int
GameBoard::NumNeighbours(const Cell& cell) {
BoundingBox searchBox;
if (cell.x == 0) {
searchBox._x = 0;
searchBox._width = 1;
} else {
searchBox._x = cell.x - 1;
searchBox._width = 2;
}
if (cell.y == 0) {
searchBox._y = 0;
searchBox._height = 1;
} else {
searchBox._y = cell.y - 1;
searchBox._height = 2;
}
CellSet neighbours;
_quadTree.FindPoints(searchBox, neighbours);
// The original cell is in the search box, so should
// be at least one. If a dead cell, we only look at
// dead cells next to alive ones so there should be at least one.
assert(neighbours.size() > 0);
return cell.isAlive ? neighbours.size() - 1 : neighbours.size();
}
Cell
GameBoard::FindNearest(const Cell& cell) const {
if (_liveCells.count(cell)) {
return cell;
}
// Select random cell, find all cells in the minimal bounding
// box such that the random cell is on the edge.
// Repeat until there is only one cell in the bounding box.
CellSet candidateSet = _liveCells;
srand(time(0));
while (candidateSet.size() > 1) {
int index = rand() % candidateSet.size();
CellSet::iterator it = candidateSet.begin();
for (int i = 0; i < index; ++i) {
++it;
assert(it != candidateSet.end());
}
Cell nextCandidate = *it;
unsigned long boxWidth = (nextCandidate.x > cell.x) ?
nextCandidate.x - cell.x :
cell.x - nextCandidate.x;
unsigned long boxHeight = (nextCandidate.y > cell.y) ?
nextCandidate.y - cell.y :
cell.y - nextCandidate.y;
unsigned long boxX = cell.x >= (0 + boxWidth) ? cell.x - boxWidth : 0;
unsigned long boxY = cell.y >= (0 + boxHeight) ? cell.y - boxHeight : 0;
candidateSet.clear();
_quadTree.FindPoints(BoundingBox(boxX, boxY,
boxWidth * 2, boxHeight * 2),
candidateSet);
}
assert(candidateSet.size() == 1);
return *candidateSet.begin();
}
// Insert the new cell just below the lowest boundary cell
void ZOrderedCells::insertCell(Cell * cell)
{
// Get boundary cells
CellSet boundary = cell->boundary();
// Insert at appropriate position
if(boundary.size() == 0)
{
// Insert last
insertLast(cell);
}
else
{
// Insert before boundary
Iterator it = begin();
while(it!=end() && !boundary.contains(*it))
++it;
list_.insert(it,cell);
}
}