extern std::vector<Real> SolveQuadratic(const Real & a, const Real & b, const Real & c, const Real & min = 0, const Real & max = 1);
- extern std::vector<Real> SolveCubic(const Real & a, const Real & b, const Real & c, const Real & d, const Real & min = 0, const Real & max = 1, const Real & delta = 1e-4);
+ extern std::vector<Real> SolveCubic(const Real & a, const Real & b, const Real & c, const Real & d, const Real & min = 0, const Real & max = 1, const Real & delta = 1e-9);
/** A _cubic_ bezier. **/
struct Bezier
}
// Performs one round of De Casteljau subdivision and returns the [t,1] part.
- Bezier DeCasteljauSubdivideRight(const Real& t)
+ Bezier DeCasteljauSubdivideLeft(const Real& t)
{
Real one_minus_t = Real(1) - t;
// X Coordinates
- Real x01 = x0*t + x1*one_minus_t;
- Real x12 = x1*t + x2*one_minus_t;
- Real x23 = x2*t + x3*one_minus_t;
+ Real x01 = x1*t + x0*one_minus_t;
+ Real x12 = x2*t + x1*one_minus_t;
+ Real x23 = x3*t + x2*one_minus_t;
- Real x012 = x01*t + x12*one_minus_t;
- Real x123 = x12*t + x23*one_minus_t;
+ Real x012 = x12*t + x01*one_minus_t;
+ Real x123 = x23*t + x12*one_minus_t;
- Real x0123 = x012*t + x123*one_minus_t;
+ Real x0123 = x123*t + x012*one_minus_t;
// Y Coordinates
- Real y01 = y0*t + y1*one_minus_t;
- Real y12 = y1*t + y2*one_minus_t;
- Real y23 = y2*t + y3*one_minus_t;
+ Real y01 = y1*t + y0*one_minus_t;
+ Real y12 = y2*t + y1*one_minus_t;
+ Real y23 = y3*t + y2*one_minus_t;
- Real y012 = y01*t + y12*one_minus_t;
- Real y123 = y12*t + y23*one_minus_t;
+ Real y012 = y12*t + y01*one_minus_t;
+ Real y123 = y23*t + y12*one_minus_t;
- Real y0123 = y012*t + y123*one_minus_t;
+ Real y0123 = y123*t + y012*one_minus_t;
return Bezier(x0, y0, x01, y01, x012, y012, x0123, y0123);
}
- // Performs one round of De Casteljau subdivision and returns the [0,t] part.
- Bezier DeCasteljauSubdivideLeft(const Real& t)
+ // Performs one round of De Casteljau subdivision and returns the [t,1] part.
+ Bezier DeCasteljauSubdivideRight(const Real& t)
{
Real one_minus_t = Real(1) - t;
// X Coordinates
- Real x01 = x0*t + x1*one_minus_t;
- Real x12 = x1*t + x2*one_minus_t;
- Real x23 = x2*t + x3*one_minus_t;
+ Real x01 = x1*t + x0*one_minus_t;
+ Real x12 = x2*t + x1*one_minus_t;
+ Real x23 = x3*t + x2*one_minus_t;
- Real x012 = x01*t + x12*one_minus_t;
- Real x123 = x12*t + x23*one_minus_t;
+ Real x012 = x12*t + x01*one_minus_t;
+ Real x123 = x23*t + x12*one_minus_t;
- Real x0123 = x012*t + x123*one_minus_t;
+ Real x0123 = x123*t + x012*one_minus_t;
// Y Coordinates
- Real y01 = y0*t + y1*one_minus_t;
- Real y12 = y1*t + y2*one_minus_t;
- Real y23 = y2*t + y3*one_minus_t;
+ Real y01 = y1*t + y0*one_minus_t;
+ Real y12 = y2*t + y1*one_minus_t;
+ Real y23 = y3*t + y2*one_minus_t;
- Real y012 = y01*t + y12*one_minus_t;
- Real y123 = y12*t + y23*one_minus_t;
+ Real y012 = y12*t + y01*one_minus_t;
+ Real y123 = y23*t + y12*one_minus_t;
- Real y0123 = y012*t + y123*one_minus_t;
+ Real y0123 = y123*t + y012*one_minus_t;
return Bezier(x0123, y0123, x123, y123, x23, y23, x3, y3);
}
// Find points of intersection with the rectangle.
Debug("Clipping Bezier to Rect %s", r.Str().c_str());
- // Convert bezier coefficients -> cubic coefficients
- Real xd = x0 - r.x;
- Real xc = Real(3)*(x1 - x0);
- Real xb = Real(3)*(x2 - x1) - xc;
- Real xa = x3 - x0 - xc - xb;
// Find its roots.
- std::vector<Real> x_intersection = SolveCubic(xa, xb, xc, xd);
+ std::vector<Real> x_intersection = SolveXParam(r.x);
// And for the other side.
- xd = x0 - r.x - r.w;
- std::vector<Real> x_intersection_pt2 = SolveCubic(xa, xb, xc, xd);
+ std::vector<Real> x_intersection_pt2 = SolveXParam(r.x + r.w);
x_intersection.insert(x_intersection.end(), x_intersection_pt2.begin(), x_intersection_pt2.end());
- // Similarly for y-coordinates.
- // Convert bezier coefficients -> cubic coefficients
- Real yd = y0 - r.y;
- Real yc = Real(3)*(y1 - y0);
- Real yb = Real(3)*(y2 - y1) - yc;
- Real ya = y3 - y0 - yc - yb;
-
// Find its roots.
- std::vector<Real> y_intersection = SolveCubic(ya, yb, yc, yd);
+ std::vector<Real> y_intersection = SolveYParam(r.y);
- // And for the other side.
- yd = y0 - r.y - r.h;
-
- std::vector<Real> y_intersection_pt2 = SolveCubic(ya, yb, yc, yd);
+ std::vector<Real> y_intersection_pt2 = SolveYParam(r.y+r.h);
y_intersection.insert(y_intersection.end(), y_intersection_pt2.begin(), y_intersection_pt2.end());
// Merge and sort.
std::sort(x_intersection.begin(), x_intersection.end());
Debug("Found %d intersections.\n", x_intersection.size());
+ for(auto t : x_intersection)
+ {
+ Real ptx, pty;
+ Evaluate(ptx, pty, t);
+ Debug("Root: t = %f, (%f,%f)", t, ptx, pty);
+ }
std::vector<Bezier> all_beziers;
if (x_intersection.size() <= 2)
Debug(" -- t0: %f to t1: %f", t0, t1);
Real ptx, pty;
Evaluate(ptx, pty, ((t1 + t0) / Real(2)));
- if (true || r.PointIn(ptx, pty))
+ if (r.PointIn(ptx, pty))
{
all_beziers.push_back(this->ReParametrise(t0, t1));
}