private Node FindNode(Node root, int width, int height)
{
if (root.Used){
return FindNode(root.Right, width, height) ?? FindNode(root.Down, width, height);
}
if ((width <= root.Width) && (height <= root.Height))
return root;
return null;
}
private Node GrowDown(int width, int height)
{
_root = new Node() { Used = true, X = 0, Y = 0, Width = _root.Width, Height = _root.Height + height,
Down = new Node() { X = 0, Y = _root.Height, Width = _root.Width, Height = height },
Right = new Node() { Down = _root.Down, Height = _root.Height, Right = _root.Right, Used = _root.Used, Width = _root.Width, X = _root.X, Y = _root.Y }
};
var node = FindNode(_root, width, height);
return node != null ? SplitNode(node, width, height) : null;
}
public SpriteSheet Combine(FrameList frameList)
{
// http://codeincomplete.com/posts/2011/5/7/bin_packing/
// http://jwezorek.com/2013/01/sprite-packing-in-python/
// http://www.blackpawn.com/texts/lightmaps/default.html
var sortedList = frameList.Frames.OrderByDescending(f => f.Height*f.Width);
_root = new Node() { Width = sortedList.First().Width, Height = sortedList.First().Height };
foreach (var frame in sortedList){
var node = FindNode(_root, frame.Width, frame.Height);
if (node != null){
var fit = SplitNode(node, frame.Width, frame.Height);
frame.PositionInSheetX = fit.X;
frame.PositionInSheetY = fit.Y;
}
else{
var fit = GrowNode(frame.Width, frame.Height);
frame.PositionInSheetX = fit.X;
frame.PositionInSheetY = fit.Y;
}
}
var finalImage = new Bitmap(_root.Width, _root.Height);
using (var g = Graphics.FromImage(finalImage)) {
//set background color
g.Clear(Color.Transparent);
foreach (var frame in frameList.Frames) {
g.DrawImage(frame.Bitmap, new Rectangle(frame.PositionInSheetX, frame.PositionInSheetY, frame.Width, frame.Height));
}
}
return new SpriteSheet(frameList, finalImage, frameList.Name);
}
private Node SplitNode(Node node, int width, int height)
{
node.Used = true;
node.Down = new Node() { X = node.X, Y = node.Y + height, Width = node.Width, Height = node.Height - height };
node.Right = new Node() { X = node.X + width, Y = node.Y, Width = node.Width - width, Height = height };
return node;
}
