public static int Fit(ref Texture_Atlas_T atlas, int index, int width, int height)
{
Node node = atlas.Nodes[index];
int x = node.X;
int y = node.Y;
int widthleft = width;
int i = index;
// can the new width be fitted into the atlas total width?
if ((width + x) > (atlas.Width - 1))
{
return(-1);
}
while (widthleft > 0)
{
Node anode = atlas.Nodes[i];
if (node.Y > y)
{
y = node.Y;
}
if ((y + height) > (atlas.Height - 1))
{
return(-1);
}
widthleft -= node.Z;
i++;
}
return(y);
}
/// <summary>
/// Allocate a new region in the atlas.
/// </summary>
/// <param name="atlas">a texture atlas structure</param>
/// <param name="width">width of the region to allocate</param>
/// <param name="height">height of the region to allocate</param>
/// <returns>Coordinates of the allocated region</returns>
public static Region GetRegion(ref Texture_Atlas_T atlas, int width, int height)
{
int y;
int bestindex = -1;
int bestwidth = int.MaxValue;
int bestheght = int.MaxValue;
Node node;
Node prev;
Region region = new Region(0, 0, width, height);
for (int i = 0; i < atlas.Nodes.Count; i++)
{
y = Fit(ref atlas, i, width, height);
if (y >= 0)
{
node = atlas.Nodes[i];
if (((node.Y + height) < bestheght) || ((node.Y + height) == bestheght) && (node.Z > 0 && node.Z < bestwidth))
{
bestheght = y + height;
bestindex = i;
bestwidth = node.Z;
region.X = node.X;
region.Y = y;
}
}
}
if (bestindex == -1)
{
return(new Region(-1, -1, 0, 0));
}
atlas.Nodes.Insert(bestindex, new Node(region.X, region.Y + height, width));
for (int i = bestindex + 1; i < atlas.Nodes.Count; i++)
{
node = atlas.Nodes[i];
prev = atlas.Nodes[i - 1];
if (node.X < (prev.X + prev.Z))
{
int shrink = prev.X + prev.Z - node.X;
node.X += shrink;
node.Z -= shrink;
if (node.Z <= 0)
{
atlas.Nodes.RemoveAt(i);
--i;
}
else
{
break;
}
}
else
{
break;
}
}
Merge(ref atlas);
atlas.Used += width * height;
return(region);
}
/// <summary>
/// Remove all allocated regions from the atlas.
/// </summary>
/// <param name="atlas">a texture atlas structure</param>
public static void Clear(ref Texture_Atlas_T atlas)
{
Node node = new Node(1, 1, 1);
atlas.Nodes.Clear();
atlas.Used = 0;
node.Z = atlas.Width - 2;
atlas.Nodes.Add(node);
atlas.Data = new byte[atlas.Width * atlas.Height * atlas.Depth];
}
public static void Merge(ref Texture_Atlas_T atlas)
{
for (int i = 0; i < atlas.Nodes.Count - 1; i++)
{
Node node = atlas.Nodes[i];
Node next = atlas.Nodes[i + 1];
if (node.Y == next.Y)
{
node.Z += next.Z;
atlas.Nodes.RemoveAt(i + 1);
--i;
}
}
}
/// <summary>
/// Creates a new empty texture atlas.
/// </summary>
/// <param name="width">width of the atlas</param>
/// <param name="height"> height of the atlas</param>
/// <param name="depth">bit depth of the atlas</param>
/// <returns> a new empty texture atlas.</returns>
public static Texture_Atlas_T NewAtlas(int width, int height, int depth)
{
Texture_Atlas_T atlas = new Texture_Atlas_T();
// We want a one pixel border around the whole atlas to avoid any artefact when
// sampling texture
Node node = new Node(1, 1, width - 2);
if (!(depth == 1 || depth == 3 || depth == 4))
{
throw new ArgumentException("Invaild depth value must be 1,3 or 4");
}
atlas.Nodes = new System.Collections.Generic.List <Node>();
atlas.Nodes.Add(node);
atlas.Width = width;
atlas.Height = height;
atlas.Depth = depth;
atlas.Used = 0;
atlas.Id = 0;
int arraysize = width * height * depth;
atlas.Data = new byte[arraysize];
return(atlas);
}
/// <summary>
/// Upload data to the specified atlas region.
/// </summary>
/// <param name="atlas">a texture atlas structure</param>
/// <param name="x">a texture atlas structure</param>
/// <param name="y">y coordinate the region</param>
/// <param name="width">width of the region</param>
/// <param name="height">height of the region</param>
/// <param name="data">data to be uploaded into the specified region</param>
/// <param name="stride">stride of the data</param>
public static void SetRegion(ref Texture_Atlas_T atlas, int x, int y, int width, int height, byte[] data, int stride)
{
int destinationstartpoint = ((y + 0) * atlas.Width + x) * atlas.Depth;
Array.Copy(data, 0, atlas.Data, destinationstartpoint, data.Length);
}
