/// <summary>
/// Creates texture atlas image from a given texture atlas
/// </summary>
/// <param name="atlasTextureLayout">Input texture atlas</param>
/// <param name="srgb">True if the texture atlas should be generated to a SRgb texture</param>
/// <returns></returns>
public static Image CreateTextureAtlas(AtlasTextureLayout atlasTextureLayout, bool srgb)
{
var atlasTexture = Image.New2D(atlasTextureLayout.Width, atlasTextureLayout.Height, 1, srgb ? PixelFormat.R8G8B8A8_UNorm_SRgb : PixelFormat.R8G8B8A8_UNorm);
unsafe
{
var ptr = (Color *)atlasTexture.DataPointer;
// Clean the data
for (var i = 0; i < atlasTexture.PixelBuffer[0].Height * atlasTexture.PixelBuffer[0].Width; ++i)
{
ptr[i] = Color.Zero;
}
}
// Fill in textureData from AtlasTextureLayout
foreach (var element in atlasTextureLayout.Textures)
{
var isSourceRotated = element.SourceRegion.IsRotated;
var isDestinationRotated = element.DestinationRegion.IsRotated;
var sourceTexture = element.Texture;
var sourceTextureWidth = sourceTexture.Description.Width;
var addressModeU = element.BorderModeU;
var addressModeV = element.BorderModeV;
var borderColor = element.BorderColor;
// calculate the source region guaranteed to be in the source texture.
var sourceSize = new Int2(sourceTexture.Description.Width, sourceTexture.Description.Height);
var safeSourceRegion = new Rectangle
{
X = Math.Max(0, element.SourceRegion.X),
Y = Math.Max(0, element.SourceRegion.Y),
Width = Math.Min(sourceSize.X, element.SourceRegion.Right),
Height = Math.Min(sourceSize.Y, element.SourceRegion.Bottom),
};
safeSourceRegion.Width -= safeSourceRegion.X;
safeSourceRegion.Height -= safeSourceRegion.Y;
// calculate the size of the source region and the starting offsets taking into account the rotation
var sourceRegionSize = new Int2(safeSourceRegion.Width, safeSourceRegion.Height);
var destRegionSize = new Int2(element.DestinationRegion.Width, element.DestinationRegion.Height);
var sourceStartOffsets = new Int2(Math.Min(0, element.SourceRegion.X), Math.Min(0, element.SourceRegion.Y));
if (isDestinationRotated)
{
var oldSourceStartOffsetX = sourceStartOffsets.X;
if (isSourceRotated)
{
sourceStartOffsets.X = sourceStartOffsets.Y;
sourceStartOffsets.Y = sourceRegionSize.X - sourceStartOffsets.X - destRegionSize.Y + 2 * element.BorderSize;
}
else
{
sourceStartOffsets.X = sourceRegionSize.Y - sourceStartOffsets.Y - destRegionSize.X + 2 * element.BorderSize;
sourceStartOffsets.Y = oldSourceStartOffsetX;
}
Core.Utilities.Swap(ref sourceRegionSize.X, ref sourceRegionSize.Y);
}
{
var format = sourceTexture.Description.Format;
GetColorDelegate getPixel = GetColorBlack;
if (format == PixelFormat.R8G8B8A8_UNorm_SRgb || format == PixelFormat.R8G8B8A8_UNorm)
{
getPixel = GetColorRGBA;
}
if (format == PixelFormat.A8_UNorm || format == PixelFormat.R8_UNorm)
{
getPixel = GetColorRRR1;
}
if (format == PixelFormat.R8G8_UNorm)
{
getPixel = GetColorRG01;
}
for (var y = 0; y < element.DestinationRegion.Height; ++y)
{
for (var x = 0; x < element.DestinationRegion.Width; ++x)
{
// Get index of source image, if it's the border at this point sourceIndexX and sourceIndexY will be -1
var sourceCoordinateX = GetSourceTextureCoordinate(x - element.BorderSize + sourceStartOffsets.X, sourceRegionSize.X, addressModeU);
var sourceCoordinateY = GetSourceTextureCoordinate(y - element.BorderSize + sourceStartOffsets.Y, sourceRegionSize.Y, addressModeV);
// Check if this image uses border mode, and is in the border area
var isBorderMode = sourceCoordinateX < 0 || sourceCoordinateY < 0;
if (isDestinationRotated)
{
// Modify index for rotating
var tmp = sourceCoordinateY;
if (isSourceRotated)
{
// Since intemediateTexture.DestinationRegion contains the border, we need to delete the border out
sourceCoordinateY = sourceCoordinateX;
sourceCoordinateX = safeSourceRegion.Width - 1 - tmp;
}
else
{
// Since intemediateTexture.DestinationRegion contains the border, we need to delete the border out
sourceCoordinateY = safeSourceRegion.Height - 1 - sourceCoordinateX;
sourceCoordinateX = tmp;
}
}
// Add offset from the region
sourceCoordinateX += safeSourceRegion.X;
sourceCoordinateY += safeSourceRegion.Y;
var readFromIndex = sourceCoordinateY * sourceTextureWidth + sourceCoordinateX; // read index from source image
// Prepare writeToIndex
var targetCoordinateX = element.DestinationRegion.X + x;
var targetCoordinateY = element.DestinationRegion.Y + y;
var writeToIndex = targetCoordinateY * atlasTextureLayout.Width + targetCoordinateX; // write index to atlas buffer
SetPixel(atlasTexture.DataPointer, writeToIndex, isBorderMode ? borderColor : getPixel(sourceTexture.DataPointer, readFromIndex));
}
}
}
}
return(atlasTexture);
}
/// <summary>
/// Create the best atlas layout possible given the elementsToPack to pack, the algorithm and the atlas maximum size.
/// Note: when all the elementsToPack cannot fit into the texture, it tries to pack as much as possible of them.
/// </summary>
/// <returns>False if</returns>
private AtlasTextureLayout CreateBestAtlasLayout(List <AtlasTextureElement> elementsToPack, TexturePackingMethod algorithm, out List <AtlasTextureElement> remainingElements)
{
remainingElements = elementsToPack;
var textureAtlas = new AtlasTextureLayout();
var bestElementPackedCount = int.MaxValue;
// Generate sub size array
var subSizeArray = CreateSubSizeArray(atlasMaxSize.X, atlasMaxSize.Y, 512, 512);
foreach (var subArray in subSizeArray)
{
var currentRemaingElements = new List <AtlasTextureElement>(elementsToPack);
// Reset packer state
maxRectPacker.Initialize(subArray.Width, subArray.Height, AllowRotation);
// Pack
maxRectPacker.PackRectangles(currentRemaingElements, algorithm);
// Find true size from packed regions
var packedSize = CalculatePackedRectanglesBound(maxRectPacker.PackedElements);
// Alter the size of atlas so that it is a power of two
if (!AllowNonPowerOfTwo)
{
packedSize.Width = MathUtil.NextPowerOfTwo(packedSize.Width);
packedSize.Height = MathUtil.NextPowerOfTwo(packedSize.Height);
if (packedSize.Width > subArray.Width || packedSize.Height > subArray.Height)
{
continue;
}
}
if (currentRemaingElements.Count >= bestElementPackedCount)
{
continue;
}
// Found new best pack, cache it
bestElementPackedCount = currentRemaingElements.Count;
// Resize texture atlas
textureAtlas.Width = packedSize.Width;
textureAtlas.Height = packedSize.Height;
textureAtlas.Textures.Clear();
// Store all packed regions into Atlas
foreach (var element in maxRectPacker.PackedElements)
{
textureAtlas.Textures.Add(element.Clone());
}
remainingElements = currentRemaingElements;
}
return(textureAtlas);
}
