internal OcTree(int colorDepth)
{
this._colorDepth = colorDepth;
_maxColors = 1 << _colorDepth;
ReducibleNodes = new OcTreeNode[colorDepth];
_rootNode = new OcTreeNode(colorDepth, 0, this);
}
void Reduce()
{
int index;
for (index = _colorDepth - 1; (index > 0 && ReducibleNodes[index] == null); index--)
{
}
OcTreeNode node = ReducibleNodes[index];
ReducibleNodes[index] = node.NextReducible;
leaves -= node.Reduce();
_prefixNode = null;
}
/// <summary>
/// 八叉树的构造函数
/// </summary>
/// <param name="colorDepth"></param>
/// <param name="level">层级</param>
/// <param name="tree"></param>
internal OcTreeNode(int colorDepth, int level, OcTree tree)
{
this.ColorDepth = colorDepth;
this.Leaf = (colorDepth == level);
this.Level = level;
if (!Leaf)
{
NextReducible = tree.ReducibleNodes[level];
tree.ReducibleNodes[level] = this;
Children = new OcTreeNode[8];
}
else
{
tree.IncrementLeaves();
}
}
internal int GetPaletteIndex(Color32 *pixel, int level)
{
int pindex = paletteIndex;
if (!Leaf)
{
int shift = 7 - level;
int index = ((pixel->Red & mask[level]) >> (shift - 2)) |
((pixel->Green & mask[level]) >> (shift - 1)) |
((pixel->Blue & mask[level]) >> (shift));
OcTreeNode child = Children[index];
if (child != null)
{
child.GetPaletteIndex(pixel, level + 1);
}
else
{
throw new Exception("不可预料的事情发生了!");
}
}
return(pindex);
}
internal void AddColor(Color32 *pixel, int level, OcTree tree)
{
//如果是树叶了，表示一个颜色像素添加完成
if (this.Leaf)
{
Increment(pixel);
tree.TracePrevious(this);
return;
}
int shift = 7 - level;
int index = ((pixel->Red & mask[level]) >> (shift - 2)) |
((pixel->Green & mask[level]) >> (shift - 1)) |
((pixel->Blue & mask[level]) >> (shift));
OcTreeNode child = Children[index];
if (child == null)
{
child = new OcTreeNode(ColorDepth, level + 1, tree);
Children[index] = child;
}
child.AddColor(pixel, ++level, tree);
}
internal void TracePrevious(OcTreeNode node)
{
this._prefixNode = node;
}