Пример #1
0
  public Vector2 V2AddII(Vector2 a, Vector2 b) {
    Vector2 c = new Vector2();

    c.xset(a.xval() + b.xval());
    c.yset(a.yval() + b.yval());
    return (c);
  }
Пример #2
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  public Vector2 V2ScaleIII(Vector2 a, double s) {
    Vector2 result = new Vector2();

    result.xset(s * a.xval());
    result.yset(s * a.yval());

    return (result);
  }
Пример #3
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 /* return vector sum c = a+b */
 public Vector2 V2Add(Vector2 a, Vector2 b, Vector2 c) {
   // c = new Vector2();
   c.xset(a.xval() + b.xval());
   c.yset(a.yval() + b.yval());
   // System.out.println("V2Add: "+a.xval()+" + "+b.xval()+" = "+c.xval() );
   // System.out.println("V2Add: "+a.yval()+" + "+b.yval()+" = "+c.yval()+"\n");
   return (c);
 }
Пример #4
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  public Vector2 V2Scale(Vector2 v, double newlen) {
    double len = v.V2Length();
    if (len != 0.0) {
      double temp;

      temp = v.xval();
      v.xset(temp * newlen / len);

      temp = v.yval();
      v.yset(temp * newlen / len);
    }
    return (v);
  }
Пример #5
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  public Vector2 ComputeCenterTangent(Vector2[] d, int center)
        /* d;                     Digitized points */

        /*center;          Index to point inside region        */
      {
    Vector2 V1, V2, tHatCenter;

    V1 = V2SubII(d[center - 1], d[center]);
    V2 = V2SubII(d[center], d[center + 1]);

    tHatCenter = new Vector2();
    tHatCenter.xset((V1.xval() + V2.xval()) / 2.0);
    tHatCenter.yset((V1.yval() + V2.yval()) / 2.0);
    tHatCenter.V2Normalize();
    return tHatCenter;
  }
Пример #6
0
  /*
   *  GenerateBezier :
   *  Use least-squares method to find Bezier control points for region.
   *
   */
  public Vector2[] GenerateBezier(
      Vector2[] d, int first, int last, double uPrime[], Vector2 tHat1, Vector2 tHat2)
        /* d:  Array of digitized points   */
        /* first last:  Indices defining region     */
        /* uPrime: Parameter values for region */
        /* tHat1, tHat2:  Unit tangents at endpoints  */
      {
    int i;
    double C[][] = new double[2][2]; /* Matrix C             */
    double[] X = new double[2]; /* Matrix X                     */
    Vector2 A[][]; /* Precomputed rhs for eqn      */
    int nPts; /* Number of pts in sub-curve */
    double det_C0_C1, /* Determinants of matrices     */ det_C0_X, det_X_C1;
    double alpha_l, /* Alpha values, left and right */ alpha_r;
    Vector2 tmp; /* Utility variable             */
    Vector2[] bezCurve = new Vector2[4]; /* RETURN bezier curve ctl pts  */

    // System.out.println("ENTERING GENERATE BEZIER "+tHat1.xval()+" "+tHat1.yval()+"
    // "+tHat2.xval()+" "+tHat2.yval());

    for (i = 0; i < 4; i++) bezCurve[i] = new Vector2();

    /*    bezCurve = (Vector2 *)malloc(4 * sizeof(Vector2)); */
    nPts = last - first + 1;

    A = new Vector2[nPts][2];

    /* Compute the A's  */
    for (i = 0; i < nPts; i++) {
      Vector2 v1 = new Vector2();
      Vector2 v2 = new Vector2();

      v1.xset(tHat1.xval());
      v1.yset(tHat1.yval());
      v2.xset(tHat2.xval());
      v2.yset(tHat2.yval());
      // System.out.println("PT: "+i);
      // System.out.print("that1 length "+tHat1.V2Length()+" "+tHat1.xval()+" "+tHat1.yval() );
      // System.out.print("that2 length "+tHat2.V2Length()+" "+tHat2.xval()+" "+tHat2.yval() );
      // System.out.print("Before: "+v1.xval() +" "+v1.yval() );
      V2Scale(v1, B1(uPrime[i]));
      // System.out.println("after : "+v1.xval() +" "+v1.yval() );
      // System.out.print("Before: "+v2.xval() +" "+v2.yval() );
      V2Scale(v2, B2(uPrime[i]));
      // System.out.println("after : "+v2.xval() +" "+v2.yval() );

      A[i][0] = new Vector2();
      A[i][0].xset(v1.xval());
      A[i][0].yset(v1.yval());
      A[i][1] = new Vector2();
      A[i][1].xset(v2.xval());
      A[i][1].yset(v2.yval());
      //	System.out.println("A[i][0] "+A[i][0].xval()+" "+A[i][0].yval());
      //	System.out.println("A[i][1] "+A[i][1].xval()+" "+A[i][1].yval());
      //	System.out.println("B1 "+B1(uPrime[i])+" B2 "+B2(uPrime[i]));
    }

    /* Create the C and X matrices      */
    C[0][0] = 0.0;
    C[0][1] = 0.0;
    C[1][0] = 0.0;
    C[1][1] = 0.0;
    X[0] = 0.0;
    X[1] = 0.0;

    for (i = 0; i < nPts; i++) {
      C[0][0] += V2Dot(A[i][0], A[i][0]);
      C[0][1] += V2Dot(A[i][0], A[i][1]);
      /*                                      C[1][0] += V2Dot(A[i][0], A[i][1]);*/
      C[1][0] = C[0][1];
      C[1][1] += V2Dot(A[i][1], A[i][1]);

      tmp =
          V2SubII(
              d[first + i],
              V2AddII(
                  V2ScaleIII(d[first], B0(uPrime[i])),
                  V2AddII(
                      V2ScaleIII(d[first], B1(uPrime[i])),
                      V2AddII(
                          V2ScaleIII(d[last], B2(uPrime[i])),
                          V2ScaleIII(d[last], B3(uPrime[i]))))));

      X[0] += V2Dot(A[i][0], tmp);
      X[1] += V2Dot(A[i][1], tmp);
    }

    System.out.println("C " + C[0][0] + " " + C[0][1] + " " + C[1][0] + " " + C[1][1]);
    System.out.println("X " + X[0] + " " + X[1]);

    /* Compute the determinants of C and X      */
    det_C0_C1 = C[0][0] * C[1][1] - C[1][0] * C[0][1];
    det_C0_X = C[0][0] * X[1] - C[0][1] * X[0];
    det_X_C1 = X[0] * C[1][1] - X[1] * C[0][1];

    /* Finally, derive alpha values     */
    if (det_C0_C1 == 0.0) {
      det_C0_C1 = (C[0][0] * C[1][1]) * 10e-12;
    }
    alpha_l = det_X_C1 / det_C0_C1;
    alpha_r = det_C0_X / det_C0_C1;

    // System.out.println("\n\n\nalpha_l "+alpha_l+" alpha_r "+alpha_r);

    /*  If alpha negative, use the Wu/Barsky heuristic (see text) */

    if (alpha_l < 0.0 || alpha_r < 0.0) {
      int ddd;
      double dist = V2DistanceBetween2Points(d[last], d[first]) / 3.0;

      for (ddd = 0; ddd < 4; ddd++) bezCurve[ddd] = new Vector2();

      bezCurve[0] = d[first];
      bezCurve[3] = d[last];
      // System.out.println("HERE!!!!");

      V2Add(bezCurve[0], V2Scale(tHat1, dist), bezCurve[1]);
      V2Add(bezCurve[3], V2Scale(tHat2, dist), bezCurve[2]);
      return (bezCurve);
    }

    /*  First and last control points of the Bezier curve are */
    /*  positioned exactly at the first and last data points */
    /*  Control points 1 and 2 are positioned an alpha distance out */
    /*  on the tangent vectors, left and right, respectively */
    bezCurve[0] = new Vector2();
    bezCurve[1] = new Vector2();
    bezCurve[2] = new Vector2();
    bezCurve[3] = new Vector2();
    bezCurve[0].xset(d[first].xval());
    bezCurve[0].yset(d[first].yval());
    bezCurve[3].xset(d[last].xval());
    bezCurve[3].yset(d[last].yval());
    // System.out.println("EDW??? 1");
    V2Add(bezCurve[0], V2Scale(tHat1, alpha_l), bezCurve[1]);

    // System.out.println("EDW??? 2");
    V2Add(bezCurve[3], V2Scale(tHat2, alpha_r), bezCurve[2]);

    // System.out.println("BEZ_CURVE is "+bezCurve[0].xval()+" "+bezCurve[0].yval()+" and
    // "+bezCurve[3].xval()+" "+bezCurve[3].yval());
    // System.out.println("BEZ_CURVE is "+bezCurve[1].xval()+" "+bezCurve[1].yval()+" and
    // "+bezCurve[2].xval()+" "+bezCurve[2].yval());

    // System.out.println("EXITING GENERATE BEZIER");
    return (bezCurve);
  }