/**
* Gets all neighbors of a location that satisfy abs(x-X) + abs(y-Y) + abs(z-Z) <= dist. This
* region forms an <a href="http://images.google.com/images?q=octahedron">octohedron</a> 2*dist+1
* cells from point to opposite point inclusive, centered at (X,Y,Y). If dist==1 this is
* equivalent to the six neighbors above, below, left, and right, front, and behind (X,Y,Z)), plus
* (X,Y,Z) itself. Places each x, y, and z value of these locations in the provided IntBags xPos,
* yPos, and zPos, clearing the bags first. Then places into the result IntBag the elements at
* each of those <x,y,z> locations clearning it first. Returns the result IntBag (constructing one
* if null had been passed in). null may be passed in for the various bags, though it is more
* efficient to pass in a 'scratch bag' for each one.
*/
public final void getNeighborsHamiltonianDistance(
final int x,
final int y,
final int z,
final int dist,
final boolean toroidal,
IntBag result,
IntBag xPos,
IntBag yPos,
IntBag zPos) {
if (xPos == null) xPos = new IntBag();
if (yPos == null) yPos = new IntBag();
if (zPos == null) zPos = new IntBag();
getNeighborsHamiltonianDistance(x, y, z, dist, toroidal, xPos, yPos, zPos);
if (result != null) {
result.clear();
result.resize(xPos.size());
} else result = new IntBag(xPos.size());
for (int i = 0; i < xPos.numObjs; i++)
result.add(field[xPos.objs[i]][yPos.objs[i]][zPos.objs[i]]);
}
public void getNeighborsHamiltonianDistance(
final int x,
final int y,
final int z,
final int dist,
final boolean toroidal,
IntBag xPos,
IntBag yPos,
IntBag zPos) {
// won't work for negative distances
if (dist < 0) {
throw new RuntimeException(
"Runtime exception in method getNeighborsHamiltonianDistance: Distance must be positive");
}
if (xPos == null || yPos == null || zPos == null) {
throw new RuntimeException(
"Runtime exception in method getNeighborsHamiltonianDistance: xPos and yPos should not be null");
}
xPos.clear();
yPos.clear();
zPos.clear();
// local variables are faster
final int height = this.height;
final int width = this.width;
final int length = this.length;
// for toroidal environments the code will be different because of wrapping arround
if (toroidal) {
// compute xmin and xmax for the neighborhood
final int xmax = x + dist;
final int xmin = x - dist;
for (int x0 = xmin; x0 <= xmax; x0++) {
final int x_0 = stx(x0, width);
// compute ymin and ymax for the neighborhood; they depend on the curreny x0 value
final int ymax = y + (dist - ((x0 - x >= 0) ? x0 - x : x - x0));
final int ymin = y - (dist - ((x0 - x >= 0) ? x0 - x : x - x0));
for (int y0 = ymin; y0 <= ymax; y0++) {
final int y_0 = sty(y0, height);
final int zmax =
z + (dist - ((x0 - x >= 0) ? x0 - x : x - x0) - ((y0 - y >= 0) ? y0 - y : y - y0));
final int zmin =
z - (dist - ((x0 - x >= 0) ? x0 - x : x - x0) - ((y0 - y >= 0) ? y0 - y : y - y0));
for (int z0 = zmin; z0 <= zmax; z0++) {
final int z_0 = stz(z0, length);
if (x_0 != x || y_0 != y || z_0 != z) {
xPos.add(x_0);
yPos.add(y_0);
zPos.add(z_0);
}
}
}
}
} else // not toroidal
{
// compute xmin and xmax for the neighborhood such that they are within boundaries
final int xmax = ((x + dist <= width - 1) ? x + dist : width - 1);
final int xmin = ((x - dist >= 0) ? x - dist : 0);
for (int x0 = xmin; x0 <= xmax; x0++) {
final int x_0 = x0;
// compute ymin and ymax for the neighborhood such that they are within boundaries
// they depend on the curreny x0 value
final int ymax =
((y + (dist - ((x0 - x >= 0) ? x0 - x : x - x0)) <= height - 1)
? y + (dist - ((x0 - x >= 0) ? x0 - x : x - x0))
: height - 1);
final int ymin =
((y - (dist - ((x0 - x >= 0) ? x0 - x : x - x0)) >= 0)
? y - (dist - ((x0 - x >= 0) ? x0 - x : x - x0))
: 0);
for (int y0 = ymin; y0 <= ymax; y0++) {
final int y_0 = y0;
final int zmin =
((z - (dist - ((x0 - x >= 0) ? x0 - x : x - x0) - ((y0 - y >= 0) ? y0 - y : y - y0))
>= 0)
? z
- (dist
- ((x0 - x >= 0) ? x0 - x : x - x0)
- ((y0 - y >= 0) ? y0 - y : y - y0))
: 0);
final int zmax =
((z + (dist - ((x0 - x >= 0) ? x0 - x : x - x0) - ((y0 - y >= 0) ? y0 - y : y - y0))
<= length - 1)
? z
+ (dist
- ((x0 - x >= 0) ? x0 - x : x - x0)
- ((y0 - y >= 0) ? y0 - y : y - y0))
: length - 1);
for (int z0 = zmin; z0 <= zmax; z0++) {
final int z_0 = z0;
if (x_0 != x || y_0 != y || z_0 != z) {
xPos.add(x_0);
yPos.add(y_0);
zPos.add(z_0);
}
}
}
}
}
}
