/// <summary>
/// Encodes an image into the signed BC5 format.
/// </summary>
/// <param name="image">The image to encode.</param>
/// <param name="rChan">The channel to pull red values from.</param>
/// <param name="gChan">The channel to pull green values from.</param>
/// <returns>The encoded signed BC5 image data.</returns>
public BCnImage <BC5SBlock> EncodeBC5S(FloatImage image,
int rChan = 0, int gChan = 1)
{
if (image == null)
{
throw new ArgumentNullException("image");
}
if (rChan < 0 || rChan >= image.ChannelCount)
{
throw new ArgumentOutOfRangeException("rChan");
}
if (gChan < 0 || gChan >= image.ChannelCount)
{
throw new ArgumentOutOfRangeException("gChan");
}
var ret = new BCnImage <BC5SBlock>(image.Width, image.Height);
ImageEncodingHelper.EncodeBlocks(ret,
() =>
{
var encBC4 = new BC4BlockEncoder();
return((chanData, index, pitch) =>
{
BC5SBlock block;
encBC4.LoadBlock(chanData[0], index, pitch);
block.R = encBC4.EncodeSigned();
encBC4.LoadBlock(chanData[1], index, pitch);
block.G = encBC4.EncodeSigned();
return block;
});
},
image, new int[] { rChan, gChan });
return(ret);
}
/// <summary>
/// Encodes an image into a block-compressed bitmap.
/// </summary>
/// <typeparam name="T">
/// The block type to encode to.
/// </typeparam>
/// <param name="destImage">
/// The bitmap to encode into. Encoding
/// will overwrite its contents.
/// </param>
/// <param name="encoderFactory">
/// A factory function to create encoder objects.
/// Encoders must be thread-safe (see remarks).
/// </param>
/// <param name="srcImage">
/// The image to encode.
/// </param>
/// <param name="channelIndices">
/// The image channels to pass to the encoder. If this
/// parmeter is <c>null</c>, all of the image's channels
/// will be passed directly. A channel index of <c>-1</c>
/// selects a <c>null</c> channel (this can be used to pad
/// the array for encoders that expect their input data
/// to be at specific channel indices).
/// </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="destImage"/>, <paramref name="encoderFactory"/>,
/// or <paramref name="srcImage"/> is null.
/// </exception>
/// <exception cref="ArgumentException">
/// <paramref name="destImage"/> and <paramref name="srcImage"/> are
/// not the same size.
/// </exception>
/// <remarks>
/// Blocks may be encoded in parallel. This function will call
/// <paramref name="encoderFactory"/> multiple times, creating
/// a unique encoder for each thread. Individual encoders will
/// only run on one thread at a time, but multiple encoder objects
/// may execute at once. Take care with any shared encoder state.
/// </remarks>
public static void EncodeBlocks <T>(
BCnImage <T> destImage,
Func <DataEncoder <T> > encoderFactory,
FloatImage srcImage, int[] channelIndices = null)
where T : struct
{
if (encoderFactory == null)
{
throw new ArgumentNullException("encoderFactory");
}
if (destImage == null)
{
throw new ArgumentNullException("destBitmap");
}
if (srcImage == null)
{
throw new ArgumentNullException("image");
}
if (destImage.Width != srcImage.Width || destImage.Height != srcImage.Height)
{
throw new ArgumentException("image and destBitmap must be the same size.");
}
var imageWidth = srcImage.Width;
var imageHeight = srcImage.Height;
var blockWidth = BCnImage <T> .BlockWidth;
var blockHeight = BCnImage <T> .BlockHeight;
var nBlocksW = destImage.WidthInBlocks;
var nBlocksH = destImage.HeightInBlocks;
var nWholeBlocksW = nBlocksW;
var nWholeBlocksH = nBlocksH;
if (imageWidth < nBlocksW * blockWidth)
{
nWholeBlocksW--;
}
if (imageHeight < nBlocksH * blockHeight)
{
nWholeBlocksH--;
}
float[][] chanData = srcImage.GetChannelStorage(channelIndices);
var targetData = destImage.GetBlockStorage();
Parallel.For(0, nWholeBlocksW * nWholeBlocksH,
encoderFactory, (iBlock, loopState, encoder) =>
{
int y = iBlock / nWholeBlocksW;
int x = iBlock - y * nWholeBlocksW;
int srcIndex =
(y * blockHeight) * imageWidth +
(x * blockWidth);
targetData[y * nBlocksW + x] =
encoder(chanData, srcIndex, imageWidth);
return(encoder);
}, _ => { });
//the uncommon case: finish off any partial edge tiles on the main thread
if (nWholeBlocksW != nBlocksW || nWholeBlocksH != nBlocksH)
{
var blockArea = blockWidth * blockHeight;
var tmp = new float[chanData.Length][];
for (int iChan = 0; iChan < tmp.Length; iChan++)
{
tmp[iChan] = chanData[iChan] != null ? new float[blockArea] : null;
}
var encoder = encoderFactory();
if (nWholeBlocksH < nBlocksH)
{
//get the row across the bottom
for (int xBlock = 0; xBlock < nBlocksW; xBlock++)
{
LoadEdgeBlockData(tmp, blockWidth, blockHeight,
chanData, imageWidth, imageHeight,
xBlock, nWholeBlocksH);
targetData[nWholeBlocksH * nBlocksW + xBlock] =
encoder(tmp, 0, blockWidth);
}
//munge this so the next pass doesn't recompress the corner block
nBlocksH--;
}
if (nWholeBlocksW < nBlocksW)
{
//get the column at the right
for (int yBlock = 0; yBlock < nBlocksH; yBlock++)
{
LoadEdgeBlockData(tmp, blockWidth, blockHeight,
chanData, imageWidth, imageHeight,
nWholeBlocksW, yBlock);
targetData[yBlock * nBlocksW + nWholeBlocksW] =
encoder(tmp, 0, blockWidth);
}
}
}
}
/// <summary>
/// Encodes an image into the BC1 format.
/// </summary>
/// <param name="image">The image to encode.</param>
/// <param name="rChan">The channel to pull red values from.</param>
/// <param name="gChan">The channel to pull green values from.</param>
/// <param name="bChan">The channel to pull blue values from.</param>
/// <returns>The encoded BC1 image data.</returns>
public BCnImage <BC1Block> EncodeBC1(FloatImage image,
int rChan = 0, int gChan = 1, int bChan = 2)
{
return(InternalEncodeBC1(image, rChan, gChan, bChan, -1));
}
