return result;
}
+ // 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 x012 = x01*t + x12*one_minus_t;
+ Real x123 = x12*t + x23*one_minus_t;
+
+ Real x0123 = x012*t + x123*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 y012 = y01*t + y12*one_minus_t;
+ Real y123 = y12*t + y23*one_minus_t;
+
+ Real y0123 = y012*t + y123*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)
+ {
+ 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 x012 = x01*t + x12*one_minus_t;
+ Real x123 = x12*t + x23*one_minus_t;
+
+ Real x0123 = x012*t + x123*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 y012 = y01*t + y12*one_minus_t;
+ Real y123 = y12*t + y23*one_minus_t;
+
+ Real y0123 = y012*t + y123*one_minus_t;
+
+ return Bezier(x0123, y0123, x123, y123, x23, y23, x3, y3);
+ }
+
Bezier ReParametrise(const Real& t0, const Real& t1)
{
- // This function is very, very ugly, but with luck my derivation is correct (even if it isn't optimal, performance wise)
- // (Very) rough working for the derivation is at: http://davidgow.net/stuff/cubic_bezier_reparam.pdf
Debug("Reparametrise: %f -> %f",t0,t1);
Bezier new_bezier;
- Real tdiff = t1 - t0;
- Real tdiff_squared = tdiff*tdiff;
- Real tdiff_cubed = tdiff*tdiff_squared;
+ // Subdivide to get from [0,t1]
+ new_bezier = DeCasteljauSubdivideLeft(t1);
+ // Convert t0 from [0,1] range to [0, t1]
+ Real new_t0 = t0 / t1;
+ Debug("New t0 = %f", new_t0);
+ new_bezier = new_bezier.DeCasteljauSubdivideRight(new_t0);
- Real t0_squared = t0*t0;
- Real t0_cubed = t0*t0_squared;
-
- // X coordinates
- Real Dx0 = x0 / tdiff_cubed;
- Real Dx1 = x1 / (tdiff_squared - tdiff_cubed);
- Real Dx2 = x2 / (tdiff - Real(2)*tdiff_squared + tdiff_cubed);
- Real Dx3 = x3 / (Real(1) - Real(3)*tdiff + Real(3)*tdiff_squared - tdiff_cubed);
-
- new_bezier.x3 = Dx3*t0_cubed + Real(3)*Dx3*t0_squared + Real(3)*Dx3*t0 + Dx3 - Dx2*t0_cubed - Real(2)*Dx2*t0_squared - Dx2*t0 + Dx1*t0_cubed + Dx1*t0_squared - Dx0*t0_cubed;
- new_bezier.x2 = Real(3)*Dx0*t0_squared - Real(2)*Dx1*t0 - Real(3)*Dx1*t0_squared + Dx2 + Real(4)*Dx2*t0 + Real(3)*Dx2*t0_squared - Real(3)*Dx3 - Real(6)*Dx3*t0 - Real(3)*Dx3*t0_squared + Real(3)*new_bezier.x3;
- new_bezier.x1 = Real(-3)*Dx0*t0 + Real(3)*Dx1*t0 + Dx1 - Real(2)*Dx2 - Real(3)*Dx2*t0 + Real(3)*Dx3 + Real(3)*Dx3*t0 + Real(2)*new_bezier.x2 - Real(3)*new_bezier.x3;
- new_bezier.x0 = Dx0 - Dx1 + Dx2 - Dx3 + new_bezier.x1 - new_bezier.x2 + new_bezier.x3;
-
- // Y coordinates
- Real Dy0 = y0 / tdiff_cubed;
- Real Dy1 = y1 / (tdiff_squared - tdiff_cubed);
- Real Dy2 = y2 / (tdiff - Real(2)*tdiff_squared + tdiff_cubed);
- Real Dy3 = y3 / (Real(1) - Real(3)*tdiff + Real(3)*tdiff_squared - tdiff_cubed);
-
- new_bezier.y3 = Dy3*t0_cubed + Real(3)*Dy3*t0_squared + Real(3)*Dy3*t0 + Dy3 - Dy2*t0_cubed - Real(2)*Dy2*t0_squared - Dy2*t0 + Dy1*t0_cubed + Dy1*t0_squared - Dy0*t0_cubed;
- new_bezier.y2 = Real(3)*Dy0*t0_squared - Real(2)*Dy1*t0 - Real(3)*Dy1*t0_squared + Dy2 + Real(4)*Dy2*t0 + Real(3)*Dy2*t0_squared - Real(3)*Dy3 - Real(6)*Dy3*t0 - Real(3)*Dy3*t0_squared + Real(3)*new_bezier.y3;
- new_bezier.y1 = Real(-3)*Dy0*t0 + Real(3)*Dy1*t0 + Dy1 - Real(2)*Dy2 - Real(3)*Dy2*t0 + Real(3)*Dy3 + Real(3)*Dy3*t0 + Real(2)*new_bezier.y2 - Real(3)*new_bezier.y3;
- new_bezier.y0 = Dy0 - Dy1 + Dy2 - Dy3 + new_bezier.y1 - new_bezier.y2 + new_bezier.y3;
-
-
- Debug("(%f,%f),(%f,%f),(%f,%f),(%f,%f) -> (%f,%f),(%f,%f),(%f,%f),(%f,%f)", x0, y0, x1, y1, x2, y2, x3, y3, new_bezier.x0, new_bezier.y0, new_bezier.x1, new_bezier.y1, new_bezier.x2, new_bezier.y2, new_bezier.x3, new_bezier.y3);
+ Debug("%s becomes %s", this->Str().c_str(), new_bezier.Str().c_str());
return new_bezier;
}
// Merge and sort.
x_intersection.insert(x_intersection.end(), y_intersection.begin(), y_intersection.end());
+ x_intersection.push_back(Real(0));
+ x_intersection.push_back(Real(1));
std::sort(x_intersection.begin(), x_intersection.end());
Debug("Found %d intersections.\n", x_intersection.size());
for (auto it = x_intersection.begin()+1; it != x_intersection.end(); ++it)
{
Real t1 = *it;
+ if (t1 == t0) continue;
Debug(" -- t0: %f to t1: %f", t0, t1);
- all_beziers.push_back(this->ReParametrise(t0, t1));
+ Real ptx, pty;
+ Evaluate(ptx, pty, ((t1 + t0) / Real(2)));
+ if (r.PointIn(ptx, pty))
+ {
+ all_beziers.push_back(this->ReParametrise(t0, t1));
+ }
t0 = t1;
}
return all_beziers;
case BEZIER:
{
Rect child_node_bounds = TransformFromQuadChild({0,0,1,1}, type);
- std::vector<Bezier> new_curves = m_objects.beziers[m_objects.data_indices[object_id]].ClipToRectangle(child_node_bounds);
- Rect obj_bounds = TransformToQuadChild(m_objects.bounds[object_id], type);
+ Rect clip_bezier_bounds;
+ clip_bezier_bounds.x = (child_node_bounds.x - m_objects.bounds[object_id].x) / m_objects.bounds[object_id].w;
+ clip_bezier_bounds.y = (child_node_bounds.y - m_objects.bounds[object_id].y) / m_objects.bounds[object_id].h;
+ clip_bezier_bounds.w = child_node_bounds.w / m_objects.bounds[object_id].w;
+ clip_bezier_bounds.h = child_node_bounds.h / m_objects.bounds[object_id].h;
+ std::vector<Bezier> new_curves = m_objects.beziers[m_objects.data_indices[object_id]].ClipToRectangle(clip_bezier_bounds);
for (size_t i = 0; i < new_curves.size(); ++i)
{
+ Rect new_bounds = TransformToQuadChild(m_objects.bounds[object_id], type);
+ //new_bounds = TransformToQuadChild(new_bounds, type);
+ //Bezier new_curve_data = new_curves[i].ToRelative(new_bounds);
unsigned index = AddBezierData(new_curves[i]);
- m_objects.bounds.push_back(obj_bounds);
+ m_objects.bounds.push_back(new_bounds);
m_objects.types.push_back(BEZIER);
m_objects.data_indices.push_back(index);
}