Esempio n. 1
0
  /**
   * Find intersections of hyperbolic arm with an axes-aligned line segment. Arm must intersect
   * segment, not its underlying (infinite) line. The intersection points are sorted into increasing
   * parameter values w.r.t. the arm.
   *
   * @param s0 : start of line segment
   * @param s1 : end of line segment
   * @param ipts : intersection points returned here
   * @param reverseOrder : if true, points are sorted by decreasing parameter values
   * @param dbFlag : true to print debug information
   */
  public void findOrthogonalIntersect(
      FPoint2 s0, FPoint2 s1, DArray ipts, boolean reverseOrder, boolean dbFlag) {

    final boolean db = true && dbFlag;

    if (db) {
      System.out.println(
          "findOrthogonalIntersect " + s0 + " -> " + s1 + " rev:" + Tools.f(reverseOrder));
    }

    // Determine whether this is a vertical or horizontal line segment.

    boolean vert = (Math.abs(s1.y - s0.y) > Math.abs(s1.x - s0.x));
    if (db) {
      System.out.println(" vert=" + Tools.f(vert));
    }

    // Find the quadratic to solve.
    Polyn p;
    PlaneCurve cv = getCurve();
    if (vert) {
      p = cv.solveForX(s0.x);
    } else {
      p = cv.solveForY(s0.y);
    }

    DArray lst = new DArray();
    p.solve(lst);

    if (db) {
      System.out.println(" curve=" + cv.toString(true));
      System.out.println(" polyn=" + p.toString(true));
      System.out.println(" roots=" + Tools.d(lst));
    }

    // Sort points, discarding those not on line segment,
    // and those not on the correct arm.
    ipts.clear();

    for (int i = 0; i < lst.size(); i++) {
      double ta = lst.getDouble(i);
      FPoint2 pt;
      if (vert) {
        pt = new FPoint2(s0.x, ta);
      } else {
        pt = new FPoint2(ta, s0.y);
      }

      if (db) {
        System.out.println(" position on arm for ta=" + ta + " is " + pt);
      }
      double t = MyMath.positionOnSegment(pt, s0, s1);
      if (db) {
        System.out.println("  pt=" + pt + " t=" + t);
      }
      if (t < 0 || t > 1) {
        if (db) {
          System.out.println("   not on segment, skipping");
        }
        continue;
      }

      FPoint2 cpt = toCurveSpace(pt, null);
      if (db) {
        System.out.println("  curveSpace=" + cpt);
      }
      if (cpt.x < 0) {
        if (db) {
          System.out.println("   skipping...");
        }
        continue;
      }

      double t1 = calcParameter(pt);
      int j = 0;
      while (true) {
        if (j == ipts.size()) {
          break;
        }
        double t2 = calcParameter(ipts.getFPoint2(j));
        if (!reverseOrder) {
          if (t1 < t2) {
            break;
          }
        } else if (t1 > t2) {
          break;
        }
        j++;
      }
      ipts.add(j, pt);
    }
    if (db) {
      System.out.println(" ipts=" + Tools.d(ipts));
    }
  }
Esempio n. 2
0
  /**
   * Find intersections between two hyperbolas
   *
   * @param a Hyperbola
   * @param b Hyperbola
   * @param iPts where to store intersection points; null to construct
   */
  public static DArray findIntersections(Hyperbola a, Hyperbola b, DArray iPts) {
    final boolean db = false;

    if (iPts == null) iPts = new DArray();
    iPts.clear();
    final DArray jPts = new DArray();
    // a.initClipIfNec();
    //    b.initClipIfNec();
    if (db) {
      System.out.println(
          "finding intersections between:\n" + a.toString(true) + "\n" + b.toString(true));
    }

    PlaneCurve.findIntersect(a.getCurve(), b.getCurve(), jPts);

    // filter out false intersections
    if (db) {
      System.out.println("prefilter # intersections= " + jPts.size());
    }

    FPoint2 ptc = new FPoint2();

    for (int i = 0; i < jPts.size(); i++) {
      FPoint2 pt = jPts.getFPoint2(i);

      // make sure calculated intersect point is actually on both arms
      {
        FPoint2 data = a.calcParameterAndDistance(pt);
        if (data.y > .001) continue;
        data = b.calcParameterAndDistance(pt);
        if (data.y > .001) continue;
      }

      if (!a.isLine()) {
        // put in curve space to verify it's to the right of the y axis
        a.toCurveSpace(pt, ptc);
        if (db) {
          System.out.println("Filter " + i + " in curveA= " + ptc);
        }
        if (ptc.x <= 0) {
          if (db) {
            System.out.println(" < 0");
          }
          continue;
        }
      }
      if (!b.isLine()) {
        b.toCurveSpace(pt, ptc);
        if (db) {
          System.out.println("        in curveB= " + ptc);
        }
        if (ptc.x <= 0) {
          if (db) {
            System.out.println(" < 0");
          }
          continue;
        }
      }
      if (db) {
        System.out.println(" adding " + pt);
      }
      iPts.add(pt);
    }
    return iPts;
  }