private void GenerateTree(MT19337 rng)
{
root = new BSPMapNode(0, 0, MapRequirements.Width, MapRequirements.Height);
all_nodes = new List <BSPMapNode> {
root
};
leaf_nodes = new HashSet <BSPMapNode> {
root
};
while (true)
{
var new_leafs = new List <BSPMapNode>();
foreach (var split_leaf in leaf_nodes.ToList().
Where(l => l.Width > MAX_LEAF_SIZE || l.Height > MAX_LEAF_SIZE || rng.Between(0, 3) < 3). // always split if too big, or on a 3/4 chance.
Where(l => l.Split(rng))) // only select leafs that actually successfully split
{
// if we did split, add the new leafs to the list
new_leafs.Add(split_leaf.LeftChild);
new_leafs.Add(split_leaf.RightChild);
leaf_nodes.Remove(split_leaf);
}
if (new_leafs.Count == 0)
{
break;
}
all_nodes.AddRange(new_leafs);
leaf_nodes.UnionWith(new_leafs);
}
}
public bool Split(MT19337 rng)
{
// begin splitting the leaf into two children
if (LeftChild != null || RightChild != null)
{
return(false); // we're already split! Abort!
}
// determine direction of split
// if the width is >25% larger than height, we split vertically
// if the height is >25% larger than the width, we split horizontally
// otherwise we split randomly
bool split_horizontally;
if (Width > Height && Width / Height >= 1.25)
{
split_horizontally = false;
}
else if (Height > Width && Height / Width >= 1.25)
{
split_horizontally = true;
}
else
{
split_horizontally = rng.Between(0, 1) == 0;
}
int max = (split_horizontally ? Height : Width) - BSPTreeEngine.MIN_LEAF_SIZE; // determine the maximum height or width
if (max <= BSPTreeEngine.MIN_LEAF_SIZE)
{
return(false); // the area is too small to split any more...
}
int split = rng.Between(BSPTreeEngine.MIN_LEAF_SIZE, max); // determine where we're going to split
// create our left and right children based on the direction of the split
if (split_horizontally)
{
LeftChild = new BSPMapNode(X, Y, Width, split);
RightChild = new BSPMapNode(X, Y + split, Width, Height - split);
}
else
{
LeftChild = new BSPMapNode(X, Y, split, Height);
RightChild = new BSPMapNode(X + split, Y, Width - split, Height);
}
return(true); // split successful!
}
