public bool FindIntersect(Curve that, double[] yrange, double ymin, int slevel, int tlevel, double s0, double xs0, double ys0, double s1, double xs1, double ys1, double t0, double xt0, double yt0, double t1, double xt1, double yt1) { /* string pad = " "; pad = pad+pad+pad+pad+pad; pad = pad+pad; System.out.println("----------------------------------------------"); System.out.println(pad.substring(0, slevel)+ys0); System.out.println(pad.substring(0, slevel)+ys1); System.out.println(pad.substring(0, slevel)+(s1-s0)); System.out.println("-------"); System.out.println(pad.substring(0, tlevel)+yt0); System.out.println(pad.substring(0, tlevel)+yt1); System.out.println(pad.substring(0, tlevel)+(t1-t0)); */ if (ys0 > yt1 || yt0 > ys1) { return false; } if (Math.Min(xs0, xs1) > Math.Max(xt0, xt1) || Math.Max(xs0, xs1) < Math.Min(xt0, xt1)) { return false; } // Bounding boxes intersect - back off the larger of // the two subcurves by half until they stop intersecting // (or until they get small enough to switch to a more // intensive algorithm). if (s1 - s0 > TMIN) { double s = (s0 + s1) / 2; double xs = XforT(s); double ys = YforT(s); if (s == s0 || s == s1) { throw new SystemException("no s progress!"); } if (t1 - t0 > TMIN) { double t = (t0 + t1) / 2; double xt = that.XforT(t); double yt = that.YforT(t); if (t == t0 || t == t1) { throw new SystemException("no t progress!"); } if (ys >= yt0 && yt >= ys0) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel + 1, s0, xs0, ys0, s, xs, ys, t0, xt0, yt0, t, xt, yt)) { return true; } } if (ys >= yt) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel + 1, s0, xs0, ys0, s, xs, ys, t, xt, yt, t1, xt1, yt1)) { return true; } } if (yt >= ys) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel + 1, s, xs, ys, s1, xs1, ys1, t0, xt0, yt0, t, xt, yt)) { return true; } } if (ys1 >= yt && yt1 >= ys) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel + 1, s, xs, ys, s1, xs1, ys1, t, xt, yt, t1, xt1, yt1)) { return true; } } } else { if (ys >= yt0) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel, s0, xs0, ys0, s, xs, ys, t0, xt0, yt0, t1, xt1, yt1)) { return true; } } if (yt1 >= ys) { if (FindIntersect(that, yrange, ymin, slevel + 1, tlevel, s, xs, ys, s1, xs1, ys1, t0, xt0, yt0, t1, xt1, yt1)) { return true; } } } } else if (t1 - t0 > TMIN) { double t = (t0 + t1) / 2; double xt = that.XforT(t); double yt = that.YforT(t); if (t == t0 || t == t1) { throw new SystemException("no t progress!"); } if (yt >= ys0) { if (FindIntersect(that, yrange, ymin, slevel, tlevel + 1, s0, xs0, ys0, s1, xs1, ys1, t0, xt0, yt0, t, xt, yt)) { return true; } } if (ys1 >= yt) { if (FindIntersect(that, yrange, ymin, slevel, tlevel + 1, s0, xs0, ys0, s1, xs1, ys1, t, xt, yt, t1, xt1, yt1)) { return true; } } } else { // No more subdivisions double xlk = xs1 - xs0; double ylk = ys1 - ys0; double xnm = xt1 - xt0; double ynm = yt1 - yt0; double xmk = xt0 - xs0; double ymk = yt0 - ys0; double det = xnm * ylk - ynm * xlk; if (det != 0) { double detinv = 1 / det; double s = (xnm * ymk - ynm * xmk) * detinv; double t = (xlk * ymk - ylk * xmk) * detinv; if (s >= 0 && s <= 1 && t >= 0 && t <= 1) { s = s0 + s * (s1 - s0); t = t0 + t * (t1 - t0); if (s < 0 || s > 1 || t < 0 || t > 1) { } double y = (YforT(s) + that.YforT(t)) / 2; if (y <= yrange[1] && y > yrange[0]) { yrange[1] = y; return true; } } } //System.out.println("Testing lines!"); } return false; }
public int CompareTo(Curve that, double[] yrange) { /* System.out.println(this+".compareTo("+that+")"); System.out.println("target range = "+yrange[0]+"=>"+yrange[1]); */ double y0 = yrange[0]; double y1 = yrange[1]; y1 = Math.Min(Math.Min(y1, GetYBot()), that.GetYBot()); if (y1 <= yrange[0]) { throw new SystemException("backstepping from " + yrange[0] + " to " + y1); } yrange[1] = y1; if (GetXMax() <= that.GetXMin()) { if (GetXMin() == that.GetXMax()) { return 0; } return -1; } if (GetXMin() >= that.GetXMax()) { return 1; } // Parameter s for thi(s) curve and t for tha(t) curve // [st]0 = parameters for top of current section of interest // [st]1 = parameters for bottom of valid range // [st]h = parameters for hypothesis point // [d][xy]s = valuations of thi(s) curve at sh // [d][xy]t = valuations of tha(t) curve at th double s0 = TforY(y0); double ys0 = YforT(s0); if (ys0 < y0) { s0 = RefineTforY(s0, ys0, y0); ys0 = YforT(s0); } double s1 = TforY(y1); if (YforT(s1) < y0) { s1 = RefineTforY(s1, YforT(s1), y0); //System.out.println("s1 problem!"); } double t0 = that.TforY(y0); double yt0 = that.YforT(t0); if (yt0 < y0) { t0 = that.RefineTforY(t0, yt0, y0); yt0 = that.YforT(t0); } double t1 = that.TforY(y1); if (that.YforT(t1) < y0) { t1 = that.RefineTforY(t1, that.YforT(t1), y0); //System.out.println("t1 problem!"); } double xs0 = XforT(s0); double xt0 = that.XforT(t0); double scale = Math.Max(Math.Abs(y0), Math.Abs(y1)); double ymin = Math.Max(scale * 1E-14, 1E-300); if (FairlyClose(xs0, xt0)) { double bump = ymin; double maxbump = Math.Min(ymin * 1E13, (y1 - y0) * .1); double y = y0 + bump; while (y <= y1) { if (FairlyClose(XforY(y), that.XforY(y))) { if ((bump *= 2) > maxbump) { bump = maxbump; } } else { y -= bump; while (true) { bump /= 2; double newy = y + bump; if (newy <= y) { break; } if (FairlyClose(XforY(newy), that.XforY(newy))) { y = newy; } } break; } y += bump; } if (y > y0) { if (y < y1) { yrange[1] = y; } return 0; } } while (s0 < s1 && t0 < t1) { double sh = NextVertical(s0, s1); double xsh = XforT(sh); double ysh = YforT(sh); double th = that.NextVertical(t0, t1); double xth = that.XforT(th); double yth = that.YforT(th); /* System.out.println("sh = "+sh); System.out.println("th = "+th); */ try { if (FindIntersect(that, yrange, ymin, 0, 0, s0, xs0, ys0, sh, xsh, ysh, t0, xt0, yt0, th, xth, yth)) { break; } } catch (Exception) { return 0; } if (ysh < yth) { if (ysh > yrange[0]) { if (ysh < yrange[1]) { yrange[1] = ysh; } break; } s0 = sh; xs0 = xsh; ys0 = ysh; } else { if (yth > yrange[0]) { if (yth < yrange[1]) { yrange[1] = yth; } break; } t0 = th; xt0 = xth; yt0 = yth; } } double ymid = (yrange[0] + yrange[1]) / 2; return Orderof(XforY(ymid), that.XforY(ymid)); }