Beispiel #1
0
  /**
   * Computes a <code>Box</code> that bounds a specified buffer of points. Principal axes are
   * computed for the points and used to form a <code>Box</code>. This returns <code>null</code> if
   * the buffer is empty or contains only a partial point.
   *
   * <p>The buffer must contain XYZ coordinate tuples which are either tightly packed or offset by
   * the specified stride. The stride specifies the number of buffer elements between the first
   * coordinate of consecutive tuples. For example, a stride of 3 specifies that each tuple is
   * tightly packed as XYZXYZXYZ, whereas a stride of 5 specifies that there are two elements
   * between each tuple as XYZabXYZab (the elements "a" and "b" are ignored). The stride must be at
   * least 3. If the buffer's length is not evenly divisible into stride-sized tuples, this ignores
   * the remaining elements that follow the last complete tuple.
   *
   * @param buffer the buffer containing the point coordinates for which to compute a bounding
   *     volume.
   * @param stride the number of elements between the first coordinate of consecutive points. If
   *     stride is 3, this interprets the buffer has having tightly packed XYZ coordinate tuples.
   * @return the bounding volume, with axes lengths consistent with the conventions described in the
   *     <code>Box</code> class overview.
   * @throws IllegalArgumentException if the buffer is null or empty, or if the stride is less than
   *     three.
   */
  public static Box computeBoundingBox(FloatBuffer buffer, int stride) {
    if (buffer == null) {
      String msg = Logging.getMessage("nullValue.BufferIsNull");
      Logging.error(msg);
      throw new IllegalArgumentException(msg);
    }

    if (stride < 3) {
      String msg = Logging.getMessage("generic.StrideIsInvalid", stride);
      Logging.error(msg);
      throw new IllegalArgumentException(msg);
    }

    Vec4[] axes = WWMath.computePrincipalAxes(buffer, stride);
    if (axes == null) {
      String msg = Logging.getMessage("generic.BufferIsEmpty");
      Logging.error(msg);
      throw new IllegalArgumentException(msg);
    }

    Vec4 r = axes[0];
    Vec4 s = axes[1];
    Vec4 t = axes[2];

    // Find the extremes along each axis.
    double minDotR = Double.MAX_VALUE;
    double maxDotR = -minDotR;
    double minDotS = Double.MAX_VALUE;
    double maxDotS = -minDotS;
    double minDotT = Double.MAX_VALUE;
    double maxDotT = -minDotT;

    for (int i = buffer.position(); i <= buffer.limit() - stride; i += stride) {
      double x = buffer.get(i);
      double y = buffer.get(i + 1);
      double z = buffer.get(i + 2);

      double pdr = x * r.x + y * r.y + z * r.z;
      if (pdr < minDotR) minDotR = pdr;
      if (pdr > maxDotR) maxDotR = pdr;

      double pds = x * s.x + y * s.y + z * s.z;
      if (pds < minDotS) minDotS = pds;
      if (pds > maxDotS) maxDotS = pds;

      double pdt = x * t.x + y * t.y + z * t.z;
      if (pdt < minDotT) minDotT = pdt;
      if (pdt > maxDotT) maxDotT = pdt;
    }

    if (maxDotR == minDotR) maxDotR = minDotR + 1;
    if (maxDotS == minDotS) maxDotS = minDotS + 1;
    if (maxDotT == minDotT) maxDotT = minDotT + 1;

    return new Box(axes, minDotR, maxDotR, minDotS, maxDotS, minDotT, maxDotT);
  }
Beispiel #2
0
  /**
   * Compute a <code>Box</code> that bounds a specified list of points. Principal axes are computed
   * for the points and used to form a <code>Box</code>.
   *
   * @param points the points for which to compute a bounding volume.
   * @return the bounding volume, with axes lengths consistent with the conventions described in the
   *     overview.
   * @throws IllegalArgumentException if the point list is null or empty.
   */
  public static Box computeBoundingBox(Iterable<? extends Vec4> points) {
    if (points == null) {
      String msg = Logging.getMessage("nullValue.PointListIsNull");
      Logging.error(msg);
      throw new IllegalArgumentException(msg);
    }

    Vec4[] axes = WWMath.computePrincipalAxes(points);
    if (axes == null) {
      String msg = Logging.getMessage("generic.PointListIsEmpty");
      Logging.error(msg);
      throw new IllegalArgumentException(msg);
    }

    Vec4 r = axes[0];
    Vec4 s = axes[1];
    Vec4 t = axes[2];

    // Find the extremes along each axis.
    double minDotR = Double.MAX_VALUE;
    double maxDotR = -minDotR;
    double minDotS = Double.MAX_VALUE;
    double maxDotS = -minDotS;
    double minDotT = Double.MAX_VALUE;
    double maxDotT = -minDotT;

    for (Vec4 p : points) {
      if (p == null) continue;

      double pdr = p.dot3(r);
      if (pdr < minDotR) minDotR = pdr;
      if (pdr > maxDotR) maxDotR = pdr;

      double pds = p.dot3(s);
      if (pds < minDotS) minDotS = pds;
      if (pds > maxDotS) maxDotS = pds;

      double pdt = p.dot3(t);
      if (pdt < minDotT) minDotT = pdt;
      if (pdt > maxDotT) maxDotT = pdt;
    }

    if (maxDotR == minDotR) maxDotR = minDotR + 1;
    if (maxDotS == minDotS) maxDotS = minDotS + 1;
    if (maxDotT == minDotT) maxDotT = minDotT + 1;

    return new Box(axes, minDotR, maxDotR, minDotS, maxDotS, minDotT, maxDotT);
  }