/**
* 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);
}
/**
* 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);
}
