_radius+tol ) ? 1 : 0;
A = line_point;
ON_3dVector V = line_point - axis_point;
if ( bFiniteCyl ) {
V = V - (V*cylinder.circle.plane.zaxis)*cylinder.circle.plane.zaxis;
}
V.Unitize();
B = axis_point + cylinder_radius*V;
if ( rc == 1 ) {
// check for overlap
ON_3dPoint P = axis.ClosestPointTo(line.from);
d = P.DistanceTo(line.from);
if ( fabs(d-cylinder_radius) <= tol ) {
P = axis.ClosestPointTo(line.to);
d = P.DistanceTo(line.to);
if ( fabs(d-cylinder_radius) <= tol ) {
rc = 3;
A = cylinder.ClosestPointTo(line.from);
B = cylinder.ClosestPointTo(line.to);
}
}
}
}
else {
// transform to coordinate system where equation of cyl
// is x^2 + y^2 = R^2 and solve for line parameter(s).
ON_Xform xform;
xform.Rotation( cylinder.circle.plane, ON_xy_plane );
ON_Line L = line;
L.Transform(xform);
const double x0 = L.from.x;
const double x1 = L.to.x;
const double x1mx0 = x1-x0;
double ax = x1mx0*x1mx0;
double bx = 2.0*x1mx0*x0;
double cx = x0*x0;
const double y0 = L.from.y;
const double y1 = L.to.y;
const double y1my0 = y1-y0;
double ay = y1my0*y1my0;
double by = 2.0*y1my0*y0;
double cy = y0*y0;
double t0, t1;
int qerc = ON_SolveQuadraticEquation(ax+ay, bx+by, cx+cy-cylinder_radius*cylinder_radius,
&t0,&t1);
if ( qerc == 2 ) {
// complex roots - ignore (tiny) imaginary part caused by computational noise.
t1 = t0;
}
A = cylinder.ClosestPointTo(line.PointAt(t0));
B = cylinder.ClosestPointTo(line.PointAt(t1));
d = A.DistanceTo(B);
if ( d <= ON_ZERO_TOLERANCE ) {
A = line_point;
ON_3dVector V = line_point - axis_point;
if ( bFiniteCyl ) {
V = V - (V*cylinder.circle.plane.zaxis)*cylinder.circle.plane.zaxis;
}
V.Unitize();
B = axis_point + cylinder_radius*V;
rc = 1;
}
else
rc = 2;
}
return rc;
}
bool ON_Intersect( const ON_Line& lineA, const ON_Line& lineB,
double* lineA_parameter,
double* lineB_parameter
)
{
// If you are looking at this code because you don't like an
// answer you are getting, then the first thing to try is
// to read the header file comments and try calling
// ON_IntersectLineLine.
bool rc = false;
double M_zero_tol = 0.0;
int i, rank;
double pr_tolerance, pivot, X[2], Y[2];
ON_3dVector A = lineA.Direction();
ON_3dVector B = lineB.Direction();
ON_3dVector C = lineB[0] - lineA[0];
ON_Matrix M(2,2);
M[0][0] = ON_DotProduct( A, A );
M[1][1] = ON_DotProduct( B, B );
M[0][1] = M[1][0] = -ON_DotProduct( A, B );
// this swap done to get row+col pivot accuracy
if ( M[0][0] < M[1][1] ) {
M.SwapCols(0,1);
i = 1;
}
else {
i = 0;
}
pr_tolerance = fabs(M[1][1])*ON_SQRT_EPSILON;
M_zero_tol = fabs(M[1][1])*ON_EPSILON;
Y[0] = ON_DotProduct( A, C );
Y[1] = -ON_DotProduct( B, C );
rank = M.RowReduce( M_zero_tol, Y, &pivot );
if ( rank == 2 )
{
// 19 November 2003 Dale Lear and Chuck
// Added lineA.from/to == lineB.from/to tests
// so exact answer gets returned when people
// expect it.
rc = true;
if ( lineA.from == lineB.from )
{
if ( lineA_parameter )
*lineA_parameter = 0.0;
if ( lineB_parameter )
*lineB_parameter = 0.0;
}
else if ( lineA.from == lineB.to )
{
if ( lineA_parameter )
*lineA_parameter = 0.0;
if ( lineB_parameter )
*lineB_parameter = 1.0;
}
else if ( lineA.to == lineB.from )
{
if ( lineA_parameter )
*lineA_parameter = 1.0;
if ( lineB_parameter )
*lineB_parameter = 0.0;
}
else if ( lineA.to == lineB.to )
{
if ( lineA_parameter )
*lineA_parameter = 1.0;
if ( lineB_parameter )
*lineB_parameter = 1.0;
}
else
{
rc = M.BackSolve( 0.0, 2, Y, X );
if ( rc )
{
if ( lineA_parameter )
*lineA_parameter = X[i];
if ( lineB_parameter )
*lineB_parameter = X[1-i];
if ( fabs(pivot) <= pr_tolerance )
{
// test answer because matrix was close to singular
// (This test is slow but it is rarely used.)
ON_3dPoint pA = lineA.PointAt(X[i]);
ON_3dPoint pB = lineB.PointAt(X[1-i]);
double d = pA.DistanceTo(pB);
if ( d > pr_tolerance && d > ON_ZERO_TOLERANCE ) {
ON_3dPoint qA = lineA.ClosestPointTo(pB);
ON_3dPoint qB = lineB.ClosestPointTo(pA);
double dA = pA.DistanceTo(qB);
double dB = pB.DistanceTo(qA);
if ( 1.1*dA < d ) {
rc = false;
}
else if ( 1.1*dB < d ) {
rc = false;
}
}
}
}
}
}
return rc;
}
bool ON_Line::IsFartherThan( double d, const ON_Line& L ) const
{
ON_3dPoint A, B;
double a, b, t, x;
bool bCheckA, bCheckB;
a = from.x; if (to.x < a) {b=a; a = to.x;} else b = to.x;
if ( b+d < L.from.x && b+d < L.to.x )
return true;
if ( a-d > L.from.x && a-d > L.to.x )
return true;
a = from.y; if (to.y < a) {b=a; a = to.y;} else b = to.y;
if ( b+d < L.from.y && b+d < L.to.y )
return true;
if ( a-d > L.from.y && a-d > L.to.y )
return true;
a = from.z; if (to.z < a) {b=a; a = to.z;} else b = to.z;
if ( b+d < L.from.z && b+d < L.to.z )
return true;
if ( a-d > L.from.z && a-d > L.to.z )
return true;
if ( !ON_Intersect(*this,L,&a,&b) )
{
// lines are parallel or anti parallel
if ( Direction()*L.Direction() >= 0.0 )
{
// lines are parallel
a = 0.0;
L.ClosestPointTo(from,&b);
// If ( b >= 0.0), then this->from and L(b) are a pair of closest points.
if ( b < 0.0 )
{
// Othersise L.from and this(a) are a pair of closest points.
b = 0.0;
ClosestPointTo(L.from,&a);
}
}
else
{
// lines are anti parallel
a = 1.0;
L.ClosestPointTo(to,&b);
// If ( b >= 0.0), then this->to and L(b) are a pair of closest points.
if ( b < 0.0 )
{
// Othersise L.to and this(a) are a pair of closest points.
b = 0.0;
ClosestPointTo(L.from,&a);
}
}
}
A = PointAt(a);
B = L.PointAt(b);
x = A.DistanceTo(B);
if (x > d)
return true;
bCheckA = true;
if ( a < 0.0) a = 0.0; else if (a > 1.0) a = 1.0; else bCheckA=false;
if (bCheckA )
{
A = PointAt(a);
L.ClosestPointTo(A,&t);
if (t<0.0) t = 0.0; else if (t > 1.0) t = 1.0;
x = L.PointAt(t).DistanceTo(A);
}
bCheckB = true;
if ( b < 0.0) b = 0.0; else if (b > 1.0) b = 1.0; else bCheckB=false;
if ( bCheckB )
{
B = L.PointAt(b);
ClosestPointTo(B,&t);
if (t<0.0) t = 0.0; else if (t > 1.0) t = 1.0;
t = PointAt(t).DistanceTo(B);
if ( bCheckA )
{
if ( t<x ) x = t;
}
else
{
x = t;
}
}
return (x > d);
}
int ON_ArePointsOnLine( // returns 0=no, 1 = yes, 2 = pointset is (to tolerance) a single point on the line
int dim, // 2 or 3
int is_rat,
int count,
int stride, const double* point,
const ON_BoundingBox& bbox, // if needed, use ON_GetBoundingBox(dim,is_rat,count,stride,point)
const ON_Line& line, // line to test
double tolerance
)
{
double w;
int i, j, k;
if ( count < 1 )
return 0;
if ( !line.IsValid() )
{
ON_ERROR("line parameter not valid");
return 0;
}
if ( !bbox.IsValid() )
{
ON_ERROR("bbox parameter not valid");
return 0;
}
if ( !ON_IsValid(tolerance) || tolerance < 0.0 )
{
ON_ERROR("tolerance parameter not valid");
return 0;
}
if ( dim < 2 || dim > 3 )
{
ON_ERROR("dim parameter not valid");
return 0;
}
if ( 0 == point )
{
ON_ERROR("point parameter not valid");
return 0;
}
if ( stride < (is_rat?(dim+1):dim) )
{
ON_ERROR("stride parameter not valid");
return 0;
}
int rc = 0;
if ( tolerance == 0.0 ) {
tolerance = bbox.Tolerance();
}
ON_3dPoint Q;
// test bounding box to quickly detect the common coordinate axis cases
rc = (count == 1 || bbox.Diagonal().Length() <= tolerance) ? 2 : 1;
for ( i = 0; rc && i < 2; i++ ) {
Q.x = bbox[i].x;
for ( j = 0; rc && j < 2; j++) {
Q.y = bbox[j].y;
for ( k = 0; rc && k < 2; k++) {
Q.z = bbox[k].z;
if ( Q.DistanceTo( line.ClosestPointTo( Q ) ) > tolerance )
rc = 0;
}
}
}
if ( !rc ) {
// test points one by one
Q.Zero();
rc = (count == 1 || bbox.Diagonal().Length() <= tolerance) ? 2 : 1;
if ( is_rat ) {
for ( i = 0; i < count; i++ ) {
w = point[dim];
if ( w == 0.0 ) {
ON_ERROR("rational point has zero weight");
return 0;
}
ON_ArrayScale( dim, 1.0/w, point, &Q.x );
if ( Q.DistanceTo( line.ClosestPointTo( Q ) ) > tolerance ) {
rc = 0;
break;
}
point += stride;
}
}
else {
for ( i = 0; i < count; i++ ) {
memcpy( &Q.x, point, dim*sizeof(Q.x) );
if ( Q.DistanceTo( line.ClosestPointTo( Q ) ) > tolerance ) {
rc = 0;
break;
}
point += stride;
}
}
}
return rc;
}
