internal static void ToVector4 <TPixel>(
Configuration configuration,
PixelOperations <TPixel> pixelOperations,
ReadOnlySpan <TPixel> sourcePixels,
Span <Vector4> destVectors,
PixelConversionModifiers modifiers)
where TPixel : struct, IPixel <TPixel>
{
Guard.NotNull(configuration, nameof(configuration));
Guard.DestinationShouldNotBeTooShort(sourcePixels, destVectors, nameof(destVectors));
int count = sourcePixels.Length;
// Not worth for small buffers:
if (count < Vector4ConversionThreshold)
{
Default.UnsafeToVector4(sourcePixels, destVectors, modifiers);
return;
}
// Using the last quarter of 'destVectors' as a temporary buffer to avoid allocation:
int countWithoutLastItem = count - 1;
ReadOnlySpan <TPixel> reducedSource = sourcePixels.Slice(0, countWithoutLastItem);
Span <Rgba32> lastQuarterOfDestBuffer = MemoryMarshal.Cast <Vector4, Rgba32>(destVectors).Slice((3 * count) + 1, countWithoutLastItem);
pixelOperations.ToRgba32(configuration, reducedSource, lastQuarterOfDestBuffer);
// 'destVectors' and 'lastQuarterOfDestBuffer' are overlapping buffers,
// but we are always reading/writing at different positions:
SimdUtils.BulkConvertByteToNormalizedFloat(
MemoryMarshal.Cast <Rgba32, byte>(lastQuarterOfDestBuffer),
MemoryMarshal.Cast <Vector4, float>(destVectors.Slice(0, countWithoutLastItem)));
destVectors[countWithoutLastItem] = sourcePixels[countWithoutLastItem].ToVector4();
// TODO: Investigate optimized 1-pass approach!
ApplyForwardConversionModifiers(destVectors, modifiers);
}
